Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubility than chitosan,...Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubility than chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two N-substituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three O-substituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.展开更多
N -Butyl chitosan(NBCS) derivatives were prepared by introducing butyl groups into the amine groups of chitosan via Schiff base intermediates. The quaternization of NBCS was carried out by using ethyl iodide to pr...N -Butyl chitosan(NBCS) derivatives were prepared by introducing butyl groups into the amine groups of chitosan via Schiff base intermediates. The quaternization of NBCS was carried out by using ethyl iodide to produce water-soluble cationic polyelectrolytes. The degree of the substitution of the products was measured by means of the electron spectroscopy for a successful chemical analysis. The quaternary ammonium chitosan salt(QACS) was proved to be a novel cholesteric liquid crystalline chitin, by means of the polarized optical microscopy and the circular dichroism spectropolarimetry. The critical mass fraction of the QACS/formic acid solution forming a lyotropic liquid crystal phase was 50%, which was almost the same as that of the NBCS/formic acid solution, but much higher than that of the chitosan in the same solvent.展开更多
The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid ...The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid crystalline solution for chitin, chitosan, cyanoethyl chitosan and propionyl chitin successively increases as the chain rigidity decreases. Therefore it can be used as an indicator of the chain rigidity.展开更多
In order to provide a novel biomimetic composite substrate for tissue engineering and explore the interaction between cells and this type of material,we developed chitosan/liquid crystal(CS/LC)composite hydrogel with ...In order to provide a novel biomimetic composite substrate for tissue engineering and explore the interaction between cells and this type of material,we developed chitosan/liquid crystal(CS/LC)composite hydrogel with embedded LC phases by composing of cholesterol hydroxypropyl cellulose ester liquid crystalline material and CS.The micromorphology of CS/LC composite hydrogels exhibited‘islands-sea’phase separation structures similar to the‘fluid mosaic model’of biomembrane.In vitro cell compatibility study suggested that 3T3 is fibroblasts exhibited better initial cell adhesions and higher proliferation rates on the composite hydrogel than on the polystyrene control plate and the pure LC membrane.This novel CS/LC composite hydrogel provides more favorable interface for cell growth and proliferation and may serve as potentially active substrate for engineering interfaces to live cells.展开更多
Butyryl chitosan was synthesized and characterized by using FTIR, DSC, WAXD and PLM. Liquid crystallinity of butyryl chitosan was first reported in this paper. Comparing with chitosan, thermal stability and crystallin...Butyryl chitosan was synthesized and characterized by using FTIR, DSC, WAXD and PLM. Liquid crystallinity of butyryl chitosan was first reported in this paper. Comparing with chitosan, thermal stability and crystallinity of butyryl chitosan decreased but solubility increased, because hydrogen bond interactions between macromolecules were disrupted.展开更多
基金Financial support by Laboratory of Cellulose and Lignocellulosics Chemistry, Academia Sinica
文摘Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubility than chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two N-substituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three O-substituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.
基金Supported by the National Natural Science Foundation of China( No. 2 9974 0 2 3)
文摘N -Butyl chitosan(NBCS) derivatives were prepared by introducing butyl groups into the amine groups of chitosan via Schiff base intermediates. The quaternization of NBCS was carried out by using ethyl iodide to produce water-soluble cationic polyelectrolytes. The degree of the substitution of the products was measured by means of the electron spectroscopy for a successful chemical analysis. The quaternary ammonium chitosan salt(QACS) was proved to be a novel cholesteric liquid crystalline chitin, by means of the polarized optical microscopy and the circular dichroism spectropolarimetry. The critical mass fraction of the QACS/formic acid solution forming a lyotropic liquid crystal phase was 50%, which was almost the same as that of the NBCS/formic acid solution, but much higher than that of the chitosan in the same solvent.
基金Supported by the Laboratory of Cellulose and Lignocellulosics Chemistry. Chinese Academy of Sciences and National Natural Science Foundation. China
文摘The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid crystalline solution for chitin, chitosan, cyanoethyl chitosan and propionyl chitin successively increases as the chain rigidity decreases. Therefore it can be used as an indicator of the chain rigidity.
基金This work was supported by the Fundamental Research Funds for the Central Universities(21615436)the Science and Technology Program of Guangzhou,China(201508020035)the Science and Technology Program of Guangdong,China(2016B090913004).
文摘In order to provide a novel biomimetic composite substrate for tissue engineering and explore the interaction between cells and this type of material,we developed chitosan/liquid crystal(CS/LC)composite hydrogel with embedded LC phases by composing of cholesterol hydroxypropyl cellulose ester liquid crystalline material and CS.The micromorphology of CS/LC composite hydrogels exhibited‘islands-sea’phase separation structures similar to the‘fluid mosaic model’of biomembrane.In vitro cell compatibility study suggested that 3T3 is fibroblasts exhibited better initial cell adhesions and higher proliferation rates on the composite hydrogel than on the polystyrene control plate and the pure LC membrane.This novel CS/LC composite hydrogel provides more favorable interface for cell growth and proliferation and may serve as potentially active substrate for engineering interfaces to live cells.
文摘Butyryl chitosan was synthesized and characterized by using FTIR, DSC, WAXD and PLM. Liquid crystallinity of butyryl chitosan was first reported in this paper. Comparing with chitosan, thermal stability and crystallinity of butyryl chitosan decreased but solubility increased, because hydrogen bond interactions between macromolecules were disrupted.
