A virus removal membrane is formed from a hydrophilized synthetic polymer, in which, when a solution containing gold colloids having a diameter of 20 nm is applied through a primary surface to the virus removal membrane to allow the virus removal membrane to capture the gold colloids for measurement of brightness in a cross section of the virus removal membrane, a value obtained by dividing a standard deviation of a value of an area of a spectrum of variation in the brightness by an average of the value of the area is 0.01 or more and 1.5 or less; and a thickness of a portion, where gold colloids having a diameter of 20 nm or more and 30 nm or less are captured, in the cross section of the virus removal membrane in a wet state is 10 m or more and 30 m or less.

This disclosure generally relates to polymeric materials designed to create membranes with improved selectivity and fouling resistance, with potential capabilities that include tunable effective pore size that can be reduced to, for example, <1 nm, exceptional fouling resistance, improved chemical resistance and thermal stability, and ion selectivity. Specifically, this disclosure relates to cross-linkable and charged zwitterionic polymers and membranes made therefrom for reverse osmosis applications.