Continuously tunable emission color based on the molecular aggregation of (2Z,2′Z)-2,2′-(1,4-phenylenae)bis(3-(4-(dodecyloxy)phenyl)acrylonitrile)

RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 96196-96201 ◽  
Author(s):  
Hongbo Lu ◽  
Chao Zhang ◽  
Guo Xia ◽  
Shaojun Wu ◽  
Guobing Zhang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Photoluminescence Spectrum ◽  
Layer Structure ◽  
Helical Structure ◽  
Blue Shift ◽  
Molecular Aggregation ◽  
Emission Color ◽  
Pitch Length ◽  
Tunable Emission

A luminescent liquid crystal self-assembles to a layer structure or a helical structure with different pitch length depending on the stacking rate; a photoluminescence spectrum blue-shift from 600 nm to 506 nm.

Liquid Crystal Trimers Incorporating Saturated Isosteres of Benzene and Exhibiting Modulated Nematic Phases

2019 ◽  
Author(s):  
Adam Al-Janabi ◽  
Richard Mandle
Keyword(s):  
Liquid Crystal ◽  
Helical Structure ◽  
Molecular Shape ◽  
Saturated Hydrocarbons ◽  
Fluid System ◽  
Structural Requirement ◽  
Disubstituted Benzene ◽  
Bona Fide ◽  
Nematic Phases ◽  
Bend Angles

<p>The nematic twist-bend (N<sub>TB</sub>) liquid crystal phase possesses a local helical structure with a pitch length of a few nanometres and is the first example of spontaneous symmetry breaking in a fluid system. All known examples of the N­<sub>TB­</sub> phase occur in materials whose constituent mesogenic units are aromatic hydrocarbons. It is not clear if this is due to synthetic convenience or a <i>bona fide</i> structural requirement for a material to exhibit this phase of matter. In this work we demonstrate that materials consisting largely of saturated hydrocarbons could also give rise to this mesophase. Furthermore, replacement of 1,4-disubstituted benzene with <i>trans</i> 1,4-cyclohexane or even 1,4-cubane does not especially alter the transition temperatures of the resulting material nor does it appear to impact upon the heliconical tilt angle, suggesting the local structure of the phase is unperturbed. Calculating the probability distribution of bend angles reveals that the choice of isosteric group has little impact on the overall molecular shape, demonstrating the shape-driven nature of the N<sub>TB</sub> phase. </p>

scholarly journals Flow-assisted self-healing of the helical structure in a cholesteric liquid crystal

2021 ◽  
Vol 155 (5) ◽  
pp. 054903
Author(s):  
Jan-Christoph Eichler ◽  
Robert A. Skutnik ◽  
Marco G. Mazza ◽  
Martin Schoen
Keyword(s):  
Liquid Crystal ◽  
Cholesteric Liquid Crystal ◽  
Helical Structure ◽  
Self Healing

Effect of Photo-Isomerization of Azo Dyes on the Photonic Bandgap in Chiral Nematics

2011 ◽  
Vol 181-182 ◽  
pp. 257-260
Author(s):  
David Statman ◽  
Andrew Jockers ◽  
Daniel Brennan
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Azo Dyes ◽  
Azo Dye ◽  
Photonic Bandgap ◽  
Methyl Red ◽  
Central Wavelength ◽  
Chiral Nematic ◽  
Anchoring Energy ◽  
Pitch Length

Chiral nematic liquid crystals prepared with Grandjean texture demonstrate a photonic bandgap whose central wavelength is proportional to the pitch length, P, of the liquid crystal and whose width is given by (ne – no)P. We show that methyl red doped chiral nematics undergo a shift in the photonic bandgap upon photo-isomerization. This shift is a result of (1) photo-induced change in anchoring energy on the nematic surface, and (2) change in the natural pitch length from the photo-isomerization of the azo dye.

scholarly journals Dynamics and Protein–Solvent Interactions of Hemoglobin in T and R Quaternary Conformation

2002 ◽  
Vol 16 (3-4) ◽  
pp. 227-233 ◽  
Author(s):  
Chiara Caronna ◽  
Antonio Cupane
Keyword(s):  
Quaternary Structure ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Helical Structure ◽  
Blue Shift ◽  
Peak Frequency ◽  
The Other ◽  
Solvent Interactions ◽  
Reported Data ◽  
Increasing Temperature

In this work we report the thermal behaviour of the amide I′ band of carbonmonoxy and deoxy hemoglobin in 65% v/v glycerolD8/D2O solutions and in the temperature interval 10–295 K. Following recent suggestions in the literature, we analyze the amide I′ band in terms of two components, one at about 1630 cm−1and the other at about 1650 cm−1, that are assigned to solvent‒exposed and buried α‒helical regions, respectively.For deoxy hemoglobin (in T quaternary structure) both components are narrower with respect to carbonmonoxy hemoglobin (in R quaternary structure), while the peak frequency blue shift observed, upon increasing temperature, for the component at about 1630 cm−1is smaller. The reported data provide evidence of the dependence of hemoglobin dynamic properties upon the protein quaternary structure and suggest a more compact α‒helical structure of hemoglobin in T conformation, with reduced population of low‒frequency modes involving the solvent and protein.

scholarly journals Engineering Achiral Liquid Crystalline Polymers for Chiral Self-Recovery

2021 ◽  
Vol 22 (21) ◽  
pp. 11980
Author(s):  
Tengfei Miao ◽  
Xiaoxiao Cheng ◽  
Yilin Qian ◽  
Yaling Zhuang ◽  
Wei Zhang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Uv Light ◽  
Helical Structure ◽  
Side Chain ◽  
Liquid Crystal Polymers ◽  
Polymeric Liquid ◽  
Crystalline Polymers ◽  
Liquid Crystal System ◽  
And Storage

Flexible construction of permanently stored supramolecular chirality with stimulus-responsiveness remains a big challenge. Herein, we describe an efficient method to realize the transfer and storage of chirality in intrinsically achiral films of a side-chain polymeric liquid crystal system by combining chiral doping and cross-linking strategy. Even the helical structure was destroyed by UV light irradiation, the memorized chiral information in the covalent network enabled complete self-recovery of the original chiral superstructure. These results allowed the building of a novel chiroptical switch without any additional chiral source in multiple types of liquid crystal polymers, which may be one of the competitive candidates for use in stimulus-responsive chiro-optical devices.

Tunable emission color of Li2 SrSiO4 :Tb3+ due to cross-relaxation process and optical thermometry investigation

2018 ◽  
Vol 101 (7) ◽  
pp. 3076-3085 ◽  
Author(s):  
Xiao Zhou ◽  
Sha Jiang ◽  
Guotao Xiang ◽  
Xiao Tang ◽  
Xiaobing Luo ◽  
...  
Keyword(s):  
Relaxation Process ◽  
Cross Relaxation ◽  
Cross Relaxation Process ◽  
Emission Color ◽  
Optical Thermometry ◽  
Tunable Emission
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