1570 Synthetic Metals, 55-57 (1993) 1570-1573 MEMORY EFFECT IN POLY(4,4'-DIALKYL-2,2'-BITHIOPHENES) AND POLY(3-ALKYL- THIOPHENES) M. LAPKOWSKI Institute of Physical Chemistry and Technology of Polymers, Silesian Technical University, 44 100 Gliwice (Poland) M. ZAGORSKA and I. KULSZEWICZ-BAJER Department of Chemistry, Technical University of Warsaw, 00 664 Warszawa, Noakowskiego 3 (Poland) A. PRON Department of Materials Science and Ceramics, Academy of Mining and Metallurgy, 30 059 Krakow, Mickiewicza 30 (Poland) ABSTRACT The memory effect in poly(4,4'-dialkyl -2,2'-bithiophenes) (PDABTs) and poly(3- alkylthiophenes) (PATs) has been studied. A shift in the oxidation peak position and its intensity is much more pronounced in PDABTs than in PATs. The magnitude of this effect is associated with the difficulty of the dedoping of PDABTs in dynamic processes such as cyclic voltammetry. Thus, long wait times x at the reduced state allow for better recovery of the residual charge. INTRODUCTION Non-equlibrium phenomena in conducting polymers are frequently observed in dynamic studies such as cyclic voltammetry. One of the most characteristic features of the non-equilibrium state is a "memory effect" previously studied in polyaniline [1], polythiophene and its derivatives [2],[3]. This memory effect can easily be observed in an experiment which is a simple modification of cyclic voltammetry. In this case the polymer film deposited on the electrode is kept at the potential corresponding to its reduced state, for a given period of time x, before the triangular potential scan is applied. It has been demonstrated previously [4] that oxidative doping in PDABTs is very abrupt, occuring over a very narrow potential range. This phenomenon gives rise to significant differences in voltammetric behaviour of PATs and PDABTs which, in turn, should also be manifested in memory effect studies. Therefore, in this communication we compare memory effects in PDABTs and in PATs. 0379-6779/93/$6.00 © 1993- Elsevier Sequoia. All rights reserved