Influence of molecular structure on phase diagram and ferroelectric behaviour

Discussion on the influence of molecular structure on dynamics and ferroelectric properties of two compounds with cyanic group in achiral chain is presented. Physical properties of these two compounds have been studied by dielectric spectroscopy, DSC calorimetry, texture observations and reversal current method. Based on the results of these studies the phase sequence of the compounds and the character of the ferro- paraelectric transition have been determined. Temperature dependence of the spontaneous polarization and dielectric parameters of the soft mode suggest that the SmC* - SmA* transition is of the second order type for both compounds studied.