Liquid crystal orientation

The extra energy in the case of (a) can be calculated once the azimuth (/)(x, z) of the deviation of the director from the rr-axis has been determined. 

FIGURE 3.17. Illustration of Berreman s model [20]. (a) Deformation of the molecular distribution when the director is oriented perpendicular to the ridges on the surface, (b) No deformation is present with an orientation of the molecules parallel to the ridges and troughs on the surface. 

A minimum Prank energy is achieved under the condition 

The elastic energy density caused by the deformation of a nematic liquid crystal in the case of Fig. 3.17(a) depends on the distance z from the glass 

this model explains why it is more energetically favorable for the director of a nematic liquid crystal to be aligned along the ridges and 

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Electro-optic materials can be made using liquid crystal polymer combinations. In these applications, termed polymer-stabilized liquid crystals [83,86], the hquid crystal is not removed after polymerization of the monomer and the resulting polymer network stabilizes the liquid crystal orientation. 

Corvazier, L Zhao, Y, Induction of Liquid Crystal Orientation through Azobenzene-Containing Polymer Networks, Macromolecules 32, 3195, 1999. 

J. G., De Lange, G. A. Molecular solutes in nematic liquid crystals orientational order and electric field gradients. Chem. Phys. Lett. 1983, 99, 271-274. 

The self-organization of both thermotropic and lyotropic liquid crystals make these ordered fluids remarkable media for the dispersion and organization (alignment) of CNTs. This subject has been the focus of a recent excellent review by Scalia [231], theoretical work on anchoring at the liquid crystal/CNT interface by Popa-Nita and Kralj [458], and a number of earlier experimental reports on liquid crystal/CNT composites demonstrating that liquid crystal orientational order can be transferred to dispersed CNTs, which is commonly illustrated using polarized Raman spectroscopy [459 -62]. 

Ikeda T. (2003) Photomodulation of liquid crystal orientations for photonic applications. J Mater Chem 13 2037-2057... 

Liquid crystals orientational order and optical anisotropy... 

Liquid crystals orientational order and optical anisotropy (E.-H. Korte) 323... 

The combination of S and n appropriately describes the ordering of liquid crystals. S is the microscopic feature of molecular orientation while n is the macroscopic characteristic of liquid crystal orientation. In general, the molecular dimension of liquid crystals is about a few nm in length and a few tenth of a nm in width. The range of variation of n r) is in the order of the magnitude of microns. n r) is in fact the average orientation of a... 

Montaner et al. [74] have used electron diftraction to characterize Araya polyacetylene [21], prepared at 10°C from a Shirakawa catalyst system dissolved in a nematic liquid crystal, oriented by a magnetic field. The mosaic (orientation distribution) is broad, approximately 20° with respect to the fibre axis. A later x-... 

Patterning a polymer film to induce liquid crystal orientation... 

Corvazier, L., and Zhao, Y. Induction of liquid crystal orientation through. izoiseimmc containing polymer networks. Macromolecules i2,. 1195 (1999). 

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