The high-field cured polymer networks in nematic liquid crystals

The polymer networks formed in nematic liquid crystals at high-field condition are studied. Assuming the networks are distributed uniformly, an polymer network contribution to the system free energy is added in the form of -1/2K(a)(n . N)(2), where K-a; n and N are polymer network coefficient, liquid crystal director and polymer network unit vector, respectively. Ignoring the polymer networks elasticity, the liquid crystal director configuration and elastic energy under the influence of an external electric field are calculated numerically. The obtained electro-distortional characteristics are found to depend on the value of K, and N. The results are compared to the electro-optic threshold and hysteresis behaviors of a set of highly twisted nematic cells with different monomer concentrations. A good agreement between the monomer concentration and polymer network coefficient is presented.