Droplet oscillations driven by an electric field

A new technique for examination of interfacial electric phenomena on droplet surface in real time is proposed. The technique is based on measuring the resonant frequency of spherical and hemispherical pendant droplets driven in oscillations by a modulated electric field. The amplitudes of forced oscillations are detected by an optical system comprising a low power laser beam and a photodiode. The surface tension and viscosity can be evaluated from the obtained resonant curves.