LYOTROPIC MESOMORPHIC FORMATION OF CELLULOSE IN TRIFLUOROACETIC-ACID CHLORINATED-ALKANE SOLVENT MIXTURES AT ROOM-TEMPERATURE

Mixtures of trifluoroacetic acid (TFA)-1,2-dichloroethane (1,2-DCE); TFA-dichloromethane (Ch//2Cl//2); and TFA-trichloromethane (CHCl//3) are excellent cellulose solvents at room temperature. TFA-1,2-DCE and TFA-CH//2Cl//2 are superior to pure TFA. Lyotropic cellulose mesophases were obtained in (20% w/v) solutions of cellulose in these solvent mixtures. The optical and optical rotatory powers of the solutions suggest that the lyotropic mesophase of cellulose is cholesteric. This implies that cellulose molecules are arranged in helical form in these solvent systems.