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Georgia Tech
1.
Sepcic, Kelly Hall.
Quantification of volatile compounds in degraded engine oil.
Degree: PhD, Chemistry and Biochemistry, 2003, Georgia Tech
URL: http://hdl.handle.net/1853/5373 
Subjects/Keywords: Petroleum as fuel; Decomposition (Chemistry); Automobiles Fuel systems; Petroleum as fuel; Decomposition (Chemistry); Automobiles Fuel systems
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APA (6th Edition):
Sepcic, K. H. (2003). Quantification of volatile compounds in degraded engine oil. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/5373
Chicago Manual of Style (16th Edition):
Sepcic, Kelly Hall. “Quantification of volatile compounds in degraded engine oil.” 2003. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/5373.
MLA Handbook (7th Edition):
Sepcic, Kelly Hall. “Quantification of volatile compounds in degraded engine oil.” 2003. Web. 27 Jan 2021.
Vancouver:
Sepcic KH. Quantification of volatile compounds in degraded engine oil. [Internet] [Doctoral dissertation]. Georgia Tech; 2003. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/5373.
Council of Science Editors:
Sepcic KH. Quantification of volatile compounds in degraded engine oil. [Doctoral Dissertation]. Georgia Tech; 2003. Available from: http://hdl.handle.net/1853/5373
2.
Truax, Stuart.
A microscale chemical sensor platform for environmental monitoring.
Degree: PhD, Electrical and Computer Engineering, 2011, Georgia Tech
URL: http://hdl.handle.net/1853/45780
► The objective of this research is to apply micromachined silicon-based resonant gravimetric sensors to the detection of gas-phase volatile organic compounds (VOCs). This is done…
(more)
▼ The objective of this research is to apply micromachined silicon-based resonant
gravimetric sensors to the detection of gas-phase volatile organic compounds (VOCs). This
is done in two primary tasks: 1) the optimization and application of silicon disk resonators
to the detection of gas-phase VOCs, and 2) the development and application of a novel
gravimetric-capacitive multisensor platform for the detection of gas-phase VOCs.
In the rst task, the design and fabrication of a silicon-based disk resonator structure
utilizing an in-plane resonance mode is undertaken. The resonance characteristics of the
disk resonator are characterized and optimized. The optimized characteristics include the
resonator Q-factor as a function of geometric parameters, and the dynamic displacement
of the in-plane resonance mode. The Q-factors of the disk resonators range from 2600 to
4360 at atmosphere for disk silicon thicknesses from 7 µm to 18 µm, respectively.
The resonance frequency of the in-plane resonance mode ranges from 260 kHz up to 750 kHz.
The disk resonators are applied to the sensing of gas-phase VOCs using (poly)isobutylene
as a sensitive layer. Limits of detection for benzene, toluene and m-xylene vapors of 5.3
ppm, 1.2 ppm, and 0.6 ppm are respectively obtained. Finally, models for the limits of
detection and chemical sensitivity of the resonator structures are developed for the case of
the polymer layers used.
In the second task, a silicon-based resonator is combined with a capacitive structure
to produce a multisensor structure for the sensing of gas-phase VOCs. Fabrication of the
multisensor structure is undertaken, and the sensor is theoretically modeled. The baseline
capacitance of the capacitor component of the multisensor is estimated to be 170 fF. Finally,
initial VOC detection results for the capacitive aspect of the sensor are obtained.
Advisors/Committee Members: Oliver Brand (Committee Chair), Bernard Kippelen (Committee Member), Jiri Janata (Committee Member), Mark Allen (Committee Member), William Hunt (Committee Member).
Subjects/Keywords: Chemical sensor; Gas sensor; Resonator; Microresonator; Gravimetry; Volatile organic compounds; MEMS; Silicon; Q-factor; Capacitive sensor; Multisensor; PIB; Toluene; Polymer; In-plane; High Q; Environmental monitoring; Chemical detectors; Gas detectors
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APA (6th Edition):
Truax, S. (2011). A microscale chemical sensor platform for environmental monitoring. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/45780
Chicago Manual of Style (16th Edition):
Truax, Stuart. “A microscale chemical sensor platform for environmental monitoring.” 2011. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/45780.
MLA Handbook (7th Edition):
Truax, Stuart. “A microscale chemical sensor platform for environmental monitoring.” 2011. Web. 27 Jan 2021.
Vancouver:
Truax S. A microscale chemical sensor platform for environmental monitoring. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/45780.
Council of Science Editors:
Truax S. A microscale chemical sensor platform for environmental monitoring. [Doctoral Dissertation]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/45780
3.
West, Ryan Matthew.
Work function fluctuation analysis of polyaniline films.
Degree: PhD, Chemistry and Biochemistry, 2013, Georgia Tech
URL: http://hdl.handle.net/1853/47586
► In this thesis, the development of a novel experimental technique for measuring the spontaneous, stochastic work function (WF) fluctuations of conducting polymer films, at equilibrium,…
(more)
▼ In this thesis, the development of a novel experimental technique for measuring the spontaneous, stochastic work function (WF) fluctuations of conducting polymer films, at equilibrium, is discussed. Polyaniline (PANI) is studied as a representative conducting polymer. This technique utilizes an insulated-gate field-effect transistor (IGFET) with PANI gate electrode (PANI-IGFET). The fluctuations of PANI WF are transduced into measurable drain current fluctuations of the device. By analyzing these fluctuations while systematically controlling the temperature, electric field and doping level, a model of WF fluctuations in PANI films is developed. These experiments suggest that the source of WF fluctuations is the hopping of charge carriers, or trapping/detrapping of charge carriers, around the Fermi level of the PANI film at the PANI-insulator interface. This process is thermally activated with a field and doping dependent activation energy in the range of 0.1 to 0.5 eV. Thus, this new technique provides detailed information about charge-carrier dynamics in the space-charge region of the PANI film, at equilibrium. These results have important implications for organic electronics and furthering fundamental understanding of the relationship between doping, disorder and work function in organic semiconductors.
Advisors/Committee Members: Jiri Janata (Committee Chair), christine payne (Committee Member), Larry Bottomley (Committee Member), mira josowicz (Committee Member), steve harvey (Committee Member).
Subjects/Keywords: Noise; Field-effect transistor; Statistical mechanics; Polyaniline; Conducting polymer; Conducting polymers; Organic conductors; Electrons Emission
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APA (6th Edition):
West, R. M. (2013). Work function fluctuation analysis of polyaniline films. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/47586
Chicago Manual of Style (16th Edition):
West, Ryan Matthew. “Work function fluctuation analysis of polyaniline films.” 2013. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/47586.
MLA Handbook (7th Edition):
West, Ryan Matthew. “Work function fluctuation analysis of polyaniline films.” 2013. Web. 27 Jan 2021.
Vancouver:
West RM. Work function fluctuation analysis of polyaniline films. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/47586.
Council of Science Editors:
West RM. Work function fluctuation analysis of polyaniline films. [Doctoral Dissertation]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/47586
Georgia Tech
4.
Pierce, Carrie.
High throughput mass spectrometry for microbial identification.
