Investigation The cathodic Electrodeposition behavior of chitosan biopolymer in different solid contents

摘要

Chitosan is a linear hydrophilic polysacharid obtained by deacetylation of nature chitin. It is an attractive biocompatible and nontoxic biopolymer that exhibits excellent film forming ability. Moreover, it responsive to localized electrical signals, serves as an excellent candidate for electrodepositing process. Biopolymer chitosan with some primary amino group has PKa about 6.3. At lower pH most of the amino groups are protonated making chitosan water soluble polyelectrolyte. When the pH is higher than pKa, the amino groups are deprotonated and chitosan become insoluble. This property allows the chitosan hydrogel to be electro assemble from an aqueous bulk solution onto a conductive surface in response to cathodic signal. Although there are increasing numbers of report on application of functional device or hybrid composite in which chitosan is electrodeposited, the mechanism by which an electrodeposited film is formed are not well understood. In this report, we have focused on explanation of the electrodeposition behavior of chtitosan solution by different solid contents. Chitosan solutions(1,0.5,0.25,0.12,0.06)% (w/v) used in this study were prepared by dissolving chitosan flake (Sigma-aldrich,85% deacetylation and 50000 Da as reported by supplier)in lactic acid(1% (w/v)) and de-ionized water The chitosan dispersion were deposited on galvanized panels using rectifier at a constant voltage of 100 V and for a constant duration (180s).