High-throughput asymmetric membrane

Abstract

A microporous asymmetrical membrane formed of one or more layers wherein the “tight” side of the membrane has an “opened” face or otherwise highly-porous reticulated surface is described. The microporous asymmetrical membrane has high throughput and high flux, even when used for filtering viscous materials, such as serum or plasma. The membrane's surface can be formed by ablation or solvation, or in a two or more layered structure, through an appropriate selection of casting dopes.

1 . A method of increasing the surface porosity of a tight side of an asymmetric membrane comprising forming an asymmetric membrane having a tight side and an open side and wherein the tight side has a skin surface, performing a post-formation surface modification by contacting the preformed membrane with an electromagnetic e chemical agent suitable for increasing the porosity of an asymmetric membrane tight side wherein the increase in porosity is controlled by a method selected from the group consisting of controlling the concentration of the chemical agent, adding a nonsolvent to the membrane before contacting the tight side with the chemical agent and adding a nonsolvent to the membrane before contacting the tight side with the chemical agent while controlling the concentration of the chemical agent 
   
   
       2 . The method of  claim 1 , wherein the membrane is a multi-layered membrane. 
   
   
       3 . The method of  claim 1 , wherein the membrane is a preformed single layered membrane contacted with an electromagnetic agent suitable for increasing the porosity of an asymmetric membrane tight side. 
   
   
       4 . The method of  claim 1 , wherein the electromagnetic agent suitable for increasing the porosity of an asymmetric membrane tight side is irradiation. 
   
   
       5 . The method of  claim 1 , wherein the membrane is a multi-layered membrane. 
   
   
       6 . The method of  claim 1 , wherein the electromagnetic agent suitable for increasing the porosity of an asymmetric membrane tight side is selected from the group consisting of corona discharge, plasma ablation, and laser ablation. 
   
   
       7 . The method of  claim 1  wherein the membrane is exposed to the electromagnetic agent in an intensity, a wavelength, and for duration sufficient to remove, or render removable, exposed portions of the skin surface of the tight side.