Patent ID: 9415350
Filing Date: 2016-08-16
CPC Classification: B01D

Claim Text:
1. A method of forming a rewettable asymmetric membrane comprising: providing a porous substrate having a first major surface, interstitial pores, and a second major surface; applying a polymerizable composition to the first major surface of the porous substrate to provide a coated porous substrate, wherein the polymerizable composition wets the porous substrate through the entire thickness of the porous substrate, the polymerizable composition comprising exposing the coated porous substrate to ultraviolet radiation comprising a peak emission wavelength less than about 340 nm to polymerize the polymerizable composition in a gradient extending from the first major surface through a portion of the thickness of the porous substrate and provide the rewettable asymmetric membrane; and removing a portion of the solvent from the rewettable asymmetric membrane by evaporation to coat the copolymer on at least a portion of the second major surface and the interstitial pores unoccupied by polymerized material, the rewettable asymmetric membrane comprising polymerized material on the first major surface and a gradient of polymerized material extending from the first major surface to the second major surface with copolymer within portions of the interstitial pores unoccupied by the polymerized material, wherein the pores are partially filled with a mixture of the polymerized material and the copolymer, each interstitial pore comprising an interface between the mixture and a coating of the copolymer on the interstitial pores that extends from the interface to the second major surface, and wherein the second major surface is substantially free of the polymerized material.