Novel methanol-blocking polymer electrolyte composite membranes were prepared by inserting purple membrane (PM) to the bulk phase of Nafion (R) resin. Results of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) analyses show that PM was well-dispersed in Nafion (R) membrane. Compared with recast Nafion (R), blending PM changed the microstructure of Nafion (R) membrane and significantly improved the methanol-blocking efficiency by 31.6% in maximum. With PM content of 0.3 wt% in the composite, the highest membrane selectivity factor and single cell power density of 62.1 mW cm(-2) were achieved. This satisfactory cell performance has given a promising prospect of Nafion (R)/PM composite membranes in the application in DMFC. (C) 2011 Elsevier B.V. All rights reserved.