Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(CO2 responsive polymers). Showing records 1 – 2 of 2 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


Université de Sherbrooke

1. Dong, Liangliang. Étude de nouveaux matériaux polymères pour membranes de séparation et actionneurs contrôlés par stimuli .

Degree: 2018, Université de Sherbrooke

Stimuli-responsive materials have exhibited a wide range of applications, because the necessity of designing novel “smart” systems usually requires materials that can change their chemical and/or physical properties upon exposure to changed environmental conditions. Two representative applications are stimuli-responsive porous membranes and polymer actuators which are subjects of this thesis. On one hand, stimuli-responsive porous membranes are a class of membranes that can adjust their mass transfer and interfacial properties to manipulate permeability and selectivity in response to changing environmental conditions, such as pH, light, temperature, redox, and so on. There has been a rapid development in this field over the past decades or so. However, there are some limitations for these stimuli-responsive porous membranes. For example, for pH-responsive porous membranes, addition of acids and bases into the solution results in salt accumulation that can contaminate the system and diminish the switchability, while temperature or light responsive porous membranes may be damaged by the stimuli to a certain extent. Therefore, it is still urgent to develop environmentally friendly and cost-effective stimulation modes for stimuli-responsive porous membranes. On the other hand, polymer actuators have aroused scientists’ extensive research interest because of their potential applications in biomedicine, artificial muscles and soft robots. Instead of utilizing mechanical force to achieve motion or deformation, polymer actuators can move or deform under thermal, optical or electrical stimulation. Among them, photo-thermal-responsive polymer actuators based on liquid crystal polymer networks (LCNs) have emerged as a particularly promising materials system. For this kind of actuator, the photothermal agents are needed to convert optical energy into thermal energy to induce the LC-to-isotropic phase transition that drives the actuator to deform macroscopically. However, the photothermal reagents often have poor compatibility with organic polymeric matrices, resulting in a dilemma that reducing the doping percentages of photothermal reagents would weaken the photo-actuation speeds of the LCN actuators, whereas increasing the doping percentages would lead to serious phase segregations, and then sacrifice the mechanical properties of the LCN actuators. Moreover,fabricating photothermal-responsive LCN actuators that can perform light-driven caterpillar-type motion on untreated surfaces is also challenging. The main topic of this thesis is to learn from nature to design and fabricate the stimuli-responsive porous membranes for the size separation and nanofiltration and the stimuli-responsive polymer actuators based on LCN for remotely controlled motion. We introduce the CO2-responsive polymers into membrane separation, in a bid to develop a new external stimulus that can reversibly “open” and “close” the membrane pore sizes and further impact the size selectivity of the membrane. Compared with other stimuli, using CO2 as… Advisors/Committee Members: Zhao, Yue (advisor).

Subjects/Keywords: CO2-responsive polymers; Membrane separation; Graphene oxide; Polymer actuators; Liquid crystalline polymers

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Dong, L. (2018). Étude de nouveaux matériaux polymères pour membranes de séparation et actionneurs contrôlés par stimuli . (Doctoral Dissertation). Université de Sherbrooke. Retrieved from http://hdl.handle.net/11143/13614

Chicago Manual of Style (16th Edition):

Dong, Liangliang. “Étude de nouveaux matériaux polymères pour membranes de séparation et actionneurs contrôlés par stimuli .” 2018. Doctoral Dissertation, Université de Sherbrooke. Accessed December 06, 2019. http://hdl.handle.net/11143/13614.

MLA Handbook (7th Edition):

Dong, Liangliang. “Étude de nouveaux matériaux polymères pour membranes de séparation et actionneurs contrôlés par stimuli .” 2018. Web. 06 Dec 2019.

Vancouver:

Dong L. Étude de nouveaux matériaux polymères pour membranes de séparation et actionneurs contrôlés par stimuli . [Internet] [Doctoral dissertation]. Université de Sherbrooke; 2018. [cited 2019 Dec 06]. Available from: http://hdl.handle.net/11143/13614.

