Polymer-based film, preparation method therefor, and use thereof

A method for preparing a membrane, comprising:

• 1) dissolving at least a first polymer and a second polymer in a good solvent to form a membrane casting solution;
• 2) applying the membrane casting solution in the form of a film, exposing the film to a bath of atomized droplets for a period of time, wherein the atomized droplets are droplets of a first poor solvent for the first polymer;
• and
• 3) immersing the film obtained from step 2) in a solidification bath to obtain the membrane, wherein the solidification bath comprises a second poor solvent for the first polymer,
• wherein the first polymer is at least one selected from the group consisting of polyvinyl chloride, polysulfone, polyethersulfone, sulfonated polyethersulfone, polyacrylonitrile, cellulose acetate, polyvinylidene fluoride, polyimide, acrylonitrile-styrene copolymers, polyvinylidene fluoride modified by acrylic acid grafting, sulfonated polysulfone, maleic anhydride-grafted polysulfone, sulfonated polyethersulfone, and acrylic acid-grafted polyacrylonitrile, and
• the second polymer is at least one selected from the group consisting of chitosan, polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, and polyoxyethylene polyoxypropylene ether block copolymer,
• wherein the good solvent is selected from the group consisting of N,N-dimethylformamide, N-methylpyrrolidone, N,N-dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, acetonitrile, acetone, chloroform, toluene, benzene, hexane, octane, tetramethyl sulfoxide, and mixtures thereof, and
• the first and the second poor solvents for the first polymer are independently selected from the group consisting of water, ethanol, ethylene glycol, a mixed solvent containing water, and a solution containing a salt, an acid or a base;
• and
• wherein the resulting membrane comprises:
• a fiber skeletal structure of three-dimensionally interwoven and interconnected polymer fibers,
• pores distributed in the fiber skeletal structure having an average pore size in a range of 0.1 μm to 10 μm, and
• nano-scale protrusions distributed on the fiber skeletal structure having a size in the range of from 20 to 400 nm, and
• a volume porosity of the membrane is 50%-95%.