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Active Control of Sol-Gel-Sol Transitions of Aqueous Solutions of Doubly Responsive Hydrophilic Block Copolymers Bin Zhao, University of Tennessee Knoxville, DMR 0906913.
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Active Control of Sol-Gel-Sol Transitions of Aqueous Solutions of Doubly Responsive Hydrophilic Block CopolymersBin Zhao, University of Tennessee Knoxville, DMR 0906913 Hydrogels are used in a wide range of applications, including contact lenses, drug delivery, and tissue engineering. To meet the demand of novel injectable multiresponsive hydrogels in emerging technologies, we developed a unique strategy for the design of doubly responsive block copolymer gels. The unique feature of these block copolymers is that the transition temperatures of thermosensitive blocks can be modified by external stimuli. By incorporating a small amount of enzyme-responsive phosphate groups, we designed and synthesized thermo- and enzyme-responsive hydrophilic ABA triblock copolymers (Scheme 1), and demonstrated the enzyme-induced formation of thermoreversible micellar gels from their moderately concentrated aqueous solutions at 37 °C (Figure 1). Scheme 1. Synthesis ofthermo- and enzyme-responsive hydrophilic ABA triblock copolymers. Macromolecules2011, 44, 3556; 2011, 44, 5764; 2009, 42, 8468. J. Phys. Chem. B.2012, 116, 3125; 2011, 115, 2870. Langmuir2011, 27, 2019; 2011, 27, 13324; 2010, 26, 8787. Soft Matter 2010, 6, 3325. Figure 1. Enzyme-induced formation of hydrogel from an aqueous solution of a multiresponsive triblock copolymer.
Active Control of Sol-Gel-Sol Transitions of Aqueous Solutions of Doubly Responsive Hydrophilic Block CopolymersBin Zhao, University of Tennessee Knoxville, DMR 0906913 Education Under current and previous grants, six students have graduated with Ph.D. degrees (Jonathan Horton, 2012; Jeremiah Woodcock, 2011; Thomas O’Lenick, 2011; Xueguang Jiang, 2010; Xiaoming Jiang, 2010; Dejin Li, 2008). Three students are currently pursuing their Ph.D. degrees: Naixiong Jin (4th year), Daniel Henn (1st year), and Bin Hu (1st year). Eight undergraduates participate in this project (R. Wright, M. Gindt, S. Goddard, M. Bowman, M. Kang, P. Evans, D. Naik, and J. Taylor). Daniel Henn, Elizabeth Miller, and Debbie Fraser are discussing an experiment. • Outreach • Hosted two high school teachers, Debbie Fraser and Elizabeth Miller, in our laboratory in the summer of 2012 and worked with them to develop chemistry laboratory experiments for their classes. Nine experiments were evaluated. • Hosted a high school student, Mr. Carter Chain, in our research laboratory from 06/28/12 – 08/10/2012 and guide him to complete a project on the synthesis of a stimuli-responsive polymer. Mr. Carter Chain, a high school student is working in our research laboratory.