A study of [Os(bipy)(2)(PVP)(3.3)(PS)(6.7)Cl](+) polymer film modified electrodes using neutron reflectivity

Neutron reflectivity was used to obtain spatial distributions within [Os(bi py)(2)(PVP)(3.3)(PS)(6.7)Cl](+) modified Au electrodes (where PVP represent s poly(4-vinylpyridine) and PS represents polystyrene) in contact with incr easing concentrations of two types of electrolyte, perchlorate and p-toluen esulfonate. Film swelling and corresponding solvent ingress were observed t o be more pronounced in p-toluenesulfonate media than in perchlorate media, yet the effects were found to be of lesser magnitude than for the correspo nding homopolymer system, [Os(bipy)(2)(PVP)(10)Cl](+). Film structural chan ges upon immersion in solvent and redox cycling in electrolyte were determi ned. A comparison with the him maintained in Os-II and Os-III oxidation sta tes revealed further film swelling in the oxidized state.