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Texas A&M University
1.
Davis, Ryan.
Phase Behavior and Electrophoretic Deposition of LPEI-PAA Polyelectrolyte Complexes.
Degree: MS, Materials Science and Engineering, 2013, Texas A&M University
URL: http://hdl.handle.net/1969.1/149587 
► This project aims to discover a new means of overcoming the drawbacks of traditional layer-by-layer dip coating through the use of polyelectrolyte complexes (PECs) and…
(more)
▼ This project aims to discover a new means of overcoming the drawbacks of traditional
layer-by-
layer dip coating through the use of polyelectrolyte complexes (PECs) and electrophoretic deposition. The
layer-by-
layer process, by which oppositely charged polyelectrolytes or other charged particle are alternately adsorbed onto a substrate to produce a thin film of precisely controllable thickness, is versatile and simple to implement but suffers from requiring numerous, long deposition steps to produce uniform micron thick films. PECs are small associations of oppositely charged polyelectrolytes that, when mixed in non-stoichiometric ratios, can form charged water- soluble particles. There is much still to be determined about the phase behavior of PECs. However, it has been shown that they can exist over a range of conditions. Electrophoretic deposition is a technique used in many commercial applications for the deposition of charged particles onto a conducting substrate. It has even been shown to enhance the deposition of polyelectrolyte single layers and multilayers.
This study examines the phase behavior of PECs made of linear poly(ethyleneimine) (LPEI) and poly(acrylic acid) (PAA). PEC behavior is studied over a pH range of 4.0 to 6.0, with no salt added to the system. This study also reports the results of tests examining how soluble PECs responded to changes in pH and whether solid PECs could be made to dissolve through the addition of different salts. Light scattering is used to examine the particle size distribution and effective diameter of PECs in solution. This information is then used to electrophoretically deposit PECs with 10%, 30%, 70%, and 90% excess LPEI. Stylus profilometry is used to assess the thickness of deposited films. The results showing that PEC layers deposited under an applied voltage were 40% to 400% thicker than PECs deposited with no applied potential.
Advisors/Committee Members: Zacharia, Nicole S. (advisor), Grunlan, Jaime (committee member), Lutkenhaus, Jodie (committee member).
Subjects/Keywords: Polyelectrolyte; electrophoretic; layer-by-layer
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APA (6th Edition):
Davis, R. (2013). Phase Behavior and Electrophoretic Deposition of LPEI-PAA Polyelectrolyte Complexes. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/149587
Chicago Manual of Style (16th Edition):
Davis, Ryan. “Phase Behavior and Electrophoretic Deposition of LPEI-PAA Polyelectrolyte Complexes.” 2013. Masters Thesis, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/149587.
MLA Handbook (7th Edition):
Davis, Ryan. “Phase Behavior and Electrophoretic Deposition of LPEI-PAA Polyelectrolyte Complexes.” 2013. Web. 04 Mar 2021.
Vancouver:
Davis R. Phase Behavior and Electrophoretic Deposition of LPEI-PAA Polyelectrolyte Complexes. [Internet] [Masters thesis]. Texas A&M University; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/149587.
Council of Science Editors:
Davis R. Phase Behavior and Electrophoretic Deposition of LPEI-PAA Polyelectrolyte Complexes. [Masters Thesis]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/149587
Texas A&M University
2.
Selin, Viktar.
Chain Dynamics And Layering Within Polyelectrolyte Multilayer Films.
Degree: PhD, Materials Science and Engineering, 2018, Texas A&M University
URL: http://hdl.handle.net/1969.1/174333
► The current study is focused on understanding main factors affecting dynamics of polymer chains included within layer-by-layer (LbL) films and impact of chain dynamics on…
(more)
▼ The current study is focused on understanding main factors affecting dynamics of polymer chains included within
layer-by-
layer (LbL) films and impact of chain dynamics on film structure. LbL films, or polyelectrolyte multilayers (PEMs), can be deposited on a variety of substrates such as silicon, glass, plastics, and metals via alternating adsorption of oppositely charged polymers. Modification of surfaces with LbL films impart the substrates with new properties and functionalities, such as controlled wettability and uptake of water or capability to retain and/or controllably release small molecules. For many applications of PEMs, specifically for constructing multifunctional films for sequential, multi-step delivery of bioactive compounds, it is critically important to understand and control film structure. There are two possible modes of the PEM growth: linear growth, with a small, constant increase in the film thickness at each dipping step (lPEMs), and non-linear growth, with per-cycle film mass increasing with the number of deposited layers (nlPEMs). PEMs can switch between linear and non-linear film growth as a function of pH, temperature, or number of deposited layers. My goal was to relate polyelectrolyte chain mobility to the mechanism of PEM film growth and to establish the origin of transitions between linear and non-linear growth regimes. This goal was accomplished in experiments which allowed direct observation of chain displacements and PEM structural evolution upon exposure of these films to solutions at varied pH and ionic strength. My findings widen the fundamental knowledge about the mechanism of LbL growth and can be used for developing theories and modeling of PEM films. Moreover, these results can be useful in designing polyelectrolyte nanoassemblies for
biomedical applications, such as drug delivery coatings for medical implants or tissue engineering matrices.
Advisors/Committee Members: Sukhishvili, Svetlana (advisor), Lutkenhaus, Jodie (committee member), Elabd, Yossef (committee member), Cheng, Zhengdong (committee member).
Subjects/Keywords: polyelectrolytes; multilayers; layer-by-layer; dynamics
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APA (6th Edition):
Selin, V. (2018). Chain Dynamics And Layering Within Polyelectrolyte Multilayer Films. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/174333
Chicago Manual of Style (16th Edition):
Selin, Viktar. “Chain Dynamics And Layering Within Polyelectrolyte Multilayer Films.” 2018. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/174333.
MLA Handbook (7th Edition):
Selin, Viktar. “Chain Dynamics And Layering Within Polyelectrolyte Multilayer Films.” 2018. Web. 04 Mar 2021.
Vancouver:
Selin V. Chain Dynamics And Layering Within Polyelectrolyte Multilayer Films. [Internet] [Doctoral dissertation]. Texas A&M University; 2018. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/174333.
Council of Science Editors:
Selin V. Chain Dynamics And Layering Within Polyelectrolyte Multilayer Films. [Doctoral Dissertation]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/174333
Texas A&M University
3.
Puhr, Joseph Timothy.
The Effect of Nanoparticles on the Thermal Transitions of Hydrated Layer-by-Layer Assemblies.
Degree: MS, Materials Science and Engineering, 2014, Texas A&M University
URL: http://hdl.handle.net/1969.1/152854
► Nanoparticles can have a profound effect on a polymer’s glass transition temperature (T_(g)). Many layer-by-layer (LbL) assemblies contain nanoparticles for added functionality, but the resulting…
(more)
▼ Nanoparticles can have a profound effect on a polymer’s glass transition temperature (T_(g)). Many
layer-by-
layer (LbL) assemblies contain nanoparticles for added functionality, but the resulting effect of nanoparticles on an LbL film’s properties is not known. Previously, we have shown that a nanoparticle-free LbL film containing strong polyelectrolytes, poly(diallyldimethylammonium chloride)/poly(styrene sulfonate) (PDAC/PSS), exhibited a thermal transition somewhat akin to a glass transition using quartz crystal microblance with dissipation (QCM-D) and modulated differential
scanning calorimetry (MDSC). In the work presented here, layers of negatively charged nanoparticles of either spherical or platelet morphology have been inserted at varying locations throughout PDAC/PSS LbL films. QCM-D and MDSC were used to determine the effect that these nanoparticles have on the previously measured thermal transitions as a function of placement within the film and particle shape. Using QCM-D we observed clear, reproducible T_(g)’s in all LAP film configurations and in one particular SiO_(2) configuration. All observed T_(g)’s, regardless of nanoparticle morphology, were elevated with respect to those found in neat PDAC/PSS films. Additionally, there was little difference noted between the transition values for the two particular morphologies. It was discovered that the highest glass transition temperatures were observed for film
configurations where the nanoparticles were added during the middle bilayer. We attributed this phenomenon to the increased available nanoparticle surface area with which nearby polymer chains could form bonds. Unfortunately the extremely weak and broad thermal transitions observed with MDSC proved to be inconclusive in either supporting or refuting these observations made via QCM-D.
Advisors/Committee Members: Lutkenhaus, Jodie L (advisor), Grunlan, Jamie C (committee member), McShane, Michael J (committee member).
Subjects/Keywords: Glass Transition; Layer-by-Layer Assembly
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APA (6th Edition):
Puhr, J. T. (2014). The Effect of Nanoparticles on the Thermal Transitions of Hydrated Layer-by-Layer Assemblies. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/152854
Chicago Manual of Style (16th Edition):
Puhr, Joseph Timothy. “The Effect of Nanoparticles on the Thermal Transitions of Hydrated Layer-by-Layer Assemblies.” 2014. Masters Thesis, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/152854.
MLA Handbook (7th Edition):
Puhr, Joseph Timothy. “The Effect of Nanoparticles on the Thermal Transitions of Hydrated Layer-by-Layer Assemblies.” 2014. Web. 04 Mar 2021.
Vancouver:
Puhr JT. The Effect of Nanoparticles on the Thermal Transitions of Hydrated Layer-by-Layer Assemblies. [Internet] [Masters thesis]. Texas A&M University; 2014. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/152854.
Council of Science Editors:
Puhr JT. The Effect of Nanoparticles on the Thermal Transitions of Hydrated Layer-by-Layer Assemblies. [Masters Thesis]. Texas A&M University; 2014. Available from: http://hdl.handle.net/1969.1/152854
Texas A&M University
4.
Huang, Xiayun.
Assembly and Physico-Chemical Properties of Polyelectrolyte Multilayer Films Co-Assembled with Guest Species.
Degree: PhD, Mechanical Engineering, 2014, Texas A&M University
URL: http://hdl.handle.net/1969.1/153213
► Polyelectrolyte multilayer (PEM) films are typically made of two oppositely charged polyelectrolytes held together by electrostatic interactions. PEM films embedded with guest species, that is…
(more)
▼ Polyelectrolyte multilayer (PEM) films are typically made of two oppositely charged polyelectrolytes held together by electrostatic interactions. PEM films embedded with guest species, that is with foreign small molecules or other chemical moieties, such as surfactants, lubricants, transition metal ions or nanoparticles, have been investigated. The interaction of these various foreign species with the PEM film is of fundamental interest, influencing many properties such as strength or wettability. In one example, when assembled in the film, different types of ions or charged molecules will behave as crosslinkers and make a significant difference in film assembly and related disassembly mechanisms, compared with the more usual case of two polyelectrolytes held together by electrostatic interactions. An amphiphilic surfactant can be co-assembled to fine tune the wettability via modulation of morphology of the hydrophilic head and hydrophobic tail groups of surfactant in the film. A hydrophobic lubricant
layer can improve the omniphobicity and slide off properties of a PEM. Incorporation of transition metal ions into the polyelectrolyte multilayer structure gives us a way to modulate both the ionic crosslink density as well as incorporate optical properties unique to those ions (such as color). These doped films show a difference in response to various stimuli such as pH, salt and surfactant, as well as self-healing and swelling properties. Moreover, the transition metal ion incorporated films can be reduced in situ to form particle embedded films suitable for various for optical and catalytic applications.
Advisors/Committee Members: Zacharia, Nicole (advisor), Strzelec, Andrea (advisor), Arroyave, Raymundo (committee member), Liang, Hong (committee member), Lutkenhaus, Jodie (committee member).
Subjects/Keywords: Polyelectrolyte; Guest Species; Layer-by-Layer Assembly
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APA (6th Edition):
Huang, X. (2014). Assembly and Physico-Chemical Properties of Polyelectrolyte Multilayer Films Co-Assembled with Guest Species. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/153213
Chicago Manual of Style (16th Edition):
Huang, Xiayun. “Assembly and Physico-Chemical Properties of Polyelectrolyte Multilayer Films Co-Assembled with Guest Species.” 2014. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/153213.
MLA Handbook (7th Edition):
Huang, Xiayun. “Assembly and Physico-Chemical Properties of Polyelectrolyte Multilayer Films Co-Assembled with Guest Species.” 2014. Web. 04 Mar 2021.
Vancouver:
Huang X. Assembly and Physico-Chemical Properties of Polyelectrolyte Multilayer Films Co-Assembled with Guest Species. [Internet] [Doctoral dissertation]. Texas A&M University; 2014. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/153213.
Council of Science Editors:
Huang X. Assembly and Physico-Chemical Properties of Polyelectrolyte Multilayer Films Co-Assembled with Guest Species. [Doctoral Dissertation]. Texas A&M University; 2014. Available from: http://hdl.handle.net/1969.1/153213
University of Wollongong
5.
Sangian, Danial.
Optimisation of the layer-by-layer synthesis method for polypyrrole actuators.
Degree: Master of Engineering - Research, 2012, University of Wollongong
URL: ;
https://ro.uow.edu.au/theses/3660
► Electrochemical actuators based on conducting polymers are being developed for many applications because of their significant advantages such as low voltage operation, relatively easy…
(more)
▼ Electrochemical actuators based on conducting polymers are being developed for many applications because of their significant advantages such as low voltage operation, relatively easy synthesis process. Polypyrrole actuators are important and popular because of their similarity to natural muscles are often called “artificial muscles”. It is always important and challenging to find an efficient electropolymerization method to modify and develop polypyrrole actuators. A new electropolymerization method, which involves preparing the PPy free-standing film as a sequential series of electrodeposited layers with ethanol washing in between each deposited layer. This method, known as layer by layer electropolymerization, has been shown to be more efficient when compared to the other electropolymerization methods. Here we attempt to compare the mechanical properties and electrical conductivity of PPy free-standing films polymerized at different current densities via the layer by layer (LBL) and continuous electropolymerization methods.
