Influence of the molecular structure of compounds differing with terminal polar group on the induction of the smectic A phase. Part III

ABSTRACT

The aim of this work is to determine the influence of the terminal polar group of nematic compounds, namely -OCF₃, -NCS, -CN, -F, on the induction of the SmA phase in their mixtures with compounds having terminal non-polar groups. The former group of compounds has positive dielectric anisotropy, and the latter negative. The phase transition temperatures of binary mixtures were measured using polarising thermomicroscopy, and phase diagrams for investigated systems were constructed. The strength of the SmA phase induction increases upon the increase of the polarity of compounds. The strongest induction is observed in systems with compounds having a terminal trifluoromethoxy group. Although compounds with the cyano group have the highest polarity, their ability for the SmA phase induction is smaller due to their dimerisation.

Graphical abstract

KEYWORDS:

• Liquid crystals
• smectic a phase induction
• miscibility studies
• dipole moments

Acknowledgments

This work was supported by Military University of Technology [Project No. UGB 22-801].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Wojskowa Akademia Techniczna [UGB 22-801].