Degree: PhD, Chemistry and Biochemistry, 2011, Georgia Tech
URL: http://hdl.handle.net/1853/43741
► Bacteria cause significant morbidity and mortality throughout the world, including deadly diseases such as tuberculosis, meningitis, cholera, and pneumonia. Timely and accurate bacterial identification is…
(more)
▼ Bacteria cause significant morbidity and mortality throughout the world, including deadly diseases such as tuberculosis, meningitis, cholera, and pneumonia. Timely and accurate bacterial identification is critical in areas such as clinical diagnostics, environmental monitoring, food safety, water and air quality assessment, and identification of biological threat agents. At present, there is an established need for high throughput, sensitive, selective, and rapid methods for the detection of pathogenic bacteria, as existing methods, while nominally effective, have failed to sufficiently reduce the massive impact of bacterial contamination and infection. The work presented in this thesis focuses on addressing this need and augmenting conventional microorganism research through development of mass spectrometry (MS)-based proteomic applications. MS, a well established tool for addressing biological problems, offers a broad range of laboratory procedures that can be used for taxonomic classification and identification of microorganisms. These methods provide a powerful complement to many of the widely used molecular biology approaches and play critical functions in various fields of science. While implementation of modern biomolecule-identifying instrumentation, such as MS, has long been postulated to have a role in the microbiology laboratory, it has yet to be accepted on a large scale. Described in this document are MS methods that erect strong foundations on which new bacterial diagnostics may be based. A general introduction on key aspects of this work is presented in Chapter 1, where different approaches for detection of pathogenic bacteria are reviewed, and an overview regarding MS and microbial identification is provided. Chapter 2 presents the first implementation of microbial identification via rapid, open air Direct Analysis in Real Time MS (DART MS) to generate ions directly from microbial samples, including the disease-causing bacteria, Coxiella burnetii, Streptococcus pyogenes, and Escherichia coli. Chapter 3 expands on whole cell C. burnetii MS analysis and presents a rapid differentiation method to the strain-level for C. burnetii using mass profiling/fingerprinting matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS and multivariate pattern recognition. Chapter 4 presents a unique "top-down" proteomics approach using 15N-labeled bacteriophage amplification coupled with MALDI-TOF MS as a detector for the rapid and selective identification of Staphylococcus aureus. Chapter 5 extends the idea of using isotopically labeled bacteriophage amplification by implementing a "bottom-up" proteomics approach that not only identifies S. aureus in a sample, but also quantifies the bacterial concentration in the sample using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS) as a detector. In conclusion, Chapter 6, summarizes and contextualizes the work presented in this dissertation, and outlines how future research can build upon the experimentation detailed…
Advisors/Committee Members: Facundo M. Fernandez (Committee Chair), Al Merrill (Committee Member), Christine Payne (Committee Member), Jiri Janata (Committee Member), John R. Barr (Committee Member), Larry Bottomley (Committee Member).
Subjects/Keywords: Bacteriophage; Mass spectrometry; Bacteria; Proteomics; Microorganism; Pathogenic bacteria; Bacteriophages; Mass spectrometry Forensic applications; Microorganisms Detection
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APA (6th Edition):
Pierce, C. (2011). High throughput mass spectrometry for microbial identification. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/43741
Chicago Manual of Style (16th Edition):
Pierce, Carrie. “High throughput mass spectrometry for microbial identification.” 2011. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/43741.
MLA Handbook (7th Edition):
Pierce, Carrie. “High throughput mass spectrometry for microbial identification.” 2011. Web. 27 Jan 2021.
Vancouver:
Pierce C. High throughput mass spectrometry for microbial identification. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/43741.
Council of Science Editors:
Pierce C. High throughput mass spectrometry for microbial identification. [Doctoral Dissertation]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/43741
5.
Smith, Michael Hughes.
The design of multifunctional hydrogel nanoparticles for drug delivery.
Degree: PhD, Chemistry and Biochemistry, 2012, Georgia Tech
URL: http://hdl.handle.net/1853/43609
► Hydrogel micro- and nanoparticles (microgels and nanogels) are a promising class of drug delivery vehicles. Composed of hydrophilic polymers arranged into a cross-linked network structure,…
(more)
▼ Hydrogel micro- and nanoparticles (microgels and nanogels) are a promising class of drug delivery vehicles. Composed of hydrophilic polymers arranged into a cross-linked network structure, nanogels show several attractive features for the delivery of macromolecule therapeutics. For instance, the hydrated, porous internal cavity of the nanogel may serve as a high capacity compartment for loading macromolecules, whereas the periphery of the nanogel may be used as a scaffold for conjugating cell-specific targeting moieties. This dissertation presents recent investigations of nanogels as targeted delivery vehicles for oligonucleotides to cancer cells, while exploring new nanogel chemistries that enable future in vivo applications. For instance, synthetic efforts have produced particles capable of erosion into low molar mass constituents, providing a possible mechanism of particle clearance after repeated administration in vivo. In another example, the microgel network chemistry was tuned to promote the encapsulation of charged proteins. In parallel with those synthetic efforts, new light scattering methodologies were developed to accurately quantify the particle behaviors (e.g. loading, erosion). Using multiangle light scattering (MALS), changes in particle molar mass and radius were measured, providing a quantitative and direct approach for monitoring nanogel erosion and macromolecule encapsulation. The new particle chemistries demonstrated, together with enabling light scattering methods, will catalyze the development of improved delivery vehicles in the near future.
Advisors/Committee Members: Professor L. Andrew Lyon (Committee Chair), Professor Anselm Griffin (Committee Member), Professor Facundo Fernandez (Committee Member), Professor Jiri Janata (Committee Member), Professor Robert Dickson (Committee Member).
Subjects/Keywords: Light scattering; SiRNA; RNA interference; Microgel; Drug delivery; Hydrogel particle; Nanogel; Drug delivery systems; Nanogels; Colloids; Nanostructured materials
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APA (6th Edition):
Smith, M. H. (2012). The design of multifunctional hydrogel nanoparticles for drug delivery. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/43609
Chicago Manual of Style (16th Edition):
Smith, Michael Hughes. “The design of multifunctional hydrogel nanoparticles for drug delivery.” 2012. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/43609.
MLA Handbook (7th Edition):
Smith, Michael Hughes. “The design of multifunctional hydrogel nanoparticles for drug delivery.” 2012. Web. 27 Jan 2021.
Vancouver:
Smith MH. The design of multifunctional hydrogel nanoparticles for drug delivery. [Internet] [Doctoral dissertation]. Georgia Tech; 2012. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/43609.
Council of Science Editors:
Smith MH. The design of multifunctional hydrogel nanoparticles for drug delivery. [Doctoral Dissertation]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/43609
6.
Luzinova, Yuliya.
Mid-infrared sensors for hydrocarbon analysis in extreme environments.
Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/41156
► A number of MIR sensing platforms and methods were developed in this research work demonstrating potential applicability of MIR spectroscopy for studying hydrocarbon systems in…
(more)
▼ A number of MIR sensing platforms and methods were developed in this research work demonstrating potential applicability of MIR spectroscopy for studying hydrocarbon systems in extreme environments.
First of all, the quantitative determination of the diamondoid compound adamantane in organic media utilizing IR-ATR spectroscopy at waveguide surfaces was established. The developed analytical strategy further enabled the successful detection of adamantane in real world crude oil samples. These reported efforts provide a promising outlook for detection and monitoring of diamondoid constituents in naturally occurring crudes and petroleum samples.
IR-ATR spectroscopy was further utilized for evaluating and characterizing distribution, variations, and origin of carbonate minerals within sediment formations surrounding a hydrocarbon seep site - MC 118 in the Gulf of Mexico. An analytical model for direct detection of 13C-depleted authigenic carbonates associated with cold seep ecosystems was constructed. Potential applicability of IR-ATR spectroscopy as direct on-ship - and in future in situ - analytical tool for characterizing hydrocarbon seep sites was demonstrated.
MIR evanescent field absorption spectroscopy was also utilized to expand the understanding on the role of surfactants during gas hydrate formation at surfaces. This experimental method allowed detailed spectroscopic observations of detergent-related surface processes during SDS mediated gas hydrate formation. The obtained IR data enabled proposing a mechanism by which SDS decreases the induction time for hydrate nucleation, and promotes hydrate formation. Potential of MIR fiberoptic evanescent field spectroscopy for studying surface effects during gas hydrate nucleation and growth was demonstrated.
Next, quantifying trace amounts of water content in hexane using MIR evanescent field absorption spectroscopy is presented. The improvement in sensitivity and of limit of detection was obtained by coating an optical fiber with layer of a hydrophilic polymer. The application of the polymer layer has enabled the on-line MIR detection of water in hexane at low ppm levels. These results indicate that the MIR evanescent filed spectroscopy method shows potential for in-situ detection and monitoring of water in industrial oils and petroleum products.
Finally, quantification of trace amounts of oil content in water using MIR evanescent field absorption spectroscopy is reported. Unmodified and modified with grafted hydrophobic polymer layer silver halide optical fibers were employed for the measurements. The surface modification of the fiber has enabled the on-line MIR analysis of crude oil in water at the low ppb level. Potential application of MIR fiber-optic evanescent field spectroscopy using polymer modified waveguides toward in-situ low level detection of crude oil in open waters was demonstrated.
Advisors/Committee Members: Boris Mizaikoff (Committee Chair), Thomas Orlando (Committee Co-Chair), Facundo Fernandez (Committee Member), Jiri Janata (Committee Member), Oliver Brand (Committee Member), Seong-Soo Kim (Committee Member).
Subjects/Keywords: MIR spectroscopy; IR-ATR spectroscopy; Diamondoids; Gas hydrates; Water-crude oil emulsions; MIR sensing platforms; Hydrocarbons; Infrared detectors; Infrared technology
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APA (6th Edition):
Luzinova, Y. (2010). Mid-infrared sensors for hydrocarbon analysis in extreme environments. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/41156
Chicago Manual of Style (16th Edition):
Luzinova, Yuliya. “Mid-infrared sensors for hydrocarbon analysis in extreme environments.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/41156.
