In situ monitoring of polymerredox states by resonance μRaman spectroscopy and its applications in polymer modified microfluidic channels

Abstract

We report the application of multi-wavelength resonance Raman (rR) spectroscopy for the characterisation of vinyl-bridged polysexithiophene films formed by electropolymerisation on gold electrodes. Resonance Raman spectroscopy of the neutral, polaronic and bipolaronic states of the polymer were determined by in situ μRaman spectroelectrochemistry. In particular the differences in the UV/Vis-NIR absorption spectra of the neutral, monopolaronic and bipolaronic states of the polymer allow for characterising the redox state of the polymer films in PDMS based microfluidic channels. The information obtained in this way allows for determination of the optimum film thickness required for achieving full electrochemical switching between neutral and charged states, which is important in their use in switching surface properties. The approach taken allows for direct analysis of polymer films formed within microchannels.