Patent ID: 8039160

Claim:
A multi-layer polyelectrolyte membrane comprising two or more layers, wherein at least one of said layers comprises: a) at least one acrylic and/or vinyl resin or both having at least one ionic or ionizable group and said a) is present in average domain sizes of from 1 to 500 nm; and b) at least one additional polymer, wherein a) and b) are different, wherein said at least one ionic or ionizable group is present in an amount of from about 200 to about 2,500 EW, and wherein said membrane has a methanol crossover rate of 5×10 −16 mol/cm 2 /s or lower, and wherein at least one other layer comprises c) at least one acrylic and/or vinyl resin or both having at least one ionic or ionizable group; and d) at least one additional polymer, wherein c) and d) are different, wherein said at least one ionic or ionizable group is present in an amount of from about 200 to about 2,500 EW and wherein said other layer has the same or different composition as the first layer e) neutralizing the acrylic and/or vinyl resin by adding ammonium and/or phosphonium.