纳米通道中电渗流的分子动力学模拟  

Molecular dynamic simulation in nanochannels

作　　者：田菲[1] 陈云飞[1] 

机构地区：[1]东南大学机械工程学院,南京211189

出　　处：《功能材料与器件学报》2008年第2期288-292,共5页Journal of Functional Materials and Devices

基　　金：国家自然科学基金资助(50475077);国家重点基础研究发展计划资助(973计划)(2006CB300404)

摘　　要：采用分子动力学(MD)方法,模拟了纳米通道中NaC l溶液的电渗现象。模拟结果表明,与上下两板带同性电荷相比,当纳米通道的上下壁面所带电荷电性相反时,通道中水的浓度分布大致相同,而离子浓度分布,水的速度及通道中的电势分布相差很大。具体表现在:Na+主要聚集在带负电的硅板附近,C l-主要聚集在带正电的硅板附近,通道中部出现电荷倒置现象;在通道下部的区域水的速度为负值,而在上部区域速度为正值;电势在硅板附近呈指数分布,其值在下硅板附近为正,在上硅板附近为负,在模拟区域中段,电势在通道下部区域由正值变为负值,在通道上部区域由负值变为正值。此外,模拟结果还表明:纳米通道中的速度流型随通道壁面电荷分布的改变而改变。A NaCl solution sandwiched by two parallel silicon nanochannels is simulated by molecular dynamic simulation. Compared with silicon walls charged with same charges, when silicon walls charged with different charges, Water concentration is similar, while ion concentration and potential is different. Na^＋ ions and Cl^- ions assemble two sides of nanochannel separately, and in the middle of nanochannel charge inversion occurs; The value of water velocity in the lower nanochannel is negative and positive in the upper;The value of potential is clearly different across the nanochannl, Potential is distributed in exponential curve near the nanochannle walls, The value of potential in the lower nanochannel wall is positive and negative in the upper, while in the lower nanochannel, potential is negative and positive in the upper. By molecular dynamic simulation, it is found that velocity pattern alters when the surface charge in the nanochannel walls is different.

关 键 词：电渗流 电荷倒置 剪切流 zeta电势 

分 类 号：TG111.4[金属学及工艺—物理冶金] O657.8[金属学及工艺—金属学]