Electrocoalescence in stagnant emulsions

Electrostatic induced coalescence between water drops in stagnant water-in-oil emulsions was studied with a high-speed optical technique. Long range microscope optics was used, and up to four second long sequences of 1000 frames per second were recorded. Emulsions were made of distilled water and naphtenic oil, and prepared both with and without chemical stabilizers. The amplitude, frequency and shape of the applied ac voltage and the percentage of dispersed water in oil were systematically varied.