Singular Elastic Properties of Mixtures with the Re-entrant Nematic Phase

Abstract

The paper presents temperature behavior of the splay and bend elastic constants measured for n-hexyloxycyanobiphenyl and noctyloxycyanobiphenyl mixtures -a system exhibiting the re-entrant nematic phase. It was shown that singularities in the elastic properties of the system concern not only the nematic phase (the well-known pre-smectic effects) but first of all -the smectic A phase, in which the splay and bend deformations, normally not allowed for the layered structures, can be induced.

Determination of elastic constants of a binary system (7CPB+9.CN) showing nematic, induced smecticAdand re-entrant nematic phases

“…Uchida et al [17] developed a method in which the multi-parameter fit was not required. The voltage dependence of capacitance can be expressed as [7,[17][18][19] …”

“…[7] However, in the binary mixtures of 7CPB + 9.CN, Freedericksz transition could be induced by the application of an electric field of appropriate strength. This may be due to the fact that in the smectic A phase, the …”

“…[2] However, studies of the viscoelastic properties for systems in which the induced smectic and re-entrant nematic phases occur seem to be scanty. [2][3][4][5][6][7] In our previous works, we have reported a new system of binary mixture of 4-cyanophenyl [4ʹ (4′′-nheptylphenyl)]benzoate (7CPB) and 4-cyanophenyl 4-nonylbenzoate (9.CN) which exhibits nematicinduced smectic A d and re-entrant nematic phase sequence. [8] Detailed x-ray diffraction, [8] birefringence, [9,10] dielectric [11] and rotational viscosity measurement [12] have been reported by us.…”

Design, synthesis and characterization of a linear hydrogen bonded homologous series exhibiting reentrant smectic C ordering

“…1d. A re-entrant phenomenon in LCs is first reported by Cladis [31] and this paved way for its recognition and utility [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. Occurrence of Re-Entrant phase can be attributed to the rupture of order parameter, which in turn alters the molecular arrangement in various phases as depicted in Fig.…”

“…The RE-phenomena can be exploited in the Electro Optic (EO) sensor devices [33] and medical diagnostic [38] tools. As far as the applicational aspect is considered, Photoinduced RE-phenomena [42] and the associated EO switching emerge as highly significant fields. The central theme of this work is to study the physical and chemical properties of HBLC formed by alkyl and alkoxy carboxylic acids.…”