scholarly journals Thermo-Optical Generation of Particle-Like Structures in Frustrated Chiral Nematic Film

Crystals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 574 ◽  
Author(s):  
Sergey Shvetsov ◽  
Tetiana Orlova ◽  
Alexander V. Emelyanenko ◽  
Alexander Zolot’ko
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Laser Beam ◽  
Field Configuration ◽  
Director Field ◽  
Crystal State ◽  
Localized Structures ◽  
Optical Generation ◽  
Chiral Nematic ◽  
The Creation

The creation of metastable particle-like structures in frustrated (unwound) chiral nematic film containing light-absorbing additive is studied. It is shown that such localized structures can be generated by the thermo-optical action of a focused laser beam or arise spontaneously at a phase transition from an isotropic to a liquid crystal state. Observed axisymmetric patterns resemble cholesteric spherulites with toroidal double-twisted director-field configuration.

Effects of the preparing condition of a polymer-stabilised liquid crystal with a smectic-A−chiral nematic phase transition on its properties

2009 ◽  
Vol 36 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Guohui Pan ◽  
Yubo Cao ◽  
Renwei Guo ◽  
Huicong Cheng ◽  
Zhou Yang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Nematic Phase ◽  
Smectic A ◽  
Chiral Nematic

Experimental and DFT Studies on Well-Defined Odd-Even Effect in Organic Liquid Crystal Tetramers Incorporating Two Chiral Centers

2021 ◽  
Vol 14 ◽  
Author(s):  
Mursyida Abdul Rahim ◽  
Guan-Yeow Yeap ◽  
Wai Kit Tang ◽  
Chi-Kit Siu
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Computational Study ◽  
Organic Liquid ◽  
Spectroscopic Techniques ◽  
Texture Characteristic ◽  
Scanning Calorimetry ◽  
Spacer Length ◽  
Chiral Nematic ◽  
Phase Transition Temperatures

: A new series of organic liquid crystal tetramers containing two symmetrical mesogenic units of 4-(4’-phenoxylimino)methyl)phenol joined by methylene –(CH2)m- spacer wherein m varied from 5 to 10 has been synthesized. The length for each of the mesogenic units was extended further via connection with two chiral entities of (S)-2- methylbutyl-4-(4’-bromobutyloxyphenyl)benzoate situated at both terminal ends. The structures of these tetramers were elucidated using elemental analysis and spectroscopic techniques (FT-IR and 1H-NMR) while the texture and the phase transition temperatures were studied using polarizing optical microscopy (POM) along with differential scanning calorimetry (DSC). All the homologues in this series are enantiotropic mesogens exhibiting oily streak texture or fan shaped texture characteristic of chiral nematic phase. The odd-even effect can be observed upon increasing the methylene spacer length. The structure-properties connectivity has demonstrated that the phase transition temperature for tetramers with even- numbered methylene units in the spacer is relatively higher in comparison with the odd- numbered members. The computational study via constraint molecular dynamics performed at the DFTB level of theory has further supported that more energy is required for the even- numbered tetramer than the odd-numbered member to undergo the structural transition from folded to extended geometries.

Effects on thermo‐optical properties of the composition of a polymer‐stabilised liquid crystal with a smectic A–chiral nematic phase transition

2008 ◽  
Vol 35 (9) ◽  
pp. 1151-1160 ◽  
Author(s):  
Guohui Pan ◽  
Lilong Yu ◽  
Hongbin Zhang ◽  
Jinbao Guo ◽  
Renwei Guo ◽  
...  
Keyword(s):  
Phase Transition ◽  
Optical Properties ◽  
Liquid Crystal ◽  
Nematic Phase ◽  
Smectic A ◽  
Chiral Nematic
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