Synthesis of fluorinated amphiphilic triblock copolymer and its application in high temperature PEM fuel cells

New fluorinated amphiphilic triblock copolymers composed of fluorinated poly(arylene ether) and sulfonated poly(styrene-co-acrylonitrile) were synthesized through condensation polymerization followed by controlled radical polymerization, for application in polymer electrolyte membrane fuel cells. The morphological structure of the triblock copolymers was investigated as a function of hydrophilic block length, and was related to the proton conductivity and durability of the copolymer membranes. Unlike commercially available Nafion, which shows a decrease of the proton conductivity at high temperatures above 80 degrees C, the newly synthesized membranes exhibit high proton conductivity and continuous increases in proton conductivity with increasing temperature from 30 degrees C to 100 degrees C. They also show excellent thermal, oxidative and hydrolytic stabilities.