The Emergence of a Polar Nematic Phase: A Chemist's Insight into the Ferroelectric Nematic Phase

Abstract

The discovery of a new polar nematic phase; the ferroelectric nematic, has generated a great deal of excitement in the field of liquid crystals. To date there have been around 150 materials exhibiting the ferroelectric nematic phase, in general following three key archetypal structures with these compounds known as RM734, DIO and UUQU‐4N. In this review, the relationship between the molecular structure and the stability of the ferroelectric nematic, NF, phase will be described from a chemist’s perspective. This will look to highlight the wide variety of functionalities which have been incorporated into these archetypal structures and how these changes influence the transition temperatures of the mesophases present. The NF phase appears to be stabilised particularly by reducing the length of terminal alkyl chains present and adding fluorines laterally along the length of the molecular backbone. This review will look to introduce the background of the ferroelectric nematic phase before then showing the molecular structures of a range of materials which exhibit the phase, describing their structure‐property relationships and therefore giving an up‐to‐date account of the literature for this fascinating new mesophase.

Revealing the antipolar order in the antiferroelectric SmZA phase by means of circular alignment

“…The N F phase of RM734 is perfectly miscible with, and therefore also identical to, the lowest temperature range nematic phase in DIO 3 , 7 . Ferroelectric nematics today constitute an intense field of research 1 – 41 (so far about 150 N F materials have been reported 23 , 42 , 43 ) but the mechanisms behind spontaneously polarized nematics are still not fully understood. Especially, this holds true for the additional phase, originally called M2, located between the N F phase and the N phase in the archetype N F material DIO 2 .…”