EQCM characterization of some substituted polyterthiophenes

The electrochemical growth of polyalkylterthiophenes has been monitored in situ with the Electrochemical Quartz Crystal Microbalance (EQCM). Potential controlled synthesis of poly-3'4'-didodecyilterthiophene (3'4'-DDTT) and p oly-33 "-DDTT revealed an unexpected cathodic precipitation following the a nodic deposition. From the analysis of the experimental data we obtained an excellent fit of the cathodic precipitation curves with a first-order nucl eation law. A correlation between substitution pattern of the starting mono mers and the deposition kinetic of the resulting polymers was found. Factor s controlling the cathodic deposition of the Poly-DDTTs didn't depend on th e presence of a parent phase on the electrode. Finally, long time-scale exp eriments (500 s) with EQCM during potentiostatic synthesis of Poly-DDTTs re vealed an evolution of the deposited mass with peculiar features of a proce ss under diffusion control. (C) 1999 Elsevier Science Ltd. All rights reser ved.