engleski

Influence of an anchoring layer on the properties of chitosan-carboxymethylcellulose multilayers

The use of an anchoring layer for polyelectrolyte multilayer formation is a known practice for tuning multilayer properties, mainly to improve surface coverage, roughness, and thickness. For this, poly(ethyleneimine), PEI, has been used as an anchoring layer for different combinations of polyelectrolytes. One of such combinations is chitosan, CS, and carboxymethylcellulose, CMC. These polyelectrolytes have gained much attention in recent years due to their antibacterial and antifungal properties while being biocompatible and non-toxic to humans. Due to these properties, CS/CMC multilayers have the potential to be used in agriculture, food processing and biotechnology as protective coatings. PEI proved to be a great anchoring layer to improve CS/CMC multilayer properties, but, unfortunately, the toxicity of PEI is still a matter of debate. This fact makes it a questionable anchoring layer for a non-toxic combination of polyelectrolytes. In this study, we prepared CS/CMC multilayers using dipping technique on Si-SiO2 wafers with different anchoring layers and addition of NaCl at constant pH. Ellipsometry was used for monitoring film growth, while surface properties were determined using atomic force microscopy. Our results show that CS/CMC multilayers, up to 5 bilayers, without the addition of an anchoring layer do not coat Si-SiO2 wafers completely. With addition of PEI as an anchoring layer, prepared nanofilms are thicker and fully coat the wafer. Moreover, we also prepared highly concentrated solutions of CS as an anchoring layer which replicated the effects of PEI. Finally, the addition of NaCl to starting polyelectrolyte solutions resulted in the formation of thinner films.

Polyelectrolyte multilayers ; Ellipsometry ; Atomic force microscopy ; Nanofilm growth ; Surface properties

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