Smectic A–hexagonal columnar–B7 phase transition of acute-angle bent-core molecules

Abstract

A distinct structural transformation occurs between a 1D layered SmA phase and 2D layer undulated banana phase via a unique hexagonal columnar phase which may result from different molecular packings as a function of temperature.

Liquid crystal phases with unusual structures and physical properties formed by acute-angle bent core molecules

“…The mesomorphism of ABC-compounds with 1,7-naphthalene central core was reported by Lee et al [45]. This family of materials exhibits a broad variety of phases [17,45]. Especially interesting phase sequence was suggested for the studied 1Cl-N(1,7)-O6 [18], with the N phase being accompanied at lower temperatures by a tetragonal packing of cylinders with double-twisted director.…”

“…Mesomorphism of the acute-angle bent-core (ABC) molecules with 90   is poorly understood. Kang, Watanabe and their colleagues [15][16][17][18] brought about interesting results for ABC molecules such as the one in Fig. 1.…”

“…It produces a high-temperature uniaxial N and a low-temperature phase, identified as a tetragonal packing of long cylinders. It is claimed [15][16][17][18] that each cylinder contains a double-twisted director field which is necessarily associated with a bend. The cylinders are of alternating chirality: a left-twisted cylinder has four close neighbors of right-twisted cylinders and vice versa.…”

Two‐Dimensional Skyrmion Lattice Formation in a Nematic Liquid Crystal Consisting of Highly Bent Banana Molecules

“…[4] Furthermore,b yc ombining with long alkylsulfanyl chains,t hey can form not only an ovel switchable hexagonal columnar phase but also an optically isotropic phase with ac ubic lattice. [5] Notably,t he formation of polar Bphases provides overriding evidence that in these systems,molecules can pack along the bent direction despite the small OA of 608 8.…”

Two‐Dimensional Skyrmion Lattice Formation in a Nematic Liquid Crystal Consisting of Highly Bent Banana Molecules

“…[2] The mesomorphism of BCLC with smaller bent angles (< 908 8), the so-called "low bent-angle BCLCs", are apparently less developed, despite several early reports describing the formation of calamitic LCs. [5] Notably,t he formation of polar Bphases provides overriding evidence that in these systems,molecules can pack along the bent direction despite the small OA of 608 8. [4] Furthermore,b yc ombining with long alkylsulfanyl chains,t hey can form not only an ovel switchable hexagonal columnar phase but also an optically isotropic phase with ac ubic lattice.…”