Pristine and ferroelectric liquid crystal dispersed four ring bent core nematic: Impact of dispersion on electro-optic and dielectric properties

Abstract

The electro-optic and dielectric behaviors of a four-ring bent core nematic (BCN) liquid crystal (5-2F-2Me-10) in its pristine and two different concentration proportions (0.5 wt% and 1.0 wt%) of ferroelectric liquid crystal (W206E) dispersed states, have been studied. Polarized optical microscopy (POM) confirms the presence of a nematic and SmA phases in pure and W206E doped states of BCN. The transition temperatures corresponding to different phases of doped samples decrease as compared to the pure BCN. An interesting ferroelectric like switching has been observed in pure 5-2F-2Me-10 and 5-2F-2Me-10 + 0.5 wt% W206E samples in their nematic phases. However, it is not significant in the case of 5-2F-2Me-10 + 1.0 wt% W206E. Dielectric spectroscopy reveals the presence of cybotactic clusters in pure and doped states of BCN, which is considered the main reason for the observed polar switching in these samples in their nematic phases. This study will help to understand the nature of interactions between the host BCN and doped FLC, and gives a direction to understand the effect of doping of FLC in BCN. Further, one major problem commonly associated with BCNs is high clearing temperature, as well as their different LC phases exist relatively at high temperatures, which restricts their potential applications in electro-optic devices. In this regard, the findings of this study are useful in reducing the isotropic temperature and the temperature corresponding to the different phases of a BCN.