MLA Handbook (7th Edition):
Luzinova, Yuliya. “Mid-infrared sensors for hydrocarbon analysis in extreme environments.” 2010. Web. 27 Jan 2021.
Vancouver:
Luzinova Y. Mid-infrared sensors for hydrocarbon analysis in extreme environments. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/41156.
Council of Science Editors:
Luzinova Y. Mid-infrared sensors for hydrocarbon analysis in extreme environments. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/41156
Georgia Tech
7.
Ellis, Lisa Marie.
Oil monitoring with an optically stimulated contact potential difference sensor.
Degree: MS, Mechanical Engineering, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/5021
► This thesis utilized the concept of an optically stimulated Contact Potential Difference (osCPD) sensor to monitor oil properties. The osCPD technique is a variant of…
(more)
▼ This thesis utilized the concept of an optically stimulated Contact Potential Difference (osCPD) sensor to monitor oil properties. The osCPD technique is a variant of the contact potential difference (CPD) method used to obtain surface properties of materials. The technique uses modulated light to stimulate electron charge carriers in silicon coated with a layer of oil. Demonstration of this oil monitoring design was done by placing different oil samples on the silicon surface and monitoring the corresponding electrical signal with the osCPD sensor.
Experiments showed that the osCPD sensor produced an electrical signal that was related to the amount of time an oil sample was aged in an engine (or mileage). Further, a linear relationship was found between the relative conductivity of these oils and the osCPD signal. It is theorized that this osCPD signal is dependant on the charge transfer at the silicon and oil interface. Investigation of this interaction was carried out. Experiments showed that adding a silicon nitride passivation layer on the silicon surface eliminated the change in osCPD signal with oil properties. A model of this charge interaction was developed.
Advisors/Committee Members: Steven Danyluk (Committee Chair), Jiri Janata (Committee Member), Shreyes Melkote (Committee Member).
Subjects/Keywords: Contact potential difference; Oil monitoring
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APA (6th Edition):
Ellis, L. M. (2004). Oil monitoring with an optically stimulated contact potential difference sensor. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/5021
Chicago Manual of Style (16th Edition):
Ellis, Lisa Marie. “Oil monitoring with an optically stimulated contact potential difference sensor.” 2004. Masters Thesis, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/5021.
MLA Handbook (7th Edition):
Ellis, Lisa Marie. “Oil monitoring with an optically stimulated contact potential difference sensor.” 2004. Web. 27 Jan 2021.
Vancouver:
Ellis LM. Oil monitoring with an optically stimulated contact potential difference sensor. [Internet] [Masters thesis]. Georgia Tech; 2004. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/5021.
Council of Science Editors:
Ellis LM. Oil monitoring with an optically stimulated contact potential difference sensor. [Masters Thesis]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/5021
Georgia Tech
8.
Vega, Jose A.
Electrochemical comparison and deposition of lithium and potassium from phosphonium- and ammonium-tfsi ionic liquids.
Degree: MS, Chemical Engineering, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/28223
► In this work, ionic liquids (ILs) were investigated for use as battery electrolytes. The ILs were synthesized from quaternary ammonium and phosphonium salts and TFSI-.…
(more)
▼ In this work, ionic liquids (ILs) were investigated for use as battery electrolytes. The ILs were synthesized from quaternary ammonium and phosphonium salts and TFSI-. A dendrite free lithium metal anode was demonstrated by deposition of a lithium-potassium alloy.
Several phosphonium ILs were synthesized using the TFSI- and PF6- anions until a room temperature IL was obtained. The smaller size, highly symmetric PF6- anion yielded high melting point salts, while TFSI- yielded much lower melting point ILs. When a room temperature IL, Bu3HexP+TFSI-, was obtained the analogous ammonium IL, Bu3HexP+TFSI-, was synthesized and compared. The phosphonium-based ionic liquid showed improved stability and physical properties compared to the analogous ammonium-based IL. The phosphonium-based IL had higher conductivity, 0.43 mS/cm, than the ammonium-based IL, 0.28 mS/cm. The addition of LiTFSI to both ILs led to a decrease in conductivity and increase in viscosity. The lower viscosity and higher stability of the phosphonium-based IL led to higher current density and stability for electrodeposited lithium metal. IL reduction interfered with lithium deposition reflecting lower coulombic efficiencies and giving the appearance of an unstable lithium couple. An optimum deposition potential was found which was bounded by the electrochemical stability of each IL. The stability of lithium in the ILs increased at lower temperature due to slower reactivity with the IL. Addition of higher quantities of lithium ions caused a higher fraction of the cathodic current going to lithium deposition that was reoxidized. The stability of lithium in the ILs increased at lower temperature due to slower reactivity with the IL.
The electrodeposition and reoxidation of potassium was also demonstrated. Deposition of a lithium-potassium alloy caused slight increases in the cathodic and anodic currents along with higher coulombic efficiencies. Also, it was found that a lithium-potassium alloy could be deposited at high current for long times without the occurrence of dendrites.
Advisors/Committee Members: Paul Kohl (Committee Chair), Jiri Janata (Committee Member), Tom Fuller (Committee Member).
Subjects/Keywords: Alloy deposition; Dendrites; Phosphonium; Ammonium; Ionic liquids; Ionic solutions; Electrolytes; Lithium
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APA (6th Edition):
Vega, J. A. (2009). Electrochemical comparison and deposition of lithium and potassium from phosphonium- and ammonium-tfsi ionic liquids. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/28223
Chicago Manual of Style (16th Edition):
Vega, Jose A. “Electrochemical comparison and deposition of lithium and potassium from phosphonium- and ammonium-tfsi ionic liquids.” 2009. Masters Thesis, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/28223.
MLA Handbook (7th Edition):
Vega, Jose A. “Electrochemical comparison and deposition of lithium and potassium from phosphonium- and ammonium-tfsi ionic liquids.” 2009. Web. 27 Jan 2021.
Vancouver:
Vega JA. Electrochemical comparison and deposition of lithium and potassium from phosphonium- and ammonium-tfsi ionic liquids. [Internet] [Masters thesis]. Georgia Tech; 2009. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/28223.
Council of Science Editors:
Vega JA. Electrochemical comparison and deposition of lithium and potassium from phosphonium- and ammonium-tfsi ionic liquids. [Masters Thesis]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/28223
Georgia Tech
9.
Mess, Francis McCarthy.
A Novel Sensor to Monitor Surface Charge Interactions: The Optically Stimulated Contact Potential Difference Probe.
Degree: PhD, Mechanical Engineering, 2006, Georgia Tech
URL: http://hdl.handle.net/1853/10460
► This study addresses the development of a sensor to monitor chemical adsorption and charge transfer processes on a surface using a contact potential difference probe…
(more)
▼ This study addresses the development of a sensor to monitor chemical adsorption and charge transfer processes on a surface using a contact potential difference probe (CPD). The current investigation is an outgrowth of ongoing research on non-vibrating CPD probes (nvCPD) which led to the recent development of a novel measurement technique utilizing optical stimulation: optically stimulated CPD (osCPD). Primary outcomes of this thesis are the theoretical modeling, fabrication and demonstration of a functional osCPD sensor. The research also involved significant engineering and experimentation in the design, development, and application of this sensor to oil condition monitoring.
This technique measures dielectric and chemical properties of a fluid at the interface between the fluid and a semiconductor substrate. Chopped visible light is used to stimulate the rear surface of a semiconductor substrate, and a CPD probe measures the work function response of the semiconductor on the front surface of the substrate. The work function response is influenced by the nature and quantity of adsorbed species on the top surface, allowing the probe to detect changes in chemical composition at the substrate/fluid interface.
An analytical model is developed that relates the osCPD sensor output signal to the chemical and dielectric properties of the oil sample, as well as to the geometry, composition, and control inputs of the silicon substrate and test fixture. In this investigation, the osCPD sensor was used to evaluate dielectric and chemical properties of commercially available engine oil. Oil samples were intentionally degraded through thermal aging (oxidation) and through addition of known contaminants. The osCPD sensor shows good sensitivity to depletion of antioxidants in the oil, as well as to the presence of ferric chloride, an oil-soluble salt typically used to calibrate laboratory test equipment.
