Structural investigations on cellulose tricarbanilate: Conformation and liquid crystalline behaviour

The phase behaviour of cellulose tricarbanilate (CTC) in ethyl methyl ketone (MEK) solutions was studied in the concentration range of 0,2 – 0,8 g/ml as a function of the temperature. By analyzing the textures in the polarizing microscope and by differential scanning calorimetry experiments several different phase transitions and mesophases were detected. At a concentration below 0,6 g/ml CTC in MEK, phase transitions were observed from the crystalline through a liquid crystalline (cholesteric) to the isotropic state. At concentrations higher than 0,6 g/ml, a different behaviour of the CTC solutions was detected and several transitions were found, but only the cholesteric‐isotropic transition could be identified. The concentration dependence of the cholesteric‐isotropic transitions was determined over the whole concentration range. The conformation of the CTC molecule was studied and a stiff, almost cylindrically shaped 3/2 helix with a repeat distance of 15,25 Å is proposed.