报告题目：Influence of Knots within a Cyclic Polymer on Solution and Glass Transition Properties
报告人：Michael J. Monteiro 博士，Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Queensland 4072, Australia.
报告地点：独墅湖校区907-1445
报告时间：2017年12月7日，15:00
报告简介：Cyclic polymers with knots provide new insight into polymer properties in solution and bulk. In this work, we prepared cyclic polystyrene structures all with a similar molecular weight designed with 0 to 3 irreversible knots located at strategic sites to control the shape of the polymer coil. In addition, the number of arms attached to the knot was altered from 4 to 6. In dilute solution, the anisotropic polymers (i.e. with ellipsoidal shape) gave a measurably higher hydrodynamic radius due to their rotational (i.e. tumbling) motion. In bulk, the number of knots and the number of arms per knot greatly influenced the glass transition temperature (Tg). An increase in the number of knots and arms per knot decreased the configurational entropy, leading to a higher Tg. The data suggests that the greater compactness, anisotropy and higher Tg of knotted cyclic polymers provide a physical basis for understanding greater stability of knotted cyclic biological macromolecules against enzymatic degradation and denaturation.
(1) Md. D. Hossain, Z. Jia, and M. J. Monteiro Macromolecules, 2014, 47 (15), pp 4955–4970; (2) Hossain, M. D.; Lu, D. R.; Jia, Z. F.; Monteiro, M. J. Acs Macro Lett(2014), 3, (12), 1254-1257; (3) D. Lu, Z. Jia, M. J. Monteiro Polymer Chemistry2013, 4, 2080-2089; (4) Jia, Z. F.; Lonsdale, D. E.; Kulis, J.; Monteiro, M. J.,Acs Macro Letters2012,1 (6), 780-783; (5) Hossain, M. D.; Valade, D.; Jia, Z. F.; Monteiro, M. J., Polymer Chemistry2012,3 (10), 2986-2995, (6) Jia, Z.; Monteiro M. J. “Cyclic Polymers: Methods and Strategies” J. Polym. Sci., Part A: Polym. Chem. 2012,50 (11), 2085-2097, (7) Lonsdale, D. E.; Monteiro, M. J. J. Polym. Sci., Part A: Polym. Chem. 2011, 49, (21), 4603-4612 (8) Lonsdale, D. E.; Monteiro, M. J. Chem. Commun. 2010, 46, (42), 7945-7947
Prof. Michael J. Monteiro is the Deputy Director (Research) within the AIBN at The University of Queensland, Australia. He completed his PhD at Griffith University, Australia, on nitroxide trapping of small radical intermediates in polymerization systems. His first Postdoctoral Fellowship was with Prof. Ken O'Driscoll at the University of Waterloo, Canada on determining the effects of solvent on kp by PLP. His next Postdoctoral Fellowship was with Prof. Anton German at Eindhoven University of Technology. He then was recruited as the Scientific Officer at the University of Sydney, Australia with Professor Bob Gilbert, working on emulsion polymerization. In 1999, he was an Assistant Professor at Eindhoven University of Technology, The Netherlands, where he started with living radical polymerization using RAFT. His group was the first to study and synthesize polymer nanoparticles in water with controlled composition and morphology using the RAFT technology. He worked with Professor Virgil Percec (University of Pennsylvania) in 2001 on SET-LRP. Monteiro has published over 200 peer reviewed publications and book chapters, and is on the Advisory Boards of Biomacromolecules (2013-), Macromolecules (2009-2011) and Journal of Polymer Science Part A Polymer Chemistry (2009-). He was recently appointed as Editor to the European Polymer Journal.
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