Alkali-chitosan method was employed to synthesize cyanoethyl chitosan (CNCS) with different degree of substitution (DS) from chitosan by controlling the reaction time.The effect of DS (from 0.36 to 1.21) on the liquid crystalline behaviors of CNCS was investigated.The change of DS showed no obvious influence on the critical concentration (C*) of liquid crystalline-isotropic transition for CNCS/dichloroacetic acid (DCA) solution

because a small substitution degree is large enough to destroy most of the inter-and-intramolecular hydrogen banding.High molecular weight (Mw) chitosan was depolymerized by nitrous acid to get chitosans of different Mw

proceeded by cyanoethylation using alkali chitosan method to synthesize CNCS of different Mw

Investigation was carried to the determine the effect of Mw on the lyotropic liquid crystalline behaviors of CNCS.The C* of CNCS and their obvious dependence on Mw imply that CNCS is a semi-rigid natural polymer with reatively high chain rigidity.