permeable , porous polymeric membrane with hydrophilic character of the membrane , said character being obtained by treatment with a solution comprising one or more hydrophilic , mono - or polymeric compounds selected among soluble , oh - containing cellulose derivatives , polyvinylalcohols and low molecular weight , polyfunctional , nh - and / or oh - containing compounds , optionally in the presence of a cross - linking agent , a surfactant and a initiator followed by rendering the layer deposited during the treatment insoluble on the membrane surface by means of a catalyst reaction at elevated temperatures in order to fixate the hydrophilic material to the membrane . furthermore a process for the preparation of these membranes by means of treating a permeable , porous , polymeric membrane of hydrophobic character with the above solution in the presence of a catalyst and optionally in the presence of a cross - linking agent , a surfactant and an initiator , and curing of the coated membrane by means of heating to form an insoluble , hydrophilic surface layer . the membranes are suitable for use in ultra - and microfiltration .