Polar bent-shape liquid crystals – from molecular bend to layer splay and chirality

Eremin, Alexey; Jákli, Antal

doi:10.1039/c2sm26780b

Cited by 148 publications

(88 citation statements)

References 199 publications

(282 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Occasionally, adjacent layers will have antiparallel polarizations that suppress ferroelectricity. The orientation of polarizations in adjacent layers, combined with the tilt angle of the mesogens in each layer, will change the chirality of the supramolecular structure [75][76][77] . These structural characteristics are rooted in the spatial frustration between the flexible chains and the rigid bent core.…”

Section: Organization Of Molecular Dipolesmentioning

confidence: 99%

Supramolecular ferroelectrics

et al. 2015

View full text Add to dashboard Cite

Supramolecular chemistry uses non-covalent interactions to coax molecules into forming ordered assemblies. The construction of ordered materials with these reversible bonds has led to dramatic innovations in organic electronics, polymer science and biomaterials. Here, we review how supramolecular strategies can advance the burgeoning field of organic ferroelectricity. Ferroelectrics - materials with a spontaneous and electrically reversible polarization - are touted for use in non-volatile computer memories, sensors and optics. Historically, this physical phenomenon has been studied in inorganic materials, although some organic examples are known and strong interest exists to extend the search for ferroelectric molecular systems. Other undiscovered applications outside this regime could also emerge. We describe the key features necessary for molecular and supramolecular dipoles in organic ferroelectrics and their incorporation into ordered systems, such as porous frameworks and liquid crystals. The goal of this Review is to motivate the development of innovative supramolecular ferroelectrics that exceed the performance and usefulness of known systems.

show abstract

Section: Organization Of Molecular Dipolesmentioning

confidence: 99%

Supramolecular ferroelectrics

et al. 2015

View full text Add to dashboard Cite

show abstract

“…During the last decade, spontaneous reflection symmetry breaking has been reported in several fluid LC phases of achiral bent-core molecules, with macroscopic, chiral conglomerate domains and a wide variety of novel structural phenomena involving the interplay of chiral, polar and liquid crystalline order observed in smectic phases of tilted molecules [22][23][24][25][26][27][28][29] . Among the novel phases exhibited by bent-core mesogens, the helical nanofilament (HNF) phase is one of the most fascinating and potentially useful.…”

mentioning

confidence: 99%

Diastereomeric liquid crystal domains at the mesoscale

et al. 2015

View full text Add to dashboard Cite

In many technologies used to achieve separation of enantiomers, chiral selectors are designed to display differential affinity for the two enantiomers of a chiral compound. Such complexes are diastereomeric, differing in structure and free energy for the two enantiomers and enabling chiral discrimination. Here we present evidence for strong diastereomeric interaction effects at the mesoscale, manifested in chiral liquid crystal guest materials confined in a chiral, nanoporous network of semi-crystalline helical nanofilaments. The nanoporous host is itself an assembly of achiral, bent-core liquid crystal molecules that phase-separate into a conglomerate of 100 micron-scale, helical nanofilament domains that differ in structure only in the handedness of their homogeneous chirality. With the inclusion of a homochiral guest liquid crystal, these enantiomeric domains become diastereomeric, exhibiting unexpected and markedly different mesoscale structures and orientation transitions producing optical effects in which chirality has a dominant role.

show abstract

“…If the molecular long axes are tilted with respect to the layer normal, the symmetry is reduced and chirality can be observed although the molecules are achiral. Concerning further information about molecular constitution, structure of the mesophases and the physical properties of banana-shaped liquid crystals, we refer to some reviews [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Banana-calamitic Dimers: Further Variations of the Bent-core Mesogenic Unit

et al. 2014

View full text Add to dashboard Cite

Banana-calamitic dimers are a topic in the field of bent-core mesogens. New materials were prepared by chemical variations at the bent-core fragment that is by a cyano group terminally attached to the bent-core fragment, by lateral substitution with a chlorine atom and methyl group, respectively, and by increasing the number of phenyl rings from five to six. The bent-core and the calamitic mesogenic moieties are connected by aliphatic spacers of different length. The materials were investigated by optical microscopy, DSC, X-ray diffraction studies and electro-optical measurements. This way nematic, smectic and various types of polar columnar phases have been characterized. The low temperature phase in a sequence of two nematic phases exhibiting different properties can be classified as a nematic twist-bend phase. Such NTB phases are only formed if a bend exists along the molecular long axes. This prerequisite can be doubly achieved in banana-calamitic dimers: by the intrinsic bend of one of the mesogenic fragments and by an odd-numbered spacer.

show abstract

Polar bent-shape liquid crystals – from molecular bend to layer splay and chirality

Cited by 148 publications

References 199 publications

Supramolecular ferroelectrics

Supramolecular ferroelectrics

Diastereomeric liquid crystal domains at the mesoscale

Banana-calamitic Dimers: Further Variations of the Bent-core Mesogenic Unit

Contact Info

Product

Resources

About