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Category: Speeches

Created on Friday, 28 September 2018 16:07

Last Updated on Thursday, 11 October 2018 09:27

Published on Friday, 28 September 2018 16:08

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Speaker: Professor Hideaki Yokoyama

Topic: Structures and Properties of Dynamic Polymer Brush

Location: Room 215, College of Engineering

 

Speaker：Professor Hideaki Yokoyama

Organization：Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, JAPAN

Topic：Structures and Properties of Dynamic Polymer Brush

Date：14:00 , 2018.10.5

Location：Room 215, College of Engineering

Education：

Cornell University (U.S.A.) Materials Science and Engineering PH.D

Tokyo Institute of Technology (Japan) Polymer Chemistry MS

Tokyo Institute of Technology (Japan) Polymer Chemistry BS

Work Experience：

The University of Tokyo / Associate Professor

National Institute of Advanced Industrial Science and Technology (AIST) / Senior Researcher

Bridgestone Corporation (Tokyo) / Researcher

Abstract： 

A layer of polymer chains tethered by one end to a surface is called polymer brush and known to show various unique properties such as prevention of protein adsorption and anti-fouling activity. The surface segregation phenomena of copolymers with surface-active blocks should be useful for preparing such a brush layer in spontaneous process. We reported hydrophilic polymer brushes formed at the interface between water and hydrophobic polymer matrix by the segregation of amphiphilic diblock copolymers blended in the matrix. In this system, while the hydrophilic block with high surface energy avoids air surface it segregate to cover the interface between hydrophobic PDMS and water. The structures of formed brush layers at D2O/polymer interfaces were analyzed by neutron reflectivity (NR). The brush density was calculated to be as high as 2 chains/nm2, which is surprisingly comparable to the polymer brush fabricated by the “grafting-from” method. Moreover, even if the brush is lost or damage, the remaining block copolymers embedded in the elastomer can segregate again to repair the brush (self-repair). Therefore, the kinetics of dynamic polymer brush growth, which determine the time for self-repair, is very important. The kinetics of dynamic polymer brush formation was investigated using Quartz Crystal Microbalance (QCM), contact angle measurement and time-resolved NR.