Effect of coupling chain length on the electro-optic properties of side chain liquid crystal polymers adding BaTiO3 nanoparticles

الملخص EN

A series of siloxine centered side chain liquid crystal polymers have been arranged with asystematic variation in spacer length.

All the polymer shown a nematic phase, for which the nematic-isotropic transition temperature increased as the spacer length bigger.

The mesogenic group has syano head groups (C £N) to which positive dielectric anisotropic ( sA> 0) is accredited to bind the mesgneic group with the backbone we have used elastic spascer of (CH3) which changes from (2) to (6) units.The nematic cells that have been arranged have planer reorientation to notice the changes inside electro-optic cell Frederick's transition manner.

It found that with increasing spacer length (n) of polymer the threshold voltage is let down.

It been also institute that there is a reverse relationship between temperature and response times this scholarship also deals with the effect of elastic spacer on response times and it has been learned the response times of the polymer with short spacers are longer than response times of the polymers with long spacers, in addition the response times of the three polymers are in reorientation the spacer length lastly we have been found that there the increase in applied voltages lead to the lessening in turn on times (ton ) with the turn off times (toff ).

The difference of the threshold voltage ascends from changes to the intrinsic curvature elasticity rather than to the differences in the orientation demand.

Keywords: Barium Titanate nanoparticle's , Polysiloxane , electro - optic properties.