Polar interactions between bent–core molecules as a stabilising factor for inhomogeneous nematic phases with spontaneous bend deformations

Abstract

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Nematic twist–bend phase in an external field

“…The molecules not only selforganize into a helical structure, but also propagate long-range polar order of vanishing global polarization, transverse to the helical axis. For steric interactions the polarity is a consequence of ordering of molecular bent cores [27,28,32,33] and the other molecular interactions, like between electrostatic dipoles, are probably less relevant for thermal stability of this phase. These conclusions seem in line with recent experimental observations [34][35][36].…”

Thermotropic MIDA Boronates as a Case Study for the Role of Dipolar Interactions in Liquid Crystalline Self‐Assembly

“…[72] Polar interactions play as tabilizing role in bent-core molecules. [73] For amphiphilic, ionic, or zwitterionic liquid crystals, nanosegregation of charged molecular subunits and less polar groups together with electrostatic interactions are the major driving forces for mesophase formation.B esides chemicali ncompatibility,t he differencei nm olecular flexibility also contributes to nanosegregation. [74] Notably,t he presence of mesogenic units is not required to obtain liquid crystalline phases.…”

Molecular-statistical theory of elasticity in nematic liquid crystals composed of polar and nonpolar molecules

“…One notes that in the system of polar molecules, the one particle distribution function can be approximately expressed as [8,9,14]…”

“…The twist elastic constant is also significantly reduced in some flexible bent-core materials [6]. A number of attempts have been made to explain such an anomalous behavior by using a continuum theory [7] and a molecular theory of nematic elasticity generalized to the case of biaxial and polar molecules [8,9], although the existing theory is far from being complete.…”