scholarly journals Tuning the defect configurations in nematic and smectic liquid crystalline shells

2013 ◽  
Vol 371 (1988) ◽  
pp. 20120258 ◽  
Author(s):  
Hsin-Ling Liang ◽  
JungHyun Noh ◽  
Rudolf Zentel ◽  
Per Rudquist ◽  
Jan P.F. Lagerwall
Keyword(s):  
Boundary Conditions ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Topological Defects ◽  
Microfluidic System ◽  
Director Field ◽  
Smectic Phases ◽  
Anchor Points ◽  
External Forces ◽  
Linker Molecules

Thin liquid crystalline shells surrounding and surrounded by aqueous phases can be conveniently produced using a nested capillary microfluidic system, as was first demonstrated by Fernandez-Nieves et al. in 2007. By choosing particular combinations of stabilizers in the internal and external phases, different types of alignment, uniform or hybrid, can be ensured within the shell. Here, we investigate shells in the nematic and smectic phases under varying boundary conditions, focusing in particular on textural transformations during phase transitions, on the interaction between topological defects in the director field and inclusions in the liquid crystal (LC), and on the possibility to relocate defects within the shell by rotating the shell in the gravitational field. We demonstrate that inclusions in a shell can seed defects that cannot form in a pristine shell, adding a further means of tuning the defect configuration, and that shells in which the internal aqueous phase is not density matched with the LC will gently rearrange the internal structure upon a rotation that changes the influence of gravity. Because the defects can act as anchor points for added linker molecules, allowing self-assembly of adjacent shells, the various arrangements of defects developing in these shells and the possibility of tuning the result by modifying boundary conditions, LC phase, thickness and diameter of the shell or applying external forces make this new LC configuration very attractive.

scholarly journals Nematic and Cholesteric Liquid Crystal Structures in Cells with Tangential-Conical Boundary Conditions

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 249 ◽  
Author(s):  
Mikhail N. Krakhalev ◽  
Rashid G. Bikbaev ◽  
Vitaly S. Sutormin ◽  
Ivan V. Timofeev ◽  
Victor Ya. Zyryanov
Keyword(s):  
Boundary Conditions ◽  
Energy Minimization ◽  
Periodic Structures ◽  
Cholesteric Liquid Crystal ◽  
Topological Defects ◽  
Director Field ◽  
Surface Anchoring ◽  
Minimization Procedure ◽  
Optical Textures ◽  
Difference Time

Orientational structures formed in nematic and cholesteric layers with tangential-conical boundary conditions have been investigated. LC cells with one substrate specifying the conical surface anchoring and another substrate specifying the tangential one have been considered. The director configurations and topological defects have been identified analyzing the texture patterns obtained by polarizing microscope in comparison with the structures and optical textures calculated by free energy minimization procedure of director field and finite-difference time-domain method, respectively. The domains, periodic structures and two-dimensional defects proper to the LC cells with tangential-conical anchoring have been studied depending on the layer thickness and cholesteric pitch.

Self-Assembly Optical Components

2003 ◽  
Vol 771 ◽  
Author(s):  
Pavel I. Lazarev ◽  
Michael V. Paukshto ◽  
Elena N. Sidorenko
Keyword(s):  
Optical Properties ◽  
Self Assembly ◽  
Crystalline State ◽  
Liquid Crystalline ◽  
Film Deposition ◽  
X Ray Diffraction ◽  
Optical Components ◽  
Crystal Film ◽  
Solid Film ◽  
Thin Crystal

AbstractWe report a new method of Thin Crystal Film deposition. In the present paper we describe the method of crystallization, structure, and optical properties of Bisbenzimidazo[2,1-a:1',2',b']anthra[2,1,9-def:6,5,10-d'e'f']-diisoquinoline-6,9-dion (mixture with cis-isomer) (abbreviated DBI PTCA) sulfonation product. The Thin Crystal Film has a thickness of 200-1000 nm, with anisotropic optical properties such as refraction and absorption indices. X-ray diffraction data evidences a lyotropic liquid crystalline state in liquid phase and crystalline state in solid film. Anisotropic optical properties of the film make it useful in optical devices, e.g. liquid crystal displays.

scholarly journals Controlling the Kinetics of an Enzymatic Reaction through Enzyme or Substrate Confinement into Lipid Mesophases with Tunable Structural Parameters

2020 ◽  
Vol 21 (14) ◽  
pp. 5116
Author(s):  
Marco Mendozza ◽  
Arianna Balestri ◽  
Costanza Montis ◽  
Debora Berti
Keyword(s):  
Reaction Kinetics ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Structural Parameters ◽  
Enzymatic Reaction ◽  
X Ray Scattering ◽  
Nitrophenyl Phosphate ◽  
Vis Spectroscopy ◽  
Kinetics Of ◽  
Enzyme Alkaline Phosphatase

Lipid liquid crystalline mesophases, resulting from the self-assembly of polymorphic lipids in water, have been widely explored as biocompatible drug delivery systems. In this respect, non-lamellar structures are particularly attractive: they are characterized by complex 3D architectures, with the coexistence of hydrophobic and hydrophilic regions that can conveniently host drugs of different polarities. The fine tunability of the structural parameters is nontrivial, but of paramount relevance, in order to control the diffusive properties of encapsulated active principles and, ultimately, their pharmacokinetics and release. In this work, we investigate the reaction kinetics of p-nitrophenyl phosphate conversion into p-nitrophenol, catalysed by the enzyme Alkaline Phosphatase, upon alternative confinement of the substrate and of the enzyme into liquid crystalline mesophases of phytantriol/H2O containing variable amounts of an additive, sucrose stearate, able to swell the mesophase. A structural investigation through Small-Angle X-ray Scattering, revealed the possibility to finely control the structure/size of the mesophases with the amount of the included additive. A UV–vis spectroscopy study highlighted that the enzymatic reaction kinetics could be controlled by tuning the structural parameters of the mesophase, opening new perspectives for the exploitation of non-lamellar mesophases for confinement and controlled release of therapeutics.

