ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Molecular dynamics simulation of the distribution of potassium perfluorooctanesulfonate in water

Xianwu Jing, Lang Zhou, Shengtao Li, Yuan Xu, Qiang Liu, and Ziyi Fu

Research Institute of Natural Gas Technology, Southwest Oil and Gas Field Company, China National Petroleum Corporation, Chengdu, People’s Republic of China

E-mail: jingxw2018@petrochina.com.cn

Received: 11 June 2023  Accepted: 29 July 2023

Abstract:

We used the molecular dynamics method to simulate the behavior of potassium perfluorohexanesulfonate (KPFOS) in water/gas system. The results indicate that PFOS⁻ can spontaneously migrate to the water/gas interface and form a layered structure with hydrophobic tail chains facing the gas phase and hydrophilic sulfonic acid groups immersed in the water phase, while some PFOS⁻ molecules within the solution formed spherical micelles. Both the number density and charge density distributions confirm that PFOS⁻ and K⁺ are mainly distributed at the water/gas interface, and a small amount of PFOS⁻ and K⁺ are distributed in the bulk solution. Based on the results of radial distribution function, the probability of K⁺ appearing near oxygen atoms in PFOS⁻ is very high due to electrostatic attraction. Based on the IGMH analysis, the oxygen atoms in PFOS⁻ can form multiple hydrogen bonds with adjacent water molecules, while there is only weak van der Waals interaction between K⁺ and water molecules.

Keywords: Fluorocarbon surfactant; Molecular dynamics simulation; Weak interaction

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03018-5

Chemical Papers 77 (12) 7457–7464 (2023)