Subjects/Keywords: actuators; polypyrrole; layer by layer synthesis method
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APA ·
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APA (6th Edition):
Sangian, D. (2012). Optimisation of the layer-by-layer synthesis method for polypyrrole actuators. (Masters Thesis). University of Wollongong. Retrieved from ; https://ro.uow.edu.au/theses/3660
Chicago Manual of Style (16th Edition):
Sangian, Danial. “Optimisation of the layer-by-layer synthesis method for polypyrrole actuators.” 2012. Masters Thesis, University of Wollongong. Accessed March 04, 2021.
; https://ro.uow.edu.au/theses/3660.
MLA Handbook (7th Edition):
Sangian, Danial. “Optimisation of the layer-by-layer synthesis method for polypyrrole actuators.” 2012. Web. 04 Mar 2021.
Vancouver:
Sangian D. Optimisation of the layer-by-layer synthesis method for polypyrrole actuators. [Internet] [Masters thesis]. University of Wollongong; 2012. [cited 2021 Mar 04].
Available from: ; https://ro.uow.edu.au/theses/3660.
Council of Science Editors:
Sangian D. Optimisation of the layer-by-layer synthesis method for polypyrrole actuators. [Masters Thesis]. University of Wollongong; 2012. Available from: ; https://ro.uow.edu.au/theses/3660
Université Catholique de Louvain
6.
Mauquoy, Sara.
Fibronectin and collagen-based biomimetic surfaces to improve cell-material interactions for biomedical applications.
Degree: 2016, Université Catholique de Louvain
URL: http://hdl.handle.net/2078.1/182146
► The lack of donors for grafts has led to the development of new strategies, based on biomaterials and tissue engineering. For both approaches, a key…
(more)
▼ The lack of donors for grafts has led to the development of new strategies, based on biomaterials and tissue engineering. For both approaches, a key challenge is the control of cell-material interactions, which can be addressed by modifying the physical and/or chemical properties of material surfaces. A biomimetic way to do it is the adsorption of molecules from the extracellular matrix. In this work, two proteins, collagen (Col) and fibronectin (Fn), were chosen as building blocks to create well-organized biointerfaces to improve interactions with cells. To design biomimetic surfaces, layer-by-layer (LbL) deposition was compared to simultaneous adsorption of both proteins. The influence of the buffer composition, of a polyethyleneimine anchoring layer and of collagen denaturation on LbL assembly was studied. The results showed that true LbL building was not obtained by assembly of Col and Fn. However, multilayers were built and results showed that an anchoring layer allowed thicker films to be obtained, and that Hepes buffer allowed obtaining the most regular assembly. Moreover, comparison with simultaneous adsorption revealed interesting features. Films obtained by simultaneous adsorption were of the same thickness, or even thicker than those prepared by LbL, and they presented a different morphology, with more Col fibrils and a lower contact angle. Adipose derived mesenchymal stem cells were cultured on films obtained by both deposition methods, in Hepes, with or without anchoring layer. All the protein films supported cell adhesion and growth better than pure polystyrene. The main influence observed on cells was the one of the anchoring layer, which decreased proliferation rate but improved osteogenic differentiation. Biointerfaces were thus designed based on Col and Fn which influence cell behavior. It may open the way to new strategies for tissue engineering applications.
(AGRO - Sciences agronomiques et ingénierie biologique) – UCL, 2016
Advisors/Committee Members: UCL - SST/IMCN/BSMA - Bio and soft matter, UCL - Ingénierie biologique, agronomique et environnementale, Dupont, Christine, Demoustier, Sophie, Knoops, Bernard, Lansoulsi, Jessem, Pauthe, Emmanuel, Gaigneaux, Eric.
Subjects/Keywords: Fibronectin; Collagen; Layer-by-layer; Biomimetic interfaces
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APA (6th Edition):
Mauquoy, S. (2016). Fibronectin and collagen-based biomimetic surfaces to improve cell-material interactions for biomedical applications. (Thesis). Université Catholique de Louvain. Retrieved from http://hdl.handle.net/2078.1/182146
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Mauquoy, Sara. “Fibronectin and collagen-based biomimetic surfaces to improve cell-material interactions for biomedical applications.” 2016. Thesis, Université Catholique de Louvain. Accessed March 04, 2021.
http://hdl.handle.net/2078.1/182146.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Mauquoy, Sara. “Fibronectin and collagen-based biomimetic surfaces to improve cell-material interactions for biomedical applications.” 2016. Web. 04 Mar 2021.
Vancouver:
Mauquoy S. Fibronectin and collagen-based biomimetic surfaces to improve cell-material interactions for biomedical applications. [Internet] [Thesis]. Université Catholique de Louvain; 2016. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2078.1/182146.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Mauquoy S. Fibronectin and collagen-based biomimetic surfaces to improve cell-material interactions for biomedical applications. [Thesis]. Université Catholique de Louvain; 2016. Available from: http://hdl.handle.net/2078.1/182146
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Clemson University
7.
Conrad, Catherine Alexis.
Synthesis and Characterization of Novel Diphosphonium Polymers with the Emphasis on Supramolecular Assembly.
Degree: MS, Chemistry, 2018, Clemson University
URL: https://tigerprints.clemson.edu/all_theses/2829
► Three different series of diphosphonium polymers were synthesized in order to analyze the supramolecular assembly of these polyelectrolytes with varying polyanions. Variation of the rigidity…
(more)
▼ Three different series of diphosphonium polymers were synthesized in order to analyze the supramolecular assembly of these polyelectrolytes with varying polyanions. Variation of the rigidity of the spacer between the phosphonium units determined that flexibility leads to increased absorption and consistency to film growth when observed through
layer-by-
layer assembly with UV-vis spectroscopy and atomic force microscopy. With the flexible ethylene spacer, films formed linearly up to 800 bilayers thick. An additional series of xylene based flexible diphosphonium polymers were synthesized with increasing numbers of methylene unit spacers. Analysis of materials was conducted through thermogravimetric analysis, X-ray crystallography, and
layer-by-
layer analysis tracked with UV-vis spectroscopy and atomic force microscopy. Consistency of film formation was dependent on even or odd number of the methylene spacer. Odd numbered methylene spacers lead to more consistent film growth with greater polythiophene deposition. Another series of polyelectrolytes were generated with the same methylene spacers, but with octyloxy units branching from the backbone to explore the influence of increased hydrophobicity on the previous study. Similar characterization was done with the addition of dip-cast films analyzed for critical surface energy and antimicrobial activity. The thermal stability of the octyloxy series was lower than their xylene counterparts and also demonstrated less dependence on the inter-ion spacing in the film growth formation. Extensive studies on the solvent systems for casting both the
layer-by-
layer films as well as the dip-cast films elucidated the high dependence and tune ability of these films by solvent systems. The presence of the hydrophobic side chain lead to an increased antibacterial activity especially when interacting with the gram-positive Staphylococcus aureus.
Advisors/Committee Members: Dr. Rhett C. Smith, Committee Chair, Dr. Andrew Tennyson, Dr. Julia Brumaghim.
Subjects/Keywords: Film formation; Layer-by-layer; Phosphonium; Polyelectrolytes
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APA (6th Edition):
Conrad, C. A. (2018). Synthesis and Characterization of Novel Diphosphonium Polymers with the Emphasis on Supramolecular Assembly. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/2829
Chicago Manual of Style (16th Edition):
Conrad, Catherine Alexis. “Synthesis and Characterization of Novel Diphosphonium Polymers with the Emphasis on Supramolecular Assembly.” 2018. Masters Thesis, Clemson University. Accessed March 04, 2021.
https://tigerprints.clemson.edu/all_theses/2829.
MLA Handbook (7th Edition):
Conrad, Catherine Alexis. “Synthesis and Characterization of Novel Diphosphonium Polymers with the Emphasis on Supramolecular Assembly.” 2018. Web. 04 Mar 2021.
Vancouver:
Conrad CA. Synthesis and Characterization of Novel Diphosphonium Polymers with the Emphasis on Supramolecular Assembly. [Internet] [Masters thesis]. Clemson University; 2018. [cited 2021 Mar 04].
Available from: https://tigerprints.clemson.edu/all_theses/2829.
Council of Science Editors:
Conrad CA. Synthesis and Characterization of Novel Diphosphonium Polymers with the Emphasis on Supramolecular Assembly. [Masters Thesis]. Clemson University; 2018. Available from: https://tigerprints.clemson.edu/all_theses/2829
University of Akron
8.
Cheng, Kuan.
Magnet-assisted Layer-by-layer Assembly on Nanoparticles
Based on 3D-printed Microfluidic Devices.
Degree: MS, Polymer Science, 2019, University of Akron
URL: http://rave.ohiolink.edu/etdc/view?acc_num=akron1554984796295339
► The synthesis of core/shell structure nanoparticles based on the layer-by-layer assembly approach is potentially interesting for both biomedical and material engineering areas. Conventional methods face…
(more)
▼ The synthesis of core/shell structure nanoparticles
based on the
layer-by-
layer assembly approach is potentially
interesting for both biomedical and material engineering areas.
Conventional methods face significant limitation in requiring
tedious experiment time and unavoidable material impurity. This
work describes a novel strategy to obtain encapsulated particles
which improves the material purity and dramatically reduces the
preparation time. An efficient, transparent, serpentine
microfluidic mixer has been designed and fabricated through
three-dimensional stereolithography technology. Chaotic mixing can
be easily achieved by combining a series of “F” shape units in this
device. Inherently negative charged iron oxide particles traveled
in the fluidic channel by flow field and magnetic attraction,
derived from a strong Niobium magnet. Additionally, a well-studied
polyelectrolytes pair, poly(allylamine hydrochloride)
(PAH)/poly(sodium 4-styrenesulfonate) (PSS), were injected from
opposite inlets of the device in turn and mixed with particles
vigorously in the stream. Our motivation is to simplify the
conventional
layer-by-
layer assembly process in nanoscale. Results
of zeta-potential data demonstrate the successive deposition of ten
polymer layers on bare particles. Also, this method also gives a
new perspective for the biomedical application like hyperthermia
therapy.
Advisors/Committee Members: Amis, Eric (Advisor).
Subjects/Keywords: Polymers; Layer-by-layer; 3D-printing; Microfluidic
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APA (6th Edition):
Cheng, K. (2019). Magnet-assisted Layer-by-layer Assembly on Nanoparticles
Based on 3D-printed Microfluidic Devices. (Masters Thesis). University of Akron. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=akron1554984796295339
Chicago Manual of Style (16th Edition):
Cheng, Kuan. “Magnet-assisted Layer-by-layer Assembly on Nanoparticles
Based on 3D-printed Microfluidic Devices.” 2019. Masters Thesis, University of Akron. Accessed March 04, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=akron1554984796295339.
MLA Handbook (7th Edition):
Cheng, Kuan. “Magnet-assisted Layer-by-layer Assembly on Nanoparticles
Based on 3D-printed Microfluidic Devices.” 2019. Web. 04 Mar 2021.
Vancouver:
Cheng K. Magnet-assisted Layer-by-layer Assembly on Nanoparticles
Based on 3D-printed Microfluidic Devices. [Internet] [Masters thesis]. University of Akron; 2019. [cited 2021 Mar 04].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=akron1554984796295339.
Council of Science Editors:
Cheng K. Magnet-assisted Layer-by-layer Assembly on Nanoparticles
Based on 3D-printed Microfluidic Devices. [Masters Thesis]. University of Akron; 2019. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=akron1554984796295339
University of Minnesota
9.
Sakkos, Jonathan.
Engineering Biocatalytic Materials: Encapsulation Systems for Biotechnology.
Degree: PhD, Mechanical Engineering, 2018, University of Minnesota
URL: http://hdl.handle.net/11299/217154
► My dissertation presents scientific and engineering contributions. Both sol-gel and layer-by-layer technologies were used to study prokaryotic cells under confinement and the role that the…
(more)
▼ My dissertation presents scientific and engineering contributions. Both sol-gel and layer-by-layer technologies were used to study prokaryotic cells under confinement and the role that the encapsulation material plays in affecting these cells. My work focused on the development, synthesis, and use of biologically active materials for water treatment based on silica gel bioencapsulation. Silica gels were developed with improved mechanical properties while ensuring that these materials were cytocompatible. The ratio of the silicon alkoxide crosslinker to silica nanoparticles was crucial in adjusting the maximum stress at failure. I demonstrated a 6-fold improvement in the compressive stress at failure in a silica bioencapsulation matrix containing metabolically active cells. These gels were organically modified to study the effect of encapsulation matrix hydrophobicity on the relative adsorption and biodegradation of organic pollutants. The ratio of biodegradation to adsorption was a strong function of the hydrophobicity of the pollutant. A layer-by-layer approach was used to minimize the diffusion length and protect the encapsulated biocatalyst from environmental stressors. I showed that targeting the cytoplasmic membrane with detergents increased its permeability and enabled a 15-fold enhancement in the rate of biocatalysis. To demonstrate the protective effects of the microbial exoskeleton, the coated cells were exposed to environmental stressors ranging from heat shock and desiccation to enzymatic attack and predation by protozoa. With a minimum of 4 layers, the biocatalytic activity was preserved for all cases examined. The translational application of cyanuric acid hydrolase (CAH) was also studied. By treating the cells with glutaraldehyde to crosslink the membrane-bound proteins, the cell was stabilized and CAH was retained within the whole cell biocatalyst.
