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Abstract
A novel, low-cost method is developed to study the kinetics of homeotropic alignment in uniaxial materials. The technique is evaluated relative to existing methods and calibrated against conoscopy. The kinetics of alignment of poly(MO6ONS) in alternating electric fields are studied, using the novel method, while the sample cools from the isotropic to the smectic phase. The dependence on sample thickness, field strength and cooling rate are examined. These results, together with differential scanning calorimetry (DSC) and optical clarity studies, are used to investigate the nature of the isotropic-smectic phase transition. The orientation and conductivity of a side chain liquid crystalline polymer are monitored while the sample is cooled in d.c. electric fields. Different effects are seen for a.c. and d.c. fields, particularly at temperatures just above the isotropic-smectic transition. A mechanism for the effects is proposed and related to the molecular structure of the material.