4[4’-(phenylazo)phenylazo]phenol was synthesized and characterized. Optical-induced Freedericksz transition of 5CB liquid crystal doped with trace diazophenyl was studied. It was observed that the doped 5CB dramatica...4[4’-(phenylazo)phenylazo]phenol was synthesized and characterized. Optical-induced Freedericksz transition of 5CB liquid crystal doped with trace diazophenyl was studied. It was observed that the doped 5CB dramatically decreased the optical field threshold, and the Freedericksz transition threshold occurred at optical intensity level of 0.3 mW/mm2 for the 12.5 μm thickness planar alignment doped 5CB, which is three orders of magnitude lower than that for the pure 5CB. This new phenomenon indicated that trans-cis isomerization of diazophenyl plays an important role in the decrease of the Freedericksz transition threshold.展开更多
We consider the dynamics of the director in a nematic liquid crystal when under the influence of an applied electric field.Using an energy variational approach we derive a dynamic model for the director including both...We consider the dynamics of the director in a nematic liquid crystal when under the influence of an applied electric field.Using an energy variational approach we derive a dynamic model for the director including both dissipative and inertial forces.A numerical scheme for the model is proposed by extending a scheme for a related variational wave equation.Numerical experiments are performed studying the realignment of the director field when applying a voltage difference over the liquid crystal cell.In particular,we study how the relative strength of dissipative versus inertial forces influence the time scales of the transition between the initial configuration and the electrostatic equilibrium state.展开更多
基金the National Natural Science Foundation of China (Grant No. 19474073) and the Natural Science Foundation of Guangdong Province (Grant No. 980346).
文摘4[4’-(phenylazo)phenylazo]phenol was synthesized and characterized. Optical-induced Freedericksz transition of 5CB liquid crystal doped with trace diazophenyl was studied. It was observed that the doped 5CB dramatically decreased the optical field threshold, and the Freedericksz transition threshold occurred at optical intensity level of 0.3 mW/mm2 for the 12.5 μm thickness planar alignment doped 5CB, which is three orders of magnitude lower than that for the pure 5CB. This new phenomenon indicated that trans-cis isomerization of diazophenyl plays an important role in the decrease of the Freedericksz transition threshold.
基金The work of Peder Aursand and Johanna Ridder has been funded by the Research Council of Norway(project numbers 213638 and 214495,respectively).
文摘We consider the dynamics of the director in a nematic liquid crystal when under the influence of an applied electric field.Using an energy variational approach we derive a dynamic model for the director including both dissipative and inertial forces.A numerical scheme for the model is proposed by extending a scheme for a related variational wave equation.Numerical experiments are performed studying the realignment of the director field when applying a voltage difference over the liquid crystal cell.In particular,we study how the relative strength of dissipative versus inertial forces influence the time scales of the transition between the initial configuration and the electrostatic equilibrium state.
