Polarizing Optical Microscopic Characterization of Nematic Liquid Crystal Confined in Porous Silicon

2011 ◽  
Vol 181-182 ◽  
pp. 83-87
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Experimental Study ◽  
Liquid Crystal ◽  
Porous Silicon ◽  
Optical Microscopy ◽  
Nematic Liquid Crystal ◽  
Experimental Investigations ◽  
Electro Optic ◽  
The Given

With polarizing optical microscopy we have investigated the electro-optic properties of a nematic liquid crystal 4-n-pentyl-4′-cyanobipheny confined in the microchannels of porous silicon. Experimental study shows clearly that the liquid crystal molecules tend to align parallel to the direction of the pore columns in porous silicon. Schlieren textures with S = +1 and +2 disclinations were recorded. Our experimental investigations show that uniaxial alignment, the planar radial and the escaped radial configurations exist around the given microchannels of porous silicon.

scholarly journals Chemical-Physical Characterization of a Binary Mixture of a Twist Bend Nematic Liquid Crystal with a Smectogen

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1110
Author(s):  
Abir Aouini ◽  
Maurizio Nobili ◽  
Edouard Chauveau ◽  
Philippe Dieudonné-George ◽  
Gauthier Damême ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Liquid Crystalline ◽  
Smectic A ◽  
Liquid Crystalline Phases ◽  
Electro Optic ◽  
Optical Dielectric

Nematic twist-bend phases (NTB) are new types of nematic liquid crystalline phases with attractive properties for future electro-optic applications. However, most of these states are monotropic or are stable only in a narrow high temperature range. They are often destabilized under moderate cooling, and only a few single compounds have shown to give room temperature NTB phases. Mixtures of twist-bend nematic liquid crystals with simple nematogens have shown to strongly lower the nematic to NTB phase transition temperature. Here, we examined the behaviour of new types of mixtures with the dimeric liquid crystal [4′,4′-(heptane-1,7-diyl)bis(([1′,1″-biphenyl]4″-carbo-nitrile))] (CB7CB). This now well-known twist-bend nematic liquid crystal presents a nematic twist-bend phase below T ≈ 104 °C. Mixtures with other monomeric alkyl or alkoxy -biphenylcarbonitriles liquid crystals that display a smectic A (SmA) phase also strongly reduce this temperature. The most interesting smectogen is 4′-Octyl-4-biphenylcarbonitrile (8CB), for which a long-term metastable NTB phase is found at room and lower temperatures. This paper presents the complete phase diagram of the corresponding binary system and a detailed investigation of its thermal, optical, dielectric, and elastic properties.

Orientation, interaction and laser assisted self-assembly of organic single-crystal micro-sheets in a nematic liquid crystal

Soft Matter ◽  
2015 ◽  
Vol 11 (38) ◽  
pp. 7674-7679 ◽  
Author(s):  
M. V. Rasna ◽  
K. P. Zuhail ◽  
U. V. Ramudu ◽  
R. Chandrasekar ◽  
J. Dontabhaktuni ◽  
...  
Keyword(s):  
Experimental Study ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Single Crystal ◽  
Nematic Liquid Crystal ◽  
Self Assembly ◽  
Nematic Liquid Crystals ◽  
Directed Assembly ◽  
Orientation Interaction ◽  
Organic Single Crystal

In this paper we report first experimental study on the orientation, interaction and directed-assembly of single crystal micro-sheets in nematic liquid crystals.

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