近壁亚微米尺度下纳米粒子布朗运动实验研究

项目名称： 近壁亚微米尺度下纳米粒子布朗运动实验研究

项目编号： No.11272322

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 李战华

作者单位： 中国科学院力学研究所

项目金额： 92万元

中文摘要： 粒子布朗扩散运动虽已有经典的Stokes-Einstein公式描述，但该理论针对无界流场中光滑刚性粒子。在微纳米流动中，作布朗运动的纳米粒子往往处在受限空间内，受到近壁流场、壁面静电场及粒子表面特性的影响，特别是最近实验发现纳米粒子垂直扩散系数的测量值与经过近壁水动力学修正的S-E公式不符。本课题组在前期基金资助下，已经建立了全内反射荧光显微镜系统，可观测到近壁500nm以内的流场。本申请目的是继续在受限条件下研究粒子布朗运动，着重测量荧光纳米粒子垂向扩散系数Dz，研究壁面和粒子表面特性对纳米粒子布朗运动的影响，并根据福克-普朗克方程对近壁扩散运动进行理论分析。此研究有助于阐明粒子受限扩散的机理，而且有利于开发纳米粒子探针在微流控中的应用。

中文关键词： 受限布朗运动；纳米粒子；全内反射隐失波；扩散系数；

英文摘要： Brownian motion of nanoparticles has been well described by classical theory like Stokes-Einstein equation, however, this theory is suitable for rigid particles with smooth surface in unlimited flow field. In micro/nanoflows, the Brownian motion of nanoparitcles are usually confined, influenced by fluid flow near wall, electrostatic field of solid surface and particle surface properties, especially from recent observation, experimental data of vertical diffusion coefficient Dz are not consistent with the Stokes-Einstein equation prediction with the near wall hydrodynamic correction. With previous support of NSFC, we have built the TIRFM system which can be used to measure the flow field within 500nm to wall. This application will continue to utilize this system to study confined Brownian motion. We focus on measuring the vertical diffusion coefficient Dz of nanoparticles, studying the influences of wall and particle surfaces on Brownian motion， and analyzing theoretically the diffusion very close to wall based on fokke-plank equation. This research will not only contribute to understand the mechanism of particle confined diffusion, but also help develop the nanoparticle probe in microfluidics.

英文关键词： Confined Brownian motion；Nanoparticle；Total internal reflection evanescent wave；diffusion coefficient；