engleski

Effect of metal substrate on properties of poly(allylamine hydrochloride) / poly(acrylic acid) multilayer

Polyelectrolytes are macromolecules that consist of a repeating sequence of subunits which can be charged in the solution. Positively charged polyelectrolytes are called polycations, while negatively charged are called polyanions. Polyelectrolyte multilayers are films which are formed by alternating adsorption of polycations and polyanions on a surface, most often with layer-by-layer (LbL) method. The properties of a film depend on the polyelectrolyte type, as well as on experimental conditions such as pH, ionic strength, type of the background salt and used substrates. Polyelectrolyte multilayers are also particularly interesting due to their wide application in medicine and biotechnology, especially as antibacterial protection. The aim of presented study was to show how the type of metal substrate affects the properties of multilayer prepared from poly(allylamine hydrochloride), PAH, and poly(acrylic acid), PAA. Commercially available silicon, titanium and aluminum plates were used as metal substrates. The metal substrates were characterized by ellipsometry, atomic force microscopy and contact angle measurements. Afterwards, ten-layer films were prepared on the mentioned substrates and the growth (thickness) of multilayers was monitored by ellipsometry. The morphology and surface roughness of the prepared multilayers was determined by atomic force microscopy. It was observed that the thickness and surface roughness of films increase depending on the used substrate in the order: silicon, titanium and aluminum. These differences could primarily be explained by isoelectric points of used substrates which follow the same trend.

Polyelectrolyte ; Polyelectrolyte multilayer ; Substrate

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