β-chitosan-clay films: Characterization and antibacterial study using response surface methodology

Properties of the chitosan films can be improved by incorporating clay minerals. So, solvent-cast films of the β-chitosan containing stevensite-rich or kaolinitic-illitic clays (up to 50 mass %) were characterized for their structural and mechanical properties. The effects of molecular weight (MW) and deacetylation degree (DD) of chitosan and the clay/chitosan mass ratio on the inhibition growth of Escherichia coli and Staphylococcus aureus were studied using the response surface methodology (RSM). The films consisted of exfoliated/intercalated or flocculated composites, and the electrostatic bonds formed between the functional moieties of the chitosan and the clay particles active sites essentially influenced their mechanical strength. The results of the study using RSM showed that the optimal value of MW required for the inhibition of the bacteria varied according to the film used, and high antibacterial activity necessitated high DD (89–97%). Graphical Abstract