Coupled Monte Carlo and Molecular Dynamics Simulations on Interfacial Properties of Antifouling Polymer Membranes

We use molecular simulation to study
the wetting behavior of antifouling
polymer-tethered membranes. We obtain the interfacial properties (e.g.,
contact angle) of water at various temperatures for five polymer membranes,
including a base polysulfone (PSF) membrane and four other PSF membranes
grafted with antifouling polymers (two poly­(ethylene glycol) (PEG)
tethers and two zwitterionic tethers). We implement a coupled Monte
Carlo (MC)/molecular dynamics (MD) approach to determine the interface
potentials of water on the membrane surfaces in an efficient manner.
Within this method, short MC and MD simulations are performed in cycles
to collect the surface excess free energy of a thin water film on
polymer membrane surfaces. Simulation results show that the grafting
of zwitterionic tethers provides a more significant enhancement in
the hydrophilicity of the PSF membrane than that of the PEG tethers.
Water completely wets the surface of zwitterionic polymer membranes.