I&EC 139 |
| LCST (Lower Critical Solution Temperature)-type phase separations have been observed in aqueous (synthetic- and bio-) polymer solutions. It is a rare phenomenon that Gibbs free energy of mixing (ΔGmix) moves from negative to positive with increasing temperature. The LCST-type phase separation phenomena are brought about under condition of negative enthalpy (ΔHmix) and entropy (ΔSmix) values of mixing. In the case of aqueous polymer solutions, the LCST-type phase separation is induced by the specific character of water. When hydrophobic molecules are put into water, water molecules form clusters around them, and the solution becomes to have structural order, resulting in a decrease in ΔSmix. Here, we report the first observation of LCST-type phase separation of polymers in ionic liquids. The LCST-type phase separation of this system seems to be attributed to the specific clathrate-like structure formation to decrease mixing entropy. |
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Ionic Liquids: Not Just Solvents Anymore OR Ionic Liquids: Parallel Futures (Sponsored by Green Chemistry and Engineering, Separation Science and Technology and Novel Chemistry with Industrial Applications Sub-Divisions)
8:00 PM-10:00 PM, Sunday, 26 March 2006 Georgia World Congress Center -- Ex. Hall B4, Poster
Division of Industrial and Engineering Chemistry |