主讲人:伊藤教授    日本东京大学

时间: 2012-3-29    下午3点30分 

地点: 逸夫会议中心多功能厅

【内容介绍】
They have recently developed a novel type of polymer network called slidering materials by cross-linking polyrotaxane, the supramolecular architecture with topological characteristics. In the network, polymer chains are topologically interlocked by figure-of-eight cross-links. Hence, these cross-links can pass along the polymer chains freely to equalize the tension of the threading polymer chains similarly to pulleys. Because the cross-linking junction can move in the polymer network, the structure and physical properties of the polymeric materials are drastically different from conventional cross-linked or noncross-linked materials. For instance, the slide-ring gel or elastomer shows quite small Young’s modulus, which is not proportional to the cross-linking density and much lower than those of chemical gels with the same density. This arises from the difference in the molecular mechanism of the entropic elasticity: While the conformational entropy is mainly responsible for the elasticity in usual chemical gels or rubbers, the mechanical properties of the slide-ring gel should be inherently governed by the arrangement entropy of free cyclic molecules in polyrotaxane as well as the conformational entropy of axis polymer. This means that the softness in the slide-ring gel is due to the novel entropic elasticity, which is also expected to yield sliding state and sliding transition. The concept of the slide-ring gel has recently yielded various new kinds of gels and fibers. It is not limited with cross-linked gels but also includes elastomer, cross-linked polymeric materials without solvent. Accordingly it can be applied to wide area such as soft contact lens, inter ocular lens, cosmetic, textiles, paints, rubbers, household goods, farming materials, polymer battery, fuel cell, soft actuator and so on. This is important not only for the development of high-performance gels but also as a new framework for general polymeric materials.

【主讲人简介】
Professor Division of Transdisciplinary Sciences Department of Advanced Materials Science Group of New Materials and Interfaces