Formulation, characterization, and sensing applications of transparent poly(vinyl alcohol) polyelectrolyte blends

Several new optically clear polymer blends have been formulated for selectively incorporating solution-phase anions and cations. In all of the blends poly(vinyl alcohol) was the host matrix and it was cross-linked with glutaraldehyde to entrap polyelectrolytes including poly(acrylic acid), Nafion, poly(diallyldimethylammonium chloride), poly(vinylbenzyltrimethyl-ammonium chloride), and poly(styrenesulfonic acid). [RU(BiPy)(3)](2+) and Fe(CN)(6)(3-) were used as prototypical analytes to study the ion-exchange properties of the new blends. The thicknesses of spin-coated thin films of the blends were variable over a wide range (0.70 mu m being typical), as determined by an optical interference method. Thin film coatings of three of the blends were optimized for single-step covalent coating on activated oxide surfaces. Two silane coupling agents, 3-glycidoxypropyltrimethoxysilane and 3-aminopropyltriethoxysilane, were used to covalently attach these three blends to glass and ITO-coated glass surfaces. The potential use of these materials for chemical sensing has been demonstrated by applying them to multiple internal reflection and spectroelectrochemical devices as thin films.