Advisors/Committee Members: Steven Danyluk (Committee Chair), Ajeet Rohatgi (Committee Member), Jiri Janata (Committee Member), Peter Hesketh (Committee Member), Thomas Kurfess (Committee Member).
Subjects/Keywords: Kelvin probe; Volta effect; Probes (Electronic instruments) Design and construction
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APA (6th Edition):
Mess, F. M. (2006). A Novel Sensor to Monitor Surface Charge Interactions: The Optically Stimulated Contact Potential Difference Probe. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/10460
Chicago Manual of Style (16th Edition):
Mess, Francis McCarthy. “A Novel Sensor to Monitor Surface Charge Interactions: The Optically Stimulated Contact Potential Difference Probe.” 2006. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/10460.
MLA Handbook (7th Edition):
Mess, Francis McCarthy. “A Novel Sensor to Monitor Surface Charge Interactions: The Optically Stimulated Contact Potential Difference Probe.” 2006. Web. 27 Jan 2021.
Vancouver:
Mess FM. A Novel Sensor to Monitor Surface Charge Interactions: The Optically Stimulated Contact Potential Difference Probe. [Internet] [Doctoral dissertation]. Georgia Tech; 2006. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/10460.
Council of Science Editors:
Mess FM. A Novel Sensor to Monitor Surface Charge Interactions: The Optically Stimulated Contact Potential Difference Probe. [Doctoral Dissertation]. Georgia Tech; 2006. Available from: http://hdl.handle.net/1853/10460
Georgia Tech
10.
Charlton, Christy.
Quantum Cascade Lasers for Mid-Infrared Chemical Sensing.
Degree: PhD, Chemistry and Biochemistry, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/13953
► The mid-infrared (MIR) spectral range (2-20 m) is particularly useful for chemical sensing due to the excitation of fundamental rotational and vibrational modes. In the…
(more)
▼ The mid-infrared (MIR) spectral range (2-20 m) is particularly useful for chemical sensing due to the excitation of fundamental rotational and vibrational modes. In the fingerprint region (10-20 m), most organic analytes have unique absorption patterns; absorption measurements in this region provide molecule-specific information with high sensitivity.
Quantum cascade lasers (QCLs) present an ideal light source for (MIR) chemical sensing due to their narrow linewidth, high spectral density, compact size, and ease of fabrication of nearly any MIR wavelength. As the emission wavelength is dependent on layer size within the heterostructure rather than material composition, various wavelengths in the MIR can be achieved through bandstructure engineering.
High sensitivity measurements have been achieved in both gas and liquid phase by developing integrated sensing systems. The laser emission frequency is selected to match a strong absorption feature for the analyte of interest where no other interfering bands are located. A waveguide is then developed to fit the application and wavelength used.
Gas sensing applications incorporate silica hollow waveguides (HWG) and an OmniGuide fiber (or photonic bandgap HWG). Analyte gas is injected into the hollow core allowing the HWG or OmniGuide to serve simultaneously as a waveguide and miniaturized gas cell. Sensitivities of parts per billion are achieved with a response time of 8 s and a sample volume of approximately 1 mL.
Liquid sensing is achieved via evanescent wave measurements with planar waveguides of silver halide (AgX) and gallium arsenide (GaAs). GaAs waveguides developed in this work have a thickness on the order of the wavelength of light achieving single-mode waveguides, providing a significant improvement in evanescent field strength over conventional multimode fibers. Liquid samples of L volume at the waveguide surfaces are detected.
QCLs have begun to be utilized as a light source in the MIR regime over the last decade. The next step in this field is the development of compact and highly integrated device platforms which take full advantage of this technology. The sensing demonstrations in this work advance the field towards finding key applications in medical, biological, environmental, and atmospheric measurements.
Advisors/Committee Members: Boris Mizaikoff (Committee Chair), Jiri Janata (Committee Member), Mohan Srinivasarao (Committee Member), Peter Hesketh (Committee Member), Thomas Orlando (Committee Member).
Subjects/Keywords: Evanescent field; Absorption; Optical; Silver halide; Planar waveguide; Photonic band gap; Hollow waveguides; Liquid phase; Gas phase
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APA (6th Edition):
Charlton, C. (2005). Quantum Cascade Lasers for Mid-Infrared Chemical Sensing. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/13953
Chicago Manual of Style (16th Edition):
Charlton, Christy. “Quantum Cascade Lasers for Mid-Infrared Chemical Sensing.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/13953.
MLA Handbook (7th Edition):
Charlton, Christy. “Quantum Cascade Lasers for Mid-Infrared Chemical Sensing.” 2005. Web. 27 Jan 2021.
Vancouver:
Charlton C. Quantum Cascade Lasers for Mid-Infrared Chemical Sensing. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/13953.
Council of Science Editors:
Charlton C. Quantum Cascade Lasers for Mid-Infrared Chemical Sensing. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/13953
Georgia Tech
11.
Steeb, Jennifer L.
Nickel-63 microirradiators and applications.
Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/34773
► In this thesis, manufacturing of microirradiators, electrodeposition of radioactive elements such as Ni-63, and applications of these radioactive sources are discussed. Ni-63 has a half…
(more)
▼ In this thesis, manufacturing of microirradiators, electrodeposition of radioactive elements such as Ni-63, and applications of these radioactive sources are discussed. Ni-63 has a half life of 100 years and a low energy beta electron of 67 keV, ideal for low dose low linear energy transfer (LET) research. The main focus of the research is on the novel Ni-63 microirradiator. It contains a small amount of total activity of radiation but a large flux, allowing the user to safely handle the microirradiator without extensive shielding. This thesis is divided into nine chapters. Properties of microirradiators and various competing radioactive sources are compared in the introduction (chapter 1). Detailed description of manufacturing Ni-63 microirradiator using the microelectrode as the starting point is outlined in chapter 2. The microelectrode is a 25 µm in diameter Pt disk sealed in a pulled 1 mm diameter borosilicate capillary tube, as a protruding wire or recessed disk microelectrode. The electrochemically active surface area of each is verified by cyclic voltammetry. Electrodeposition of nickel with a detailed description of formulation of the electrochemical bath in a cold "non-radioactive setting" was optimized by using parameters as defined by pourbaix diagrams, radioactive electroplating of Ni-63, and incorporation of safety regulations into electrodeposition. Calibration and characterization of the Ni-63 microirradiators as protruding wire and recessed disk microirradiators is presented in chapter 3. In chapters 4 through 6, applications of the Ni-63 microirradiators and wire sources are presented. Chapter 4 provides a radiobiological application of the recessed disk microirradiator and a modified flush microirradiator with osteosarcoma cancer cells. Cells were irradiated with 2000 to 1 Bq, and real time observations of DNA double strand breaks were observed. A novel benchtop detection system for the microirradiators is presented in chapter 5. Ni-63 is most commonly measured by liquid scintillation counters, which are expensive and not easily accessible within a benchtop setting. Results show liquid scintillation measurements overestimates the amount of radiation coming from the recessed disk. A novel 10 µCi Ni-63 electrochemically deposited wire acting as an ambient chemical ionization source for pharmaceutical tablets in mass spectrometry is in chapter 6. Typically, larger radioactive sources (15 mCi) of Ni-63 have been used in an ambient ionization scenario. Additionally, this is the first application of using Ni-63 to ionize in atmosphere pharmaceutical tablets, leading to a possible field portable device. In the last chapters, chapters 7 through 8, previous microirradiator experiments and future work are summarized. Chapter 7 illustrates the prototype of the electrochemically deposited microirradiator, the Te-125 microirradiator. In conjunction with Oak Ridge National Laboratory, Te-125m is a low dose x-ray emitting element determined to be the best first prototype of an electrochemically deposited…
Advisors/Committee Members: Jiri Janata (Committee Chair), Chris Wang (Committee Member), Facundo Fernandez (Committee Member), Lawrence Bottomley (Committee Member), Mira Josowicz (Committee Member).
Subjects/Keywords: Electrodeposition; Nickel-63; Microirradiator; Radiobiology; Radiation delivery; Radioisotope; Electroplating; Nickel-plating; Plating baths; Liquid scintillation counting
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APA (6th Edition):
Steeb, J. L. (2010). Nickel-63 microirradiators and applications. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/34773
Chicago Manual of Style (16th Edition):
Steeb, Jennifer L. “Nickel-63 microirradiators and applications.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/34773.
MLA Handbook (7th Edition):
Steeb, Jennifer L. “Nickel-63 microirradiators and applications.” 2010. Web. 27 Jan 2021.
