Membrane comprising self-assembled block copolymer and process for producing the same by spray coating (Ic)

A method of preparing a porous membrane comprising a diblock copolymer of the formula (I):

• wherein:
• R1 is a C1-C22 alkyl group optionally substituted with a substituent selected from halo, alkoxy, alkylcarbonyl, alkoxycarbonyl, amido, and nitro, or a C3-C11 cycloalkyl group, optionally substituted with a substituent selected from alkyl, halo, alkoxy, alkylcarbonyl, alkoxycarbonyl, amido, and nitro;
• R2 is a C6-C20 aryl group or a heteroaryl group, optionally substituted with a substituent selected from hydroxy, amino, halo, alkoxy, alkylcarbonyl, alkoxycarbonyl, amido, and nitro;
• one of R3 and R4 is a C6-C14 aryl group, optionally substituted with a substituent selected from hydroxy, halo, amino, and nitro, and the other of R3 and R4 is a C1-C22 alkoxy group, optionally substituted with a substituent selected from carboxy, amino, mercapto, alkynyl, alkenyl, halo, azido, and heterocyclyl;
• and
• n and m are independently about 10 to about 2000;
• wherein the volume fraction of the monomeric unit bearing R2 to that of the monomeric unit bearing R1 in the block copolymer is about 2.3 to about 5.6:1;
• wherein the porous membrane has cylindrical morphology;
• the method comprising:
• (i) dissolving the diblock copolymer in a solvent system to obtain a polymer solution;
• (ii) spray coating the polymer solution onto a substrate;
• and
• (iii) annealing the coating obtained in (ii) in a vapor comprising a solvent or a mixture of solvents to obtain a self-assembled porous membrane.