Specific effects of calcium acetate on the self-assembly of chitosan molecules on mica surface observed with atomic force microscopy

The well-organized chitosan film on mica surface has drawn wide attention for its potential applications and studies on the process of self-assembly. In this article, atomic force microscopy was used to investigate the ultrastructure of the self-assembly of chitosan molecules with calcium ions in different concentrations. It was showed that calcium ions might affect the self-assembly of chitosan to a certain extent, and chitosan molecules gathered from fibrils to circular, and finally formed to film with the increasing concentration of calcium ions. Further, the formation mechanism of Ca(II)-chitosan conjugates was adapted to explain the effects of calcium ions on the self-assembly of chitosan. These results and the related analysis would be valuable for guiding the pattern of chitosan self-assembly with a potential application in food packaging science and engineering.