| abstract |
Method for producing a porous film of the present invention is a method of casting a polymer solution in a film form on a substrate, a porous film by a phase inversion method, the surface tension of the polymer constituting the porous film Sa [mN / m] A polymer and a substrate are used in which the difference (Sa-Sb) between the surface tension Sb [mN / m] and the substrate becomes -10 or more. According to this method, a porous film having a high porosity on the surface of the film and having homogeneous micropores from the surface of the film to the inside can be obtained. The porous film of the present invention is a porous film having a plurality of micropores having communication properties, the film has a thickness of 5 to 200 µm, and an average pore diameter of the surface of 0.01 to 10 µm for both surfaces of the film, The ratio A / B of the average pore A and the internal mean pore B is 0.3 to 3, and the ratio C / D of the average pore rate C on the surface and the average pore rate D on the inside is 0.7 to 1.5.n n n Porous film, polymer solution, phase inversion method, surface tension, porosity, average pore size |