MF-4SC membranes containing a 1-30% grafted carbon phase (CPh) were produced by radiation induced polymerization of polyvinyliden chloride (PVDC) with following dehydrochlorination of the grafted polymer. It was shown that the different CPh-distribution in the modified membranes (in the surface layer or in volume) was realized by grafting PVDC into the starting MF-4SC samples with different chemical structures. Water uptake, proton conductivity, water diffusion, methanol- and hydrogen permeability of modified membranes were investigated by different methods as a function of the CPh-content. It was shown that these characteristics depend on the CPh-distribution in the modified membranes. Nearby 1.5 times reduction of methanol permeability was obtained when the CPh-phase surface layers were formed. (C) 2010 Published by Elsevier B.V.