Polymer-Super critical CO2 Systems |
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Materials:
Organic
Semiconductors
Nanomaterials
Composites
Application: Nanotechnology Electronic Technique: Characterization |
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Liquid and supercritical CO2 are attractive alternatives to organic solvents in many polymer processes. Sorption of CO2 into polymers induces significant swelling and plasticization, lowering the glass transition temperature Tg of amorphous polymers, inducing crystallization in crystalline polymers. The order-disorder transition (ODT) temperatures and ordering kinetics of block copolymers are also influenced significantly by CO2. Aside from the environmentally benign properties and easily accessible critical conditions (Tc=31oC and Pc=73.8 bar) of CO2, the solvent strength of CO2 can be tuned markedly with pressure and temperature. To date, research has focused on bulk polymer systems in Sc-CO2, little is known about the effects of Sc-CO2 on thin polymer films. Studies in our laboratories have suggested a strong influence of Sc-CO2 on the sorption, on the glass transition temperatures (Tg), on the morphological instability of homopolymer thin films and on the ordering transition of block copolymer thin films. Our research group has developed a collaboration with Professor Keith Johnston at the University of Texas at Austin. This topic is particular significance as it related to low temperature processing and fabrication of polymer thin film systems for applications that range from organic electronics to biomedical applications. |