Polymer-stabilized liquid crystalline topological defect network for micro-pixelated optical devices

2018 ◽  
Author(s):  
Fumito Araoka ◽  
Shuji Fujii ◽  
Hiroshi Orihara ◽  
Yuji Sasaki ◽  
Khoa Le
Keyword(s):  
Liquid Crystalline ◽  
Topological Defect ◽  
Optical Devices ◽  
Polymer Stabilized

scholarly journals Polymer Stabilized Cholesteric Liquid Crystal Siloxane for Temperature-Responsive Photonic Coatings

2020 ◽  
Vol 21 (5) ◽  
pp. 1803 ◽  
Author(s):  
Weixin Zhang ◽  
Johan Lub ◽  
Albertus P.H.J. Schenning ◽  
Guofu Zhou ◽  
Laurens T. de Haan
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Cholesteric Liquid Crystal ◽  
Uv Curing ◽  
Blue Shift ◽  
Polymer Coatings ◽  
Chain Extension ◽  
Reflective Coating ◽  
Temperature Responsive ◽  
Polymer Stabilized

Temperature-responsive photonic coatings are appealing for a variety of applications, including smart windows. However, the fabrication of such reflective polymer coatings remains a challenge. In this work, we report the development of a temperature-responsive, infrared-reflective coating consisting of a polymer-stabilized cholesteric liquid crystal siloxane, applied by a simple bar coating method. First, a side-chain liquid crystal oligosiloxane containing acrylate, chiral and mesogenic moieties was successfully synthesized via multiple steps, including preparing precursors, hydrosilylation, deprotection, and esterification reactions. Products of all the steps were fully characterized revealing a chain extension during the deprotection step. Subsequently, the photonic coating was fabricated by bar-coating the cholesteric liquid crystal oligomer on glass, using a mediator liquid crystalline molecule. After the UV-curing and removal of the mediator, a transparent IR reflective polymer-stabilized cholesteric liquid crystal coating was obtained. Notably, this fully cured, partially crosslinked transparent polymer coating retained temperature responsiveness due to the presence of non-reactive liquid-crystal oligosiloxanes. Upon increasing the temperature from room temperature, the polymer-stabilized cholesteric liquid crystal coating showed a continuous blue-shift of the reflection band from 1400 nm to 800 nm, and the shift was fully reversible.

Polymer-Stabilized Chromonic Liquid-Crystalline Polarizer

2011 ◽  
Vol 21 (11) ◽  
pp. 2129-2139 ◽  
Author(s):  
Seul-Ki Park ◽  
So-Eun Kim ◽  
Dae-Yoon Kim ◽  
Shin-Woong Kang ◽  
Seunghan Shin ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Polymer Stabilized

Polymerization and Properties of Polymer-Stabilized Ferroelectric Liquid Crystals

MRS Bulletin ◽  
1997 ◽  
Vol 22 (9) ◽  
pp. 15-20 ◽  
Author(s):  
Christopher N. Bowman ◽  
C. Allan Guymon
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Scanning Calorimetry ◽  
Ferroelectric Liquid Crystals ◽  
University Of Colorado ◽  
Crystalline Environment ◽  
Polarized Infrared Spectroscopy ◽  
The Many ◽  
The University ◽  
Polymer Stabilized

The following is based on the presentation made by Christopher N. Bowman, recipient of the MRS Outstanding Investigator Award, at the 1997 MRS Spring Meeting.I would like to focus on our recent work involving photopolymerizations of monomers in a liquid-crystalline environment. This work is one of the many aspects of photopolymerizations that we are focusing on at the University of Colorado. In particular this effort concentrates on understanding the influence of a liquid-crystalline medium and monomer segregation on polymerization behavior and polymer structure. These studies are of considerable importance for polymer-stabilized ferroelectric liquid crystals (FLCs) because of the enormous potential impact on the area.I will briefly introduce liquid crystals (LCs), FLCs, and photopolymerizations. I will then discuss the observed electrooptic properties and how these properties change as the LC phase during polymerization is varied. Finally I will address how polymerization kinetics are affected by the LC phase and monomer segregation. This discussion will include results from x-ray diffraction, polarized infrared spectroscopy, and differential scanning calorimetry experiments.

Investigation of Polymer Stabilized Liquid Crystal Formation Using Fluorinated and Aliphatic Monoacrylates

2001 ◽  
Vol 709 ◽  
Author(s):  
Demetrius McCormick ◽  
C. Allan Guymon
Keyword(s):  
Liquid Crystal ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Smectic Phase ◽  
Crystal Formation ◽  
Polymerization Mechanism ◽  
Smectic Liquid Crystal ◽  
Before And After ◽  
Polymer Stabilized

ABSTRACTThis study focuses on the photo-polymerization of a fluorinated monoacrylate monomer and aliphatic analog within a room temperature smectic liquid crystal (LC) in an effort to understand how factors such as LC order, monomer segregation, and monomer chemical structure affects the polymerization mechanism in polymer stabilized liquid crystalline systems (PSLC). Specifically, a fluorinated monoacrylate exhibits significantly enhanced polymerization rates when compared to an aliphatic monoacrylate. Moreover, this rate enhancement is particularly pronounced in the smectic phase of the LC, where the fluorinated monoacrylate displays a polymerization rate in the smectic phase that is over three times faster than the aliphatic monoacrylate in the smectic phase. Also the fluorinated monoacrylate exhibits enhanced segregation between the smectic layers of the LC both before and after polymerization, whereas the aliphatic monoacrylate phase separates during polymerization. The results of this study demonstrate how changes in the monomer chemical structure (i.e. fluorination) can significantly impact the polymerization mechanism and segregation in polymer stabilized systems. This study also offers the potential to further the understanding of tailoring these unique systems for display applications.

scholarly journals Photocontrollable Crystallization at the Topological Defect of a Liquid Crystalline Droplet

2021 ◽  
Author(s):  
Kenji Katayama ◽  
Yota Sakai
Keyword(s):  
Light Absorption ◽  
Liquid Crystalline ◽  
Topological Defect ◽  
Surfactant Solution ◽  
Light Irradiation ◽  
Crystal Formation ◽  
Dye Molecules

Abstract Photo-controllable crystallization at the topological defect in an LC droplet was demonstrated. The dye molecules dissolved in a surfactant solution outside the LC droplet were promoted to move into the droplet by the light absorption. Nuclei emerged tens of seconds after light irradiation and moved toward the topological defect located at the droplet center, forming a branch-shaped crystal. This phenomenon was reproduced for three different dyes, and photo-induced migration, nucleation, and crystal formation were discussed as a possible mechanism.

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