scholarly journals Liquid crystal self-assembly of upconversion nanorods enriched by depletion forces for mesostructured material preparation

Nanoscale ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 4218-4227 ◽  
Author(s):  
Yong Xie ◽  
Yuanyuan Li ◽  
Guoqing Wei ◽  
Qingkun Liu ◽  
Haridas Mundoor ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Material Preparation ◽  
Mesostructured Material ◽  
Depletion Forces

A mesostructured orientationally ordered material with polarized upconversion properties is formed by using the liquid crystalline colloidal self-assembly of semiconductor nanorods.

A Biological System Producing a Self-Assembling Cholesteric Protein Liquid Crystal

1971 ◽  
Vol 8 (1) ◽  
pp. 93-109
Author(s):  
A. C. NEVILLE ◽  
B. M. LUKE
Keyword(s):  
Liquid Crystal ◽  
Electron Density ◽  
Electron Micrographs ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Density Variation ◽  
Self Assembling ◽  
The Matrix ◽  
Electron Density Variation ◽  
Helicoidal Structure

The protein in the oothecal glands of praying mantids (Sphodromantis tenuidentata, Miomantis monacha) exists in the form of lamellar liquid crystalline spherulites, which coalesce as they flow out of a punctured gland tubule. Electron micrographs of sections of these spherulites after fixation show parabolic patterns of an electron-light component, set in a continuous matrix of protein. Such patterns arise in helicoidal systems (e.g. arthropod cuticle) and microdensitometric scans of the matrix show a rhythmical electron-density variation consistent with helicoidal structure. Double spiral patterns identical to those seen in liquid crystal spherulites are illustrated. These properties resemble those of cholesteric liquid crystals. The constructional units appear to be molecular rather than fibrillar as described by previous authors. The helicoidal architecture arises by self-assembly in the gland lumen. Lamellar surface structures self-assembled spontaneously on glass coverslips when the protein was left to stand for several days. When heated to 55 °C, the birefringent liquid crystalline protein abruptly changes to an isotropic gel, with associated loss of parabolic patterning in electron micrographs and of the rhythmical electron-density variation on microdensitometric scans. This behaviour is compared to the formation of gelatin from collagen, in terms of the randomization of an originally ordered secondary structure.

scholarly journals Mechanisms of Chiral Transfer in Optically Active Dopant – Nematic Liquid Crystal Systems

2020 ◽  
Vol 20 (4) ◽  
pp. 6-26
Author(s):  
V. A. Burmistrov ◽  
V. V. Aleksandriiskii ◽  
I. V. Novikov ◽  
O. I. Koifman
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
High Efficiency ◽  
Stationary Phases ◽  
Theoretical Description ◽  
Optically Active ◽  
Axial Coordination ◽  
Chiral Dopants

Induction of helical mesophases by incorporating chiral dopants into the nematics matrix is the promising modern trends in the chemistry of liquid crystals. This process is associated with a unique phenomenon - an amplification of chirality in liquid-crystalline phases, which ensures the detection of enantiomers by their chiral induction, much more sensitive than other methods. The relevance of this approach is due to the need to create perspective electro-optical devices operating with ultra-low control voltages based on twist effects, chromatographic stationary phases with high chiral selectivity, flexible magnets, photo-sensitive nanostructures, and other smart LC materials. The successful solution of these problems is impossible without experimental research and theoretical comprehension of the mechanisms of third level chiral transfer optically active dopant – nematic liquid crystal. In the last decade, a large number of works have appeared on the solution of these problems. This review is devoted to a generalization of the experimental results and a theoretical description of the transfer of molecular chirality to orientationally ordered systems with the participation of both chiral molecular substituents with an asymmetric carbon atom and planar or quasi-planar fragments chirally distorted relative to each other. The stereochemical aspects of induction associated with the structural correspondences of the dopant and nematic liquid crystal, as well as the main classes of optically active additives, are discussed. Application of metal complexes, both Werner and macroheterocyclic, are presented. Special attention is paid to the results of the mechanisms study of chiral transfer due to various intermolecular interactions: hydrogen bonding, axial coordination, and the formation of inclusion compounds. The high efficiency of induction of spiral mesophases has been demonstrated with a combination of different self-assembly mechanisms in liquid crystal - chiral additive systems.

