Molecular mass determination in the liquid crystalline state ‐ lyotropic cholesteric phase of a cellulose derivative

Lyotropic cholesteric phases of cellulose derivative/solvent systems exhibit a reflection wavelength or supermolecular helicoidal pitch dependency on molecular mass besides the well known variation of the pitch by temperature and concentration. This observation allows a molecular mass determination by spectroscopic means (UV/VIS‐, ORD‐, CD‐spectra) or by an evaluation of the colours seen in a polarizing microscope or by a direct measurement of the pitch with the Cano‐Grandjean technique.