Subjects/Keywords: biocatalysis; bioencapsulation; layer-by-layer; sol-gel
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APA (6th Edition):
Sakkos, J. (2018). Engineering Biocatalytic Materials: Encapsulation Systems for Biotechnology. (Doctoral Dissertation). University of Minnesota. Retrieved from http://hdl.handle.net/11299/217154
Chicago Manual of Style (16th Edition):
Sakkos, Jonathan. “Engineering Biocatalytic Materials: Encapsulation Systems for Biotechnology.” 2018. Doctoral Dissertation, University of Minnesota. Accessed March 04, 2021.
http://hdl.handle.net/11299/217154.
MLA Handbook (7th Edition):
Sakkos, Jonathan. “Engineering Biocatalytic Materials: Encapsulation Systems for Biotechnology.” 2018. Web. 04 Mar 2021.
Vancouver:
Sakkos J. Engineering Biocatalytic Materials: Encapsulation Systems for Biotechnology. [Internet] [Doctoral dissertation]. University of Minnesota; 2018. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/11299/217154.
Council of Science Editors:
Sakkos J. Engineering Biocatalytic Materials: Encapsulation Systems for Biotechnology. [Doctoral Dissertation]. University of Minnesota; 2018. Available from: http://hdl.handle.net/11299/217154
10.
Ilyas, Shazia.
Multicouches multifonctionnelles de polyelectrolytes pour des applications en filtration membranaire : Multifunctional weak polyelectrolyte multilayers for membrane applications.
Degree: Docteur es, Génie des procédés et de l'environnement, 2017, Université Toulouse III – Paul Sabatier
URL: http://www.theses.fr/2017TOU30386
► Dans ce travail, nous démontrons que la technique de dépôt multicouche dite layer by layer (LbL) est une technique polyvalente où les propriétés des multicouches…
(more)
▼ Dans ce travail, nous démontrons que la technique de dépôt multicouche dite layer by layer (LbL) est une technique polyvalente où les propriétés des multicouches telles que l'épaisseur, la charge et la densité peuvent être facilement contrôlées par le choix des polyélectrolytes (PE), le nombre d'étapes et les conditions de dépôt (pH, force ionique, etc.). Nous démontrons que des multicouches de PE faible (PAH / PAA) peuvent être utilisées pour fournir une double fonction aux membranes (PEM) en tant que couche de séparation NF et comme revêtement sacrificiel permettant un nettoyage facile de la membrane. Ces membranes à base de PEM montrent des performances de rejet des solutés dans une gamme typique des membranes NF, c'est-à-dire rejetant peu les ions monovalents (NaCl) (<24%), tout en rejetant> 60% de l'ion divalent SO42- et la molécule organique neutre sulfaméthoxazole (SMX). Par un rinçage et un lavage à contre-courant à basse pression avec une solution stimuli appropriée, nous obtenons un nettoyage sacrificiel réussi d'une membrane colmatée, ce qui ramène la résistance d'une membrane colmatée à celle de la membrane vierge. Après un nouveau dépôt sur la membrane avec le même système PEM, la résistance de la membrane est égale à la résistance du PEM d'origine, ce qui démontre la réutilisation de cette approche. Le mécanisme de rejet des membranes étudiées s'est révélé principalement déterminé par l'exclusion stérique mais aussi par l'exclusion de Donnan. Nous avons étudié notre système PEM pour préparer des membranes pour des applications de nanofiltration résistant aux solvants (SRNF). Des membranes de SRNF avec une couche de séparation de PEM ont été préparées sur un support UF de polyacrylonitrile hydrolysé (PAN-H). Les résultats de cette étude montrent une manière simple et polyvalente d'utiliser le pH pendant le revêtement pour régler les performances de la membrane pour une application SRNF spécifique. Afin d'amener l'approche PEM et du nettoyage sacrificiel à leur maturité et de modifier des modules existants, nous avons simplifié la procédure LbL pour des membranes fibres creuses en utilisant un "dépôt dynamique" ou un "dépôt actif" qui consiste à rincer les solutions du PE à travers le canal interne de la membrane fibre creuse. Cette méthode de dépôt avec sa reproductibilité et son homogénéité permet de revêtir les modules de membrane UF existants.
In this work, we demonstrate that layer by layer (LbL) is a versatile technique where control over multilayer properties such as thickness, charge and density, can be easily achieved simply by the choice of polyelectrolytes, number of coating steps and coating conditions (pH, ionic strength etc.). We demonstrate that multilayers of weak PEs (PAH/PAA) can be used to provide a dual function to membranes (PEM) i.e., as NF separation layer and as a sacrificial coating that allows easy membrane cleaning. These PEM based membranes, shows rejection performance of solutes in a range typical for NF membranes i.e., hardly rejecting monovalent ions (NaCl) (<24%), while…
Advisors/Committee Members: Aimar, Pierre (thesis director), Lahitte, Jean-François (thesis director).
Subjects/Keywords: Membrane; Filtration; Layer by layer; Couche sacrificielle; Résistance au solvant; NF; Layer by layer; Sacrificial layer; Solvent resistant; NF
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APA (6th Edition):
Ilyas, S. (2017). Multicouches multifonctionnelles de polyelectrolytes pour des applications en filtration membranaire : Multifunctional weak polyelectrolyte multilayers for membrane applications. (Doctoral Dissertation). Université Toulouse III – Paul Sabatier. Retrieved from http://www.theses.fr/2017TOU30386
Chicago Manual of Style (16th Edition):
Ilyas, Shazia. “Multicouches multifonctionnelles de polyelectrolytes pour des applications en filtration membranaire : Multifunctional weak polyelectrolyte multilayers for membrane applications.” 2017. Doctoral Dissertation, Université Toulouse III – Paul Sabatier. Accessed March 04, 2021.
http://www.theses.fr/2017TOU30386.
MLA Handbook (7th Edition):
Ilyas, Shazia. “Multicouches multifonctionnelles de polyelectrolytes pour des applications en filtration membranaire : Multifunctional weak polyelectrolyte multilayers for membrane applications.” 2017. Web. 04 Mar 2021.
Vancouver:
Ilyas S. Multicouches multifonctionnelles de polyelectrolytes pour des applications en filtration membranaire : Multifunctional weak polyelectrolyte multilayers for membrane applications. [Internet] [Doctoral dissertation]. Université Toulouse III – Paul Sabatier; 2017. [cited 2021 Mar 04].
Available from: http://www.theses.fr/2017TOU30386.
Council of Science Editors:
Ilyas S. Multicouches multifonctionnelles de polyelectrolytes pour des applications en filtration membranaire : Multifunctional weak polyelectrolyte multilayers for membrane applications. [Doctoral Dissertation]. Université Toulouse III – Paul Sabatier; 2017. Available from: http://www.theses.fr/2017TOU30386
11.
Mauroy, Cyprien.
Films multicouches nanocristaux de cellulose/Ge-Imogolite pour l'élaboration de nouveaux matériaux nanoporeux : Elaboration of cellulose nanocrystal/Ge-imogolite multilayered thin film to design new nanoporous materials.
Degree: Docteur es, Géosciences de l'environnement, 2017, Aix Marseille Université
URL: http://www.theses.fr/2017AIXM0265
► Lors des dix dernières années, les films multicouches ont suscité l’intérêt de la communauté scientifique pour leurs propriétés innovantes. Principalement issus de l’association de polyélectrolytes…
(more)
▼ Lors des dix dernières années, les films multicouches ont suscité l’intérêt de la communauté scientifique pour leurs propriétés innovantes. Principalement issus de l’association de polyélectrolytes et/ou de nanoparticules de différentes morphologies, ils ont ouvert la voie à la fabrication d’une nouvelle catégorie de matériaux nanoporeux, possédant des propriétés optiques attractives telles que la coloration structurale et l’antireflet. Les films multicouches à base de deux nanoparticules de charges opposées sont plus rares et permettent de jumeler les propriétés des deux nanoparticules utilisées et d’en faire émerger de nouvelles. Dans cette étude, nous nous sommes intéressés à deux nanoparticules anisotropes, de facteurs d’aspects contrôlés et respectivement bio/geosourcées : les nanocristaux de cellulose (NCC) et des nanotubes d’imogolite. Le but de cette étude est d’étudier la possibilité de créer un film multicouche bio-géo inspiré à base de ces deux nanoparticules par immersion et d’en étudier les propriétés optiques. Dans un premier temps, nous avons comparé les films multicouches NCC/Ge-imogolites à ceux plus communément décrits dans la littérature, à savoir, des films à base de NCC ou d’imogolite associés à un polyélectrolyte de charge opposée. Les différents paramètres de trempage comme le temps d’immersion et la force ionique de la suspension ont été variés afin d’obtenir une densité de film optimale. Pour finir la porosité des films et leur comportement dans l’eau ont été étudiés par QCM-D, ainsi que leurs propriétés optiques par mesure de transmittance.
In the past decade, multilayer thin films drew the scientific community attention for their unique properties. Indeed, principally made of an association of polyelectrolytes and/or nanoparticles, of various morphologies and chemistries, they allow the design of a range of porous nanomaterials with unique optical properties, such as structural colors or anti-reflectivity. Less commonly described, thin films made of two nanoparticles of opposite charges are gaining interest since they combine the properties of the two nanoparticles used, and generate new ones through their association. In this study, multilayer coatings were formed through the association of two anisotropic oppositely charged nanorods of well-controlled aspect ratio, i.e. bio-based anionic cellulose nanocrystals (CNC) and geo-based cationic Imogolites. This study deals with the feasibility to create a bio-geo-inspired multilayer thin film based on these two nanoparticles by dipping and characterize their optical properties. Firstly, elaboration of multilayered thin films from CNC and Ge-Imogolites nanorods, were studied in comparison with reference films incorporating CNC or Imogolites with polyelectrolytes bearing opposite charges of the nanorods. Multilayered thin films were assembled by the dipping procedure and various parameters (adsorption time, ionic strength, etc.) were varied to investigate the optimal density for the film. To finish, film porosities were investigated using…
Advisors/Committee Members: Rose, Jérôme (thesis director), Levard, Clément (thesis director), Cathala, Bernard (thesis director).
Subjects/Keywords: Nanomateriaux; Nanocristaux de cellulose; Imogolite; Film mince; Layer-By-Layer; Porosité; Nanomaterial; Cellulose nanocrystal; Imogolite; Thin film; Layer-By-Layer; Porosity
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APA (6th Edition):
Mauroy, C. (2017). Films multicouches nanocristaux de cellulose/Ge-Imogolite pour l'élaboration de nouveaux matériaux nanoporeux : Elaboration of cellulose nanocrystal/Ge-imogolite multilayered thin film to design new nanoporous materials. (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2017AIXM0265
Chicago Manual of Style (16th Edition):
Mauroy, Cyprien. “Films multicouches nanocristaux de cellulose/Ge-Imogolite pour l'élaboration de nouveaux matériaux nanoporeux : Elaboration of cellulose nanocrystal/Ge-imogolite multilayered thin film to design new nanoporous materials.” 2017. Doctoral Dissertation, Aix Marseille Université. Accessed March 04, 2021.
http://www.theses.fr/2017AIXM0265.
MLA Handbook (7th Edition):
Mauroy, Cyprien. “Films multicouches nanocristaux de cellulose/Ge-Imogolite pour l'élaboration de nouveaux matériaux nanoporeux : Elaboration of cellulose nanocrystal/Ge-imogolite multilayered thin film to design new nanoporous materials.” 2017. Web. 04 Mar 2021.
Vancouver:
Mauroy C. Films multicouches nanocristaux de cellulose/Ge-Imogolite pour l'élaboration de nouveaux matériaux nanoporeux : Elaboration of cellulose nanocrystal/Ge-imogolite multilayered thin film to design new nanoporous materials. [Internet] [Doctoral dissertation]. Aix Marseille Université 2017. [cited 2021 Mar 04].
Available from: http://www.theses.fr/2017AIXM0265.
Council of Science Editors:
Mauroy C. Films multicouches nanocristaux de cellulose/Ge-Imogolite pour l'élaboration de nouveaux matériaux nanoporeux : Elaboration of cellulose nanocrystal/Ge-imogolite multilayered thin film to design new nanoporous materials. [Doctoral Dissertation]. Aix Marseille Université 2017. Available from: http://www.theses.fr/2017AIXM0265
University of Utah
12.
Mishra, Deepa.
Effective nuclear delivery of therapeutic molecules.
