NOVELTY - A polyelectrolyte (P1) comprises acrylic and/or vinyl resin (a1) having at least one ionic or ionizable group, and additional polymer (b1). (a1) has domain size of at most 500 (preferably at most 100) nm.    USE - In a membrane electrode assembly useful in a fuel cell operating with a liquid hydrocarbon fuel (claimed); in films, membranes, fuel cells, coatings, ion exchange resins, oil recovery, biological membranes and batteries.    ADVANTAGE - (P1) when formed into a film, has a conductivity of at least 20 (preferably 50 - 200) mS/cm. (P1) has higher chemical resistance and mechanical strength; has ionic functionalities; avoid a high liquid crossover through the membrane; can be made directly from a dispersion or solution of a polymer without separate sulfonation steps; has a reduced thickness, and yet achieves improved reduced fuel crossover and reduced areal resistance. The ionic or ionizable functionality is chemically bond to the polymer chain via polymerization thus avoiding grafting techniques. The need to use environmentally unfriendly solvent solution is avoided, also there is no need for post-sulfonation of resin using acids such as sulfuric acid or its derivative. Since the ionic or ionizable group is polymerized, its distribution along the polymer chain is easily controlled by conventional techniques such as shot addition, continuous feed and late addition. Thus, the resulting group distribution in a membrane formed form the polymer blend can be more easily controlled than previously and the tailoring of various properties, such as homogeneous, random, heterogeneous can be achieved. The domain sizes of the acrylic resin or vinyl resin are dramatically decreased in the additional polymer such that the phases are compatible to the point where the domain sizes are less than at most 1000 (preferably at most500, especially at most 100) nm and to the point where the domains are barely detectable.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a multi-layer polyelectrolyte membrane comprising at least two layers, where at least one layer comprises (a1) and (b1), where ionic or ionizable group is present in an amount of 200 - 2500 EW and the membrane has a methanol crossover rate of at most 5x10-16 mol/cm2/s.