Molecular insights on NaCl crystals formation approaching the PVDF membranes functionalized with graphene
Membrane assisted crystallization is an emerging technology where microporous hydrophobic membranes are used not as selective barriers but to promote the water vapor transfer between phases inducing supersaturation in solution. This has been successfully tested in the crystallization of ionic salts, low molecular organic acids and proteins. In this work, molecular dynamics simulations were used to study the crystal nucleation and growth of sodium chloride in contact with hydrophobic polymer surfaces at a supersaturated concentration of salt. Pristine polyvinylidene fluoride (PVDF) surface and PVDF containing different concentrations of graphene platelets were studied. Membrane crystallization tests were performed in parallel, in order to compare the experimental results with the computational ones. Here, with an integrated experimental–computational approach, we demonstrate that graphene-containing membranes assisted the crystal-growth for NaCl, speeding up crystal nucleation in comparison to the pristine PVDF membranes. Computational results agreed with experimental data, making real the possibility of exploring nanomaterials behavior in membrane processes from a microscopic level.