ELECTROOPTIC PROPERTIES OF THE FERROELECTRIC SMECTIC-C PHASE INDUCED BY CHIRAL DOPANTS IN HOBA AND OOBA

A ferroelectric smectic C state was induced in 4-n-octyloxybenzoic acid (OOBA) and 4-n-heptyloxybenzoic acid (HOBA) by the chiral dopants-cholesteryl benzoate (CB) and DOBAMBC—M1 and M2 mixtures respectively. A strong electrooptic effect was found for a DC electric field in the ferroelectric state of the M1 mixture stabilized by the boundaries. This effect is characterised by six increasing electric field thresholds (E (1)th-E (6)th), where drastic textural and colour changes occur. The electrooptic responses in AC electric field for the two mixtures are discussed. A qualitative model to explain the observed phenomenon is presented. © 1990 Taylor & Francis Group, LLC.