Abstract
	The controlled deposition of polymer thin films composed of silver nanoparticles capped with sodium alginate and poly (diallyl-dimethylammonium chloride) (PDADMAC) is reported. The thin films were built by sequential dipping of a glass substrate in solutions containing either silver nanoparticles or the poly-cationic PDADMAC. The thin film thickness was monitored with a UV-Vis spectrophotometer, which measure the change in absorbance at 430 nm corresponding to the surface plasmon absorbance band of the silver nanoparticles on the thin film. The effect of three parameters namely the concentration in polyelectrolyte, the dilution factor of the silver nanoparticles solution and the ionic strength of the solution were investigated. Results show that the ionic strength of the solution has a major effect on the growth of the film and that the optimum NaCl concentration is comprised between 0.2 and 0.3 M NaCl. Our experiments show that the concentration in PDADMAC and silver nanoparticles have a minor effect on the final absorbance of the thin film as long as they are kept above a critical concentration of 1mM for PDADMAC and a dilution factor not higher than 2.