Electrostatic interactions between polyelectrolytes and a titania precursor: Thin film and solution studies

A facile approach, based on the polyelectrolyte-mediated electrostatic adsorption of a water-soluble titania precursor, titanium (IV) bis (ammonium lactato) dihydroxide (TALH), is presented for the formation of multilayered thin films of defined thickness and composition. The thin films were formed by the alternate deposition of TALH and positively charged polyelectrolyte [poly (diallyldimethylammonium chloride), PDADMAC, poly (allylamine hydrochloride), PAH, and chitosan, CH] utilizing electrostatic interactions for film formation. Layer-by-layer film growth was monitored by UV−vis spectrophotometry, ellipsometry, and by a quartz crystal microbalance (QCM). The UV−vis, ellipsometric, and QCM data all showed that a uniform amount of TALH was deposited with each alternate deposition cycle of polyelectrolyte and TALH, indicating that TALH binds to positively charged polyelectrolytes. Using PDADMAC/TALH as a model system, the influence of drying on multilayer film formation was examined by QCM. These experim...