Abstract
A facile method for the preparation of a polymer surfactant (P-Cn-Chitosan) derived from chitosan was proposed. Chitosan was dissolved into water with lactic acid or pyrrolidone-2-carboxilic acid (PCA), then was partially acylated with acid anhydrides possessing long alkyl chains. P-Cn-Chitosan showed a strong emulsifying activity on the 1:1 mixture of squalane and water. The structure of this emulsion was o/w type and the role of the alkyl chains for emulsification was clarified by the spin probe method, showing that P-Cn-Chitosan acts as a cationic surfactant and covers the surface of the oil droplet by anchoring its alkyl chains. DSC study revealed that the lipid bilayer of liposome prepared from dipalmitoylphosphatidylcholine was stabilized by the surface adsorption of P-Cn-Chitosan. P-Cn-Chitosan did not show acute toxicity to a fish, Orizias Latipes, and was degraded by microorganisms in a river water. These results suggested that P-Cn-Chitosan is usable as a surfactant for medicines, cosmetics and foods.