Degree: PhD, Bioengineering, 2011, University of Utah
URL: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/418/rec/804
► Many strides have been made towards utilizing gene therapy to treat genetic disorders in humans. Low gene expression and formulation stability during storage have hindered…
(more)
▼ Many strides have been made towards utilizing gene therapy to treat genetic disorders in humans. Low gene expression and formulation stability during storage have hindered the use of nonviral carriers thus far. The purpose of this research was to develop a cationic PLGA-b-bPEI micelle-based delivery system to co-deliver genes and small therapeutic drugs to the cell nucleus that could also be lyophilized for long-term storage and reconstituted as needed by simply adding water. Several PLGA-b-bPEI copolymers were synthesized and characterized for their potential to form reconstitutable micelle-based gene therapeutic delivery systems that showed enhanced nuclear delivery over other current cationic nonviral delivery systems. The first section of this dissertation addresses the characterization of a reconstitutable charged polymeric micelle system to assess its suitability for gene therapeutics delivery. A PLGA-b-bPEI block copolymer was synthesized and characterized for buffering capacity, particle size, zeta potential, complexation ability, cytotoxicity, transfection efficiency and reporter gene expression, and retention of physicochemical and biological characteristics upon lyophilization and reconstitution. Results showed that micelles and micelle/pDNA complexes retained their physicochemical characteristics following lyophilization and reconstitution. Transfection levels were enhanced using reconstituted complexes compared to their fresh counterparts without significant cellular toxicity even with pDNA doses up to 20?g, and transfection increased linearly with increasing pDNA dose. The second section of this dissertation investigates the use of dexamethasone-loaded micelles for enhanced nuclear accumulation of a reporter gene. PLGA-b-bPEI polymers synthesized in the first section were used to prepare dexamethasone-loaded micelles and complexed with pDNA. Gene expression was significantly enhanced using dexamethasone-loaded micelle/pDNA complexes compared to blank micelle/pDNA complexes, particularly for complexation weight ratios less than 1. Dex-micelles achieved gene expression equivalent to the blank system using a fraction of the polymer (weight ratio 0.25 versus 1), indicating that dexamethasone increased nuclear accumulation of polyplexes. Gene expression was nearly equivalent to a bPEI control carrier, leading to future plans of co-loading the micelle system with other types of drugs and examining this system’s suitability for specific applications such as treating patients suffering from asthma or other inflammatory diseases where dexamethasone treatment could be additionally beneficial for its anti-inflammatory properties.
Subjects/Keywords: Dexamethasone; Gene delivery; Layer-by-layer; Micelle; PLGA; Polyethylenimine
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APA (6th Edition):
Mishra, D. (2011). Effective nuclear delivery of therapeutic molecules. (Doctoral Dissertation). University of Utah. Retrieved from http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/418/rec/804
Chicago Manual of Style (16th Edition):
Mishra, Deepa. “Effective nuclear delivery of therapeutic molecules.” 2011. Doctoral Dissertation, University of Utah. Accessed March 04, 2021.
http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/418/rec/804.
MLA Handbook (7th Edition):
Mishra, Deepa. “Effective nuclear delivery of therapeutic molecules.” 2011. Web. 04 Mar 2021.
Vancouver:
Mishra D. Effective nuclear delivery of therapeutic molecules. [Internet] [Doctoral dissertation]. University of Utah; 2011. [cited 2021 Mar 04].
Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/418/rec/804.
Council of Science Editors:
Mishra D. Effective nuclear delivery of therapeutic molecules. [Doctoral Dissertation]. University of Utah; 2011. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/418/rec/804
San Jose State University
13.
Tek, Andy Theodora.
Star Polymer-Based Thin Film Materials for Biomedical Applications.
Degree: MS, Biomedical, Chemical & Materials Engineering, 2013, San Jose State University
URL: https://doi.org/10.31979/etd.a5z7-qvpa
;
https://scholarworks.sjsu.edu/etd_theses/4317
► There are numerous applications of nanostructured, functional thin films, but this work focused on biomedical applications, particularly antimicrobial surface coatings and drug delivery thin…
(more)
▼ There are numerous applications of nanostructured, functional thin films, but this work focused on biomedical applications, particularly antimicrobial surface coatings and drug delivery thin film using functionalized star polymers. In the first part of this study, star polymer-based antimicrobial surface coatings, prepared on glass substrates, were shown to reduce methicillin-resistant Staphylococcus aureus (MRSA) contamination 200-400% faster than the current industry standard, copper. Star polymer films showed no cytotoxic effect on human liver cells, red blood cells, or epidermal skin cells.
In the second part of the study, surface-based drug delivery thin films were prepared by using a layer-by-layer self-assembly method of complimentary amine- and carboxylic acid-functionalized star polymers, namely PS-DMAEMA and PS-[PEGM/PAA], respectively. Three model dyes, representing three different drugs, were loaded into the interstitial regions of the star polymers through self-assembly to form three different occlusion complexes. The layer-by-layer self-assembly of the occlusion complexes in phosphate-buffered saline (PBS) was monitored using surface plasmon resonance (SPR), and the layer growth was found to be uniform. Topographical analysis by atomic force microscopy (AFM) revealed granular morphology with a closely-packed arrangement of the star polymers.
Subjects/Keywords: layer-by-layer self-assembly; star polymers; thin film
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APA (6th Edition):
Tek, A. T. (2013). Star Polymer-Based Thin Film Materials for Biomedical Applications. (Masters Thesis). San Jose State University. Retrieved from https://doi.org/10.31979/etd.a5z7-qvpa ; https://scholarworks.sjsu.edu/etd_theses/4317
Chicago Manual of Style (16th Edition):
Tek, Andy Theodora. “Star Polymer-Based Thin Film Materials for Biomedical Applications.” 2013. Masters Thesis, San Jose State University. Accessed March 04, 2021.
https://doi.org/10.31979/etd.a5z7-qvpa ; https://scholarworks.sjsu.edu/etd_theses/4317.
MLA Handbook (7th Edition):
Tek, Andy Theodora. “Star Polymer-Based Thin Film Materials for Biomedical Applications.” 2013. Web. 04 Mar 2021.
Vancouver:
Tek AT. Star Polymer-Based Thin Film Materials for Biomedical Applications. [Internet] [Masters thesis]. San Jose State University; 2013. [cited 2021 Mar 04].
Available from: https://doi.org/10.31979/etd.a5z7-qvpa ; https://scholarworks.sjsu.edu/etd_theses/4317.
Council of Science Editors:
Tek AT. Star Polymer-Based Thin Film Materials for Biomedical Applications. [Masters Thesis]. San Jose State University; 2013. Available from: https://doi.org/10.31979/etd.a5z7-qvpa ; https://scholarworks.sjsu.edu/etd_theses/4317
San Jose State University
14.
Shah, Shimul.
Formation of nanostructured magnetic films using layer-by-layer self-assembly of star polymers and magnetic nanoparticles.
Degree: MS, Chemical and Materials Engineering, 2011, San Jose State University
URL: https://doi.org/10.31979/etd.em8g-cwue
;
https://scholarworks.sjsu.edu/etd_theses/3966
► In this work, multi-layered thin film materials comprised of cobalt ferrite (CoFe2O4) magnetic nanoparticles and polystyrene amine-functionalized (PS-NH2) star polymers have been prepared on…
(more)
▼ In this work, multi-layered thin film materials comprised of cobalt ferrite (CoFe2O4) magnetic nanoparticles and polystyrene amine-functionalized (PS-NH2) star polymers have been prepared on silicon dioxide surfaces by means of organometallic-driven layer-by-layer (LBL) self-assembly. The films formed were characterized using surface plasmon resonance (SPR) spectroscopy, which indicated the rapid formation (sub-second to second time frames) of reproducible molecular thin layers. Atomic force microscopy (AFM) showed that the films produced were contiguous and stable in the dry state. The film thickness and layer uniformity were characterized by transmission electron microscopy (TEM), which showed cross-sectional separation of the individual inorganic layers of the films in the dry state. Mechanical stability of the film was achieved by forming a thin silicate coating over the film surface. The ability to nanostructure the films by a layer-by-layer self-assembly technique presents a promising way to produce high-density data storage materials for application in magnetic media.
Subjects/Keywords: Layer-by-layer self assembly; Magnetic Nanoparticles; Star Polymers
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APA (6th Edition):
Shah, S. (2011). Formation of nanostructured magnetic films using layer-by-layer self-assembly of star polymers and magnetic nanoparticles. (Masters Thesis). San Jose State University. Retrieved from https://doi.org/10.31979/etd.em8g-cwue ; https://scholarworks.sjsu.edu/etd_theses/3966
Chicago Manual of Style (16th Edition):
Shah, Shimul. “Formation of nanostructured magnetic films using layer-by-layer self-assembly of star polymers and magnetic nanoparticles.” 2011. Masters Thesis, San Jose State University. Accessed March 04, 2021.
https://doi.org/10.31979/etd.em8g-cwue ; https://scholarworks.sjsu.edu/etd_theses/3966.
MLA Handbook (7th Edition):
Shah, Shimul. “Formation of nanostructured magnetic films using layer-by-layer self-assembly of star polymers and magnetic nanoparticles.” 2011. Web. 04 Mar 2021.
Vancouver:
Shah S. Formation of nanostructured magnetic films using layer-by-layer self-assembly of star polymers and magnetic nanoparticles. [Internet] [Masters thesis]. San Jose State University; 2011. [cited 2021 Mar 04].
Available from: https://doi.org/10.31979/etd.em8g-cwue ; https://scholarworks.sjsu.edu/etd_theses/3966.
Council of Science Editors:
Shah S. Formation of nanostructured magnetic films using layer-by-layer self-assembly of star polymers and magnetic nanoparticles. [Masters Thesis]. San Jose State University; 2011. Available from: https://doi.org/10.31979/etd.em8g-cwue ; https://scholarworks.sjsu.edu/etd_theses/3966
15.
Geraldo, Vananélia Pereira Nunes.
Filmes nanoestruturados contendo lipossomos para liberação controlada do Ibuprofeno.
Degree: Mestrado, Ciência e Engenharia de Materiais, 2008, University of São Paulo
URL: http://www.teses.usp.br/teses/disponiveis/88/88131/tde-17062008-120210/
;
► A liberação controlada de fármacos é um tópico importante para várias iniciativas em nanotecnologia devido ao possível impacto para a sociedade, com a criação de…
(more)
▼ A liberação controlada de fármacos é um tópico importante para várias iniciativas em nanotecnologia devido ao possível impacto para a sociedade, com a criação de sistemas otimizados que garantam a liberação num sítio específico e a uma taxa controlada. Dentre os vários paradigmas de liberação controlada destaca-se o uso de lipossomos, uma vez que muitos fármacos e drogas podem ser transportados. Este trabalho descreve a fabricação de filmes automontados de lipossomos que incorporam o fármaco ibuprofeno. Os lipossomos foram preparados de dipalmitoil fosfatidil colina (DPPC), dipalmitoil fosfatidil glicerol (DPPG) e palmitoil-oleoil fosfatidil glicerol (POPG), cujas camadas foram alternadas por interações eletrostáticas com camadas do dendrímero PAMAM geração 4. Medidas de espalhamento dinâmico de luz indicaram que a incorporação do ibuprofeno tornou os lipossomos de DPPC e DPPG mais estáveis, com uma diminuição no diâmetro médio de 140 para 74 nm e 132 para 63nm, respectivamente. Ao contrário, os lipossomos de POPG ficaram menos estáveis, com aumento do diâmetro de 110 para 160 nm. A influência na estabilidade foi confirmada em medidas de microscopia de força atômica nos filmes automontados, que mostraram grande tendência à ruptura nos lipossomos de POPG com a incorporação de ibuprofeno. O crescimento dos filmes automontados foi investigado com espectroscopia de fluorescência e uma balança de cristal de quartzo. A intensidade da fluorescência devida ao ibuprofeno aumentou exponencialmente com o número de camadas depositadas, mas não por causa de uma crescente adsorção de ibuprofeno. Ao contrário, a quantidade de material adsorvido nas primeiras camadas aumentou inicialmente, mas depois diminuiu drasticamente após a 6ª. bicamada, e o filme praticamente pára de crescer a partir da 10ª. bicamada. Portanto, a grande fluorescência para filmes espessos deve ser associada a um ambiente favorável, que aumenta a emissão quântica do ibuprofeno. A liberação do ibuprofeno, estudada com medidas de fluorescência, é mais lenta quando incorporado em lipossomos. Em experimentos com uma membrana de diálise, notamos que o tempo de decaimento do ibuprofeno puro é 5,2 h, enquanto este tempo aumentou para 9,2 e 8 h para ibuprofeno encapsulado em lipossomos de DPPG e POPG, respectivamente. O ibuprofeno também foi liberado de filmes automontados contendo lipossomos de DPPG e POPG, o que é promissor para o uso em bandagens (patches).
Controlled drug delivery is a key issue in a number of nanotechnology endeavors owing to the large impact on society that may achieved if improved systems are created which allows for delivery at a specific target and with a controlled rate. Among the various paradigms employed in drug delivery, the use of liposomes is prominent because a variety of drug molecules can be carried. This work describes the fabrication of layer-by-layer (LbL) films made with liposomes incorporating ibuprofen. The liposomes were made with dipalmitoyl phosphatidyl choline (DPPC), dipalmitoyl phosphatidyl glycerol (DPPG) and…
Advisors/Committee Members: Oliveira Junior, Osvaldo Novais de.
Subjects/Keywords: Drug release; Filmes automontados; Layer-by-layer films; Liberação; Liposomes; Lipossomo
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APA (6th Edition):
Geraldo, V. P. N. (2008). Filmes nanoestruturados contendo lipossomos para liberação controlada do Ibuprofeno. (Masters Thesis). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/88/88131/tde-17062008-120210/ ;
Chicago Manual of Style (16th Edition):
Geraldo, Vananélia Pereira Nunes. “Filmes nanoestruturados contendo lipossomos para liberação controlada do Ibuprofeno.” 2008. Masters Thesis, University of São Paulo. Accessed March 04, 2021.
http://www.teses.usp.br/teses/disponiveis/88/88131/tde-17062008-120210/ ;.
MLA Handbook (7th Edition):
Geraldo, Vananélia Pereira Nunes. “Filmes nanoestruturados contendo lipossomos para liberação controlada do Ibuprofeno.” 2008. Web. 04 Mar 2021.
