Polymer electrolyte for a direct oxidation fuel cell, method of preparing the same, and direct oxidation fuell cell comprising the same

A polymer electrolyte membrane (14) for a direct oxidation fuel cell includes a porous polymer supporter (10) having a plurality of pores, and a hydrocarbon fuel diffusion barrier layer (12) which is formed on the polymer supporter and contains an inorganic additive dispersed in a cation exchange resin.