Features of crystallization of chitosan with different molecular mass and its mixtures with pluronic F-127 according to atomic force microscopy and X-ray diffraction data

Abstract

The structure of chitosan with different molecular mass and its mixtures with pluronic F-127 (triblock copolymer of ethylene and propylene oxide) crystallized from aqueous solutions was analyzed by atomic force microscopy and X-ray diffraction methods. It was established that the low-molecular-mass chitosan (Mw = 20000) had a highly ordered macrocrystalline structure, whereas the high-molecular-mass chitosan (Mw = 250000) was characterized by a poorly ordered quasi-crystalline structure. It was shown that, after evaporation of the aqueous solution of high-molecular-mass chitosan and pluronic F-127, chitosan formed a continuous film on the mica surface and pluronic formed dendritic structures on the chitosan surface. At the same time, the evaporation of the solution of the low-molecular-mass chitosan and pluronic F-127 mixture resulted in the formation of interpenetrating dendrites of chitosan and pluronic on the mica surface. In the low-molecular-mass chitosan-pluronic systems, a pluronic crystalline phase was formed at a lower pluronic content than in the case of high-molecular-mass chitosan-pluronic systems.