Synthesis of azobenzene-containing liquid crystalline block copolymer nanoparticles via polymerization induced hierarchical self-assembly

2021 ◽  
Author(s):  
Wei Wen ◽  
Wangqi Ouyang ◽  
Song Guan ◽  
Aihua Chen
Keyword(s):  
Block Copolymer ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Facile Synthesis ◽  
Liquid Crystalline Nanoparticles

A facile synthesis of non-spherical photoresponsive azobenzene-containing liquid crystalline nanoparticles via polymerization-induced hierarchical self-assembly (PIHSA).

Synthesis, Self-Assembly and Solution-Processed Field-Effect Transistors of a Liquid Crystalline Bis(dithienothiophene) Derivative

2009 ◽  
Vol 113 (36) ◽  
pp. 16232-16237 ◽  
Author(s):  
Shiming Zhang ◽  
Yunlong Guo ◽  
Ling Wang ◽  
Qikai Li ◽  
Kai Zheng ◽  
...  
Keyword(s):  
Self Assembly ◽  
Field Effect ◽  
Liquid Crystalline ◽  
Field Effect Transistors ◽  
Solution Processed

scholarly journals A Structurally Variable Hinged Tetrahedron Framework from DNA Origami

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
David M. Smith ◽  
Verena Schüller ◽  
Carsten Forthmann ◽  
Robert Schreiber ◽  
Philip Tinnefeld ◽  
...  
Keyword(s):  
Self Assembly ◽  
Gel Electrophoresis ◽  
Imaging Techniques ◽  
Building Blocks ◽  
Dna Origami ◽  
Microscopy Technique ◽  
Wire Frame ◽  
Wide Range ◽  
Potential Applications ◽  
Linker Molecules

Nanometer-sized polyhedral wire-frame objects hold a wide range of potential applications both as structural scaffolds as well as a basis for synthetic nanocontainers. The utilization of DNA as basic building blocks for such structures allows the exploitation of bottom-up self-assembly in order to achieve molecular programmability through the pairing of complementary bases. In this work, we report on a hollow but rigid tetrahedron framework of 75 nm strut length constructed with the DNA origami method. Flexible hinges at each of their four joints provide a means for structural variability of the object. Through the opening of gaps along the struts, four variants can be created as confirmed by both gel electrophoresis and direct imaging techniques. The intrinsic site addressability provided by this technique allows the unique targeted attachment of dye and/or linker molecules at any point on the structure's surface, which we prove through the superresolution fluorescence microscopy technique DNA PAINT.

Thermal phase transition behaviours of the blue phase of bent-core nematogen and chiral dopant mixtures under different boundary conditions

Soft Matter ◽  
2014 ◽  
Vol 10 (41) ◽  
pp. 8224-8228 ◽  
Author(s):  
Min-Jun Gim ◽  
Gohyun Han ◽  
Suk-Won Choi ◽  
Dong Ki Yoon
Keyword(s):  
Phase Transition ◽  
Boundary Conditions ◽  
Liquid Crystalline ◽  
Isotropic Phase ◽  
Different Boundary Conditions ◽  
Various Boundary Conditions ◽  
Thermal Phase Transition ◽  
Thermal Phase ◽  
Blue Phase ◽  
Chiral Dopants

We have investigated dramatic changes in the thermal phase transition of a liquid-crystalline (LC) blue phase (BP) consisting of bent-core nematogen and chiral dopants under various boundary conditions during cooling from the isotropic phase.

scholarly journals Experimental and Computational Study of a Liquid Crystalline Dimesogen Exhibiting Nematic, Twist-Bend Nematic, Intercalated Smectic, and Soft Crystalline Mesophases

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 532
Author(s):  
Emily E. Pocock ◽  
Richard J. Mandle ◽  
John W. Goodby
Keyword(s):  
Liquid Crystalline ◽  
Computational Study ◽  
Structure Property ◽  
Correlation Lengths ◽  
Aspect Ratios ◽  
Smectic Phases ◽  
Out Of Plane ◽  
Lower Temperature ◽  
Soft Crystal ◽  
Optical Textures

Liquid crystalline dimers and dimesogens have attracted significant attention due to their tendency to exhibit twist-bend modulated nematic (NTB) phases. While the features that give rise to NTB phase formation are now somewhat understood, a comparable structure–property relationship governing the formation of layered (smectic) phases from the NTB phase is absent. In this present work, we find that by selecting mesogenic units with differing polarities and aspect ratios and selecting an appropriately bent central spacer we obtain a material that exhibits both NTB and intercalated smectic phases. The higher temperature smectic phase is assigned as SmCA based on its optical textures and X-ray scattering patterns. A detailed study of the lower temperature smectic ‘’X’’ phase by optical microscopy and SAXS/WAXS demonstrates this phase to be smectic, with an in-plane orthorhombic or monoclinic packing and long (>100 nm) out of plane correlation lengths. This phase, which has been observed in a handful of materials to date, is a soft-crystal phase with an anticlinic layer organisation. We suggest that mismatching the polarities, conjugation and aspect ratios of mesogenic units is a useful method for generating smectic forming dimesogens.

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