Anomalous shear flow alignment in nematic 8CB

Abstract

The members 5CB, 6CB, 7CB and 8CB of the cyano-biphenyl series of nematic liquid crystals have been studied in a linear shear flow apparatus to determine the sign of the viscous torque on the director, which is initially parallel to the shear direction. The flow behaviour, particularly the existence of flow alignment, depends critically on the sign of this torque, as can be observed in a torsional shear flow experiment, where characteristic new flow patterns are seen for 8CB.