The Study Of Self-assembly Film Systems Of Chitosan/Chondroitin Sulfate By AFM

The properties of self-assembly films of Chitosan and Chondroitin sulfate are researched by AFM in this paper.For Chitosan, when the concentration of chitosan is under 0.1mg/ml, the structure of molecular chain can be observed by AFM. At the same time, the refined structure of lyotropic liquid crystal of chitosan and the changes of structure were studied . Films with liquid crystalline texture can be prepared from diluted solutions which concentration is lower than critical concentration of liquid crystal. With the volatilization of solvent, The structures can chang from disc or hexagon to cube with the variety of environment and interior reciprocity. It is the result of self-assembly of molecules and embodiment of dissipative structure under the imbalance state.For Chondroitin sulfate(CS), the self-assembly behavior of CS in the presence of Ca2+ is studied by AFM. The result shows that CS can be formed integrated self-assembly films when its concentration exceeds 1.0mg/ml . At the same time , the structure which presents fractal characteristics can be changed with the reaction time. On the other hand, the phenomenon which CaC2O4 agglomerates in the self-assembly film of CS is observed by AFM . The results show that Liesegang loops can be formed from CaCa2O4 when the concentration of CS is just fit for forming reticulation (1.0g/l) . The elementary explanation is presented in this study including electric charge conglomeration and the matching of geometry crystal lattice . In addition, Chondroitin sulfate/ Chitosan composite films are self-assembled through electrostatic attraction on the positively charges mica substrate.The interaction and mechanism of forming the composite films were introduced. When the concentration of chitosan is 5 mg/ml and the concentration of chondroitin sulfate is 1 mg/ml, the composite films exhibited a good miscibility at a molecular scale. This kind of composite films is promising in the field of medical materials.