Disclosed are copolymers suitable for hydrophilically modifying the surface of porous fluoropolymer supports, for example, a copolymer of the formula (I) or (II): wherein Rf, Rh, Ra, Y, m, and n are as described herein. Also disclosed are a method of preparing the copolymers, a method of hydrophilically modifying porous fluoropolymer supports, hydrophilic fluoropolymer porous membranes prepared from the polymers, and a method of filtering fluids through the porous membranes.