Improved mechanical strength of partially sulfonated polystyrene-poly (dimethylsiloxane) block copolymer proton exchange membranes by nanoscale sequestration of thermally crosslinked silicone

摘要

To improve the mechanical property of sPS-b-PDMS proton conducting membrane for DMFC application, crosslinkable PDMS oligomer has been incorporated within the BCP ionomer. Premixing different amount of Sylgard 184 PDMS in the ionomer solution, and subsequent membrane casting and thermal curing revealed that the composite membrane containing 5 wt% of Sylgard 184 showed enhanced properties in the uniaxial tensile strength, toughness, methanol permeability, and even in the proton conductance. This results show that the PDMS oligomers were successfully sequestered within PDMS block of sPS-b-PDMS during casting procedure, and safely crosslinked without deterioration of the membrane microphase structure.