A method for creating a porous film through aqueous phase separation comprising: i) providing an aqueous solution comprising a responsive copolymer to form an aqueous copolymer solution, wherein the copolymer comprises a pH responsive monomer and a further hydrophobic monomer, wherein said pH responsive monomer is selected from the group consisting of 2-diethylaminoethylmethacrylate, 4-vinylpyridinium, aminostyrene, ethylene imine (El), allylamine, 2-(dimethylamino)ethyl methacrylate (DMAEMA), diallyl-dimethyl-ammonium chloride (DADMAC), (methacrylic acid), acrylic acid, maleic acid, styrenesulfonate, vinyl siloxane, sulfonated polyethersulfone (sES), sulfonated polysulfone (sSU), wherein said further hydrophobic monomer is selected from the group consisting of styrene, ethylene, propylene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-octadecene, butadiene, isobutylene, tetrafluoroethylene, difluoroethylene, stilbene, acenapthylene, wherein the copolymer is responsive to a change in pH, wherein the copolymer is an alternating copolymer; ii) forming the aqueous copolymer solution into a thin layer and contacting the thin layer of aqueous copolymer solution with an aqueous coagulation solution, having a lower pH or a higher pH compared to the aqueous copolymer solution, in which the responsive copolymer is not soluble; and iii) allowing solvent exchange between the aqueous copolymer solution and the aqueous coagulation solution to produce a porous film; wherein the aqueous copolymer solution is predominantly water-based, wherein at least 50 vol% of solvent is water. i) providing an aqueous solution comprising a responsive copolymer to form an aqueous copolymer solution, wherein the copolymer comprises a pH responsive monomer and a further hydrophobic monomer, wherein said pH responsive monomer is selected from the group consisting of 2-diethylaminoethylmethacrylate, 4-vinylpyridinium, aminostyrene, ethylene imine (El), allylamine, 2-(dimethylamino)ethyl methacrylate (DMAEMA), diallyl-dimethyl-ammonium chloride (DADMAC), (methacrylic acid), acrylic acid, maleic acid, styrenesulfonate, vinyl siloxane, sulfonated polyethersulfone (sES), sulfonated polysulfone (sSU), wherein said further hydrophobic monomer is selected from the group consisting of styrene, ethylene, propylene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-octadecene, butadiene, isobutylene, tetrafluoroethylene, difluoroethylene, stilbene, acenapthylene, wherein the copolymer is responsive to a change in pH, wherein the copolymer is an alternating copolymer; wherein said pH responsive monomer is selected from the group consisting of 2-diethylaminoethylmethacrylate, 4-vinylpyridinium, aminostyrene, ethylene imine (El), allylamine, 2-(dimethylamino)ethyl methacrylate (DMAEMA), diallyl-dimethyl-ammonium chloride (DADMAC), (methacrylic acid), acrylic acid, maleic acid, styrenesulfonate, vinyl siloxane, sulfonated polyethersulfone (sES), sulfonated polysulfone (sSU), wherein said further hydrophobic monomer is selected from the group consisting of styrene, ethylene, propylene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-octadecene, butadiene, isobutylene, tetrafluoroethylene, difluoroethylene, stilbene, acenapthylene, wherein the copolymer is responsive to a change in pH, wherein the copolymer is an alternating copolymer; ii) forming the aqueous copolymer solution into a thin layer and contacting the thin layer of aqueous copolymer solution with an aqueous coagulation solution, having a lower pH or a higher pH compared to the aqueous copolymer solution, in which the responsive copolymer is not soluble; and iii) allowing solvent exchange between the aqueous copolymer solution and the aqueous coagulation solution to produce a porous film; wherein the aqueous copolymer solution is predominantly water-based, wherein at least 50 vol% of solvent is water.