Vancouver:
Steeb JL. Nickel-63 microirradiators and applications. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/34773.
Council of Science Editors:
Steeb JL. Nickel-63 microirradiators and applications. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/34773
Georgia Tech
12.
Captain, Janine Elizabeth.
Non-thermal Interactions on Low Temperature Ice and Aqueous Interfaces.
Degree: PhD, Chemistry and Biochemistry, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/6995
► Electron-impact ionization of low-temperature water ice leads to H+, H2+, and H+(H2O)n=1-8 desorption. The threshold energy for ESD of H2+ from CI and H3O+ from…
(more)
▼ Electron-impact ionization of low-temperature water ice leads to H+, H2+,
and H+(H2O)n=1-8 desorption. The threshold energy for ESD of H2+ from CI and H3O+ from PASW and ASW is 22 ± 3 eV. There is also a H2+ yield increase at 40 ± 3 eV and a 70 ± 3 eV threshold for ESD of H+(H2O)n=2-8
from PASW and ASW. H2+
production and desorption involves direct molecular elimination and reactive
scattering of an energetic proton. Both
of these channels likely involve localized two-hole one-electron and/or
two-hole final states containing 4a1, 3a1 and/or 2a1
character. The 70 eV
cluster ion threshold implicates either an initial (2a1-2)
state localized on a monomer or the presence of at least two neighboring water
molecules each containing a single hole.
The resulting correlated two-hole or two-hole, one-electron
configurations are localized within a complex and result in an intermolecular
Coulomb repulsion and cluster ion ejection.
The changes in the yields with
phase and temperature are associated with structural and physical changes in
the adsorbed water and longer lifetimes of excited state configurations
containing a1 character. The dependence
of the ESD cation yields on the local potential has
been utilized to examine the details of HCl
interactions on low temperature ice surfaces.
The addition of HCl increases cluster ion
yields from pure ice while decreasing H+ and H2+
yields. These changes reflect the
changes in the local electronic potential due to the changing bond lengths at
the surface of the ice as HCl ionizes and the
surrounding water molecules reorient to solvate the ions.
This work has been extended to
ionic solutions at higher temperatures using a liquid jet and ultraviolet
photoionization to interrogate the surface of aqueous ionic
interfaces. Desorption of protonated
water clusters and solvated sodium ion clusters were measured over a range of
concentrations from NaCl, NaBr,
and NaI solutions.
The flux dependence indicated a multiple photon process and the proposed
mechanism involves a Coulomb explosion resulting from the repulsion of nearby
ions. The surface is investigated with
regard to its importance in heterogeneous atmospheric chemistry.
Advisors/Committee Members: Thomas Orlando (Committee Chair), Boris Mizaikoff (Committee Member), Greg Huey (Committee Member), Jiri Janata (Committee Member), Paul Wine (Committee Member).
Subjects/Keywords: Ice surface; Ionic interface; Electron stimulated desorption; Liquid jet
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APA (6th Edition):
Captain, J. E. (2005). Non-thermal Interactions on Low Temperature Ice and Aqueous Interfaces. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/6995
Chicago Manual of Style (16th Edition):
Captain, Janine Elizabeth. “Non-thermal Interactions on Low Temperature Ice and Aqueous Interfaces.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/6995.
MLA Handbook (7th Edition):
Captain, Janine Elizabeth. “Non-thermal Interactions on Low Temperature Ice and Aqueous Interfaces.” 2005. Web. 27 Jan 2021.
Vancouver:
Captain JE. Non-thermal Interactions on Low Temperature Ice and Aqueous Interfaces. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/6995.
Council of Science Editors:
Captain JE. Non-thermal Interactions on Low Temperature Ice and Aqueous Interfaces. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/6995
Georgia Tech
13.
Heintz, Eva Liang-Huang.
Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles.
Degree: PhD, Chemistry and Biochemistry, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/4944
► Surface Biological Modification and Cellular Interactions of Magnetic Spinel Nanoparticles Eva Liang-Huang Heintz 191 Pages Directed by Dr. Z. John Zhang The interest in magnetic…
(more)
▼ Surface Biological Modification and Cellular Interactions of Magnetic Spinel Nanoparticles
Eva Liang-Huang Heintz
191 Pages
Directed by Dr. Z. John Zhang
The interest in magnetic nanoparticles is multi-dimensional. Fundamentally, it is important to be able to control their magnetic properties and to correlate to specific applications. In biology, magnetic nanoparticles offer promising potential as magnetic carriers or chaperones for magnetic localization and manipulation of therapeutic reagents.
The synthesis of superparamagnetic CoFe2-xSmxO4 nanoparticles and the tunability of their magnetic properties by size and composition variations are discussed. An increase in size of CoSm0.19Fe1.81O4 nanoparticles produced an increase in blocking temperature and saturation magnetization, but a non-linear coercitivity response was observed with change in size. By varying the composition, the saturation magnetization of CoFe2-xSmxO4 decreased dramatically while the coercitivity increased when compared to native cobalt spinel ferrite (CoFe2O4) nanoparticles. These results demonstrate how the magnetic properties of cobalt spinel ferrite nanoparticles can be tailored to specific applications.
Surface modifications of cobalt spinel ferrite nanoparticles facilitated the conjugation of oligonucleotides. Using a transfection reagent, CoFe2O4 ??igonucleotide conjugates were delivered into mammalian cells. Post transfection, synchronized movement of cells in response to an external magnetic field was observed. This demonstrated the possibility of magnetic manipulation and localization of therapeutic reagents coupled to CoFe2O4 magnetic nanoparticles.
Results from this thesis demonstrate the potential role of magnetic spinel nanoparticles in cell biology and will facilitate the progress towards in vivo testing.
Advisors/Committee Members: Dr. Z. John Zhang (Committee Chair), Dr. Christopher Jones (Committee Member), Dr. Jiri Janata (Committee Member), Dr. L. Andrew Lyon (Committee Member), Dr. Laren Tolbert (Committee Member).
Subjects/Keywords: Magnetic nanoparticles; Spinel ferrite; Transfection; Magnetic manipulation; Samarium; Surface modification
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APA (6th Edition):
Heintz, E. L. (2004). Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/4944
Chicago Manual of Style (16th Edition):
Heintz, Eva Liang-Huang. “Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/4944.
MLA Handbook (7th Edition):
Heintz, Eva Liang-Huang. “Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles.” 2004. Web. 27 Jan 2021.
Vancouver:
Heintz EL. Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/4944.
Council of Science Editors:
Heintz EL. Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/4944
Georgia Tech
14.
Poggi, Mark Andrew.
Interfacial and Mechanical Properties of Carbon Nanotubes: A Force Spectroscopy Study.
Degree: PhD, Chemistry and Biochemistry, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/4948
► Next generation polymer composites that utilize the high electrical conductivity and tensile strength of carbon nanotubes are of interest. To effectively disperse carbon nanotubes into…
(more)
▼ Next generation polymer composites that utilize the high electrical conductivity and tensile strength of carbon nanotubes are of interest. To effectively disperse carbon nanotubes into polymers, a more fundamental understanding of the polymer/nanotube interface is needed. This requires the development of new analytical methods and techniques for measuring the adhesion between a single molecule and the sidewalls of carbon nanotubes.
Atomic Force Microscopy is an integral tool in the characterization of materials on the nanoscale. The objectives of this research were to: 1) characterize the binding force between single molecules and the backbone of a single walled carbon nanotube (SWNT), and 2) measure and interpret the mechanical response of carbon-based nano-objects to compressive loads using an atomic force microscope.
To identify chemical moieties that bind strongly to the sidewall of the nanotubes, two experimental approaches have been explored. In the first, force volume images of SWNT paper were obtained using gold-coated AFM tips functionalized with terminally substituted alkanethiols and para-substituted arylthiols. Analysis of these images enabled quantification of the adhesive interactions between the functionalized tip and the SWNT surface. The resultant adhesive forces were shown to be dependent upon surface topography, tip shape, and the terminal group on the alkanethiol.
The mechanical response of several single- and multi-walled carbon nanotubes under compressive load was examined with an AFM. When the scanner, onto which the substrate has been mounted, was extended and retracted in a cyclic fashion, cantilever deflection, oscillation amplitude and resonant frequency were simultaneously monitored. By time-correlating cantilever resonance spectra, deflection and scanner motion, precise control over the length of nanotube in contact with the substrate, analogous to fly-fishing was achieved. This multi-parameter force spectroscopy method is applicable for testing the mechanical and interfacial properties of a wide range of nanoscale objects.
