A method for preparing a durably hydrophilic and uniform-pore ultrafiltration membrane is disclosed herein. Chemical reactions between the functional groups and the active bonds of the molecular chains in the membrane materials are initiated perform the grafting of hydrophilic chains on the polymer chains under conventional dissolution conditions of the polymer membrane material (dissolution with synchronized hydrophilization), so as to realize durable hydrophilization of the membrane materials. The resulting hydrophilized polymer solution (a nascent-state membrane) is introduced into a coagulation bath to initiate a crosslinking reaction among the hydrophilic chains. The resulting crosslinking serves to synergistically regulate subsequent phase separation and membrane formation (phase separation under synergistic crosslinking).

The present disclosure provides an article including an isoporous membrane disposed on a porous substrate. The isoporous membrane includes a triblock copolymer or a pentablock copolymer. The isoporous membrane has a thickness and is isoporous throughout its thickness. A method of making an article is also provided, which does not require a solvent exchange process. The method includes depositing a composition on a porous substrate, thereby forming a fdm, and removing at least a portion of the solvent from the film, thereby forming an isoporous membrane having numerous pores. The composition contains a solvent and solids including a triblock copolymer or a pentablock copolymer. The article advantageously can be hydrophilic and provides sharp molecular weight cut-offs and high flux.