超临界CO_2中表面钝化Au纳米粒子的分子动力学模拟

Molecular dynamics simulation of passivated Au nanoparticles dispersed in supercritical CO_2

通过分子动力学模拟方法研究了353.15 K下多个氟化的硫醇烷烃钝化的Au纳米粒子在超临界CO2中的分散行为。结果表明:在单分子自组装层的钝化下,Au纳米粒子在超临界CO2溶剂中可以得到稳定分散。通过对径向分布函数、有效平均力势能、渗透压第二维里系数等数据进行分析发现,在超临界流体中,自组装单分子保护层(SAM)的存在可以有效阻止纳米粒子间的团聚,增加溶剂密度和链长,可以提高纳米粒子之间的相互排斥作用,从而有利于纳米粒子的分散。

Molecular dynamics simulations were carried out to investigate the dispersion behavior of fluori- nated alkanethiols passivated gold nanoparticles in supercritical CO2 at 353.15 K. Results indicated that the gold nanoparticles passivated with self-assembled monolayer （SAM） could be stably dispersed in the supercritical dioxide solvent. By analyzing the radial distribution function, effective pair potential of mean force and osmotic second Virial coefficient, it was observed that in supercritical fluid, the existence of SAM could effectively prevent reunion between the nanopartieles. The increase of solvent density and chain length could improve the mutual repulsion interaction between nanoparticles, thus it was help for the dispersion of nanoparticles.