Vancouver:
Geraldo VPN. Filmes nanoestruturados contendo lipossomos para liberação controlada do Ibuprofeno. [Internet] [Masters thesis]. University of São Paulo; 2008. [cited 2021 Mar 04].
Available from: http://www.teses.usp.br/teses/disponiveis/88/88131/tde-17062008-120210/ ;.
Council of Science Editors:
Geraldo VPN. Filmes nanoestruturados contendo lipossomos para liberação controlada do Ibuprofeno. [Masters Thesis]. University of São Paulo; 2008. Available from: http://www.teses.usp.br/teses/disponiveis/88/88131/tde-17062008-120210/ ;
University of Alberta
16.
Xing, Xiao.
Layer-by-layer assembly of multilayers on carbon surfaces
and molecular electronic junctions.
Degree: MS, Department of Chemistry, 2010, University of Alberta
URL: https://era.library.ualberta.ca/files/4f16c354s
► In the research described in this thesis, two molecular layers were successfully anchored on carbon surfaces (pyrolyzed photoresist films, PPFs) sequentially through two independent approaches.…
(more)
▼ In the research described in this thesis, two
molecular layers were successfully anchored on carbon surfaces
(pyrolyzed photoresist films, PPFs) sequentially through two
independent approaches. The first molecular layer, styrene, was
covalently bonded on PPF surfaces via the method of reduction of in
situ generated diazonium ions. The resulting molecular films were
characterized by AFM measurements, and catechol and ferrocyanide
voltammetry. The second molecular layer, ferrocene-thiol, was
anchored on top of the first molecular layer through the method of
thiol-ene reaction, which is an effective method for building up
multilayers through layer-by-layer assembly. As ferrocene is an
electrochemically active species, quantitative surface coverage was
calculated according to the amount of surface-bound ferrocene
through electrochemical measurements. Finally, molecular junctions
were fabricated by depositing metal top contacts based on the
molecular layers through electron-beam evaporation and the
electronic characteristics of these molecular junctions were
investigated.
Subjects/Keywords: covalent multilayers; molecular electronic junction; layer-by-layer assembly
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APA (6th Edition):
Xing, X. (2010). Layer-by-layer assembly of multilayers on carbon surfaces
and molecular electronic junctions. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/4f16c354s
Chicago Manual of Style (16th Edition):
Xing, Xiao. “Layer-by-layer assembly of multilayers on carbon surfaces
and molecular electronic junctions.” 2010. Masters Thesis, University of Alberta. Accessed March 04, 2021.
https://era.library.ualberta.ca/files/4f16c354s.
MLA Handbook (7th Edition):
Xing, Xiao. “Layer-by-layer assembly of multilayers on carbon surfaces
and molecular electronic junctions.” 2010. Web. 04 Mar 2021.
Vancouver:
Xing X. Layer-by-layer assembly of multilayers on carbon surfaces
and molecular electronic junctions. [Internet] [Masters thesis]. University of Alberta; 2010. [cited 2021 Mar 04].
Available from: https://era.library.ualberta.ca/files/4f16c354s.
Council of Science Editors:
Xing X. Layer-by-layer assembly of multilayers on carbon surfaces
and molecular electronic junctions. [Masters Thesis]. University of Alberta; 2010. Available from: https://era.library.ualberta.ca/files/4f16c354s
Cornell University
17.
Trejo, Nidia.
Loading Polymer Coated Magnetite Nanoparticles On Nylon 6 Nanomembranes By Three Methods.
Degree: M.S., Fiber Science, Fiber Science, 2015, Cornell University
URL: http://hdl.handle.net/1813/39394
► In this study carboxylic acid coated magnetite nanoparticles (CA-Fe3O4 NPs) were applied to mechanically robust, Nylon 6 nanomembranes by three different techniques; 1) simultaneous electrospraying-electrospinning,…
(more)
▼ In this study carboxylic acid coated magnetite nanoparticles (CA-Fe3O4 NPs) were applied to mechanically robust, Nylon 6 nanomembranes by three different techniques; 1) simultaneous electrospraying-electrospinning, 2)
layer-by-
layer (LbL) assembly, and 3) chemical grafting of NPs onto Nylon 6. The aim of this study was to evaluate the NP treatment homogeneity by the three methods and examine the durability on the membranes for potential wastewater treatment applications. The carboxylic acid polymeric coating on the NPs facilitated loading by all methods to display differing chemical bonding pathways: hydrogen bonding, ionic bonding, and covalent bonding. Electrospinning the fibers while simultaneously electrospraying is a simple method to incorporate NPs within fibers independent of polymer-particle solvent compatibilities. LbL assembly can allow for the number of NP layers to be controlled. The grafting method can allow for the formation of a durable, covalent bond between the carboxylate groups of the NPs and amine end groups on Nylon 6. Main characterization techniques included electron microscopy, CIELAB spectrophotometry, and ICP-AES analysis. Results reveal that electrospinning-electrospraying and chemical grafting methods produced a homogeneous NP dispersion on the membranes. ICP-AES results indicate that the durability of the treatments is pH dependent and driven by electrostatic interactions. These surface treatment methods have not been previously attempted with Nylon 6 fibers and polymer coated Fe3O4 NPs. Additionally, few studies evaluate the durability of NP treatments on fibers although it is an issue of high concern and the NP treatment should be long lasting for the intended end-use.
Advisors/Committee Members: Frey, Margaret W (chair), Estroff, Lara A. (committee member).
Subjects/Keywords: Electrospraying; Layer-by-Layer assembly; EDC/NHS chemical grafting
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APA (6th Edition):
Trejo, N. (2015). Loading Polymer Coated Magnetite Nanoparticles On Nylon 6 Nanomembranes By Three Methods. (Masters Thesis). Cornell University. Retrieved from http://hdl.handle.net/1813/39394
Chicago Manual of Style (16th Edition):
Trejo, Nidia. “Loading Polymer Coated Magnetite Nanoparticles On Nylon 6 Nanomembranes By Three Methods.” 2015. Masters Thesis, Cornell University. Accessed March 04, 2021.
http://hdl.handle.net/1813/39394.
MLA Handbook (7th Edition):
Trejo, Nidia. “Loading Polymer Coated Magnetite Nanoparticles On Nylon 6 Nanomembranes By Three Methods.” 2015. Web. 04 Mar 2021.
Vancouver:
Trejo N. Loading Polymer Coated Magnetite Nanoparticles On Nylon 6 Nanomembranes By Three Methods. [Internet] [Masters thesis]. Cornell University; 2015. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1813/39394.
Council of Science Editors:
Trejo N. Loading Polymer Coated Magnetite Nanoparticles On Nylon 6 Nanomembranes By Three Methods. [Masters Thesis]. Cornell University; 2015. Available from: http://hdl.handle.net/1813/39394
Texas A&M University
18.
Guin, Tyler C.
Improving Layer-by-Layer Assembly for Superior Flame Retardant and Gas Barrier Thin Films.
Degree: PhD, Chemical Engineering, 2015, Texas A&M University
URL: http://hdl.handle.net/1969.1/156424
► Layer-by-layer (LbL) assembly is a promising technique for depositing multi-functional thin films from dilute aqueous solutions. These films have found use as environmentally-benign flame retardants,…
(more)
▼ Layer-by-
layer (LbL) assembly is a promising technique for depositing multi-functional thin films from dilute aqueous solutions. These films have found use as environmentally-benign flame retardants, replacing halogenated flame retardants, and as flexible gas barrier thin films, replacing vacuum-deposited inorganic oxide thin films. Unfortunately, LbL assembly has drawbacks that have not been adequately addressed, such as stiffening of coated substrates and the high number of deposition steps required.
Thin films of chitosan and poly(sodium phosphate) were deposited on cotton fabric via LbL assembly to reduce flammability. The fabric was rinsed in an ultrasonication bath between deposition steps to improve the softness (i.e., hand) of the coated fabric. Ultrasonication is believed to remove weakly adhered polyelectrolyte and eliminate bridging of individual fibers, preventing the fabric from becoming stiff while improving the flame retardant behavior.
Incorporating amine salts into the cationic polyelectrolyte and its associated rinse enables LbL clay-containing films to achieve large thickness (>1 μm) with relatively few deposition steps. This technique is potentially universal, exhibiting thick growth with multiple types of nanoclay, including montmorillonite and vermiculite, a variety of amine salts (e.g., hexylamine and tris), and a host of cationic polyelectrolytes, such as poly(allylamine) and chitosan. The characteristic ordered structure found in LbL-assembled films is maintained despite the increased thickness. These films display extraordinary gas barrier and flame resistance with fewer than 8 deposition cycles.
Advisors/Committee Members: Grunlan, Jaime C (advisor), Batteas, James (committee member), Balbuena, Perla (committee member), Lutkenhaus, Jodie (committee member).
Subjects/Keywords: Layer-by-layer assembly; multilayer; flame retardant; chitosan
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APA (6th Edition):
Guin, T. C. (2015). Improving Layer-by-Layer Assembly for Superior Flame Retardant and Gas Barrier Thin Films. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/156424
Chicago Manual of Style (16th Edition):
Guin, Tyler C. “Improving Layer-by-Layer Assembly for Superior Flame Retardant and Gas Barrier Thin Films.” 2015. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/156424.
MLA Handbook (7th Edition):
Guin, Tyler C. “Improving Layer-by-Layer Assembly for Superior Flame Retardant and Gas Barrier Thin Films.” 2015. Web. 04 Mar 2021.
Vancouver:
Guin TC. Improving Layer-by-Layer Assembly for Superior Flame Retardant and Gas Barrier Thin Films. [Internet] [Doctoral dissertation]. Texas A&M University; 2015. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/156424.
Council of Science Editors:
Guin TC. Improving Layer-by-Layer Assembly for Superior Flame Retardant and Gas Barrier Thin Films. [Doctoral Dissertation]. Texas A&M University; 2015. Available from: http://hdl.handle.net/1969.1/156424
Texas A&M University
19.
Smith, Ryan Joseph.
Development of Polyelectrolyte Complex Thin Films for Polymer Surface Functionalization.
Degree: PhD, Chemistry, 2018, Texas A&M University
URL: http://hdl.handle.net/1969.1/173660
► Polyelectrolyte complexes (PEC) are composites of two or more polyelectrolytes, that when processed appropriately, can create thin films. These films can have a wide array…
(more)
▼ Polyelectrolyte complexes (PEC) are composites of two or more polyelectrolytes, that when processed appropriately, can create thin films. These films can have a wide array of properties and can serve to functionalize a wide variety of surfaces. This dissertation discusses the functionalization of polymeric surfaces with polyelectrolyte complexes. The
layer-by-
layer assembly method was used to sequentially build up the PEC on the substrate. This process generally requires several steps to manufacture a film of sufficient thickness and/or surface coverage. In an effort to reduce the number of processing steps to form PEC thin films, development of a single step deposition method was also developed.
Halloysite-based multilayer composites were found to significantly reduce the flammability of polyurethane foam. There was a 60% reduction in the peak heat release rate and total smoke release, and coated foam self-extinguished in open flame testing. This coating worked by forming a physical barrier that reduces heat and mass transfer during combustion, eventually leading to the flame extinguishing. Because of the environmentally-benign nature of the ingredients used, this coating provides a safe alternative to traditional flame retardant materials.
Polyelectrolyte complex multilayers were applied to polyester fabric and bacterial adhesion was significantly reduced after a simple water rinse. >99% of deposited bacteria was removed after rinsing. Bioluminescent Staphylococcus aureus was used to evaluate viable bacteria on the fabric surface. Electrostatic repulsion
iii
between the negatively charged surface and the negatively charged bacteria combined with increasing surface roughness is believed to be the reason for reduced bacterial adhesion.
Polyelectrolyte complexes were deposited to polyester fabric and film in a single step. Film structure and morphology are dependent on how the film is cured (i.e. formation of electrostatic network). Rough aggregated films were found to form when the coating is cured while it is still wet on the substrate surface, and is ideal for coating complex substrates (e.g. fabric). This coating was found to reduce bacterial adhesion and >95% of deposited bacteria is removed after a simple rinse with water. When the PEC coatings are cured after the film is dried to the surface of the substrate, a conformal relatively smooth coating is formed, and when applied to PET film, reduces oxygen transmission by two orders of magnitude. The transparency of this coating was found to be dependent on the concentration and ionic strength of the buffer in which the films are cured. These processes significantly reduce processing steps required to deposit films with similar properties using
layer-by-
layer.
Advisors/Committee Members: Grunlan, Jaime C (advisor), Fang, Lei (committee member), Cirillo, Jeffery (committee member), Banerjee, Sarbajit (committee member).
Subjects/Keywords: Polyelectrolyte complexes; Layer-by-layer Flame retardant; bacterial adhesion; Oxygen barrier
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APA (6th Edition):
Smith, R. J. (2018). Development of Polyelectrolyte Complex Thin Films for Polymer Surface Functionalization. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/173660
Chicago Manual of Style (16th Edition):
Smith, Ryan Joseph. “Development of Polyelectrolyte Complex Thin Films for Polymer Surface Functionalization.” 2018. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/173660.
MLA Handbook (7th Edition):
Smith, Ryan Joseph. “Development of Polyelectrolyte Complex Thin Films for Polymer Surface Functionalization.” 2018. Web. 04 Mar 2021.
