The effect of morpholine and polymer network structure on electro-optical properties of polymer stabilized cholesteric liquid crystals

2019 ◽  
Author(s):  
Daniel Anreas Lippert
2013 ◽  
Vol 634-638 ◽  
pp. 2523-2526
Author(s):  
Hui Chang ◽  
Wen Juan Fan ◽  
Xiao Li Liu ◽  
Hong Ying Huo

The polymer stabilized liquid crystals (PSLC) films was prepared subsequently based on the mesogenic diacrylate monomer 4,4’-bis[6-(acryloyloxy)-hexyloxy]biphenyl (BAB6). The effects of BAB6 on the morphology of polymer network as well as the electro-optical properties of the PSLC films were investigated. The helical structure of liquid crystals was observed in the morphology of polymer network by SEM. Further, a single switching process was observed at lower monomer concentration in this study compared with the former publication. When BAB6 concentration reached 7 %, the response time and contrast ratio of PSLC film were 7 ms and 16.8, respectively.


2002 ◽  
Vol 277 (1) ◽  
pp. 75-83 ◽  
Author(s):  
V. Laux ◽  
F. Roussel ◽  
J.-M. Buisine

2016 ◽  
Vol 18 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Byeong-Hun Yu ◽  
Seong-Min Ji ◽  
Jin-Hun Kim ◽  
Jae-Won Huh ◽  
Tae-Hoon Yoon

2007 ◽  
Vol 34 (10) ◽  
pp. 1151-1158 ◽  
Author(s):  
Eric R. Beckel ◽  
Lalgudi V. Natarajan ◽  
Vincent P. Tondiglia ◽  
Richard L. Sutherland ◽  
Timothy J. Bunning

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 746 ◽  
Author(s):  
Kyung Min Lee ◽  
Ecklin P. Crenshaw ◽  
Mariacristina Rumi ◽  
Timothy J. White ◽  
Timothy J. Bunning ◽  
...  

It has previously been shown that for polymer-stabilized cholesteric liquid crystals (PSCLCs) with negative dielectric anisotropy, the position and bandwidth of the selective reflection notch can be controlled by a direct-current (DC) electric field. The field-induced deformation of the polymer network that stabilizes the devices is mediated by ionic charges trapped in or near the polymer. A unique and reversible electro-optic response is reported here for relatively thin films (≤5 μm). Increasing the DC field strength redshifts the reflection notch to longer wavelength until the reflection disappears at high DC fields. The extent of the tuning range is dependent on the cell thickness. The transition from the reflective to the clear state is due to the electrically controlled, chirped pitch across the small cell gap and not to the field-induced reorientation of the liquid crystal molecules themselves. The transition is reversible. By adjusting the DC field strength, various reflection wavelengths can be addressed from either a different reflective (colored) state at 0 V or a transparent state at a high DC field. Relatively fast responses (~50 ms rise times and ~200 ms fall times) are observed for these thin PSCLCs.


Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 7
Author(s):  
Kyung M. Lee ◽  
Timothy J. Bunning ◽  
Timothy J. White ◽  
Michael E. McConney ◽  
Nicholas P. Godman

We have previously reported that the application of a DC field can adjust the position and/or bandwidth of the selective reflection notch in polymer-stabilized cholesteric liquid crystals (PSCLCs). The proposed mechanism of these electro-optic (EO) response is ion-facilitated electromechanical deformation of the polymer stabilizing network. Accordingly, the concentration of ions trapped within the polymer network should considerably influence the EO response of PSCLC. Our prior studies have indicated that photoinitiators can increase ion density in PSCLC by an order of magnitude. Here, we isolate the contribution of ionic impurities associated with liquid crystal monomers (LCMs) by utilizing initiator-less polymerization. PSCLCs prepared with LCM with low ion concentration show bandwidth broadening of the reflection band whereas PSCLCs prepared with LCM with high ion concentration exhibit a red shifting tuning of the reflection band. The extent of the tuning or bandwidth broadening of the CLC reflection band depends on the concentration of LCMs and the chirality of the LCM.


2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Rishi Kumar

Cholesteric liquid crystal (Ch-LC) exhibits many remarkable optical properties due to formation of a macroscopic helical structure. A low amount of monomer (5wt.%) is dispersed into cholesteric liquid crystal and get polymerized under UV radiations to form polymer stabilized cholesteric texture (PSCT). The thermo-chromic response made this device suitable for the developing applications in thermal imaging. Temperature based measurements of PSCT exploits the key property of some polymer stabilized cholesteric liquid crystals (PSCLC) to reflect definite colors at specific temperatures. The selective color of PSCT texture shifts with raise in temperature from 30oC to 85oC, which can be utilized in thermal imaging applications.


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