A new torsion pendulum technique to measure the twist elastic constant of liquid crystals
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چکیده
منابع مشابه
A new torsion pendulum technique to measure the twist elastic constant of liquid crystals
2014 A new experimental method to measure the twist elastic constant of nematic liquid crystals is proposed. The method is based on a direct measurement of the torque which the nematic liquid crystal exerts on the surfaces when a magnetic field is applied. The reliability of this technique is tested by measuring the twist elastic constant of the nematic liquid crystal 4-n-pentyl-4’-cyanobipheny...
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The effect of director pretilt on the twist magnetic Fréedericksz transition of nematics was investigated in a planar cell. The director configuration was calculated as a function of magnetic inductance. The dielectric and optical response of the nematic liquid crystal was numerically modeled. A dielectric measurement method for determining the elastic constant K_{22} is presented. The influenc...
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We demonstrate a simple method for measuring the twist elastic constant (K22) of a nematic liquid crystal (LC). By adding some chiral dopant to an LC host, the LC directors rotate 180° in a homogeneous cell, which is known as 180° super-twisted nematic (STN) cell. By preparing two such STN cells with different chiral concentrations and measuring their Fréedericksz threshold voltages, we can obt...
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The observed anisotropy of the diamagnetic susceptibility, AX, for oriented nematic liquid crystals of poly-y-benzyl-L-glutamate (PBLG) in dichloromethane is 6.8 &0.7 x 10-9 emu/cm3. For a PBLG axial ratio of 150, a value of the twist elastic constant K22 = 582 x 10-8 dynes is calculated by measuring the critical magnetic field for untwisting the cholesteric supramolecular structure in the PBLG...
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ژورنال
عنوان ژورنال: Journal de Physique Lettres
سال: 1985
ISSN: 0302-072X
DOI: 10.1051/jphyslet:019850046018088100