Unveiling the Behavior of Perfluoro (2-Ethoxyethane) Sulfonic Acid Potassium (PESK) in Water/Gas System: Molecular Dynamics Simulation

Abstract

Molecular dynamics method (MD) was used to study the distribution of potassium perfluoro (2-ethoxyethane) sulfonic acid (PESK) in water/gas systems. When the PESK aqueous solution system reaches equilibrium, the vast majority the fluorocarbon chain is facing toward the gas phase, while the sulfonic acid radical faces toward the water, with a very small quantity of PES− is still in the bulk solution. The weak intermolecular interactions were analyzed by IGMH method, and the interaction energy between PES− and water mainly comes from the h-bonds formed by the oxygen atom in the sulfonic acid group and hydrogen atom in water molecules. K+ are mainly distributed inside the aqueous solution, and there is only van der Waals interaction between K+ and H2O molecules. According to the distribution of ESP analysis of PES−, it is mainly the sulfonic acid groups that are negatively charged.