Method for preparing loose cross-sectional asymmetric isoporous membrane based on thermally induced phase separation process

A method for preparing a loose cross-sectional asymmetric isoporous membrane based on a thermally induced phase separation process, comprising:

• S1:
• stirring a block copolymer, a diluent, and a pore-forming agent at 40° C. to 185° C. to form a homogeneous membrane casting solution, wherein the block copolymer comprises a hydrophobic chain segment and a hydrophilic chain segment, the hydrophobic chain segment is polystyrene, and the hydrophilic chain segment is a water-soluble polymer or a polymer formed by polymerizing a water-soluble monomer, the diluent is cyclohexanol and/or an ethylene glycol derivative, and the membrane casting solution is phase homogenous at high-temperature and phase separation at low-temperature, or phase homogeneity at high-temperature and gelation at low-temperature;
• S2:
• preheating a porous cloth or a metal plate, evenly spreading the membrane casting solution on the porous cloth or the metal plate, and evaporating the spread solution at 40° C. to 150° C. for 5 s to 45 s, and transferring into a coolant for cooling and gelling;
• and
• S3:
• immersing a cooled and gelled membrane into an extracting agent for solvent extraction from solid or gelled membrane, and transferring into deionized water for soaking, to obtain the asymmetric isoporous membrane.