This research has led to a clearer understanding of the chemistry at the nanotube/polymer interface, as well as the mechanical response of nanoscale materials. A new force spectroscopic tool, multi-parameter force spectroscopy, should be extremely helpful in characterizing the mechanical response of a myriad of nanoscale objects and enable nanoscale devices to become a reality.
Advisors/Committee Members: Lawrence A. Bottomley (Committee Chair), Boris Mizaikoff (Committee Member), F. Levent Degertekin (Committee Member), Jiri Janata (Committee Member), Robert L. Whetten (Committee Member), Thomas M. Orlando (Committee Member).
Subjects/Keywords: Composites; Nanotube composites; Single wall carbon nanotubes; Multiwall carbon nanotubes; MPFS; Multi-parameter force spectroscopy; Force spectroscopy; Atomic force microscopy; Carbon nanotubes; Spectrum analysis; Polymeric composites; Nanotubes Mechanical properties; Carbon Mechanical properties; Atomic force microscopy
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APA (6th Edition):
Poggi, M. A. (2004). Interfacial and Mechanical Properties of Carbon Nanotubes: A Force Spectroscopy Study. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/4948
Chicago Manual of Style (16th Edition):
Poggi, Mark Andrew. “Interfacial and Mechanical Properties of Carbon Nanotubes: A Force Spectroscopy Study.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/4948.
MLA Handbook (7th Edition):
Poggi, Mark Andrew. “Interfacial and Mechanical Properties of Carbon Nanotubes: A Force Spectroscopy Study.” 2004. Web. 27 Jan 2021.
Vancouver:
Poggi MA. Interfacial and Mechanical Properties of Carbon Nanotubes: A Force Spectroscopy Study. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/4948.
Council of Science Editors:
Poggi MA. Interfacial and Mechanical Properties of Carbon Nanotubes: A Force Spectroscopy Study. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/4948
Georgia Tech
15.
Nayak, Satish Prakash.
Design, Synthesis and Characterization of Multiresponsive Microgels.
Degree: PhD, Chemistry and Biochemistry, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/6845
► This thesis is geared towards using hydrogel nanoparticles in various biotechnological applications. The polymer that was used in making these nanoparticles was poly(N-isopropylacrylamide), which is…
(more)
▼ This thesis is geared towards using hydrogel nanoparticles in various biotechnological applications. The polymer that was used in making these nanoparticles was poly(N-isopropylacrylamide), which is a thermoresponsive polymer. These particles were used in making fast responsive polymer films, which can be used in optics. It was observed that the rate of deswelling increased as the concentration of the nanoparticles in the film was increased. These particles were also used in making photoresponsive materials. In this case a photoresponsive dye (malachite green) was conjugated to these nanoparticles and in presence of light of appropriate wavelength the particles undergo a phase transition. A core/shell construct was synthesized where the core was composed of degradable cross-links and the shell of composed of non-degradable cross-links. The degradable cross-linker had vicinal diols, which can be cleaved by sodium periodate. Hence after degrading the core, hollow particles were obtained. Zwitterionic particles were made by incorporating a cationic and anionic comonomer. These microgels go from a positively charged state to zwitterionic to negatively charged state on increasing the pH. One of the important potential applications for these microgels is drug delivery. Microgels were used for targeting cancer cells. Folic acid was used as the targeting ligand. The microgels were conjugated with folic acid and were able to target cells that overexpress folate receptors. In one other application core/shell microgels were made which exhibit pore-size dependent permeation of proteins.
Advisors/Committee Members: Dr. L. Andrew Lyon (Committee Chair), Dr. Christopher W. Jones (Committee Member), Dr. Jiri Janata (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Nicholas V. Hud (Committee Member).
Subjects/Keywords: pNIPAm; Core/Shell; Nanoparticles; Hydrogels; Polymers; Thin films; Polymers Thermal properties; Polymers Optical properties; Nanoparticles Synthesis; Colloids
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APA (6th Edition):
Nayak, S. P. (2005). Design, Synthesis and Characterization of Multiresponsive Microgels. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/6845
Chicago Manual of Style (16th Edition):
Nayak, Satish Prakash. “Design, Synthesis and Characterization of Multiresponsive Microgels.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/6845.
MLA Handbook (7th Edition):
Nayak, Satish Prakash. “Design, Synthesis and Characterization of Multiresponsive Microgels.” 2005. Web. 27 Jan 2021.
Vancouver:
Nayak SP. Design, Synthesis and Characterization of Multiresponsive Microgels. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/6845.
Council of Science Editors:
Nayak SP. Design, Synthesis and Characterization of Multiresponsive Microgels. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/6845
Georgia Tech
16.
Varga, Tamas.
Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials.
Degree: PhD, Chemistry and Biochemistry, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/6905
► Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials Tamas Varga 370 pages Directed by Dr. Angus P. Wilkinson The high-pressure behavior of…
(more)
▼ Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials
Tamas Varga
370 pages
Directed by Dr. Angus P. Wilkinson
The high-pressure behavior of several negative thermal expansion materials was studied by different methods. In-situ high-pressure x-ray and neutron diffraction studies on several compounds of the orthorhombic Sc2W3O12 structure revealed an unusual bulk modulus collapse at the orthorhombic to monoclinic phase transition. In some members of the A2M3O12 family, a second phase transition and/or pressure-induced amorphization were also seen at higher pressure. The mechanism for volume contraction on compression is different from that on heating.
A combined in-situ high pressure x-ray diffraction and absorption spectroscopic study has been carried out for the first time. The pressure-induced amorphization in cubic ZrW2O8 and ZrMo2O8 was studied by following the changes in the local coordination environments of the metals. A significant change in the average tungsten coordination was found in ZrW2O8, and a less pronounced change in the molybdenum coordination in ZrMo2O8 on amorphization. A kinetically frustrated phase transition to a high-pressure crystalline phase or a kinetically hindered decomposition, are likely driving forces of the amorphization. A complementary ex-situ study confirmed the greater distortion of the framework tetrahedra in ZrW2O8, and revealed a similar distortion of the octahedra in both compounds.
The possibility of stabilizing the low thermal expansion high-temperature structure in AM2O7 compounds to lower temperatures through stuffing of ZrP2O7 was explored. Although the phase transition temperature was suppressed in MIxZr1-xMIIIxP2O7 compositions, the chemical modification employed was not successful in stabilizing the high-temperature structure to around room temperature.
An attempt has been made to control the thermal expansion properties in materials of the (MIII0.5MV0.5)P2O7-type through the choice of the metal cations and through manipulating the ordering of the cations by different heat treatment conditions. Although controlled heat treatment resulted in only short-range cation ordering, the choice of the MIII cation had a marked effect on the thermal expansion behavior of the materials.
Different grades of fluorinert were examined as pressure-transmitting media for high-pressure diffraction studies. All of the fluorinerts studied became nonhydrostatic at relatively low pressures (~1 GPa).
Advisors/Committee Members: Dr. Angus P. Wilkinson (Committee Chair), Dr. Jiri Janata (Committee Member), Dr. L. Andrew Lyon (Committee Member), Dr. Meilin Liu (Committee Member), Dr. Z. John Zhang (Committee Member).
Subjects/Keywords: Negative thermal expansion; High pressure; X-ray diffraction; X-ray absorption spectroscopy; Pressure-induced amorphization; Thermal behavior; Expansion (Heat); Materials Thermal properties; Cations
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APA (6th Edition):
Varga, T. (2005). Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/6905
Chicago Manual of Style (16th Edition):
Varga, Tamas. “Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/6905.
MLA Handbook (7th Edition):
Varga, Tamas. “Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials.” 2005. Web. 27 Jan 2021.
Vancouver:
Varga T. Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/6905.
Council of Science Editors:
Varga T. Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/6905
Georgia Tech
17.
McGrath, Jonathan G.
Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials.
