Method for preparing composite positive permeable membrane by layer-by-layer self-assembly interfacial polymerization

The invention discloses a method for preparing a composite positive permeable membrane by layer-by-layer self-assembly interfacial polymerization. According to the method, a polyether sulfone basementmembrane is prepared by using polyether sulfone as a membrane material, using polyvinyl alcohol as a hydrophilic modifier and using polydopamine as a cross-linking agent through thermally induced phase separation; and then by using m-phenylenediamine as a water-phase monomer and using trimesoyl chloride as an oil-phase monomer, layer-by-layer self-assembly interfacial polymerization is carried out on the polyether sulfone basement membrane to prepare the composite positive permeable membrane. The composite positive permeable membrane prepared by the method disclosed by the invention is stablein chemical property, high in mechanical strength, compact in composite layer, firm in combination, difficult to fall off, good in hydrophilicity, high in anti-pollution capacity, large in pure waterflux and low in salt inver