Novel Ferroelectric Liquid Crystalline δ-Valerolactone Derivatives with Very Large Spontaneous Polarization

Abstract

A series of new chiral compounds with a 6-valerolactone ring were synthesized and the physical properties of these compounds as well as the electrical properties of their ferroelectric liquid crystal (FLC) mixtures were investigated. The magnitude of spontaneous polarization ( P I ) in the chiral srnectic C phase (SmC*) was found to be as high as 384 nC/cm' for (2R, 5R)-2-(4'-octyloxybiphenyl-4-carboxy)-5-butyl-6-valerolactone at AT = Tc -T = 5"C, where Tc is the temperature of transition from the isotropic phase to the SmC* phase and T is the temperature at which the experiments were carried out. An FLC mixture containing 2% by weight of the optical isomer, (2S, 5R)-2-(4'-octyloxy-biphenyl-4-carboxy)-5-hexyl-6-valerolactone exhibited a response time as fast as 96 p seconds at 25°C. for an applied square-wave voltage of ? 10 volts. The relationship between the structural properties and the thermal properties, magnitude and polarity of Ps as well as the response times for their FLC mixtures are discussed.

Chiral Smectic Liquid Crystals: Synthesis of Chiral Smectic Liquid Crystals

“…Therefore similarly large values for P, are to be expected and this is observed to be the case, see Table 15 [ 86]. Large differences in P, are observed for the cis and trans configurations (Structure 5 ) , although the value for the trans-isomer is greater than that of the cis-isomer, where the opposite is the case for the ylactones.…”

Ferroelectric Smectic Liquid Crystals

“…Some chiral dopants are presented in Figure 21. [42], CD-2 [43], CD-3 [38], and CD-4 [44]. The carbon indicated by asterisk is an asymmetric carbon.…”

“…Figure 21.Molecular structure of chiral dopants, CD-1[42], CD-2[43], CD-3[38], and CD-4[44]. The carbon indicated by asterisk is an asymmetric carbon.…”

Stereochemical studies of optically active 2-hydroxy-5-alkyl-δ-valerolactone derivatives as chiral dopant for ferroelectric liquid crystals

“…In a previous paper [3], we showed that the sign of P, was determined by the absolute configuration of the C-2 atom of the 6-valerolactone ring and that the values of P, of ferroelectric liquid crystals containing 2 mol% of 2-(4'-octyloxybiphenyl-4-carboxy)-5-alkyl 6-valerolactones (1) with different relative configurations were almost the same. Sakaguchi et al [4] have synthesized a series of y-butyrolactone derivatives as chiral dopants for ferroelectric liquid crystals and reported that the value of P, for a ferroelectric liquid crystal containing 2 wt% of these derivatives with the cis configuration (2) was about 10 times as large as that with the trans configuration (3).…”