Molecular dynamics coupled with experimental study of the effects of polyethylene glycol on the structure and antifouling properties of polyethersulfone membranes

Abstract

Polyethylene glycol (PEG), as a hydrophilic molecule, exerts a significant influence on the morphology and performance of membranes. However, the mechanism by which PEG influences polyethersulfone (PES) membranes remains unclear. In this work, the addition of varying concentrations (4, 12, 24 wt%) and molecular weights (200, 400, and 600 Da) of PEG on the PES membrane was investigated by molecular dynamics (MD) simulation and experimental study. Compared to the concentration of PEG (4, 12, and 24 wt%), the molecular weight of PEG (PEG200, PEG400, and PEG600) had little effect on the membrane pore size. The radial distribution function and fractional free volume results of MD simulation both proved that. Additionally, both the experimental adsorption capacity (QHA) and the calculated adsorption energy (Eads) revealed that the adsorption of humic acid (HA) on the PES membrane with 4 wt% PEG was higher than that on the pure PES membrane, which meant that PEG was not beneficial to the anti‐fouling property but improved the water flux of PES membranes. The results of this study not only provide theoretical predictions and a scientific basis for the formulation of PES membranes but also promotes an approach for exploring the mechanism by which additives affect polymer membranes.