scholarly journals Effect of Central Longitudinal Dipole Interactions on Chiral Liquid-Crystal Phases

2018 ◽  
Vol 19 (9) ◽  
pp. 2715 ◽  
Author(s):  
Takuma Nozawa ◽  
Paul Brumby ◽  
Kenji Yasuoka
Keyword(s):  
Liquid Crystals ◽  
Phase Behavior ◽  
Coarse Grained ◽  
Systematic Analysis ◽  
Dipole Interactions ◽  
Liquid Phases ◽  
Systematic Understanding ◽  
Chiral Systems ◽  
Chiral Liquid Crystals ◽  
Strong Dipole

Monte Carlo simulations of chiral liquid-crystals, represented by a simple coarse-grained chiral Gay–Berne model, were performed to investigate the effect of central longitudinal dipole interactions on phase behavior. A systematic analysis of the structural properties and phase behavior of both achiral and chiral systems, with dipole interactions, reveals differing effects; strong dipole interactions enhance the formation of layered structures; however, chiral interactions may prevent the formation of such phases under certain conditions. We also observed a short-ranged smectic structure within the cholesteric phases with strong dipole interactions. This constitutes possible evidence of presmectic ordering and/or the existence of chiral line liquid phases, which have previously been observed in X-ray experiments to occur between the smectic twisted grain boundary and cholesteric phases. These results provide a systematic understanding of how the phase behavior of chiral liquid-crystals changes when alterations are made to the strength of dipole interactions.

scholarly journals Mesoscale structure of wrinkle patterns and defect-proliferated liquid crystalline phases

2020 ◽  
Vol 117 (8) ◽  
pp. 3938-3943 ◽  
Author(s):  
Oleh Tovkach ◽  
Junbo Chen ◽  
Monica M. Ripp ◽  
Teng Zhang ◽  
Joseph D. Paulsen ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Primary Source ◽  
Fixed Number ◽  
Coarse Grained ◽  
Buffer Zones ◽  
Ginzburg Landau ◽  
Mesoscale Structure ◽  
Liquid Crystalline Phases ◽  
Chiral Liquid Crystals

Thin solids often develop elastic instabilities and subsequently complex, multiscale deformation patterns. Revealing the organizing principles of this spatial complexity has ramifications for our understanding of morphogenetic processes in plant leaves and animal epithelia and perhaps even the formation of human fingerprints. We elucidate a primary source of this morphological complexity—an incompatibility between an elastically favored “microstructure” of uniformly spaced wrinkles and a “macrostructure” imparted through the wrinkle director and dictated by confinement forces. Our theory is borne out of experiments and simulations of floating sheets subjected to radial stretching. By analyzing patterns of grossly radial wrinkles we find two sharply distinct morphologies: defect-free patterns with a fixed number of wrinkles and nonuniform spacing and patterns of uniformly spaced wrinkles separated by defect-rich buffer zones. We show how these morphological types reflect distinct minima of a Ginzburg–Landau functional—a coarse-grained version of the elastic energy, which penalizes nonuniform wrinkle spacing and amplitude, as well as deviations of the actual director from the axis imposed by confinement. Our results extend the effective description of wrinkle patterns as liquid crystals [H. Aharoni et al., Nat. Commun. 8, 15809 (2017)], and we highlight a fascinating analogy between the geometry–energy interplay that underlies the proliferation of defects in the mechanical equilibrium of confined sheets and in thermodynamic phases of superconductors and chiral liquid crystals.

scholarly journals Direct mapping of local director field of nematic liquid crystals at the nanoscale

2015 ◽  
Vol 112 (50) ◽  
pp. 15291-15296 ◽  
Author(s):  
Yu Xia ◽  
Francesca Serra ◽  
Randall D. Kamien ◽  
Kathleen J. Stebe ◽  
Shu Yang
Keyword(s):  
Liquid Crystals ◽  
Soft Matter ◽  
Real Space ◽  
Colloidal Systems ◽  
Director Field ◽  
Silica Surfaces ◽  
Dipole Interactions ◽  
Molecular Ordering ◽  
New Type ◽  
Strong Dipole

Liquid crystals (LCs), owing to their anisotropy in molecular ordering, are of wide interest in both the display industry and soft matter as a route to more sophisticated optical objects, to direct phase separation, and to facilitate colloidal assemblies. However, it remains challenging to directly probe the molecular-scale organization of nonglassy nematic LC molecules without altering the LC directors. We design and synthesize a new type of nematic liquid crystal monomer (LCM) system with strong dipole–dipole interactions, resulting in a stable nematic phase and strong homeotropic anchoring on silica surfaces. Upon photopolymerization, the director field can be faithfully “locked,” allowing for direct visualization of the LC director field and defect structures by scanning electron microscopy (SEM) in real space with 100-nm resolution. Using this technique, we study the nematic textures in more complex LC/colloidal systems and calculate the extrapolation length of the LCM.

Dibenzophospholes: Phase Behavior of Novel Phosphorus-Based Chiral Liquid Crystals

2002 ◽  
Vol 381 (1) ◽  
pp. 43-57 ◽  
Author(s):  
Ernesto Durán ◽  
Dolores Velasco ◽  
Francisco López-Calahorra ◽  
Heino Finkelmann
Keyword(s):  
Liquid Crystals ◽  
Phase Behavior ◽  
Chiral Liquid Crystals

A 2*2 fiber optic switch using chiral liquid crystals

1990 ◽  
Vol 2 (2) ◽  
pp. 147-149 ◽  
Author(s):  
N.K. Shankar ◽  
J.A. Morris ◽  
C.P. Yakymyshyn ◽  
C.R. Pollock
Keyword(s):  
Liquid Crystals ◽  
Fiber Optic ◽  
Chiral Liquid Crystals

Phase Behavior of a New Class of Anthraquinone-Based Discotic Liquid Crystals

Langmuir ◽  
2017 ◽  
Vol 33 (48) ◽  
pp. 13849-13860 ◽  
Author(s):  
Joydip De ◽  
Santosh Prasad Gupta ◽  
Indu Bala ◽  
Sandeep Kumar ◽  
Santanu Kumar Pal
Keyword(s):  
Liquid Crystals ◽  
Phase Behavior ◽  
Discotic Liquid Crystals ◽  
New Class

OPTICAL ACTIVITY AND LIGHT SCATTERING IN HIGHLY CHIRAL LIQUID CRYSTALS

1992 ◽  
Vol 06 (08) ◽  
pp. 425-446 ◽  
Author(s):  
PETER J. COLLINGS
Keyword(s):  
Liquid Crystals ◽  
Light Scattering ◽  
Optical Activity ◽  
Smectic A ◽  
Scattering Effects ◽  
Smectic A Phase ◽  
Blue Phases ◽  
Chiral Liquid Crystals

Theoretical and experimental optical activity and light scattering work in highly chiral liquid crystals is reviewed, starting from the early studies twenty years ago and ending with the most current investigations. Pretransitional effects in the isotropic and smectic A phases of highly chiral liquid crystals are discussed, as well as optical activity and light scattering effects in both the blue phases and smectic A * phase.

Sign in / Sign up

Export Citation Format

Share Document