Treated microporous membrane

A method for treating a filtration device, wherein the filtration device is in the form of hollow fibers, a tubular device, a spiral wound filtration device or a pleated filtration device, the filtration device comprising a microporous membrane, the microporous membrane comprising an organic thermoplastic matrix;

• finely divided particulate, substantially water-insoluble inorganic filler distributed throughout the matrix;
• a network of interconnecting pores communicating throughout the microporous membrane, and an acid-functional acrylic layer on at least one surface of the microporous membrane, wherein the acid-functional acrylic layer is bonded to the filler via siloxane functional groups;
• the method comprising in sequence:
• (1) contacting at least one surface of the acid-functional acrylic layer on the microporous membrane with a dispersion comprising an amine-functional polysaccharide dispersed in an aqueous medium containing an organic acid, to form a polysaccharide-treated membrane;
• (2) contacting at least one surface of the polysaccharide-treated membrane formed in (1) with an aqueous acid;
• and
• (3) contacting the polysaccharide-treated membrane with an amine-functional alkoxysilane to form a polysaccharide hydrogel layer on the membrane.

A treated microporous membrane comprising:

• (1) a microporous membrane comprising an organic thermoplastic matrix;
• finely divided particulate, substantially water-insoluble inorganic filler distributed throughout the matrix;
• and a network of interconnecting pores communicating throughout the microporous membrane, wherein the membrane is a component of a hollow fiber filtration device, a tubular filtration device, a spiral wound filtration device or a pleated filtration device;
• (2) an acrylic layer on at least one surface of the microporous membrane, wherein the acrylic layer is formed from a mixture of vinyl monomers comprising:
• (i) a (meth)acrylic acid monomer and (ii) a silane-functional acrylic monomer, and wherein the acrylic layer is bonded to the filler via siloxane functional groups;
• and
• (3) a hydrogel layer on at least one surface of the acrylic layer, wherein the hydrogel layer is formed from an amine-functional polysaccharide and an amine-functional alkoxysilane.