in polymer electrolyte membrane fuel cells and electrolyzes , attaining and maintaining high membrane conductivity and durability is crucial for performance and efficiency . the use of low equivalent weight perfluorinated ionomers is one of the few options available to improve membrane conductivity . however , excessive dimensional changes of low ew ionomers upon application of wet / dry or freeze / thaw cycles yield catastrophic losses in membrane integrity . incorporation of ionomers within porous , dimensionally - stable perforated polymer electrolyte membrane substrates provides improved pem performance and longevity . the present invention provides novel methods using micromolds to fabricate the perforated polymer electrolyte membrane substrates . these novel methods using micromolds create uniform and well - defined pore structures . in addition , these novel methods using micromolds described herein may be used in batch or continuous processing .