Gas bubble phenomenon in nanoscale liquid film under external electric field

The effects of an external electric field on liquid films confined within a nanogap between a smooth plate and a highly polished steel ball have been investigated. It was found that some gas microbubbles emerged around the edge of the Hertz central region and then moved off the central region. Experimental results indicated that the emergence of the bubbles was largely dependent on the liquid polarity and the external voltage. It is thought that the emergence of the bubbles is due to the liquid surface vibration.