Modification of poly(3-methylthiophene) (PMeT) structure during electrochemical doping-undoping, studied by in situ atomic force microscopy (ECAFM)

Doping and undoping of poly(3-methylthiophene) (PMeT) layers were performed in an electrochemical atomic force microscopy (ECAFM) microcell, and images accounting for modification of the polymer surface were continuously recorded. The main result is that the variation of polymer morphology is very slow in relation to the modification of doping charge. The discrepancy between the two time constants, related respectively with ion and solvent molecule transfer and by electronic charge transfer, was emphasized by in situ ellipsometry. In this case the variation of optical properties against doping charge is very fast.