Degree: PhD, Chemistry and Biochemistry, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/14537
► This dissertation describes the use of spherical micro- and nanoparticles as building blocks for the fabrication of colloidal crystals. The polymer component used in all…
(more)
▼ This dissertation describes the use of spherical micro- and nanoparticles as building blocks for the fabrication of colloidal crystals. The polymer component used in all of the projects that are described herein is poly-N-isopropylacrylamide (pNIPAm). The polymeric identity of particles composed of this soft, hydrogel material, which is also thermoresponsive, contributes to particle self-assembly to form ordered structures. Specifically, particles that possess a core/shell topology were investigated to allow for the localization of distinct polymeric properties. Chapter 2 examines a characterization technique using fluorescence resonance energy transfer (FRET) that was explored to investigate the structure of pNIPAm particles that possess this core/shell topology. Chapters 4-6 investigate strategies to impart both stability and flexibility to the particles so that these properties could assist in particle self-assembly as well as provide a stable construct for the production of robust crystalline materials. Styrene was used as the main monomer component in a copolymer synthesis with NIPAm to achieve poly(styrene-co-N-isopropylacrylamide particles (pS-co-NIPAm) that exhibited both hard and soft properties. Simple drying procedures were used to form crystal assemblies with these particles and the application of these pS-co-NIPAm particle suspensions as processable, photonic inks is also investigated. Chapter 7 examines the ability to physically cross-link colloidal crystals composed of pS-co-NIPAm particles by simple heating methods to produce robust films. The optical properties of these crystal films could be tuned by simple rehydration of the film due to the hydrogel character of the crystal building blocks. Chapters 3 and 5 examine the synthesis and self-assembly strategies of core/shell particles using the properties of pNIPAm shell layers that have been added to different types of core particles (silver or pS-co-NIPAm) for the purposes of fabricating colloidal crystals with enhanced properties using thermal annealing procedures. Chapter 8 explores the use of silver particles as tracers for the characterization of colloidal crystals composed of thermally annealed colloidal crystals composed of pNIPAm hydrogel particles.
Advisors/Committee Members: Dr. L. Andrew Lyon (Committee Chair), Dr. Boris Mizaikoff (Committee Member), Dr. Facundo Fernandez (Committee Member), Dr. Jiri Janata (Committee Member), Dr. Victor Breedveld (Committee Member).
Subjects/Keywords: Colloidal crystal; Core/Shell; Nanoparticles; Microparticles; Ink; N-isopropylacrylamide; Nanoparticles; Colloidal crystals Synthesis; Colloidal crystals Structure
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APA (6th Edition):
McGrath, J. G. (2007). Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/14537
Chicago Manual of Style (16th Edition):
McGrath, Jonathan G. “Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials.” 2007. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/14537.
MLA Handbook (7th Edition):
McGrath, Jonathan G. “Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials.” 2007. Web. 27 Jan 2021.
Vancouver:
McGrath JG. Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/14537.
Council of Science Editors:
McGrath JG. Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/14537
Georgia Tech
18.
White, Kathleen Madara.
Low Temperature Synthesis and Characterization of Some Low Positive and Negative Thermal Expansion Materials.
Degree: PhD, Chemistry and Biochemistry, 2006, Georgia Tech
URL: http://hdl.handle.net/1853/11582
► LOW TEMPERATURE SYNTHESIS AND CHARACTERIZATION OF SOME LOW POSITIVE AND NEGATIVE THERMAL EXPANSION MATERIALS Kathleen Madara White 151 pages Directed by Dr. Angus P. Wilkinson…
(more)
▼ LOW TEMPERATURE SYNTHESIS AND CHARACTERIZATION OF SOME LOW POSITIVE AND NEGATIVE THERMAL EXPANSION MATERIALS
Kathleen Madara White
151 pages
Directed by Dr. Angus P. Wilkinson
Low temperature non-hydrolytic sol-gel synthesis was used to explore the possibility of lowering the crystallization temperatures of some known AIVMV2O7 compounds. Crystallization temperatures for ZrP2O7 and ZrP2O7 were unaffected by the use of non-hydrolytic sol-gel methods; however, successful synthesis of these compounds broadens the range of materials that can be produced using this method and suggests the possibility of synthesizing solid solutions (or composites) including ZrP2O7 or ZrV2O7.
This research presents for the first time the direct synthesis of ZrP2O7 from separate zirconium and phosphorus starting materials using mild autoclave methods.
Characterization of some AIVMV2O7 compounds, using lab and high resolution synchrotron powder XRD, led to the assignment of a new symmetry for CeP2O7 and to the suggestion that the reported structure for PbP2O7 was inadequate. Studies using in situ high temperature lab and synchrotron powder XRD for PbP2O7 and CeP2O7 provided the opportunity to report their thermal properties for the first time, and to compare their behavior to that of some other AIVMV2O7. High pressure diffraction measurements on CeP2O7 provided data for the estimation of bulk moduli and suggested two possible pressure-induced phase transitions.
A broad range of MIIIMVP4O14 compounds were prepared using low temperature hydrolytic sol-gel synthesis. Thermal studies revealed nearly linear trends in CTEs and lattice constants with respect to the sizes of MIIIMV cations. Some lower ionic radii compounds had CTEs comparable to that of ZrP2O7 at low temperature, suggesting a similar superstructure. Three compounds were found to exhibit temperature-induced phase transitions.
Advisors/Committee Members: Angus P. Wilkinson (Committee Chair), E. Kent Barefield (Committee Member), Jiri Janata (Committee Member), John Zhang (Committee Member), Meilin Liu (Committee Member).
Subjects/Keywords: Thermal expansion; Negative thermal expansion; Low temperature synthesis; Pyrophosphates; Cation substitution; Materials Thermal properties; Pyrophosphates; Expansion (Heat); Expansion of solids
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APA (6th Edition):
White, K. M. (2006). Low Temperature Synthesis and Characterization of Some Low Positive and Negative Thermal Expansion Materials. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/11582
Chicago Manual of Style (16th Edition):
White, Kathleen Madara. “Low Temperature Synthesis and Characterization of Some Low Positive and Negative Thermal Expansion Materials.” 2006. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/11582.
MLA Handbook (7th Edition):
White, Kathleen Madara. “Low Temperature Synthesis and Characterization of Some Low Positive and Negative Thermal Expansion Materials.” 2006. Web. 27 Jan 2021.
Vancouver:
White KM. Low Temperature Synthesis and Characterization of Some Low Positive and Negative Thermal Expansion Materials. [Internet] [Doctoral dissertation]. Georgia Tech; 2006. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/11582.
Council of Science Editors:
White KM. Low Temperature Synthesis and Characterization of Some Low Positive and Negative Thermal Expansion Materials. [Doctoral Dissertation]. Georgia Tech; 2006. Available from: http://hdl.handle.net/1853/11582
Georgia Tech
19.
Penescu, Mihaela.
Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy.
Degree: PhD, Chemistry and Biochemistry, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/29740
► Diffusion of linear and cyclic poly(oxyethylene) (POE) oligomers in poly(methyl methacrylate) (PMMA) matrix was investigated in situ using attenuated total reflectance (ATR) infrared (IR) spectroscopy…
(more)
▼ Diffusion of linear and cyclic poly(oxyethylene) (POE) oligomers in poly(methyl methacrylate) (PMMA) matrix was investigated in situ using attenuated total reflectance (ATR) infrared (IR) spectroscopy technique. The temperatures of studies were 60 °C, 85 °C and 110 °C. A film of PMMA was solution-cast onto an ATR zinc selenide crystal and POE was added to the surface. The IR peak at 1109 cm-1 characteristic to ether bond present in POE was used for quantitative analysis. Deconvolution of this peak from IR spectra allowed us to determine the absorbance of diffusing component as a function of interdiffusion time. The data were fit using appropriate mathematical models from where the interdiffusion constants were extracted and used in diffusion interpretation. By looking at different molecular weight of cyclic and linear POE oligomers diffusing into high molecular weight PMMA matrix, it was possible to analyze how penetrant topology and its molecular weight are influencing the diffusion process. The results indicated that cyclic POE moves faster than linear analogous one and an increase in penetrant molecular weight slows down the interdiffusion. The knowledge gained from this study gives us a deeper understanding of transport behavior of low-molecular-weight additives, such as oligomers into polymer matrices and, in particular the influence of topology on diffusion.
Advisors/Committee Members: Haskell W. Beckham (Committee Chair), David Bucknall (Committee Co-Chair), Andrew Lyon (Committee Member), Jiri Janata (Committee Member), Lawrence Bottomley (Committee Member), Mohan Srinivasarao (Committee Member).
Subjects/Keywords: Case II; Fickian; Matrix relaxation; Mutual diffusion; Diffusion; Oligomers Confomation; Molecular structure; Infrared spectroscopy
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APA ·
Chicago ·
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Export
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APA (6th Edition):
Penescu, M. (2009). Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/29740
Chicago Manual of Style (16th Edition):
Penescu, Mihaela. “Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy.” 2009. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/29740.
MLA Handbook (7th Edition):
Penescu, Mihaela. “Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy.” 2009. Web. 27 Jan 2021.
