Structure-function Properties of Microphase Separated Ion Conducting Block Copolymer Thin Films*

In this talk, we will discuss the role of the ion conduction path on the electrochemical behavior of ion conducting block copolymer (BCP) thin films. A BCP thin film with one ion conducting block (poly(2-vinyl n-methylpyridinium iodide)) and one ion insulating block (polystyrene) was micro-phase separated into a variety of conduction paths on top of interdigitated electrodes (IDEs). A random copolymer was grafted onto the IDE surface to align the domains perpendicular to the surface. Therefore, simple top down surface metrology techniques could be used to characterize all of the ion conduction pathways from one electrode to the other. The conductivity and capacitance values, calculated from complex impedance spectra, changed by orders of magnitude when the morphology of the BCP film was altered. Additionally, visual analysis of the conduction paths along with molecular dynamic simulations were used to predict the measured resistance of the film within experimental error.