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.

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.

Biforked mesogens : a new type of thermotropic liquid crystals

1986 ◽  
Vol 47 (4) ◽  
pp. 553-557 ◽  
Author(s):  
Nguyen Huu Tinh ◽  
C. Destrade ◽  
A.M. Levelut ◽  
J. Malthete
Keyword(s):  
Liquid Crystals ◽  
Thermotropic Liquid Crystals ◽  
New Type

scholarly journals Emergence and stabilization of transient twisted defect structures in confined achiral liquid crystals at a phase transition.

Soft Matter ◽  
2021 ◽  
Author(s):  
Jose X Velez ◽  
Zhaofei Zheng ◽  
Daniel A. Beller ◽  
Francesca Serra
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Soft Matter ◽  
Capillary Tube ◽  
Nematic Liquid Crystals ◽  
Defect Structures

Spontaneous emergence of chirality is a pervasive theme in soft matter. We report a transient twist forming in achiral nematic liquid crystals confined to a capillary tube with square cross...

Modelling and computation of liquid crystals

Acta Numerica ◽  
2021 ◽  
Vol 30 ◽  
pp. 765-851
Author(s):  
Wei Wang ◽  
Lei Zhang ◽  
Pingwen Zhang
Keyword(s):  
Liquid Crystals ◽  
Numerical Methods ◽  
Mathematical Models ◽  
Soft Matter ◽  
Scientific Research ◽  
Crystalline Solids ◽  
The Past ◽  
Tremendous Progress

Liquid crystals are a type of soft matter that is intermediate between crystalline solids and isotropic fluids. The study of liquid crystals has made tremendous progress over the past four decades, which is of great importance for fundamental scientific research and has widespread applications in industry. In this paper we review the mathematical models and their connections to liquid crystals, and survey the developments of numerical methods for finding rich configurations of liquid crystals.

Application of video microscopy in experimental soft matter physics

2018 ◽  
Vol 32 (18) ◽  
pp. 1840012
Author(s):  
Hao Feng ◽  
Huaguang Wang ◽  
Zexin Zhang
Keyword(s):  
Video Processing ◽  
Soft Matter ◽  
Colloidal Suspensions ◽  
Real Space ◽  
Video Microscopy ◽  
Quantitative Image ◽  
Soft Matter Physics ◽  
Microscopic World ◽  
The One ◽  
Microscopic Measurement

Combining precise microscopic measurement with quantitative image analysis, video microscopy has become one of the most important, real-space experiment techniques to study the microscopic properties of soft matter systems. On the one hand, it provides a basic tool to observe and record the microscopic world. On the other hand, it offers a powerful experiment method to study the underlying physics of the microscopic world. In this paper, we review the development of the video microscopy, introduce the corresponding hardware and video processing software, and summarize the typical applications and recent progresses of video microscopy in colloidal suspensions. The future of the video microscopy in the soft condensed matter physics and interdisciplinary research is discussed.

scholarly journals Multivalency Pattern Recognition to Sort Colloidal Assemblies

2020 ◽  
Author(s):  
Sebastian Loescher ◽  
Andreas Walther
Keyword(s):  
Pattern Recognition ◽  
Self Assembly ◽  
Soft Matter ◽  
Biological Response ◽  
Interaction Patterns ◽  
Colloidal Systems ◽  
Binding Motifs ◽  
Important Principle ◽  
Additional Control ◽  
20 Nm

<i>Multivalent interactions are an important principle for self-assembly, and have been widely used to assemble colloidal systems. However, binding partners on colloids are typically statistically distributed, which falls short of the possibilities arising from geometrically controlled multivalency patterns as for instance found in viruses. Herein, we use the ultimate precision provided by 3D DNA origamis to introduce colloidal scale multivalency pattern recognition via designing geometrically precise interaction patterns at patches of patchy nanocylinder. This gives rise to self-sorting of colloidal assemblies despite having the same type and number of supramolecular binding motifs – solely based on the pattern located on a 20 x 20 nm cross section. The degree of sorting can be modulated by the geometric overlap of patterns and homo, mixed and alternating supracolloidal polymerizations are demonstrated. We demonstrate that geometric positioning of multivalency patterns provides additional control to organize soft matter, and we believe the concept to be of importance for engineering biological response and to be generalizable for other precision nanoparticles and soft matter objects.</i>

Nano World

2014 ◽  
pp. 218-247
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystals ◽  
Soft Matter ◽  
Venture Capitalists ◽  
Atoms And Molecules ◽  
Advanced Technologies ◽  
Molecular Scale

This part of the book provides information and projects for the readers about the omnipresence of nanoscale objects – soft matter, colloids, liquid crystals, carbon nanotubes, nanoshells, and the developments in nanoscale and molecular-scale technologies involving these small structures. Nanotechnology concerns structures measuring between 1 and 100 nanometers and allows manipulating individual atoms and molecules. Since Norio Taniguchi of Tokyo Science University first used the term nanotechnology in 1974, the governments, corporations, and venture capitalists invest every year billions of dollars in nanotechnology and more than a half of advanced technologies incorporate nanotechnology products in different ways. In addition, developments in nanotechnology demand hiring in millions of trained nanotechnology workforce (Nano.gov, 2012).

4. States of matter

2014 ◽  
pp. 51-69
Author(s):  
Peter Atkins
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Liquid Crystals ◽  
Magnetic Resonance ◽  
Equation Of State ◽  
Soft Matter ◽  
Van Der Waals ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Van Der Waals Equation ◽  
Intermediate States

‘States of matter’ describes the three traditional states — gas, liquid, and solid — and the models used to predict and understand their behaviour. The van der Waals equation of state captures many of the properties of real gases. The classical way of studying the motion of molecules in liquids is to measure its viscosity. Techniques include neutron scattering and nuclear magnetic resonance. X-ray diffraction is used to determine the structures of solids. Intermediate states of matter — where liquid meets gas and liquid meets solid — are also considered. Examples include supercritical fluids, soft matter such as liquid crystals, and graphene, a remarkable and essentially two-dimensional material.

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