Ordering in the Smectic Phase Owing to Electric Fields

A recent article contained results which showed that in the smectic phase of ethyl-[p-(p-methoxybenzylidene)amino] cinnamate, the molecules preferred a direction with the long axes parallel to a 5000 Hz electric field and perpendicular to a dc field. It was suggested that the anomalous effect in the dc field might be associated with the conductivity anisotropy, since the conductivity was greatest in a direction perpendicular to the long axes of the molecules in the smectic phase. Results are presented which show how the ordering varies with the frequency of the applied field for frequencies below 5000 Hz in the smectic phase of ethyl-[p-(p-methoxybenzylidene)amino] cinnamate. The ordering in the nematic phase of this material owing to dc and ac electric fields is also described. A few comments are made concerning the nematic and smectic phases of p-heptyloxybenzoic acid.