LAUSR

Abstract A facile self-assembly procedure was developed for the preparation of silver nanoparticle shells at polystyrene microparticles (PSMPs) modified by poly(diallyldimethylammonium chloride) (PDADMAC). Initially, physicochemical properties of microparticles, silver particles and (PDADMAC) were determined for various ionic strength and pHs. Then, PDADAMAC adsorption on the PSMPs was studied in situ via electrokinetic measurements. The influence of polyelectrolyte bulk concentration on electrokinetic properties of PDADMAC-coated microparticles for different ionic strength was investigated. The coverage of PDADMAC monolayer was estimated applying an electrokinetic model. The stability of PDADMAC-modified microparticles under controlled conditions of pH and ionic strength was also evaluated. It was confirmed that under acidic conditions (pH 4–5.6) the microparticles were stable for at least two weeks. The modified microparticles were used as substrate for silver nanoparticle immobilization carried out under a diffusion controlled self-assembly process. The coverage of nanoparticles was precisely determined using electrophoretic mobility measurements, the concentration depletion method involving atomic force microscopy and via direct scanning electron microscopy imaging of particles. A large stability of the silver particle monolayers was confirmed. These monolayers of well-defined coverage and acid-base properties can be used for controlled delivery of silver nanoparticles.