Helical <i>vs.</i> non-helical nematic and lamellar proper ferroelectric liquid crystal phases.

Pociecha, D; Thornborrow, Z; Karcz, J; Bakiera, M; Herman, J; Makal, A; Szydłowska, J; Górecka, E · Soft Matter · 2026

basic_science · Level V

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Abstract

A new homologous series of mesogenic compounds with nearly linear mesogenic cores was studied, and it showed a strong discrimination between nematic and smectic phases with respect to the length of the terminal chain. For short homologues a ferroelectric nematic, N<sub>F</sub> and a heliconical nematic, N<sub>TBF</sub> phases were observed, while for longer ones they were replaced with ferroelectric smectic A<sub>F</sub> and C<sub>F</sub> phases. The <i>n</i> = 3 homologue exhibits a unique sequence of SmC<sub>F</sub> and its heliconical analogue SmCHP. Replacing an alkyne linkage in the mesogenic core with an alkene one favoured smectic phases and led to the appearance of a modulated-type SmA<sub>AF</sub> phase.