scholarly journals Polarized photoluminescence of the polymer networks obtained by in situ photopolymerization of fluorescent monomer in a nematic liquid crystal

2016 ◽  
Vol 6 (9) ◽  
pp. 2956 ◽  
Author(s):  
Vijay Kumar Baliyan ◽  
Vineet Kumar ◽  
Jinsoo Kim ◽  
Shin-Woong Kang
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Polymer Networks

scholarly journals Reverse switching of surface roughness in a self-organized polydomain liquid crystal coating

2015 ◽  
Vol 112 (13) ◽  
pp. 3880-3885 ◽  
Author(s):  
Danqing Liu ◽  
Ling Liu ◽  
Patrick R. Onck ◽  
Dirk J. Broer
Keyword(s):  
Surface Roughness ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Light Exposure ◽  
Polymer Network ◽  
Polymer Networks ◽  
Domain Size ◽  
Interference Microscopy ◽  
Light Illumination ◽  
Modulation Amplitude

In this work we propose randomly ordered polydomain nematic liquid crystal polymer networks to reversibly generate notable jagged relief patterns at a polymer coating surface by light illumination. The domain size is controlled by the addition of traces of partly insoluble fluorinated acrylate. The photoresponse of the coating is induced by a small amount of copolymerized azobenzene monomers. Upon exposure to UV light, azobenzene undergoes trans to cis isomerization, resulting in a change in molecular order and packing within each domain. The extent of this effect and its directionality depends on the domain orientation. Localized to domain level, this morphological change forms large 3D spikes at the surface with a modulation amplitude of more than 20% of the initial thickness. The process is reversible; the surface topographical patterns erase within 10 s by stopping the light exposure. A finite element model is applied to simulate the surface topography changes of the polydomain coating. The simulations describe the formation of the topographic features in terms of light absorption and isomerization process as a function of the director orientation. The random director distribution leads to surface structures which were found to be in close agreement with the ones measured by interference microscopy. The effect of domain size on surface roughness and depth modulation was explored and related to the internal mechanical constraints. The use of nematic liquid crystal polydomains confined in a polymer network largely simplifies the fabrication of smart coatings with a prominent triggered topographic response.

scholarly journals Wavelength-tuneable laser emission from stretchable chiral nematic liquid crystal gels via in situ photopolymerization

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 31919-31924 ◽  
Author(s):  
S. M. Wood ◽  
F. Castles ◽  
S. J. Elston ◽  
S. M. Morris
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Liquid Crystalline ◽  
Laser Emission ◽  
Mechanical Strain ◽  
Chiral Nematic

We describe a technique for creating multi-coloured liquid crystalline laser gels which may be selectively and reversibly wavelength-tuned by applying a mechanical strain.

Control of High Pretilt Angle for Nematic Liquid Crystal on Homeotropic Alignment Layer by In-situ Photoalignment Method

2004 ◽  
Vol 412 (1) ◽  
pp. 269-275 ◽  
Author(s):  
Yong-Je Jeon ◽  
Jeong-Yeon Hwang ◽  
Dae-Shik Seo ◽  
Sang-Hee Nam ◽  
Jeong-In Han
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Alignment Layer ◽  
Homeotropic Alignment ◽  
Pretilt Angle

Effect of Network Elasticity on Nematic Liquid Crystal/Cross-Linked Polymer Phase Diagram

1999 ◽  
Vol 559 ◽  
Author(s):  
D. Nwabunma ◽  
T. Kyu ◽  
R.T. Pogue ◽  
T.J. Bunning
Keyword(s):  
Phase Diagram ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Volume Fraction ◽  
Segment Length ◽  
Polymer Phase ◽  
Cross Links ◽  
Network Functionality ◽  
Experimental Diagram

ABSTRACTThe influence of elasticity on the phase behavior of a mixture of nematic liquid crystal (LC) and in-situ cross-linked polymer has been investigated. Unlike the phase diagram of the LC/pre-cured polymer, the experimental diagram of LC/cross-linked polymer phase supported by theoretical calculation showed no critical point. Instead, the binodal curve exhibits an upward asymptotic behavior as the LC volume fraction approaches unity due to domination arising from network elasticity, particularly at high LC volume fraction. An examination of the effect of cross-links segment length and network functionality on the phase diagram of LC/cross-linked polymer showed that the segment length between cross-links exerts a greater influence.

Some Properties of Nematic Liquid Crystal E7/Acrylic Polymer Networks

2011 ◽  
Vol 541 (1) ◽  
pp. 201/[439]-210/[448] ◽  
Author(s):  
Y. Derouiche ◽  
F. Dubois ◽  
R. Douali ◽  
C. Legrand ◽  
U. Maschke
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Polymer Networks ◽  
Acrylic Polymer
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