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Doubly Thermosensitive Block and Star Copolymers from Living Radical Polymerizations: Synthesis, Phase Transitions, and Applications Bin Zhao, University of Tennessee, DMR 0605663.
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Doubly Thermosensitive Block and Star Copolymers from Living Radical Polymerizations: Synthesis, Phase Transitions, and Applications Bin Zhao, University of Tennessee, DMR 0605663 We have developed a new class of well-defined thermosensitive water-soluble polymers, poly-styrenics and polyacrylates with short pendant oligo(ethylene glycol) groups, by living radical polymerization. The cloud point can be tuned by varying the length and end group of oligo(ethylene glycol) pendant. We have also synthesized a series of well-defined block copolymers that exhibit multiple transitions in water in response to external stimuli. The block copolymer shown below undergoes micellization with increasing T. Upon UV irradiation, the micelles dissociate into unimers. Further increasing T induces the formation of micelles again. Macromolecules, 2005, 38, 9509-9517; 2006, 39, 3476-3479; JPS. A 2006, 44, 2454-2467;2007, 45, 3707-3721 (a) (b) UV Irradiation UV Irradiation (a) Dynamic light scattering study of micellization and dissociation of the block copolymer in H2O (0.1 wt %); (b) fluorescence intensity of Nile red in aqueous solution of the block copolymer as a function of T.
Doubly Thermosensitive Block and Star Copolymers from Living Radical Polymerizations: Synthesis, Phase Transitions, and Applications Bin Zhao, University of Tennessee, DMR 0605663 Education Under this grant, three graduate students are pursuing their Ph.D. degrees: Mr. Dejin Li (4th Year, going to graduate in Dec, 2007), Mr. Thomas G. O’Lenick (2nd year), and Mr. Xueguang Jiang (2nd year). Three undergraduate students (Derek R. Green, Clark Moore, and Christopher A. Lavender) participated in this project. • Outreach • Hosted two high school teachers, Ms. Kristin • Baksa and Debbie Fraser, for two weeks in the • summers of 2006 and 2007, and worked with • them to develop laboratory experiments for their • classes (19 experiments were conducted). • Hosted two high school students, Mr. Dennis • Pickens Jr. and Mr. Andre Greer, in the laboratory • for four weeks and guided them to complete • a project on thermosensitive polymers. • Hosted one undergraduate student (Christopher • A. Lavender from New York Univ.) for ten weeks. Kristin Baksa and Debbie Fraser are making rubber bands and nylon rope