Self-Assembly of dPS-Liquid Crystalline Diblock Copolymer in a Nematic Liquid Crystal Solvent

2012 ◽  
Vol 45 (15) ◽  
pp. 6168-6175 ◽  
Author(s):  
Soo-Young Park ◽  
Thangavelu Kavitha ◽  
Tahseen Kamal ◽  
Waliullah Khan ◽  
Taegyu Shin ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Diblock Copolymer ◽  
Self Assembly ◽  
Liquid Crystalline

Self-Assembly of Coil/Liquid-Crystalline Diblock Copolymers in a Liquid Crystal Solvent

2009 ◽  
Vol 42 (1) ◽  
pp. 299-307 ◽  
Author(s):  
Neal R. Scruggs ◽  
Rafael Verduzco ◽  
David Uhrig ◽  
Waliullah Khan ◽  
Soo-Young Park ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Diblock Copolymers

scholarly journals Mono- and bilayer smectic liquid crystal ordering in dense solutions of “gapped” DNA duplexes

2021 ◽  
Vol 118 (12) ◽  
pp. e2019996118
Author(s):  
Prabesh Gyawali ◽  
Rony Saha ◽  
Gregory P. Smith ◽  
Miroslaw Salamonczyk ◽  
Prakash Kharel ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Smectic Layer ◽  
Bilayer Structure ◽  
Dna Duplexes ◽  
Cholesteric Phase ◽  
Smectic Liquid Crystal ◽  
Layer Structures ◽  
Gapped Dna

Although its mesomorphic properties have been studied for many years, only recently has the molecule of life begun to reveal the true range of its rich liquid crystalline behavior. End-to-end interactions between concentrated, ultrashort DNA duplexes—driving the self-assembly of aggregates that organize into liquid crystal phases—and the incorporation of flexible single-stranded “gaps” in otherwise fully paired duplexes—producing clear evidence of an elementary lamellar (smectic-A) phase in DNA solutions—are two exciting developments that have opened avenues for discovery. Here, we report on a wider investigation of the nature and temperature dependence of smectic ordering in concentrated solutions of various “gapped” DNA (GDNA) constructs. We examine symmetric GDNA constructs consisting of two 48-base pair duplex segments bridged by a single-stranded sequence of 2 to 20 thymine bases. Two distinct smectic layer structures are observed for DNA concentration in the range ∼230to∼280 mg/mL. One exhibits an interlayer periodicity comparable with two-duplex lengths (“bilayer” structure), and the other has a period similar to a single-duplex length (“monolayer” structure). The bilayer structure is observed for gap length ≳10 bases and melts into the cholesteric phase at a temperature between 30 °C and 35 °C. The monolayer structure predominates for gap length ≲10 bases and persists to >40 °C. We discuss models for the two layer structures and mechanisms for their stability. We also report results for asymmetric gapped constructs and for constructs with terminal overhangs, which further support the model layer structures.

scholarly journals A columnar liquid crystal with permanent polar order

2015 ◽  
Vol 3 (5) ◽  
pp. 985-989 ◽  
Author(s):  
J. Guilleme ◽  
J. Aragó ◽  
E. Ortí ◽  
E. Cavero ◽  
T. Sierra ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Electric Fields ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
The Self ◽  
Polar Order ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials

The self-assembly of axial dipolar subphthalocyanine molecules in the presence of electric fields leads to uniaxially oriented columnar liquid crystalline materials that exhibit permanent polarization.

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.

Reversible microscale assembly of nanoparticles driven by the phase transition of a thermotropic liquid crystal

2017 ◽  
Author(s):  
Niamh Mac Fhionnlaoich ◽  
Stephen Schrettl ◽  
Nicholas B. Tito ◽  
Ye Yang ◽  
Malavika Nair ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Self Assembly ◽  
Nematic Phase ◽  
Hierarchical Control ◽  
Building Blocks ◽  
Model System ◽  
Microscopic Level ◽  
Reversible Process ◽  
Thermotropic Liquid Crystal

The arrangement of nanoscale building blocks into patterns with microscale periodicity is challenging to achieve via self-assembly processes. Here, we report on the phase transition-driven collective assembly of gold nanoparticles in a thermotropic liquid crystal. A temperature-induced transition from the isotropic to the nematic phase leads to the assembly of individual nanometre-sized particles into arrays of micrometre-sized aggregates, whose size and characteristic spacing can be tuned by varying the cooling rate. This fully reversible process offers hierarchical control over structural order on the molecular, nanoscopic, and microscopic level and is an interesting model system for the programmable patterning of nanocomposites with access to micrometre-sized periodicities.

scholarly journals Orientational self-assembly of nanoparticles in nematic droplets

2021 ◽  
Author(s):  
Natália Tomašovičová ◽  
Marianna Batkova ◽  
Ivan Batko ◽  
Veronika Lacková ◽  
Vlasta Zavišová ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Self Assembly

The interplay between the anchoring of liquid crystal (LC) molecules at the substrate and at the surface of nanoparticles (NPs) results in an orientational self-assembly of nanoparticles in sessile nematic droplets.

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