Effect of alkyl chains length on properties of ferroelectric liquid crystals with the keto group attached to the molecule core

Abstract

In order to contribute to better understanding of the molecular structure–physical property relationship, properties of ferroelectric liquid crystalline materials derived from the lactic acid with the keto group in the molecular core have been studied. These compounds differing only by the length of the chiral and non-chiral alkyl chains exhibit the paraelectric SmA* and the ferroelectric SmC* phases over 150 K broad temperature range down to the room temperature. Temperature dependences of spontaneous polarization, tilt angle, layer spacing, helix pitch length and dielectric permittivity have been compared and discussed for all studied compounds. The effect of the alkyl chains length on mesomorphic properties has been established and discussed in comparison to that of similar materials.

Keywords:

• ferroelectric liquid crystal
• keto group
• lactic acid derivative
• spontaneous quantities
• SAXS
• helix pitch
• dielectric spectroscopy

Acknowledgements

Authors dedicate this publication to Dr Milada Glogarová at the occasion of her significant jubilee and outstanding contribution to the invention and development of the lactic acid derivatives possessing the liquid crystalline behaviour during the past three decades. This study is supported by project CSF P204/11/0723.