Sulfonated multiwalled carbon nanotube/sulfonated poly(ether sulfone) composite membrane with low methanol permeability for direct methanol fuel cells

An organic/inorganic composite membrane was prepared based on sulfonated poly(ether sulfone) (s-PES) embedded with sulfonated multiwalled carbon nanotubes (s-MWNTs). The ion exchange capacity (IEC), proton conductivity, and water uptake of the SPES membranes increased with increasing s-MWNTs content. The increased water uptake was attributed to hydrogen bond formation between the carbonyl group of the s-MWNTs and a water molecule. The composite membranes exhibited proton conductivities ranging from 3.9281 x 10-4 to 7.0788 x 10-3 S/cm at 80 degrees C, as well as low methanol permeability ranging from 4.4405 x 10-10 to 9.1008 x 10-10 cm2 s-1 at 25 degrees C. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012