报告题目：Quantitative Prediction of Position and Orientation for Platonic Nanoparticles at Liquid/Liquid Interfaces

报告人：李述周 副教授

邀请人：李 盛 副研究员

报告时间：4月30日（周二）10:00

报告地点：科技创新大楼C501室

Abstract

Platonic particles are promising materials with nanoscale light-matter interactions in plasmonics and biosensing, due to their unique structure caused by vertices, edges and facets. The position and orientation of Platonic particles play a crucial role in determining the resultant assembled structures at a liquid/liquid interface. Therefore, it is desirable to develop a reliable theory that can predict the interfacial configuration of an isolated Platonic nanoparticle from nanoparticle-solvent interactions and solvent-solvent interactions. Here, we numerically explored all possible orientations of a Platonic nanoparticle, including three specific orientations: vertex up, edge up, and facet up orientations. We found that a specific orientation is more preferred than random orientations. We also demonstrated that the free energy change theory could quantitatively predict the position and orientation of an isolated Platonic nanoparticles at a liquid/liquid interface, where the surface wettability of the nanoparticle determined the most stable position and the preferred orientation. Molecular dynamics simulations were used to test our theory where the surface wettability of a Platonic solid was adjusted from extremely hydrophobic to extremely hydrophilic by changing the charge amount on the Ag surface. The molecular dynamics simulation results were in excellent agreement with our theoretical prediction for an isolated Ag Platonic nanoparticle at a hexane/water interface. Our proposed theory bridges molecular-level simulations and assembly structure of Platonic nanoparticles in experiments, in which the insights from nanoparticle wettability in solvents can be used to predict macroscopic superlattice structure in experiments. This work advances our ability to precisely predict the final structures of the Platonic nanoparticle assemblies at a liquid/liquid interface.

个人简介

李述周，新加坡南洋理工大学材料科学与工程学院副教授。南开大学获得化学学士学位后，就读于北京大学化学与分子工程学院并且获得物理化学硕士学位。在威斯康星州麦迪逊大学时，采用原子分子动力学模拟和第一性原理计算研究叠氮化物在水中光谱扩散和振动能量弛豫，并获得物理化学博士。加入南洋理工大学之前，在西北大学做博士后，通过各种计算电动力学方法研究了表面等离子体共振，采用理论和计算的方法探索纳米材料的光学性质。目前研究主要集中在三个方向：纳米材料的自组装, 高灵敏度基质表面增强光谱学，金属和半导体复合材料的光电性质。