Vancouver:
Smith RJ. Development of Polyelectrolyte Complex Thin Films for Polymer Surface Functionalization. [Internet] [Doctoral dissertation]. Texas A&M University; 2018. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/173660.
Council of Science Editors:
Smith RJ. Development of Polyelectrolyte Complex Thin Films for Polymer Surface Functionalization. [Doctoral Dissertation]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/173660
Texas A&M University
20.
Song, Yixuan.
Processing and Functionality Improvements of Layer-By-Layer Assembled Multilayer Super Gas Barrier Nanocoatings.
Degree: PhD, Materials Science and Engineering, 2018, Texas A&M University
URL: http://hdl.handle.net/1969.1/173296
► High oxygen barrier materials are becoming increasingly important for food packaging, pressurized systems, and flexible electronics protection. The widely used traditional aluminized plastics and inorganic…
(more)
▼ High oxygen barrier materials are becoming increasingly important for food
packaging, pressurized systems, and flexible electronics protection. The widely used
traditional aluminized plastics and inorganic gas barrier coatings (SiOx and AlxOy) exhibit
low transparency and/or flexibility.
Layer-by-
layer assembly (LbL) provides a costeffective
and environmental-friendly alternative, with lower oxygen permeability and
greater transparency. This dissertation focuses on improvements of the coating process
and development of new functionalities. Four studies are discussed in detail on this topic
and two future research directions are also introduced.
Layer-by-
layer assembled multilayer nanocoatings have been shown to provide
excellent oxygen barrier to poly(ethylene terephthalate) (PET) film, which is commonly
used for encapsulation and packaging. Polymer-clay (polyethylenimine (PEI)/vermiculite
(VMT)) and all-polymer ((PEI)/poly(acrylic acid) (PAA)) multilayer systems are shown
to be equally beneficial as barrier coatings for polyolefin substrates (e.g., polyethylene and
polypropylene), which suffer from a high oxygen transmission rate. A 30 bilayer
PEI/VMT nanocoating reduces the OTR of biaxially oriented polypropylene (BOPP) by
more than 160X, rivaling most inorganic coatings. WVTR is simultaneously reduced by
43%.
In addition to VMT, montmorillonite (MMT) clay has been widely used to prepare
gas barrier nanocoatings. In an effort to produce high oxygen barrier with fewer deposition
steps, pH of the MMT aqueous suspension was reduced. In a PEI/PAA/PEI/MMT
iii
quadlayer system, the reduced pH of MMT causes the preceding PEI
layer to be more
charged, which results in more clay deposited. A compromise between high
polyelectrolyte diffusion (high pH) and high clay deposition (low pH) was found at pH 6,
where the best oxygen barrier is obtained. A 179 μm thick PET substrate, coated with just
three quadlayers (44 nm thick), exhibits an undetectable oxygen transmission rate (< 0.005
cm3/(m2 day atm)).
In another attempt to achieve better oxygen barrier of the PEI/MMT bilayer (BL)
system, a “salty clay” strategy was carried out, where an “indifferent” electrolyte (NaCl)
was introduced into the MMT suspension. NaCl alters the ionic strength of the clay
suspension and subsequently changes the rheological behavior of clay platelets. As a
result, a multilayer film with a more tortuous path and better clay coverage (and alignment)
is produced. Lower OTR is achieved as a result of this structural engineering. An 8 BL
PEI/MMT film, assembled with a clay suspension containing 5 mM NaCl, exhibits an
order of magnitude reduction in OTR relative to its no-salt counterpart.
The ability to self-repair after damaging (e.g., cracking) and restore original
properties is highly desired for polymers and composites. The PEI/PAA nanocoating has
the ability to self-heal after being cracked by stretching. Cracks in the film lead to loss of
oxygen barrier. High humidity is employed as an external healing stimulus to repair these
cracks. The OTR of a…
Advisors/Committee Members: Grunlan, Jaime (advisor), Lutkenhaus, Jodie (committee member), Sukhishvili, Svetlana (committee member), Green, Micah (committee member).
Subjects/Keywords: Gas barrier; multilayer nanocoatings; layer-by-layer assembly
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APA (6th Edition):
Song, Y. (2018). Processing and Functionality Improvements of Layer-By-Layer Assembled Multilayer Super Gas Barrier Nanocoatings. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/173296
Chicago Manual of Style (16th Edition):
Song, Yixuan. “Processing and Functionality Improvements of Layer-By-Layer Assembled Multilayer Super Gas Barrier Nanocoatings.” 2018. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/173296.
MLA Handbook (7th Edition):
Song, Yixuan. “Processing and Functionality Improvements of Layer-By-Layer Assembled Multilayer Super Gas Barrier Nanocoatings.” 2018. Web. 04 Mar 2021.
Vancouver:
Song Y. Processing and Functionality Improvements of Layer-By-Layer Assembled Multilayer Super Gas Barrier Nanocoatings. [Internet] [Doctoral dissertation]. Texas A&M University; 2018. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/173296.
Council of Science Editors:
Song Y. Processing and Functionality Improvements of Layer-By-Layer Assembled Multilayer Super Gas Barrier Nanocoatings. [Doctoral Dissertation]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/173296
Texas A&M University
21.
Holder, Kevin Michael.
Flame Retardant Nanocoatings for the Protection of Polyurethane Foam.
Degree: PhD, Materials Science and Engineering, 2016, Texas A&M University
URL: http://hdl.handle.net/1969.1/174265
► Layer-by-layer (LbL) assembly is a simple technique capable of building multifunctional thin films on a variety of surfaces from dilute aqueous solutions. LbL coatings on…
(more)
▼ Layer-by-
layer (LbL) assembly is a simple technique capable of building multifunctional thin films on a variety of surfaces from dilute aqueous solutions. LbL coatings on polyurethane foam have been successful in reducing the flammability through environmentally friendly means. This technology provides a potential avenue for replacing halogenated flame retardants which are successfully used on foams, but present a toxic threat to health and the environment.
A thin film nano-brick wall structure composed of chitosan and vermiculite clay was combined with an all-polymer film of chitosan and ammonium polyphosphate to form a stacked coating on polyurethane foam to reduce flammability. Individually, the coatings were able to reduce flammability of the foam, however the all-polymer coating was unable to prevent total degradation of the polyurethane due to inability to form char prior to the collapse of the foam. The nano-brick wall provided the necessary structure to allow the all-polymer coating to act and form an expanded insulating char
layer that prevents flame spread across the surface of the polyurethane as well as reduce the peak heat release rate of the foam significantly.
Incorporating carbon nanotubes into a LbL assembly allowed further reductions in polyurethane foam flammability. Only a few layers of nanotube-containing polymer layers were able to completely prevent flame propagation in both horizontal and vertical flame tests. Cone calorimetry revealed significant reductions in peak heat release rate as well as total smoke release. Reduction in heat release rates and smoke release are important factors towards extending escape time in a fire scenario.
Barrier fabrics are commonly used to protect flammable materials. A polyelectrolyte complex was used to coat cotton fabric and prevented flame spread and ignition of underlying polyurethane foam. This study also highlights the importance of testing combined fabric and foam assemblies as pertaining to upholstered furniture. Cone calorimetry is a useful instrument to ascertain interactions between varying fabric and foam compositions and potentially will highlight an appropriate method for flame retarding the combination.
Advisors/Committee Members: Grunlan, Jaime (advisor), Clearfield, Abraham (committee member), Creasy, Terry (committee member), Green, Micah (committee member).
Subjects/Keywords: layer-by-layer; multilayer; flame retardant; polyurethane; nanocoating
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APA (6th Edition):
Holder, K. M. (2016). Flame Retardant Nanocoatings for the Protection of Polyurethane Foam. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/174265
Chicago Manual of Style (16th Edition):
Holder, Kevin Michael. “Flame Retardant Nanocoatings for the Protection of Polyurethane Foam.” 2016. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/174265.
MLA Handbook (7th Edition):
Holder, Kevin Michael. “Flame Retardant Nanocoatings for the Protection of Polyurethane Foam.” 2016. Web. 04 Mar 2021.
Vancouver:
Holder KM. Flame Retardant Nanocoatings for the Protection of Polyurethane Foam. [Internet] [Doctoral dissertation]. Texas A&M University; 2016. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/174265.
Council of Science Editors:
Holder KM. Flame Retardant Nanocoatings for the Protection of Polyurethane Foam. [Doctoral Dissertation]. Texas A&M University; 2016. Available from: http://hdl.handle.net/1969.1/174265
Texas A&M University
22.
Hu, He 1987-.
Layer-by-Layer Assembled Smectite-Polymer Nanocomposite Film for Rapid Detection of Low-Concentration Aflatoxins.
Degree: MS, Electrical Engineering, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/148174
► Aflatoxin is a potent biological toxin produced by fungi Aspergillus flavus and A. parasiticus. Current quantification methods for aflatoxins are mostly established on immunoaffinity columns…
(more)
▼ Aflatoxin is a potent biological toxin produced by fungi Aspergillus flavus and A. parasiticus. Current quantification methods for aflatoxins are mostly established on immunoaffinity columns which are both costly and labor intensive. Inspired by smectites’ high aflatoxin adsorption capacity and affinity, a novel aflatoxin quantification sensor based on smectite-polyacrylamide (PAM) nanocomposite was fabricated. First, a smectite-PAM nanocomposite film was synthesized on flat silicon substrates which assembled smectite particles from the clay suspension. A
layer-by-
layer assembly process was developed to achieve uniform morphology and thickness of the nanocomposite films. During the aflatoxin quantification process, positive correlations between the fluorescence intensity from the aflatoxin B1 (AFB1) adsorbed smectite-PAM nanocomposite films and the AFB1 concentration in the test solutions were obtained. The smectite-PAM nanocomposite film has shown similar AFB1 adsorption capabilities as the smectite.
Second, the smectite-PAM nanocomposite film was optimized in order to achieve the aflatoxin quantification at ppb level (below 20ppb) in corn extraction solutions. The smectite was modified by Ba2+, which had demonstrated to be able to improve its aflatoxin adsorption capacity. PAM aqueous solutions with the mass concentration ranging from 0.8% to 0.001% were tested. The results showed that the nanocomposite synthesized from 0.005% concentration of PAM solution generated the best properties. After the optimization, the smectite-PAM nanocomposite films achieved the detection of aflatoxin B1, B2, G1 and G2 (AFB2, AFG1 and AFG2) in 10 ppb corn extraction solution. Aflatoxin quantifications in AFB1 and AFB2 mixture solution, AFB1 and AFB2 mixture solution and AFB1 and AFG1 mixture solution were conducted, and the recoveries of last test ranged from 90.52% to 110.11% at low aflatoxin concentration (below 20 ppb).
Third, in order to shorten the quantification duration and simplify the detection process, a novel aflatoxin detection array based on smectite-PAM nanocomposite and an improved fluorometric quantification method were developed. Through a microfluidic chip, the reaction time was reduced to 10~20min. Two concentration levels (20~80ppb/5~15ppb) of aflatoxin B1 spiked corn extraction solutions were tested. In the fluorometric quantification step, a common lab-use 365 nm ultraviolet lamp replaced the spectrofluorometer which simplified and accelerated the process.
Advisors/Committee Members: Zou, Jun (advisor), Deng, Youjun (committee member), Ji, Jim Xiuquan (committee member), Kameoka, Jun (committee member).
Subjects/Keywords: PDMS.; microfluidics; spectrofluorometer; layer by layer assembly; smectite; aflatoxin
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APA (6th Edition):
Hu, H. 1. (2012). Layer-by-Layer Assembled Smectite-Polymer Nanocomposite Film for Rapid Detection of Low-Concentration Aflatoxins. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/148174
Chicago Manual of Style (16th Edition):
Hu, He 1987-. “Layer-by-Layer Assembled Smectite-Polymer Nanocomposite Film for Rapid Detection of Low-Concentration Aflatoxins.” 2012. Masters Thesis, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/148174.
MLA Handbook (7th Edition):
Hu, He 1987-. “Layer-by-Layer Assembled Smectite-Polymer Nanocomposite Film for Rapid Detection of Low-Concentration Aflatoxins.” 2012. Web. 04 Mar 2021.
Vancouver:
Hu H1. Layer-by-Layer Assembled Smectite-Polymer Nanocomposite Film for Rapid Detection of Low-Concentration Aflatoxins. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/148174.
Council of Science Editors:
Hu H1. Layer-by-Layer Assembled Smectite-Polymer Nanocomposite Film for Rapid Detection of Low-Concentration Aflatoxins. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/148174
Texas A&M University
23.
Priolo, Morgan Alexander.
Layer-by-layer Assembly of Nanobrick Wall Ultrathin Transparent Gas Barrier Films.
Degree: PhD, Materials Science and Engineering, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11170
► Thin layers with high barrier to oxygen and other gases are a key component to many packaging applications, such as flexible electronics, food, and pharmaceuticals.…
(more)
▼ Thin layers with high barrier to oxygen and other gases are a key component to many packaging applications, such as flexible electronics, food, and pharmaceuticals. Vapor deposited thin films provide significant gas barrier, but are prone to cracking when flexed, require special, non-ambient processing environments, and can involve complex fabrication when layered with polymers. The addition of clay into polymers can enhance barrier properties relative to the neat polymer; however, these composites are
subject to clay aggregation at high loadings, which leads to increased opacity and random platelet alignment that ultimately reduce barrier improvement.
Layer-by-
layer (LbL) assembly is capable of producing thin films that exhibit super gas barrier properties, while remaining flexible and completely transparent.
