关于新加坡南洋理工大学陈虹宇副教授
学术报告的通知
报告题目：Bridging the Gap in the Micellar Transformation from Cylinders to Vesicles （表面活性剂及两亲性聚合物的自组装成胶束的机理）
报告人：新加坡南洋理工大学陈虹宇副教授
报告时间：2013年11月13日 上午10：00
报告地点：光电楼二楼会议室
报告人简介：Dr. Hongyu Chen obtained his B. Sc. from University of Science and Technology of China (USTC) in 1998. He then moved to Yale University and studied Mn complexes and water oxidation chemistry. After obtaining his Ph.D. degree in 2004, he worked as a post-doctoral fellow in Cornell University on the topic of protein-nanoparticle hybrids. In 2006, he joined the Division of Chemistry and Biological Chemistry in Nanyang Technological University in Singapore, where he is currently an Associate Professor. His main research interest is in the development of new synthetic methodologies for nanostructures and the underlying mechanisms.
报告摘要：This talk will have three parts. First, I will give a general introduction to our research directions, the mechanism of encapsulating nanoparticles with polymer shells, and the use of such encapsulation methods as means for exploring new types of complex nanostructures.
The main part of this talk will focus on our two new works, where the common point is understanding of the structural transformation of micelles. The micelles of polystyrene-block-poly(acrylic acid) (PS154-b-PAA49) are made to transform slowly, allowing continual trapping of the various intermediates from cylinders to vesicles. The analysis of surface-to-volume ratio of the intermediates gives no obvious barrier in the micellar transformation. We propose that the kinetic barrier lies in the molecular reorganization in the micelles, which is not represented in the traditional analysis of static shapes.
Lastly, we study the phase transition of mesoporous silica from MCM-41 like phase to silica vesicles. Mesoporous silica is templated by surfactant micelles but it cannot be readily tuned as such. Three factors are adapted for manipulating CTAB-silica micelles: (a) degree of swelling; (b) amount of co-surfactant; and (c) control of composition by diffusion. The inter-dependence of these factors highlights the unified system behavior. As summarized in a phase diagram, the phase outcome of the surfactant-silica co-assembly is governed by simple principles and can be rationally controlled.
References:
[1] Hong Wang et al., Accounts of Chemical Research, 2013, 46 (7), 1636-1646.
[2] Cuicui Liu et al., Small, 2013, published online, DOI:10.1002/smll.201302837.
[3] Lin Yao et al., 2013, manuscript submitted.
