Polysulfone Having Sulfonated Side Chains Prepared by Click Reaction for Polymer Electrolyte Membrane

Abstract

New sulfonated side chains were synthesized by click chemistry, which were attached to hydrophobic main chain via click chemistry. Polysulfone was functionalized by chlromethylation and azidation. This functionalized copolymer containing pendant azide moieties reacted with the sulfonated side chains synthesized using 1,4-diethynylbenzene (DEB) and 4,4-diazido-2-2-stilbenedisulfonic acid disodium salt tetrahydrate (DSDAD) by the Huisgen dipolar click cycloaddition reaction. The obtained comb-shaped polymers (Comb-X) showed high proton conductivities of 2.01 × 10-1 S/cm at 80 oC and 90% relative humidity due to distinct phase separation between hydrophobic and hydrophilic domains. Furthermore, the acid-base interactions between triazole and sulfonic acid groups in side chains induced physical cross-linking and improved mechanical properties. Thus, Comb-X polymer membranes showed high mechanical strength with tensile strength of 87 - 91 MPa, Youngs modulus of 9.7 - 10 GPa, and elongation at break of 6.7 - 6.8%.