AN IN-SITU SCANNING PROBE MICROSCOPY STUDY OF COPPER ELECTRODEPOSITION ON CONDUCTIVE POLYPYRROLE

The initial stages of copper electrodeposition onto conductive polypyr role have been directly examined with in situ scanning probe microscop y (SPM). The deposition of copper onto polypyrrole is compared with th e deposition of copper onto gold. We have examined copper deposition f rom additive-free electrolytes and also electrolytes containing an org anic additive (a benzothiazole derivative, BTD). Copper electrodeposit ion in the absence of additives is characterised by an instantaneous n ucleation and 3-dimensional growth of the copper deposit on both polyp yrrole and gold substrates. In the latter case the growth mode is Stra nski-Krastanov, since 3-D growth centres are formed directly on-top of the underpotentially deposited copper monolayer. The morphology of th e copper growth on polypyrrole is similar both in the presence or abse nce of BTD. In both cases the growth is Volmer-Weber. By contrast, the morphology of the copper growth on gold is dramatically affected by t his additive. in this case the copper deposit exhibits a quasi-2-D gro wth (quasi-Frank van der Merwe growth), with layer deposition occurrin g by a ''birth-and-spread'' mechanism. Possible reasons for the differ ences in the additive's influence upon the copper growth on gold and p olypyrrole are discussed.