Growth of Polyelectrolyte Layers Formed by Poly(4-styrenesulfonate sodium salt) and Two Different Polycations: New Insights from Study of Adsorption Kinetics

Abstract

We report an experimental study on the growth and adsorption kinetics of polyelectrolyte multilayers (PEMs). PEMs composed of poly(diallyldimethyl ammonium chloride) (PDADMAC) and poly(sodium 4-styrenesulfonate) (PSS), and of poly(allylamine hydrochloride) (PAH) and PSS polyelectrolyte pairs were built and studied via dissipative quartz crystal microbalance (D-QCM) and ellipsometry. The results have pointed out that the growth trend of PEMs may be controlled by the assembly conditions that modify the layer structure and subsequently the film features. The study of adsorption kinetics of the layers suggests that, even though interdiffusion may take place during the growth of PEMs, it does not determine the growth mechanism. Analysis of the mechanical properties allows confirmation of the scenario proposed for the explanation of the PEMs growth. Independent of growth type, the adsorption kinetics of the layers is a bimodal process. The results here presented allow us to rule out any correlation between growth mechanism and adsorption dynamics.