Abstract
Ultrasonic transducers have been developed for use as the cathodes in two different coaxial liquid-dielectric test cells. These test cells are so constructed that the liquid surrounding the transducer can be subjected to a high electric potential gradient. Results obtained show that, even with no applied field, anomalous liquid-solid interfacial behaviour occurs in polar liquids of low viscosity. This behaviour has been interpreted in terms of an attached surface layer, the thickness of which has been estimated for one polar liquid 1,2,4 trichlorobenzene. This interfacial behaviour has been found to be affected by the application of an electric field. However similar effects were found to occur for fields differing by an order of magnitude. Results indicate that an electrically stressed,low viscosity, polar liquid displays properties in the vicinity of a cathode which are interpreted as an indication of some degree of rigidity in the liquid. Small amounts of ultrasonic power were observed to affect this apparent field-induced rigidity. - Tests performed on a high viscosity liquid, the chlorinated diphenyl, Aroclor 1248, indicated that in the absence of an electric field its behaviour was Newtonian. However, under the action of a comparatively low applied field it displayed behaviour which was interpreted as a reduction in viscosity due to local heating.