| Abstract
| - A probe beam deflection (PBD) study of ion exchange between an electroactive polymer poly(allylamine)−bipyridyl−pyridine osmium complex film and liquid electrolyte is reported. The PBD measurements weremade simultaneously to chronoamperometric oxidation−reduction cycles, to be able to detect kinetic effectsin the ion exchange. Layer-by-layer (LbL) self-assembled redox polyelectrolyte films with osmium bipyridylcomplex covalently attached to poly(allylamine) (PAH−Os) and poly(styrene sulfonate) (PSS) have beenbuilt by alternate electrostatic adsorption from soluble polyelectrolytes. The ionic exchange during initialconditioning of the film (“break-in”) undergoing oxidation−reduction cycles and recovery after equilibrationin the reduced state have shown an exchange of anions and cations with time lag between them. The effectof the nature of cation on the ionic exchange has been investigated with dilute HCl, LiCl, NaCl, and CsClelectrolytes. The ratio of anion to cation exchanged at the film−electrolyte interface has a strong dependenceon the nature of charge in the topmost layer, that is, when negatively charged PSS is the capping layer, alarger proportion of cation exchange is observed. This demonstrates that the electrical potential distributionat the redox polyelectrolyte multilayer (PEM)/electrolyte interface determines the ionic flux in response tocharge injection in the film.
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