Process for making membranes

A process for making a membrane M, the process comprising:

• a) preparing a copolymer C, wherein said copolymer C comprises blocks of at least one polyarylene ether A and blocks of polyalkylene oxide PAO, wherein the content of polyalkylene oxide PAO in copolymer C is 30 to 90% by weight and wherein copolymer C is prepared in a solvent L to yield solution S;
• b) providing a dope solution D comprising at least one polymer P;
• c) mixing the solution S obtained in the preparation of copolymer C and the dope solution D to obtain a mixture;
• and
• d) preparing a membrane by bringing the mixture of the solution S and the dope solution D into contact with at least one coagulating agent.