3DOM Silica Composite Membrane Including Binary PAMPS-SPEES Polymer Electrolyte for DMFC

Three-dimensionally ordered macroporous (3DOM) silica composite membrane including a binary polymer [poly(2-acrylamido-2-methyl-1-propanesulphonic acid) (PAMPS)sulphonated poly(1,4-phenylene ether ether sulphone) (SPEES)] was fabricated by stepwise filling method. In the PAMPS-SPEES composite membrane, SPEES coated 3DOM silica surface and PAMPS occupied the remaining vacancy. Therefore, the structure of PAMPS-SPEES in the 3DOM silica was a core-shell like structure. The methanol permeability of composite membrane was successfully reduced from 1.9 x 10(-6) to 3.2 x 10(-7) cm(2) s(-1) at 30 degrees C by the stepwise filling of SPEES and then PAMPS. The proton conductivity of SPEES-3DOM composite membrane was also improved by the PAMPS impregnation. However, the increment was not very notable regardless of the high conductivity of PAMPS. This result suggests that the proton transfer in 3DOM composite membrane mainly depends on the SPEES phase coating on 3DOM pore surface. Consequently, PAMPS-SPEES-3DOM composite membrane exhibited more than ten times higher performance than Nafion as an electrolyte membrane for direct methanol fuel cells (DMFCs).