Rapid microwave assisted synthesis and characterisation of a semiconducting polymer with pKa tuneable degradation properties

Abstract

As part of ongoing efforts to develop electroactive polymers (EAPs) which are biodegradable/bioresorbable, we report on the microwave assisted synthesis and characterization of an electrically conducting and electroactive polymer that capitalises on pKa sensitivity to initiate the system’s fracture and breakdown. The system, poly(bis((thiophen-2-yl) methylene) benzene-1,4-diamine), a poly(thiophene-azomethine) co-polymer (PAZO), incorporates hydrolytically sensitive azomethine linkers amongst bithiophene units resulting in one continuously conjugated and redox-active macromolecular framework. Rapid microwave assisted synthesis allowed for facile preparation of the polymer with significantly reduced reaction times when compared to traditional synthetic routes. Electrochemical analysis indicated quasi-reversible electrochemical behaviour with sufficiently high conductivity for in vivo biomedical applications. The polymer displays tunable degradation behaviour whereby the time duration required for polymeric breakdown is a function of the pKa of the acid used to catalyse the reaction resulting in controllable degradation times ranging from 1 h to 6 months. The development of conductive polymeric materials that are fully degradable over pre-defined time periods opens up a portal to the next generation of EAPs for in vivo biomedical applications.