New ferroelectric liquid crystalline materials containing one and two lactate groups attached to the molecular core

Abstract

Several new liquid crystalline materials containing one, two or three chiral centres and having one or two lactate groups in the molecular core have been synthesized. Most of the materials show the blue phase, chiral nematic phase, paraelectric smectic A phase and orthogonal hexatic smectic B phase; some possess the ferroelectric SmC* phase. A study of the mesomorphic properties has been performed using differential scanning calorimetry, optical microscopy and X-ray diffraction. The thickness of the smectic layers and the value of the average distance between the long axes of neighbouring molecules were determined. In the SmC* phase, the temperature dependence of spontaneous polarization, spontaneous tilt angle and helical pitch was measured. The influence of the number of lactate groups on mesogenic behaviour has been established.

Ultra-short helix pitch and spiral ordering in cholesteric liquid crystal revealed by resonant soft X-ray scattering

“…Contrary to this, the studied compound EZL10/10 represents a rather simple molecular structure (Scheme 1), with a lactate in the chiral chain. In our previous research it was proved that lactate unit as a source of chirality is very efficient as was demonstrated by frequent presence of blue and twist-grain boundary phases [36][37][38]. In comparison with low pitch cholesterics studied by soft X-ray resonant scattering earlier [23,39], herein we present a simple molecular structure those pitch length can be easily varied by admixture of opposite enantiomer to get a series of structures with tailored pitches.…”

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

“…There are four main advantages of the lactic acid derivatives as a sub-class of chiral LCs that makes them attractive with respect to other materials, i.e. (i) forming of a broad variety of basic LC phases, including the cholesteric N*, paraelectric SmA* [10,11], ferroelectric SmC* [3,8,[12][13][14][15][16], antiferroelectric SmC Ã A [12,[17][18][19][20][21][22][23], polar hexatic phases [9,13,14,19,24] as well as frustrated ones like the twist grain boundary phases, namely TGB Ã A [1][2]7,12] and TGB Ã C [25] or SmQ* phase [12,26] or re-entrant SmA* [27][28][29] and re-entrant SmC* [9,13,24]; (ii) utilization of the lactic unit as a precursor of chiral centre minimizes the cost as the price ratio to the most commonly used chiral precursor material (S)-2-octanol is at least 1:100; (iii) melting points (m.p.) are often reasonable, in the range 30-70 C, and the LC phases can easily be supercooled well below room temperature and (iv) lactic acid-based LCs usually show no ageing, and are highly stable, thermally as well as chemically.…”

Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties

“…Recently, two series of chiral liquid-crystalline materials (similar to those presented in this work) with chiral lactate group or lactic acid derivative have been synthesized and studied [30–32]. These materials (with the same molecular core and nonchiral chain as TL4 ) possess different thermotropic LC phases depending on the chiral chain structure.…”