A BLUE PHASE WITH NEGATIVE DIELECTRIC ANISOTROPY IN AN ELECTRIC-FIELD - STATICS AND DYNAMICS

The behaviour of blue phase III (BPIII) of chiral liquid crystals under the influence of an electric field has been studied for a mixture consisting of the chiral compound S811 and the nematic mixture EN18 exhibiting negative dielectric anisotropy εa < 0. As in one mixture with $espilona < 0 studied previously, a dramatic increase of the intensity of reflection is observed in the fog phase. This intensity increase, which has not been observed for systems with εa > 0, increases much more rapidly than the shift of the Bragg wavelengths which is observed in BPI and BPII due to electrostriction.