engleski

Divalent cation effects on poly(diallydimethylammonium chloride)/poly(sodium 4-styrensulfonate) nanofilm deposition

Polyelectrolytes are macromolecules that consist of a repeating sequence of subunits that bear an electrolyte group. According to the charge they are divided into polycations, polyanions, and polyampholytes, while according to the degree of dissociation in solution, they are divided into strong and weak. Polyelectrolyte multilayers are films that are formed by alternating adsorption of polycations and polyanions on a surface, most often using layer-by-layer method. The properties of the deposited film depend on the experimental parameters such as used polyelectrolytes, type of substrate, ionic strength, and type of background salt. In this study, we investigated how the type of divalent cation affects the multilayer prepared from poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate). The examined cations were Mg2+, Ca2+, Sr2+, Ba2+, Ni2+, Zn2+ and Cu2+. Ellipsometry was used for monitoring the growth of the films up to ten layers, while atomic force microscopy was used to determine morphology and surface roughness. The change in surface wettability during polyelectrolyte adsorption was monitored by tensiometry. While for alkaline earth metal cations ion-specific effect was observed, for transition metal cations this was not the case. The thickness, roughness, and wettability of films prepared in the presence of transition metal cations were not significantly different. In contrast, these properties differed for multilayers prepared in the presence of alkaline earth metal cations.

divalent cations ; polyelectrolytes, nanofilm deposition

nije evidentirano