Council of Science Editors:

Dong L. Étude de nouveaux matériaux polymères pour membranes de séparation et actionneurs contrôlés par stimuli . [Doctoral Dissertation]. Université de Sherbrooke; 2018. Available from: http://hdl.handle.net/11143/13614


NSYSU

2. LIN, PEI-YI. CO2 responsiveness of Poly(N-isopropylacrylamide-co-methacrylic acid).

Degree: Master, Materials and Optoelectronic Science, 2016, NSYSU

In this study, random copolymers of poly(N-isopropylacrylamide-co-acrylic acid) (i.e., poly(NIPAAm-co-AA)) and poly(N-isopropylacrylamide-co-methacrylic acid) (i.e., poly(NIPAAm-co-MAA)) were prepared by free radical polymerizations and block copolymer of poly(methacrylic acid-b-N-isopropylacrylamide) (i.e., PMAA-b-PNIPAAm)) was prepared by reversible-addition-fragmentation chain transfer radical polymerization. Temperature, pH, and CO2 responsiveness of these copolymers were investigated. UV-vis, DSC, and digital camera were used to investigate the pH dependence of the lower critical solution temperature (LCST) for copolymer aqueous solutions. Experimental results found that LCST of all aqueous solutions were increasing with increasing pH. High pressure DSC measurements found that LCST of poly(NIPAAm-co-AA) was decreasing with increasing CO2 pressure. Tg of films as cast from aqueous solutions of as-synthesized random copolymers were increasing with increasing AA (or MAA) compositions in NIPAAm-rich copolymers but decreasing with AA (or MAA) compositions in AA (or MAA)-rich copolymers. This suggested that strong hydrogen bondings be formed between amide groups of NIPAAm units and carboxylic acid groups of AA (or MAA) units. Tg of random copolymers films as cast from aqueous solutions of different pH was seen to first decrease with pH and then increase with pH. This indicated that COOH dissociated to COO- as pH was increased, leading to a decrease of Tg because of a decrease of intermolecular hydrogen bonding, and COOH could completely dissociate to COO- as pH was increased to be high, leading to an increase of Tg with pH because the negatively charged copolymer molecules could become rigid. Following treatments in a supercritical carbon dioxide fluid (scCO2), Tg of random copolymer film was increased due to promotion of intermolecular hydrogen bonding by scCO2; however, Tg of block copolymer film was decreased due to the plasticizing effect of CO2 in the micelle of the block copolymer. Upon CO2 bubbling in aqueous solution of PMAA-b-PNIPAAm, CO2 responsiveness could be clearly seen by the change of the cloud point in aqueous solution at some particular conditions. CO2 responsiveness of poly(NIPAAm-co-AA) and poly(NIPAAm-co-MAA), however, were not clear. Advisors/Committee Members: Yeo-Wan Chiang (chair), Yeong-Tarng Shieh (chair), Jin-Long Hong (chair), Shiao-Wei Kuo (committee member).

Subjects/Keywords: N-isopropylacrylamide; acrylic acid; methacrylic acid; lower critical solution temperature; supercritical CO2; responsive polymers

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

LIN, P. (2016). CO2 responsiveness of Poly(N-isopropylacrylamide-co-methacrylic acid). (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0612116-154404

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):

LIN, PEI-YI. “CO2 responsiveness of Poly(N-isopropylacrylamide-co-methacrylic acid).” 2016. Thesis, NSYSU. Accessed December 06, 2019. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0612116-154404.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

LIN, PEI-YI. “CO2 responsiveness of Poly(N-isopropylacrylamide-co-methacrylic acid).” 2016. Web. 06 Dec 2019.

Vancouver:

LIN P. CO2 responsiveness of Poly(N-isopropylacrylamide-co-methacrylic acid). [Internet] [Thesis]. NSYSU; 2016. [cited 2019 Dec 06]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0612116-154404.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

LIN P. CO2 responsiveness of Poly(N-isopropylacrylamide-co-methacrylic acid). [Thesis]. NSYSU; 2016. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0612116-154404

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.