Pretransitional isotropic Kerr effect in eutectic mixtures E120, E130 and E140

Abstract

The pretransitional behaviour in the isotropic phase of three eutectic mixtures, E120, E130 and E140, has been studied by the electric-field Kerr effect. These nematogens differ from most pure nematogens in that (a) they exhibit a wide (ca. 8 °C) biphasic region between the nematic and isotropic phases and (b) the composition of the mixtures is such that they show very different degrees of antiparallel dipolar association in the nematic phase. By studying the behaviour of the Kerr constant over a 20 °C wide range above the start of the biphasic range (i.e.T_NI) we have shown that the biphasic behaviour appears to have little influence on the pretransitional behaviour, in contrast to the dipolar association, which does appear to be more important. These results are discussed.