Synthesis, characterization, and properties of amphiphilic chitosan copolymers with mixed side chains by click chemistry Part A Polymer chemistry

Novel amphiphilic chitosan copolymers with mixed side chains of poly(e-caprolactone) and poly(ethylene oxide) (CS-g-PCL/PEO) were successfully synthesized by graft approach via click chemistry. The melting and crystallization behaviors and crystalline morphology of CS-g-PCL/PEO copolymers can be adjusted by the alteration of the feed ratio of PCL and PEO segments. CS-g-PCL/PEO copolymers revealed crystalline morphology different from that of linear alkynyl PCL and alkynyl PEO due to the influence of brush structure of copolymers and the mutual influence of PCL and PEO segments. The hydrophilicity of the CS copolymers can be improved and adjusted by the alteration of the composition of PCL and PEO segments. Moreover, the CS copolymers can self-assemble into spherical micelles in aqueous solution. Investigation shows that the size of the CS copolymer micelles increased with the increase of the content of hydrophobic PCL segments in copolymers, which indicated that the micellar behavior of the copolymers can be controlled by the adjustment of the ratio of PCL and PEO segments in copolymer.