报告题目：Desorption-Mediated Polymer Dynamics at Solid/Liquid Interfaces

报告人：王大鹏

报告时间：5月8日（周三）16:00

报告地点：晶体所二楼报告厅

报告人简介

王大鹏，研究员，2013年1月在德国马克斯普朗克高分子所/美因茨大学获得博士学位，2013年1月至2017年4月分别在德国马普高分子所、美国科罗拉多大学从事博士后研究。曾先后获得德国马普国际奖学金和DAAD奖学金,2019年被世界胶体界面协会评选为胶体界面领域世界杰出青年学者。2017年5月入职中国科学院长春应化所高分子物理与化学国家重点实验室任研究员。主要研究方向为单分子荧光方法学，高分子表界面物理和异常扩散理论与模拟。通过运用和改进单分子技术手段，首次观测并证实了一系列高分子在表界面的异常行为，改变了人们对经典高分子体系的认识。以第一作者或通讯作者在Phys. Rev. Lett., J. Am. Chem. Soc., Adv. Mater.和ACS Nano等期刊发表文章十余篇，其中，发表在Phys. Rev. Lett.和J. Am. Chem. Soc.上关于高分子界面构象和界面动力学的文章分别被选为当期的研究亮点工作。

报告摘要

Theoretical predictions have suggested that molecular motion at interfaces – which influences processes including heterogeneous catalysis, (bio)chemical sensing, lubrication/adhesion, and nanomaterial self-assembly – may be dominated by hypothetical “hops” through the adjacent liquid phase, where a diffusing molecule re-adsorbs after a given hop according to a probabilistic “sticking coefficient”. Here, we used three-dimensional (3D) single molecule tracking to explicitly visualize this process for human serum albumin at solid/liquid interfaces that exert varying electrostatic interactions on the biomacromolecule. Following desorption from the interface, a molecule experienced multiple unproductive surface encounters before re-adsorption. An average of ~7 surface collisions was required for the repulsive surfaces, decreasing to ~2.5 for surfaces that were more attractive. The hops themselves were also influenced by long-range interactions, with increased electrostatic repulsion causing hops of longer duration and distance. These findings explicitly demonstrate that interfacial diffusion is dominated by biased 3D Brownian motion involving bulk−surface coupling, and that it can be controlled by influencing short- and long-range adsorbate-surface interactions.

Recently developed single-molecule tracking techniques allow us to image millions of individual molecules dynamically at solid/liquid and liquid/liquid interfaces. These high-throughput single-molecule experiments go beyond understanding the average behavior of adsorbates and enable us to probe variability in surface chemistry, molecular conformations, and adsorbate dynamics. Making such measurements, we often find that the behavior is much richer and more interesting than conventional wisdom suggests. In this abstract, we demonstrated that a process of desorption—readsorption at interfaces can result in plenty of anomalous behaviors that can be quantitatively modeled by continuous time random walk statistics.