Mixed organic ionic and electronic conductors are being explored for a wide range of applications, from bioelectronics to neuromorphic computing, artificial muscles and energy storage applications. These materials exploit the simultaneous transport properties of ionic and electronic carriers to enable novel device functions. Recently, polymer semiconductors have received significant amounts of attention because of their flexibility, biological compatibility and ease of fabrication. These materials, particularly thiophene-based polymers such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS) and related derivatives, have demonstrated significant enhancements in performance in a relatively short amount of time, with transconductance values of PEDOT:PSS transistors surpassing those achieved even with graphene.
Through our NSF Designing Materials to Revolutionize and Engineer our Future (DMREF) award with researchers at Cornell University and the University of Chicago, we have been investigating the synthesis of ethylene-glycol functionalized polythiophenes, their thin film morphology, and their ionic and electronic conductivities, and comparing against theoretical predictions. In this talk, the effect on the density of the ethylene-glycol side chains and their pattern of placement on ionic conductivity will be discussed.