Electron, Ions and Solvent Exchange in Redox Polyelectrolytes Self-Assembled Multilayers

TAGLIAZUCCHI, MARIO; WILLIAMS, FEDERICO J.; SZLEIFER, IGAL; CALVO, ERNESTO J.

Philadelphia

Conferencia; Amer. Chem. Soc., Division of Polymeric Materials: Science and Engineering; 2008

American Chemical Society

We describe recent results with multilayers of poly(allyl-amine) modified covalently with Os(bpy)2PyCl+ (PAH-Os) and poly(vinyl sulfonate) by sequential adsorption layer-by-layer. The intrinsic osmium redox PEMs were subject to cycles of oxidation and reduction. A ?break in? first cycle effect was observed due to the exchange of soluble ions in the electrolyte compensating charge and the break of intrinsic polyion-polyion electrostatic bonds with the formation of polyion-mobile ion bonds in the film. Upon oxidation/ reduction intake of anions or release of cations into the electrolyte has been detected with quartz crystal microbalance, ellipsometry, probe beam deflection and cyclic voltammetry. FTIR reflection-absorption spectroscopy confirmed the exchange of water during redox switch of the films with simultaneous swelling. A molecular theory that explicitly accounts for all the shape and size of all species, the interactions and the acido base and redox equilibria describes the complex system with strong local and non local coupling.