Montmorillonite (MMT) clay and branched polyethylenimine (PEI) were deposited via LbL assembly to create gas barrier films that can be tailored by altering the pH of the PEI deposition solution or the concentration of the MMT suspension. Films grow linearly as a function of layers deposited, where increasing PEI pH increases spacing between clay layers and increasing MMT concentration increases thin film clay content. An oxygen transmission rate (OTR) below the detection limit of commercial instrumentation (< 0.005 cm3/m2•day•atm) is observed after 70 layers of 0.2 wt % MMT or 24 layers of 2 wt % MMT are deposited with pH 10 PEI onto 179 µm thick poly(ethylene terephthalate) (PET) film.
Three-component films of PEI, poly(acrylic acid) (PAA), and MMT grow exponentially as a function of PEI/PAA/PEI/MMT quadlayers deposited. A transparent, ultrathin film of only four quadlayers deposited onto PET exhibits the lowest oxygen permeability ever reported for any thin film material, at only 51 nm thick.
Finally, the first example of LbL assembly using large aspect ratio vermiculite (VMT) clay was performed. PEI/VMT films grow linearly as a function of layers deposited and exhibit 95 % light transmission with 97 wt % VMT. The barrier of these films is due to the highly aligned nanobrick wall structure that creates a tortuous path for permeating molecules. Coupling high flexibility, transparency, and barrier, these coatings are good candidates for a variety of packaging applications.
Advisors/Committee Members: Grunlan, Jaime C. (advisor), Jeong, Hae-Kwon (committee member), Ross, Jr., Joseph H. (committee member), Wang, Haiyan (committee member).
Subjects/Keywords: layer-by-layer assembly; thin films; oxygen barrier; packaging; clays; nanocomposites
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APA (6th Edition):
Priolo, M. A. (2012). Layer-by-layer Assembly of Nanobrick Wall Ultrathin Transparent Gas Barrier Films. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11170
Chicago Manual of Style (16th Edition):
Priolo, Morgan Alexander. “Layer-by-layer Assembly of Nanobrick Wall Ultrathin Transparent Gas Barrier Films.” 2012. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11170.
MLA Handbook (7th Edition):
Priolo, Morgan Alexander. “Layer-by-layer Assembly of Nanobrick Wall Ultrathin Transparent Gas Barrier Films.” 2012. Web. 04 Mar 2021.
Vancouver:
Priolo MA. Layer-by-layer Assembly of Nanobrick Wall Ultrathin Transparent Gas Barrier Films. [Internet] [Doctoral dissertation]. Texas A&M University; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11170.
Council of Science Editors:
Priolo MA. Layer-by-layer Assembly of Nanobrick Wall Ultrathin Transparent Gas Barrier Films. [Doctoral Dissertation]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11170
Texas A&M University
24.
Yang, You-Hao.
Processing and Gas Barrier Behavior of Multilayer Thin Nanocomposite Films.
Degree: PhD, Chemical Engineering, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11685
► Thin films with the ability to impart oxygen and other types of gas barrier are crucial to commercial packaging applications. Commodity polymers, such as polyethylene…
(more)
▼ Thin films with the ability to impart oxygen and other types of gas barrier are crucial to commercial packaging applications. Commodity polymers, such as polyethylene (PE), polycarbonate (PC) and polyethylene terephthalate (PET), have insufficient barrier for goods requiring long shelf life. Current gas barrier technologies like plasma-enhanced vapor deposition (PECVD) often create high barrier metal oxide films, which are prone to cracking when flexed. Bulk composites composed of polymer and impermeable nanoparticles show improved barrier, but particle aggregation limits their practical utility for applications requiring high barrier and transparency.
Layer-by-
layer (LbL) assemblies allow polymers and nanoparticles to be mixed with high particle loadings, creating super gas barrier thin films on substrates normally exhibiting high gas permeability.
Branched polyethylenimine (PEI) and poly (acrylic acid) (PAA) were deposited using LbL to create gas barrier films with varying pH combinations. Film thickness and mass fraction of each component was controlled by their combined charge. With lower charge density (PEI at pH 10 and PAA at pH 4), PEI/PAA assemblies exhibit the best oxygen barrier relative to other pH combinations. An 8 BL PEI/PAA film, with a thickness of 451 nm, has an oxygen permeability lower than 4.8 x 10
-21 cm
3 * cm/cm
2 * s * Pa, which is comparable to a 100 nm SiOx nanocoating. Crosslinking these films with glutaraldehyde (GA), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide methiodide (EDC) or heating forms covalent bonds between PEI and/or PAA. Oxygen transmission rates (OTR) of 8 BL films crosslinked with 0.1M GA or 0.01M EDC show the best oxygen barrier at 100% RH.
Graphene oxide (GO) sheets and PEI were deposited via LbL with varying GO concentration. The resulting thin films have an average bilayer thickness from 4.3 to 5.0 nm and a GO mass fraction from 88 to 91wt%. Transmission electron microscopy and atomic force microscopy images reveal a highly-oriented nanobrick wall structure. A 10 BL PEI/GO film that is 91 nm thick, made with a 0.2 wt% GO suspension, exhibits an oxygen permeability of 2.5 x 10
-20 cm
3 * cm/cm
2 * s * Pa.
Finally, the influence of deposition time on thin film assembly was examined by depositing montmorillonite (MMT) or laponite (LAP) clays paired with PEI. Film growth and microstructure suggests that smaller aspect ratio LAP clay is more dip-time dependent than MMT and larger aspect ratio MMT has better oxygen barrier. A 30 BL PEI/MMT film made with 10 second dips in PEI has the same undetectable OTR as a film with 5 minute dips (with dips in MMT held at 5 minutes in both cases), indicating LbL gas barrier can be made more quickly than initially thought. These high barrier recipes, with simple and efficient processing conditions, are good candidates for a variety of packaging applications.
Advisors/Committee Members: Grunlan, Jaime C. (advisor), Ugaz, Victor (committee member), Jeong, Hae-Kwon (committee member), Batteas, James (committee member).
Subjects/Keywords: Layer-by-layer; gas barrier; moisture barrier; polyelectrolyte; crosslink; graphene oxide
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APA ·
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MLA ·
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Manager
APA (6th Edition):
Yang, Y. (2012). Processing and Gas Barrier Behavior of Multilayer Thin Nanocomposite Films. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11685
Chicago Manual of Style (16th Edition):
Yang, You-Hao. “Processing and Gas Barrier Behavior of Multilayer Thin Nanocomposite Films.” 2012. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11685.
MLA Handbook (7th Edition):
Yang, You-Hao. “Processing and Gas Barrier Behavior of Multilayer Thin Nanocomposite Films.” 2012. Web. 04 Mar 2021.
Vancouver:
Yang Y. Processing and Gas Barrier Behavior of Multilayer Thin Nanocomposite Films. [Internet] [Doctoral dissertation]. Texas A&M University; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11685.
Council of Science Editors:
Yang Y. Processing and Gas Barrier Behavior of Multilayer Thin Nanocomposite Films. [Doctoral Dissertation]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11685
University of Waterloo
25.
Halakoo, Elnaz.
Thin film composite membranes via layer-by-layer assembly for pervaporation separation.
Degree: 2019, University of Waterloo
URL: http://hdl.handle.net/10012/15291
► The aim of this study was to develop LbL membranes based on polyethyleneimine and graphene oxide (PEI/GO) and to investigate them for three different applications,…
(more)
▼ The aim of this study was to develop LbL membranes based on polyethyleneimine and graphene oxide (PEI/GO) and to investigate them for three different applications, namely the pervaporative desalination of high-salinity water, dehydration of ethylene glycol (EG) and dehydration of ethanol (EtOH) and isopropanol (IPA). Salts are non-volatile, EG has a high boiling point, and EtOH and IPA can form an azeotrope with water. To prepare LbL membranes in this work, a chlorine-treated thin film composite (TFC) polyamide membrane was used as a substrate, and PEI and GO were used as polycation and polyanion, respectively. To the best of our knowledge, it is for the first time the aforementioned LbL membranes were prepared and investigated in pervaporation applications.
Chlorine-treatment of TFC polyamide was initially studied to determine the suitable chlorination conditions. It was found that pure water flux was more than doubled after chlorination with sodium hypochlorite at 6000 ppm for 2h at room temperature. The as-chlorinated membrane showed that the water permeation flux was almost tripled (i.e., 1.3 kg/m2h ) while the salt rejection decreased by 2% (i.e., 95.8%) for pervaporative desalination of 20 wt% feed salt concentration. The chlorine-treated TFC polyamide membranes with improved flux were used as substrates throughout this study.
First, attempts were made to improve the pervaporative desalination performance. PEI/GO LbL membrane formed on the surface of chlorine-treated TFC polyamide membrane for pervaporation desalination of high-salinity water was investigated for the first time, and for this reason, concentrations of PEI and GO were 0.02 monomol/L and 100 ppm, respectively. It was shown that the incorporating PEI and GO to the chlorine-treated TFC polyamide membranes improved the salt rejection. The PEI/GO LbL membrane was tested for the desalination of aqueous solutions containing NaCl, Na2 SO4, MgSO4, and MgCl2 salts, and a water flux as high as 8 kg/m2h with a high salt rejection (>99.9%) was obtained for all the tested salts at various temperatures and feed concentrations. In order to assess the temperature dependence of the permeation flux through the membrane, the apparent activation energy for permeation of water was determined. The water permeation flux increased with an increase in temperature due to the augmented driving force and diffusivity in the membrane. The properties of the membranes surface were studied using Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), atomic force microscopy (AFM) and contact angle measurements. Based on the experimental data and stability of the PEI/GO LbL membrane, the formation of the membranes through the LbL self-assembly with PEI and GO showed potential for applications in the treatment of high-salinity water such as industrial wastewater and concentrated reverse osmosis (RO) brine.
EG is one of the important substances in gas and chemical industries. Therefore, after the efficiency of PEI/GO LbL membrane with one bilayer was found…
Subjects/Keywords: membrane separation; pervaporation; graphene oxide; layer-by-layer; polyethyleneimine
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APA (6th Edition):
Halakoo, E. (2019). Thin film composite membranes via layer-by-layer assembly for pervaporation separation. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/15291
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Halakoo, Elnaz. “Thin film composite membranes via layer-by-layer assembly for pervaporation separation.” 2019. Thesis, University of Waterloo. Accessed March 04, 2021.
http://hdl.handle.net/10012/15291.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Halakoo, Elnaz. “Thin film composite membranes via layer-by-layer assembly for pervaporation separation.” 2019. Web. 04 Mar 2021.
Vancouver:
Halakoo E. Thin film composite membranes via layer-by-layer assembly for pervaporation separation. [Internet] [Thesis]. University of Waterloo; 2019. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/10012/15291.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Halakoo E. Thin film composite membranes via layer-by-layer assembly for pervaporation separation. [Thesis]. University of Waterloo; 2019. Available from: http://hdl.handle.net/10012/15291
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Toronto
26.
Akter, Tahmina.
Surface Modifications of Nanocarbon Materials for Electrochemical Capacitors.
Degree: 2010, University of Toronto
URL: http://hdl.handle.net/1807/25404
► Multi-walled carbon nanotubes (MWCNTs) were successfully coated with two different pseudocapacitive polyoxometalates (POMs) (SiMo12O40-4 (SiMo12) and PMo12O40-3 (PMo12)) via “Layer-by-Layer” deposition. Even with merely a…
(more)
▼ Multi-walled carbon nanotubes (MWCNTs) were successfully coated with two different pseudocapacitive polyoxometalates (POMs) (SiMo12O40-4 (SiMo12) and PMo12O40-3 (PMo12)) via “Layer-by-Layer” deposition. Even with merely a “single-layer” of POM, the modified nanotubes exhibited more than 2X increase in capacitance compared with that of bare nanotubes. To further improve their electrochemical performances, the deposition sequence of the POM layers was adjusted to form “alternate layer” coating to modify MWCNT. A synergistic effect on the capacitance and kinetics was observed with the alternate layer coatings. X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM) also proved the successful coating of POMs on MWCNTs. The potential-pH relationship provided important insights in terms of the deposition mechanism and suggested that the bottom layer close to the electrode substrate was the dominating layer in alternate layer coated MWCNT electrodes.
MAST
Advisors/Committee Members: Lian, Keryn, Materials Science and Engineering.
Subjects/Keywords: Nanocarbon; Electrochemical Capacitor; Polyoxometaltes; Layer by Layer Deposition; Pseudocapacitance; MWCNT; 0794
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APA (6th Edition):
Akter, T. (2010). Surface Modifications of Nanocarbon Materials for Electrochemical Capacitors. (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/25404
Chicago Manual of Style (16th Edition):
Akter, Tahmina. “Surface Modifications of Nanocarbon Materials for Electrochemical Capacitors.” 2010. Masters Thesis, University of Toronto. Accessed March 04, 2021.
http://hdl.handle.net/1807/25404.
MLA Handbook (7th Edition):
Akter, Tahmina. “Surface Modifications of Nanocarbon Materials for Electrochemical Capacitors.” 2010. Web. 04 Mar 2021.
Vancouver:
Akter T. Surface Modifications of Nanocarbon Materials for Electrochemical Capacitors. [Internet] [Masters thesis]. University of Toronto; 2010. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1807/25404.
Council of Science Editors:
Akter T. Surface Modifications of Nanocarbon Materials for Electrochemical Capacitors. [Masters Thesis]. University of Toronto; 2010. Available from: http://hdl.handle.net/1807/25404
27.
Diwan, Anubhav.
Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications.
