Abstract: The present invention relates to a method of producing a polymeric membrane having a homogeneous porosity throughout the entire polymeric phase. The method comprises the steps of dissolving at least one amphiphillic block copolymer in a solvent to form a casting solution of the block copolymer, and contacting the extruded solution with non-solvent to induce phase separation and thereby producing an integral asymmetric polymeric membrane, wherein the amphiphillic block copolymer is an amphiphillic diblock copolymer, containing blocks of a polar copolymer and blocks of a benzocyclobutene copolymer, and wherein the integral asymmetric polymeric membrane is crosslinked by application of heat or radiation thereby producing a membrane having a homogeneous porosity throughout the entire polymeric phase.