Molecular dynamics simulation of supercritical CO2 microemulsion with ionic liquid domains: Structures and properties

doi:10.1016/j.cjche.2019.04.005

Abstract

Abstract: Supercritical carbon dioxide microemulsions are great medium to combine two immiscible substances through forming nanoscale polar cores in nonpolar continuous phase with the help of proper surfactants. The properties of microemulsions could be significantly affected by their constituents and structures. In this work, molecular dynamics simulation was implemented to study supercritical carbon dioxide microemulsions containing ionic liquid[bmim] [PF₆] and water by adding surfactant Ls-36. Results showed that the above components could form spherical aggregates in CO₂ bulk phase with[bmim] [PF₆] and some water as the inner core, surfactant headgroups and water as the intermediate shell, and surfactant tails as the outer shell. The microstructure information about the outer shell was further investigated by defining an angle between the surfactant tail and the normal direction of the aggregate outer surface, which ranged from 78° to 125°. The influence of the ionic liquid content on the size and structure of microemulsions was explored and the best molar ratio between the ionic liquid and surfactant was around 1.25 for getting maximum water solubility.

Key words: Molecular simulation, Supercritical carbon dioxide microemulsion, Ionic liquids, Microstructure, Structure parameters

摘要： Supercritical carbon dioxide microemulsions are great medium to combine two immiscible substances through forming nanoscale polar cores in nonpolar continuous phase with the help of proper surfactants. The properties of microemulsions could be significantly affected by their constituents and structures. In this work, molecular dynamics simulation was implemented to study supercritical carbon dioxide microemulsions containing ionic liquid[bmim] [PF₆] and water by adding surfactant Ls-36. Results showed that the above components could form spherical aggregates in CO₂ bulk phase with[bmim] [PF₆] and some water as the inner core, surfactant headgroups and water as the intermediate shell, and surfactant tails as the outer shell. The microstructure information about the outer shell was further investigated by defining an angle between the surfactant tail and the normal direction of the aggregate outer surface, which ranged from 78° to 125°. The influence of the ionic liquid content on the size and structure of microemulsions was explored and the best molar ratio between the ionic liquid and surfactant was around 1.25 for getting maximum water solubility.

关键词: Molecular simulation, Supercritical carbon dioxide microemulsion, Ionic liquids, Microstructure, Structure parameters

Hongyue Zhu, Ying Li, Hongrui Ren, Dan Zhou, Jianzhong Yin. Molecular dynamics simulation of supercritical CO₂ microemulsion with ionic liquid domains: Structures and properties[J]. Chinese Journal of Chemical Engineering, 2019, 27(11): 2653-2658.

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Molecular dynamics simulation of supercritical CO₂ microemulsion with ionic liquid domains: Structures and properties

Molecular dynamics simulation of supercritical CO₂ microemulsion with ionic liquid domains: Structures and properties

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