Environmentally Responsive Hairy Particles and Block Copolymer Micelles Seminar

Professor Bin Zhao
Department of Chemistry, University of Tennessee, Knoxville.

Held Tuesday, January 26, 2010, 9:45 a.m., 331 Smith Hall, University of Minnesota

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Bin Zhao – Seminar Abstract
Stimuli-sensitive soft materials can undergo spontaneous structural changes and exhibit different properties in response to environmental variations. These materials have received growing interest in recent years and have great potential in many technological applications. In this talk, I will present two types of environmentally responsive polymeric systems: mixed homopolymer brush-grafted particles and multi-responsive hydrophilic block copolymer micelles. Mixed brushes, composed of two distinct homopolymers randomly or alternately immobilized by one end on a solid surface with sufficiently high grafting densities, represent a new class of surface-responsive materials. We have developed a unique strategy to synthesize well-defined mixed brushes from asymmetric difunctional initiator-functionalized silica surfaces by combining two different living radical polymerization techniques. These brushes exhibit distinct, intriguing phase morphologies under different environmental conditions. In the second part of this talk, I will present our recent work on multi-sensitive block copolymer micelles. By incorporating various responsive groups into thermosensitive blocks, we have synthesized a series of doubly responsive hydrophilic block copolymers. These polymers can undergo multiple micellization and dissociation transitions in water in response to the combination of two external triggers.

1.Zhao, B.; Zhu, L. Macromolecules 2009, 42, 9369-9383.
2.Li, D. J.; Sheng, X.; Zhao, B. J. Am. Chem. Soc. 2005, 127, 6248-6256.
3.Zhao, B.; Zhu, L. J. Am. Chem. Soc. 2006, 128, 4574-4575.
4.Zhu, L.; Zhao, B. J. Phys. Chem. B. 2008, 112, 11529-11536.
5.Zhao, B.; Li, D. J.; Hua, F. J.; Green, D. R. Macromolecules 2005, 38, 9509-9517.
6.Hua, F. J.; Jiang, X. G.; Li, D. J.; Zhao, B. J. Polym. Sci. Part A: Polym. Chem. 2006, 44, 2454-2467.
7.Jiang, X. G., Lavender, C. A.; Woodcock, J. W.; Zhao, B. Macromolecules 2008, 41, 2632-2643.
8.Jiang, X. G.; Zhao, B. Macromolecules 2008, 41, 9366-9375.
9.Jiang, X. G.; Jin, S; Zhong, Q. X.; Dadmun, M. D.; Zhao, B. Macromolecules 2009, 42, 8468-8476.
10.O’Lenick, T. G.; Jiang X. G.; Zhao, B. Langmuir 2009, submitted.