SIMULATION OF REORIENTATION DYNAMICS IN BIPOLAR NEMATIC DROPLETS

A two-dimensional model composed of a synthesis of the Leslie-Ericksen continuum theory of nematics and the Euler-Lagrange equation for surf ace director motion is used to study the magnetic-induced director reo rientation dynamics confined in spherical bipolar droplets with viscoe lastic surfaces. The magnetic field is restricted to the droplet axis of symmetry direction. The numerical results indicate that the surface viscosity and anchoring strength must be taken into account to descri be accurately director reorientation dynamics in droplets. In addition , the numerical results replicate frequently reported experimental obs ervations on the performance of polymer dispersed liquid crystal films . These observations include the familiar exponential increase followe d by saturation in light transmittance as the external applied held in creases, and the exponential increase (decrease) followed by saturatio n as time increases in the on (off) stale. Furthermore, this model is able to predict precisely the relationships between the rise and decay times and the external applied field strength, and the fact that the switching field strength is inversely proportional to droplet size.