How Pore Hydrophilicity Influences Water Permeability?

Abstract

Membrane separation is playing increasingly important role in providing clean water. Simulations predict that membrane pores with strong hydrophobicity produce ultrahigh water permeability as a result of low friction. However, experiments demonstrate that hydrophilic pores favor higher permeability. Herein we simulate water molecules transporting through interlayers of two-dimensional nanosheets with various hydrophilicities using nonequilibrium molecular dynamics. We reveal that there is a threshold pressure drop (ΔPT), exceeding which stable water permeability appears. Strongly hydrophobic pores exhibit extremely high ΔPT, prohibiting the achievement of ultrahigh water permeability under the experimentally accessible pressures. Under pressures 99%, indicating a promising strategy to experimentally realize ultrafast membranes.