Permanent hydrophilic porous coatings and methods of making them

A porous membrane, comprising:

• a porous base membrane formed of a fluoropolymer;
• and
• an autoclavable hydrophilic coating covalently grafted to the fluoropolymer comprising a hydrophilic additive and a derivative of a hydrophilic polymer,
• wherein the porous membrane has a flow rate of water greater than about 1 mL/min-cm2 at 27 inches Hg pressure differential after 10 wet/dry cycles at room temperature,
• wherein the derivative of the hydrophilic polymer is formed prior to coating onto the base membrane and comprises at least one of a polyvinyl alcohol, a polyvinyl alcohol-polyvinyl amine copolymer, a polyacrylic acid, a polyacrylate, a polyethylene amine, a polyvinyl amine, and/or derivatives thereof wherein the reactive groups present at the ends of the hydrophilic polymer and reactive groups along the polymer chain of the hydrophilic polymer have been reacted with a material independent of the hydrophilic additive and containing electron beam reactive groups so that the hydrophilic polymer is derivatized with electron beam reactive groups adapted to form radicals under high energy irradiation and configured to react with the base membrane to form covalent bonds,
• wherein the electron beam reactive groups are present along the polymer chain of the hydrophilic polymer after the reaction with a material independent of the hydrophilic additive and comprise at least one of methacrylates, acrylates, acrylamides, vinyl ketones, styrenics, vinyl ethers, vinyl- or allyl-containing moieties, and/or benzyl and/or tertiary-carbon (CHR3) based materials;
• and
• wherein the hydrophilic additive comprises at least one of acrylate, diacrylate, triacrylate, multiacrylate, acrylamide, vinyl ketone, styrenic, vinyl ether, vinyl- or allyl-containing moiety, benzyl-carbon, tertiary-carbon (CHR3), or combinations thereof.

A process for forming an autoclavable hydrophilic surface on a porous membrane, the process comprising:

• applying hydrophilic coating comprising a hydrophilic additive and a derivative of a hydrophilic polymer having an average molecular weight of greater than 2500 Daltons and derivatized with electron beam reactive groups configured to react with a porous base membrane and form covalent bonds, wherein the electron beam reactive groups are present along the polymer chain of the hydrophilic polymer and comprise at least one of methacrylates, acrylates, acrylamides, vinyl ketones, styrenics, vinyl ethers, vinyl- or allyl-containing moieties, and/or benzyl and/or tertiary-carbon (CHR3) based materials;
• irradiating the coated porous base membrane with a high energy source;
• and covalently grafting the electron beam reactive groups to the porous base membrane to form the hydrophilic surface on the porous base membrane, wherein the porous membrane exhibits water wettability and flow rates after autoclaving and wherein the derivative of the hydrophilic polymer comprises a reaction product of at least one of a polyvinyl alcohol, a polyvinyl alcohol-polyvinyl amine copolymer, a polyacrylic acid, a polyacrylate, a polyethylene amine, a polyvinyl amine, and/or derivatives thereof with a material independent of the hydrophilic additive and containing electron beam reactive groups so that the hydrophilic polymer is derivatized with electron beam reactive groups adapted to form a radical under high energy irradiation and configured to react with the base membrane and form covalent bonds, wherein the electron beam reactive groups comprises at least one of methacrylates, acrylates, acrylamides, vinyl ketones, styrenics, vinyl ethers, vinyl- or allyl-containing moieties, and/or benzyl and/or tertiary-carbon (CHR3) based materials;
• and
• wherein the hydrophilic additive comprises at least one of acrylate, diacrylate, triacrylate, multiacrylate, acrylamide, vinyl ketone, styrenic, vinyl ether, vinyl- or allyl-containing moiety, benzyl-carbon, tertiary-carbon (CHR3), or combinations thereof.