Composite structure of temperature sensitive chitosan microgel and anomalous behavior in alcohol solutions

Poly(N-isopropylacrylamide)/chitosan (PNIPAM/CS) core–shell microgel was synthesized by graft copolymerization. The microstructure of copolymers was characterized by FT-IR spectrum and 1H-nuclear magnetic resonance (1H NMR). Transmission electron microscope (TEM) and dynamic light scattering (DLS) measurements display that the microgel has high monodispersity and with a core–shell structure. For swelling the microgel in various alcohol solutions, the particles first shrink; then flocculation occurs resulted from weak aggregation of particles with the increase of alcohol concentration. The investigation of the size of microgels as a function of temperature shows that the thermo-sensitive property is markedly exhibited when the alcohol concentration is low, and vanishes when the alcohol concentration exceeds some value where the microgels have the lowest size.

Poly(N-isopropylacrylamide)/chitosan (PNIPAM/CS) core–shell microgel was synthesized by graft copolymerization. The microstructure of copolymer was characterized by FT-IR spectrum and 1H-nuclear magnetic resonance (1H NMR). For swelling the microgel in various alcohol solutions, the particles first shrink and then flocculate when alcohol was increased to certain concentration. The investigation of the microgels size with temperature shows that the thermo-sensitive property is markedly exhibited when the alcohol concentration is lower, and vanishes while the alcohol concentration exceeds some value where the microgels have the lowest size.Figure optionsDownload as PowerPoint slide