THE DEPENDENCE OF POLARIZATION AND DIELECTRIC BIAXIALITY ON THE ENANTIOMERIC EXCESS IN CHIRAL DOPANT ADDED TO A SMECTIC-C HOST MIXTURE

The dielectric stabilization of the field-on states is an important fe ature for all SSFLC devices using the so-called C2 chevron geometry. T his requires a combination of positive dielectric biaxiality and negat ive dielectric anisotropy. In the present work we use the phenylpyrimi dine base mixture M192/62.5 as a non-chiral host and dope it by 10% of a chiral oxirane derivative with varying enantiomeric excess chi of t he R-compound. The results confirm our basic expectations: while the p olarization increases with increasing chi, the dielectric coefficients seem to be essentially independent cn the enantiomeric excess, theref ore on the spontaneous polarization. This result is remarkably differe nt from our previous results on pure compounds showing a clear correla tion between the dielectric biaxiality and spontaneous polarization in different molecular structures.