Ultrathin molybdenum polyoxometalate-polyelectrolyte multilayer films

Abstract

Ultrathin multilayer films of a novel molybdenum(VI) polyoxometalate cluster ((NH4)21[H3Mo57V 6-(NO)6O183(H2O)18]) (Mo57) and poly(allylamine hydrochloride) (PAH) have been prepared by the consecutive stepwise adsorption of Mo57 and PAH from dilute aqueous solution. The Mo57/PAH multilayer films have been characterized by optical spectroscopy and small-angle X-ray reflectivity (XR) methods. UV-vis measurements reveal regular film growth with each Mo57 adsorption. The average Mo57 surface density was found to be (1.4 ± 0.4) × 1013 clusters per cm2, corresponding to an average surface coverage of 56 ± 12%. XR experiments confirm uniform film growth, with the film thickness increasing with each..