时间: 2024年10月29日（周二）下午16:00-17:30

Time: 16:00-17:30 PM,Tuesday, Oct. 29^th,2024

主持人: 西湖大学交叉科学中心讲席教授汤雷翰

Host: Dr. Leihan Tang, Chair Professor, the Center for Interdisciplinary Studies

地点：西湖大学云谷校区学术环E10-211

Venue: E10-211, Yungu Campus

讲座语言：英文

Lecture Language: English

Prof. Xingkun Man满兴坤教授

Professor in School of physics, Beihang University

主讲人/Speaker:

Xingkun Man is Professor in School of physics, Beihang University. He graduated with a bachelor's degree from the Department of Applied Physics at Beijing University of Science and Technology in 2004. He got his PhD from the Institute of Chemistry, Chinese Academy of Sciences, in 2009. From 2009 to 2011, he was a postdoc at Tel Aviv University in Israel. From 2011 to 2013, he was a postdoc at the University of California, Santa Barbara. He began working at Beihang University in 2013. He has led and participated in six projects funded by NSFC, including Excellent Young Scientists Fund, Key Program et al. He is currently in the editor board of three journals, including Chinese Chemical Letters, Advanced Physics Research and Macromolecular Theory and Simulations.

讲座摘要/Abstract:

The glassy polymers exhibit swelling behavior that is completely different from that of soft polymers (like rubber and gels) in their good solvents. As the solvent penetrates, the thickness of the glassy polymer samples initially increases linearly over time, rather than following the typical Fickian diffusion time scale, while the area remains almost constant. After a certain period, the thickness begins to decrease while the area starts to increase, eventually reaching an equilibrium state. This unusual phenomenon has been observed in various polymer systems over the past 50 years, such as PMMA in methanol, PVC in acetone, PS in alkyl solutions, and even in other systems like ions in conjugated polymers. Although there are numerous theoretical models addressing this issue, almost all focus solely on the non-Fickian diffusion behavior of glassy polymer swelling, known as "Case II diffusion," while neglecting the problem of three-dimensional nonlinear deformation. Based on the Onsager variational principle, we propose a unified theory that describes the swelling of glassy polymers. Our theory not only provides a comprehensive and novel explanation for the swelling behavior but also predicts the relationship between diffusion rates and swelling characteristic times with material parameters and experimental conditions, offering theoretical guidance for effectively controlling this swelling behavior. In this report, I will introduce how we developed such a unified theoretical model and the novel results and predictions we obtained.

讲座联系人/Contact:

理学院，徐恺吟，邮箱：xukaiyin@westlake.edu.cn

School of Science, Kaiyin Xu, Email: xukaiyin@westlake.edu.cn