Degree: PhD, 2016, Brigham Young University
URL: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7204&context=etd
► The primary focus of my work has been to prepare new solid adsorbents for solid phase microextraction (SPME) via sputtering of silicon. The orientation of…
(more)
▼ The primary focus of my work has been to prepare new solid adsorbents for solid phase microextraction (SPME) via sputtering of silicon. The orientation of the silica substrates/fibers and the sputtering pressure induced the formation of porous and columnar structures. Sputtering was performed for different times to yield fibers with different thicknesses. Piranha treatment of the surface increased the concentration of silanol groups, which underwent condensation with vapor deposited octadecyldimethylmonomethoxy silane to incorporate octadecyl chains onto the fiber surfaces. Silanized, sputtered fibers were preconditioned for 3 h at 320 °C to remove the unreacted chains. Comparison of the extraction efficiencies of 1.0 and 2.0 µm sputtered, silanized fibers with a commercial fiber (7 µm PDMS) for a series of analyte mixtures, which included alkanes, alcohols, aldehydes, esters, and amines, was demonstrated. The silanized, sputtered fiber performed better than the commercial fiber in extraction of most of the compounds. These fibers demonstrated long life as no degradation was seen even after 300 extractions. Carry-over between runs was not observed. The repeatability of the sputtered fibers was similar to commercial ones. The extraction of more than 50 compounds from a real world botanical sample using the 2.0 µm sputtered, silanized fiber was also demonstrated. In my second project, a facile method for the preparation of superhydrophobic surfaces (SHS) on glass and silicon surfaces was developed. A two-tier topography (needed for an SHS) was created in 60 min by the aggregation of nanosilica during in situ urea-formaldehyde polymerization. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated rough topography. Vapor deposition of a low surface energy silane imparted hydrophobicity, which was confirmed by the presence of an F 1s signal in X-ray photoelectron spectroscopy (XPS). The prepared surfaces exhibited water contact angles (WCA) of greater than 150 °C with very low sliding angles. In my third project, a multilayer assembly of nitrilotris(methylene)triphosphonic acid, a corrosion inhibitor, and zirconium was constructed on alumina at room temperature. Attempts to prepare a layer-by-layer assembly at higher temperature (70 °C) was unsuccessful due to etching of the alumina surface. A suite of analytical techniques, XPS, AFM, time-of-flight secondary ion mass spectrometry, and spectroscopic ellipsometry was used to characterize these surfaces. This thesis also contains appendices of tutorial articles I wrote on modeling in ellipsometry, and data analysis tools (classical least squares and multivariate curve resolution).
Subjects/Keywords: Solid phase microextraction; surface coatings; superhydrophobic surface; layer-by-layer; Chemistry
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APA (6th Edition):
Diwan, A. (2016). Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications. (Doctoral Dissertation). Brigham Young University. Retrieved from https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7204&context=etd
Chicago Manual of Style (16th Edition):
Diwan, Anubhav. “Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications.” 2016. Doctoral Dissertation, Brigham Young University. Accessed March 04, 2021.
https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7204&context=etd.
MLA Handbook (7th Edition):
Diwan, Anubhav. “Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications.” 2016. Web. 04 Mar 2021.
Vancouver:
Diwan A. Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications. [Internet] [Doctoral dissertation]. Brigham Young University; 2016. [cited 2021 Mar 04].
Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7204&context=etd.
Council of Science Editors:
Diwan A. Novel Sputtered Stationary Phases for Solid Phase Microextraction, and Other Coatings and Materials for Surface Applications. [Doctoral Dissertation]. Brigham Young University; 2016. Available from: https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=7204&context=etd
University of Manitoba
28.
Li, Wenyan.
Properties of layer-by-layer single-cell encapsulation and the potential applications in transplantation therapy for neurologic disorders.
Degree: Human Anatomy and Cell Science, 2018, University of Manitoba
URL: http://hdl.handle.net/1993/33684
► Layer-by-layer (LbL) self-assembly is a rapidly developing biomaterial technique for fabricating multilayered structure on substrates. In this project, we report the encapsulation of single neural…
(more)
▼ Layer-by-
layer (LbL) self-assembly is a rapidly developing biomaterial technique for fabricating multilayered structure on substrates. In this project, we report the encapsulation of single neural stem cells (NSCs) using the LbL self-assembly technique with gelatin and alginate. The encapsulation did not affect normal functions of the encapsulated NSCs. When insulin-like growth factor-1 was loaded on materials, its release significantly enhanced the proliferation of the encapsulated NSCs.
Permeability of the LbL encapsulation was investigated on PC12 cells encapsulated with gelatin and hyaluronic acid (HA). The permeability was inversely proportional to molecular weight of FITC-dextran (FD), material concentration, and number of layers. Encapsulation with 0.5% of the materials for 8 layers was proven to effectively inhibit the cell apoptosis induced by tumor necrosis factor-α (TNF-α).
Since the encapsulation structure creates a favorable microenvironment for cells to survive and function, it holds significant potential for cell therapies for neurologic disorders.
Advisors/Committee Members: Kong, Jiming (Human Anatomy and Cell Science) (supervisor), Xing, Malcolm (Mechanical Engineering) Marzban, Hassan (Human Anatomy and Cell Science) Gong, Yuewen (Pharmacy) Song, Weihong (University of British Columbia) (examiningcommittee).
Subjects/Keywords: Layer-by-layer; Cell encapsulation; Drug delivery; Permeability; Microenvironment regulation
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APA (6th Edition):
Li, W. (2018). Properties of layer-by-layer single-cell encapsulation and the potential applications in transplantation therapy for neurologic disorders. (Thesis). University of Manitoba. Retrieved from http://hdl.handle.net/1993/33684
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Li, Wenyan. “Properties of layer-by-layer single-cell encapsulation and the potential applications in transplantation therapy for neurologic disorders.” 2018. Thesis, University of Manitoba. Accessed March 04, 2021.
http://hdl.handle.net/1993/33684.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Li, Wenyan. “Properties of layer-by-layer single-cell encapsulation and the potential applications in transplantation therapy for neurologic disorders.” 2018. Web. 04 Mar 2021.
Vancouver:
Li W. Properties of layer-by-layer single-cell encapsulation and the potential applications in transplantation therapy for neurologic disorders. [Internet] [Thesis]. University of Manitoba; 2018. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1993/33684.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Li W. Properties of layer-by-layer single-cell encapsulation and the potential applications in transplantation therapy for neurologic disorders. [Thesis]. University of Manitoba; 2018. Available from: http://hdl.handle.net/1993/33684
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Université Catholique de Louvain
29.
Ramirez Wong, Diana Guadalupe.
Brushes of self-assembled nanotubes for temperature-responsive biocatalysis.
Degree: 2014, Université Catholique de Louvain
URL: http://hdl.handle.net/2078.1/151206
► Inspired by the elegant solutions that Nature has provided to control and promote specific site-reactions, my work presents an attempt to mimic filamentous biocatalytic interfaces.…
(more)
▼ Inspired by the elegant solutions that Nature has provided to control and promote specific site-reactions, my work presents an attempt to mimic filamentous biocatalytic interfaces. Brushes of self-assembled nanotubes with an enzymatic component (beta-lactamase) were prepared taking advantage of preexisting nanofabrication techniques, such as layer-by-layer and hard-templating. First, the effects of geometrical confinement and its consequences were investigated by comparison of (chitosan/beta-lactamase) multilayer film assembly on flat surfaces and in nanoporous membranes. In a second stage, polyelectrolyte nanotubes with controlled dimensions were prepared in nanoporous membranes and further anchored on a surface by chemical crosslinking to obtain brushes of nanotubes. The kinetic studies revealed the presence of active enzyme in the brushes and enhanced activity preservation when beta-lactamase was deposited as the inner layers of the nanotubes. As a final step, a variety of thermo-responsive coatings with different architectures were tested to control substrate diffusion on top of beta-lactamase-based multilayer films. The integration of stable thermo-responsive elements was proven, although further experiments are required to control biocatalysis with additional layers and using more complex mechanisms, such as coupled thermal and mechanical responses. Knowing that there are more challenges to face before reaching optimum nanotube brushes and apply them for controlled biocatalysis, this study contributes with some elements that may pave the way towards the integration of different techniques for the fabrication of complex biocatalytic nanostructures.
(FSA - Sciences de l) – UCL, 2014
Advisors/Committee Members: UCL - SST/IMCN/BSMA - Bio and soft matter, UCL - Ecole Polytechnique de Louvain, Jonas, Alain M., Demoustier-Champagne, Sophie, Bonhomme, Christian, Devaux, Jacques, Dupont, Christine, Labbé, Pierre, Lavalle, Philippe, Tran, Yvette.
Subjects/Keywords: PNIPAM; Layer-by-layer; Nanostructures; Enzyme; Membrane-templating
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APA (6th Edition):
Ramirez Wong, D. G. (2014). Brushes of self-assembled nanotubes for temperature-responsive biocatalysis. (Thesis). Université Catholique de Louvain. Retrieved from http://hdl.handle.net/2078.1/151206
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Ramirez Wong, Diana Guadalupe. “Brushes of self-assembled nanotubes for temperature-responsive biocatalysis.” 2014. Thesis, Université Catholique de Louvain. Accessed March 04, 2021.
http://hdl.handle.net/2078.1/151206.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Ramirez Wong, Diana Guadalupe. “Brushes of self-assembled nanotubes for temperature-responsive biocatalysis.” 2014. Web. 04 Mar 2021.
Vancouver:
Ramirez Wong DG. Brushes of self-assembled nanotubes for temperature-responsive biocatalysis. [Internet] [Thesis]. Université Catholique de Louvain; 2014. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2078.1/151206.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Ramirez Wong DG. Brushes of self-assembled nanotubes for temperature-responsive biocatalysis. [Thesis]. Université Catholique de Louvain; 2014. Available from: http://hdl.handle.net/2078.1/151206
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Melbourne
30.
SHIMONI, OLGA.
Poly(methacrylic acid) hydrogel capsules as a platform for biomedical applications.
Degree: 2012, University of Melbourne
URL: http://hdl.handle.net/11343/37577
► The design and assembly of biocompatible nanoengineered carriers is of interest due to their potential applications in biotechnology as tools for catalysis and sensing, in…
(more)
▼ The design and assembly of biocompatible nanoengineered carriers is of interest due to their potential applications in biotechnology as tools for catalysis and sensing, in biomedicine as systems for drug delivery, in diagnostics, and in vivo imaging. The layer-by-layer (LbL) technology is a prominent technique to design carrier systems for biomedical applications. In recent years, poly(methacrylic acid) hydrogel capsules (PMA HCs), based on disulfide-stabilized poly(methacrylic acid), have been fabricated from the LbL technique, and thoroughly studied to gain control over their stability, degradability and cargo release. These capsules are obtained by the sequential deposition of thiolated poly(methacrylic acid) (PMASH) and poly(N-vinylpyrrolidone) (PVPON) onto silica particles via hydrogen bonding. Upon controlled crosslinking and removal of the silica template, PVPON is released at physiological conditions due to the disrupted hydrogen bonding between PMASH and PVPON, which results in single-component PMA hydrogel capsules. This work provides an insight into designing a novel architecture and biofunctionalization of PMA HCs for enhanced and targeted drug delivery. Specifically, this research describes novel hydrogel capsule architectures, namely subcompartmentalized hydrogel capsules (SHCs), which are designed for potential applications in drug delivery and microencapsulated biocatalysis. Examples of SHCs with tens of subcompartments are demonstrated with their successful drug/cargo loading, as well as selective degradation of the SHC carrier and/or sub-units in response to multiple chemical stimuli.
To develop a facile surface functionalization approach of the PMA hydrogel capsules, retention of PVPON was employed through modification of the polymer to obtain a bifunctional polymeric linker. The antibody-functionalized PMA/PVPON HCs demonstrate significantly enhanced cellular binding and internalization to specific cells, suggesting these capsules can specifically interact with cells through antibody/antigen recognition.
To understand the impact of aspect ratio on cellular function, PMA HCs were prepared with various aspect ratios. Careful control over aspect ratio of the silica rods provided the ability to control the aspect ratio of the PMA HCs. Upon incubation of these capsules with living cells, varied behavior was observed, suggesting different mechanisms for their interactions with cells.
Subjects/Keywords: layer-by-layer; polymer hydrogel capsules; drug delivery; microreactors
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APA (6th Edition):
SHIMONI, O. (2012). Poly(methacrylic acid) hydrogel capsules as a platform for biomedical applications. (Doctoral Dissertation). University of Melbourne. Retrieved from http://hdl.handle.net/11343/37577
Chicago Manual of Style (16th Edition):
SHIMONI, OLGA. “Poly(methacrylic acid) hydrogel capsules as a platform for biomedical applications.” 2012. Doctoral Dissertation, University of Melbourne. Accessed March 04, 2021.
http://hdl.handle.net/11343/37577.
MLA Handbook (7th Edition):
SHIMONI, OLGA. “Poly(methacrylic acid) hydrogel capsules as a platform for biomedical applications.” 2012. Web. 04 Mar 2021.
Vancouver:
SHIMONI O. Poly(methacrylic acid) hydrogel capsules as a platform for biomedical applications. [Internet] [Doctoral dissertation]. University of Melbourne; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/11343/37577.
Council of Science Editors:
SHIMONI O. Poly(methacrylic acid) hydrogel capsules as a platform for biomedical applications. [Doctoral Dissertation]. University of Melbourne; 2012. Available from: http://hdl.handle.net/11343/37577
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