The chiroptical properties of isotropic solutions, cholesteric liquid crystals and solid films prepared from selected cellulose derivatives are investigated by optical rotary dispersion (ORD) and circular dichroism (CD). Optical activity from intrinsic molecular dissymmetry, polymer conformation and cholesteric reflection properties are considered. / The chiroptical properties of cholesteric liquid crystals are interpreted according to deVries' theory. Lyotropic liquid crystalline phases formed by (hydroxypropyl)cellulose in methanol display anomalously high optical rotation at low wavelengths. The anomalies disappear on the addition of a dipolar aprotic solvent, and are absent for the ethyl ether derivative of the polymer, indicating a chiral hydrogen bonded structure is contributing to the optical activity. / Investigation of the chiroptical properties of cellulosics by circular dichroism requires the presence of a suitable chromophore, either as a chain substituent or as an added dye. Congo red exhibits induced optical activity in dilute aqueous solutions of methylcellulose and cellulose oligomers, providing evidence for the presence of a helical conformation. CD spectra of two new biphenyl derivatives also exhibit exciton splitting characteristic of a helical arrangement of chromophores. Conformational dissymmetry is not indicated in spectra of cellulose acetate although the sign of carbonyl CD band is solvent dependent. The sign of this band is interpreted in terms of the orientation of the ester substituent relative to the anhydroglucose ring. Congo red, bound in cholesteric cellulose films prepared by the deacetylation of cellulose acetate cast from mesophase solution, shows induced optical activity which, in this case, reflects the cholesteric nature of the matrix. Similar results for cellulose gels regenerated from LiCl/N,N-dimethylacetamide solution indicate that cellulose adopts a supramolecular helicoidal arrangement on slow precipitation from solution. / The optical properties of the thermotropic cholesteric liquid crystalline phase formed by a new cellulose derivative, (ethoxypropyl)cellulose, are examined by circular reflectivity measurements. / The cholesteric reflection properties of mesophase solutions of cellulose acetate in trifluoroacetic acid are characterized. The polymer undergoes rapid trifluoroacetylation in this solvent and the presence of trifluoroacetate substituents alters the handedness and the magnitude of the pitch. Although the pitch is sensitive to the nature of achiral substituents, it is not influenced by the addition of chiral solvents. (Abstract shortened with permission of author.)

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