Morphology and structure transition of surfactant/scCO₂ system: A dissipative particle dynamics simulation

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• 作者：Yongfan Zhu ; Xiaoning Yang ; ^{Yangxia@njut.edu.cn}
• 关键词：DPD simulation ; Surfactant ; Supercritical CO2 ; Self-assembly structure
• 刊名：Fluid Phase Equilibria
• 出版年：2012
• 期刊代码：32_03783812
• 类别：ce
• 出版时间：25 March, 2012
• 卷：318
• 期：Complete
• 页码：102-109
• 文件大小：1336 K

摘要

Dissipative particle dynamics (DPD) simulations have been carried out to study the morphology and structure of a surfactant/supercritical CO₂ (scCO₂) system. A copolymer-type surfactant model was used, which consists of two building blocks representing the CO₂-philic unit and the CO₂-phobic unit, respectively. Unlike traditional DPD simulation, which used equal repulsive interactions between like beads, the DPD simulation scheme in this work relates the conservative interactions directly to the solubility parameters. It can reasonably represent the density dependence of scCO₂ repulsive parameters in DPD simulation. The DPD simulation is able to describe the effect of supercritical fluid density (pressure) on the morphology transition of surfactant self-assembly in scCO₂ fluid. The obtained phase diagram in the relation of surfactant concentration with the scCO₂ density is qualitatively consistent with the experimental result. We also simulated the density-induced structure transition for the surfacetant/scCO₂ system in confined pores. An increase in supercritical fluid density can not only destroy the surface micelle structure in confined pores, but also modify the surface adsorption behavior of surfactant molecules.