Investigations on Electrooptical Effects in Chiral Discotic Columnar Mesophases

Investigations on the nature of both linear and nonlinear electrooptic eeects in columnar mesophases of chiral discotic dibenzopy-rene and triphenylene derivatives and their mixtures are presented. We specially focus on the innuence of chirality on the switching process. INTRODUCTION Ferroelectricity in tilted smectic phases of chiral molecules was predicted to occur by R. B. Meyer et al. in 1975. The experimental proof was published in the same paper 1. In 1977, Chandrasekhar et al. discovered that discotic molecules can exhibit columnar mesophases 2. It was J. Prost's merit to have combined these ndings to the prediction of ferroelectric columnar mesophases 3. However, Levelut et al. stated in 1984, that the realignment of the molecules by the electric eld in such phases was impossible due to lattice symmetry 4. The rst and to date only pure compound exhibiting a ferroelectrically switchable enantiotropic columnar mesophase was dis