Vancouver:
Penescu M. Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy. [Internet] [Doctoral dissertation]. Georgia Tech; 2009. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/29740.
Council of Science Editors:
Penescu M. Diffusion of cyclic versus linear poly(oxyethylene) oligomers in poly(methyl methacrylate) by ATR-FTIR spectroscopy. [Doctoral Dissertation]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/29740
Georgia Tech
20.
Young, Christina Rachel.
FT-IR and quantum cascade laser spectroscopy towards a hand-held trace gas sensor for benzene, toluene, and xylenes (BTX).
Degree: PhD, Chemistry and Biochemistry, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/31702
► The work described herein focuses on FT-IR and quantum cascade laser (QCL) based studies towards the development of compact and portable trace gas sensor for…
(more)
▼ The work described herein focuses on FT-IR and quantum cascade laser (QCL) based studies towards the development of compact and portable trace gas sensor for benzene, toluene, and xylenes (BTX). FT-IR broadband radiation was used to probe the mid-infrared fingerprint region for quantitatively detecting trace gas levels of BTX. Using direct absorption through a hollow waveguide, parts-per-million (ppm) detection limits for BTX with a response time of 39 seconds was demonstrated. Univariate calibration provided limits of detection (3σ) for benzene, toluene, and meta-xylene at 5, 17, and 11 ppm, respectively. Multivariate calibration using partial least squares regression algorithms were used to simulate real-world conditions with multiple analytes present within a complex sample. A calibration model was built with 110 training set standards enabled by using a customized gas mixing system. Furthermore, a preconcentration/thermal desorption (TD) step was added to the FT-IR HWG trace gas sensor enabling parts-per-billion detection of BTX. A univariate calibration was established in the laboratory with certified gas standards over a dynamic range of 1000 - 100 ppb for benzene, toluene, and the xylenes. The sensor was then taken to an industrial site during a field measurement campaign for the quantitative determination of BTX in field air samples. The laboratory calibration was used to predict unknown concentrations which were in close agreement with industrial hygiene standard techniques, and industrial prototype analyzers, that were simultaneously operated in the field environment.
In addition to FT-IR, quantum cascade laser spectroscopy was also investigated due to enhanced spectral density and efforts to precisely overlap emission with analyte absorption. Particular efforts were dedicated on a novel principle for consistent and deliberate QCL emission wavelength selection by varying the QCL cavity length. These studies experimentally confirmed that using this straight-forward post-processing technique, emission wavelength tuning across a range of one hundred wavenumbers range may be achieved. This tuning range was experimentally demonstrated for a QCL emitting across an entire absorption feature of carbon dioxide by tailoring the length of the cavity. Additionally, using an external cavity (EC) - QCL combined with a HWG gas sensor module for the first time enabled the quantitative and simultaneous determination of ethyl chloride, trichloromethane, and dichloromethane within exponential dilution experiments at ppb limits of detection. Multianalyte detection was demonstrated utilizing partial least squares regression for quantitative discrimination of individual constituents within a mixture, yet applying a single broadly tunable QCL light source.
Advisors/Committee Members: Boris Mizaikoff (Committee Chair), Facundo Fernandez (Committee Member), Jiri Janata (Committee Member), Mark Disko (Committee Member), Oliver Brand (Committee Member), Thomas Orlando (Committee Member).
Subjects/Keywords: Hollow waveguides; Trace gas sensing; BTX; Mid-infrared spectroscopy; Laser spectroscopy; Detectors; Wave guides
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APA ·
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APA (6th Edition):
Young, C. R. (2009). FT-IR and quantum cascade laser spectroscopy towards a hand-held trace gas sensor for benzene, toluene, and xylenes (BTX). (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/31702
Chicago Manual of Style (16th Edition):
Young, Christina Rachel. “FT-IR and quantum cascade laser spectroscopy towards a hand-held trace gas sensor for benzene, toluene, and xylenes (BTX).” 2009. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/31702.
MLA Handbook (7th Edition):
Young, Christina Rachel. “FT-IR and quantum cascade laser spectroscopy towards a hand-held trace gas sensor for benzene, toluene, and xylenes (BTX).” 2009. Web. 27 Jan 2021.
Vancouver:
Young CR. FT-IR and quantum cascade laser spectroscopy towards a hand-held trace gas sensor for benzene, toluene, and xylenes (BTX). [Internet] [Doctoral dissertation]. Georgia Tech; 2009. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/31702.
Council of Science Editors:
Young CR. FT-IR and quantum cascade laser spectroscopy towards a hand-held trace gas sensor for benzene, toluene, and xylenes (BTX). [Doctoral Dissertation]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/31702
Georgia Tech
21.
South, Antoinette Bonhivert.
Assembly and dynamic behavior of microgel thin films and their application to biointerfacees.
Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/34686
► Hydrogels, which are polymeric cross-linked networks that swell in aqueous environments, are versatile materials that can contain a variety of chemical functionalities, mechanical properties, and…
(more)
▼ Hydrogels, which are polymeric cross-linked networks that swell in aqueous environments, are versatile materials that can contain a variety of chemical functionalities, mechanical properties, and topographical features. Microgels are the stable colloidal form of hydrogel materials that range in size from approximately 100 nm to a few microns in diameter. While they also can exhibit similar properties to those of macrogels, microgels can be used as building blocks in a bottom-up approach to assemble films of higher complexity. In this dissertation, work is focused on understanding the assembly and behavior of microgel thin films as non-fouling surfaces, centrifugally deposited materials, self-healing coatings, and degradable constructs. Non-fouling films were assembled using PEG cross-linked microgels to reduce non-specific protein adsorption and mitigate cellular adhesion. These constructs were assembled in a polyelectrolyte multi-layered fashion, of alternating anionic microgels and cationic linear polymer, to effectively block the substrate from the biological environment and consequently exhibited control over cellular adhesion with the surface. The utility and application of these non-fouling microgel coatings on functional implants was also explored. Centrifugal deposition was used to rapidly generate non-fouling microgel multi-layered interfaces on planar surfaces, and upon closer inspection of the microgel monolayers, it was found that the centrifugally deposited films contained closer-packed microgel assemblies with microgels of smaller footprint size, compared to microgels that are passively adsorbed to the surface. Microgels that are centrifugally deposited may adopt a higher energy chain conformation than passively adsorbed microgels, and this higher energy chain conformation may translate into the multi-layered materials. Nonetheless, the centrifugally deposited non-fouling microgel multi-layered films were found to effectively block macrophage adhesion. Films were also assembled in a polyelectrolyte fashion on soft substrates, and were observed to become significantly damaged under mechanical manipulation (poking, bending, or stretching), but then self-heal upon addition of water. By altering the building blocks of the polyelectrolyte multi-layered films, such as the molecular weight of the polycation between microgel layers or by using anionic rigid spheres as the particle in the assembly, changes in the observed film damage suggest that particle-linear polymer interpenetration and polyvalency likely play an important role in the strength and integrity of the microgel thin films. Fluorescently-labeled microgels were also used to interrogate how the films reorganize in the lateral direction, and these early studies suggest that the microgel multi-layered films reorganize when damaged and also possibly when they are undamaged and simply incubated in an aqueous environment. Additional studies were also conducted on microgels synthesized with a hydrolyzable cross-linker, and by supporting…
Advisors/Committee Members: L. Andrew Lyon (Committee Chair), Andrés García (Committee Member), Jiri Janata (Committee Member), Laren Tolbert (Committee Member), Niren Murthy (Committee Member).
Subjects/Keywords: Biomaterials; Film assembly; Colloids; Thin films; Biomedical materials; Colloids in medicine; Centrifugation
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APA ·
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APA (6th Edition):
South, A. B. (2010). Assembly and dynamic behavior of microgel thin films and their application to biointerfacees. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/34686
Chicago Manual of Style (16th Edition):
South, Antoinette Bonhivert. “Assembly and dynamic behavior of microgel thin films and their application to biointerfacees.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 27, 2021.
http://hdl.handle.net/1853/34686.
MLA Handbook (7th Edition):
South, Antoinette Bonhivert. “Assembly and dynamic behavior of microgel thin films and their application to biointerfacees.” 2010. Web. 27 Jan 2021.
Vancouver:
South AB. Assembly and dynamic behavior of microgel thin films and their application to biointerfacees. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 27].
Available from: http://hdl.handle.net/1853/34686.
Council of Science Editors:
South AB. Assembly and dynamic behavior of microgel thin films and their application to biointerfacees. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/34686
. 
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