Analysis of the shear-induced pattern formation in nematic polymer liquid crystals under an applied magnetic field

The formation of the shear induced periodic patterns in the nematic polymer liquid crystal PBG is studied using linear stability analysis of the Leslie-Ericksen equations for shear flow. The unidirectional shear of a nematic director initially uniformly oriented orthogonally to the sample plane and with strong anchoring is considered. The stabilizing effect of a magnetic field applied in the same direction is studied. The results show that for tumbling nematics critical values of the Ericksen number and of the applied magnetic field show up for which the uniform flow may become unstable to a periodic tilting of the director out of the s