State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China.
J Colloid Interface Sci. 2011 Jan 1;353(1):22-9. doi: 10.1016/j.jcis.2010.09.051. Epub 2010 Oct 8.
All-atomic molecular dynamics simulations have been performed to study the interfacial structural and dynamical properties of passivated gold nanoparticles in supercritical carbon dioxide (scCO(2)). Simulations were conducted for a 55-atom gold nanocore with thiolated perfluoropolyether as the packing ligands. The effect of solvent density and surface coverage on the structural and dynamical properties of the self-assembly monolayer (SAM) has been discussed. The simulation results demonstrate that the interface between nanoparticle and scCO(2) solvent shows a depletion region due to the preclusion of SAM. The presence of scCO(2) solvent around the passivated Au nanoparticle can lead to an enhanced extension of the surface SAM. Under full coverage, the structure and conformation of SAM are insensitive to the density change of scCO(2) fluid. This simulation results clarify the microscopic solvation mechanism of passivated nanoparticles in supercritical fluid medium and is expected to be helpful in understanding the scCO(2)-based nanoparticle dispersion behavior.
已进行全原子分子动力学模拟，以研究超临界二氧化碳（scCO2）中钝化金纳米粒子的界面结构和动力学特性。模拟针对具有硫醇化全氟聚醚作为组装配体的 55 个原子金纳米核进行。讨论了溶剂密度和表面覆盖率对自组装单层（SAM）结构和动力学性质的影响。模拟结果表明，由于 SAM 的排斥，纳米粒子与 scCO2 溶剂之间的界面呈现耗尽区。在钝化 Au 纳米粒子周围存在 scCO2 溶剂会导致表面 SAM 进一步扩展。在完全覆盖的情况下，SAM 的结构和构象对 scCO2 流体密度的变化不敏感。这些模拟结果阐明了超临界流体介质中钝化纳米粒子的微观溶剂化机制，有望有助于理解基于 scCO2 的纳米粒子分散行为。
