Oligomeric A2 + B3 synthesis of highly branched polysulfone ionomers: novel candidates for ionic polymer transducers

Highly branched poly(arylene ether sulfone)s with systematically varied degrees of branching and sulfonation were synthesized through oligomeric A(2) + B-3 methods for application as ionic polymer transducer (IPT) membranes. IPTs area class of electroactive polymer devices that leverage ionomeric membranes to perform electromechanical transduction as actuators and/or sensors. Synthesis of controlled molecular weight A(2) Oligomeric polysulfones targeted the global degree of branching (DBglobal) to approximately 1-3% in the absence of gelation. Size exclusion chromatography confirmed molecular weights greater than 20 000 g mol(-1) were achieved for linear and branched polysulfones. Increased degree of sulfonation of the A(2) oligomers reduced the development of molecular weight in the oligomeric A(2) + B-3 branching reaction; the formation of tough, flexible, ion-conducting membranes is required for emerging transducer applications. Variation in the DBglobal attained did not affect the thermal transitions or elastic modulus as significantly as changes in the degree of sulfonation. However, an ionic dissociation temperature vias detected below the glass transition temperature of the polysulfone matrix and was relatively independent of the degree of sulfonation. Successful synthesis and characterization of these well-defined branched polysulfone ionomers provide a basis for future investigation of polymer topology effects on IPT performance. (C) 2009 Society of Chemical Industry