Synthesis of Long-Chain-Branched (LCB) Polysulfones for Multifunctional Transport Membranes

Abstract : Long-chain-branched (LCB) polysulfones were synthesized for potential application as multifunctional ion-transport membranes. Combination of bulky and rigid monomer units with controlled levels of branching is proposed as a method to increase free volume of the polymer matrix. Increases in free volume may allow for improved ion transport decoupled from the segmental motion of the polymer backbone, especially in these high glass transition temperature materials. Increased transport in glassy materials enables multifunctional applications that require ion transport and structural rigidity. The series of novel polymers was characterized for chemical structure, thermal transitions, and molecular weight. Ionic conductivity was tested for films cast in the presence of two lithium salts.