Electrospreading of dielectric liquid menisci on the small scale

Abstract

The effects of an external electric field (EEF) on dielectric liquid menisci formed in a small gap between a smooth plate and a high precision steel ball have been investigated. It was found that thin spreading films were pulled out and moved away from the menisci of low permittivity dielectric liquids after exposure to the EEF. During the initial period of spreading, a strong “electric wind” due to the gas discharge in the vicinity of the three-phase contact line (TCL) of the liquid meniscus was observed. However, such electrospreading phenomena were absent for the menisci of conductive liquids which were commonly used in classical electrowetting studies. It is deduced that the spreading of liquid menisci under EEFs is driven by the thermocapillary force near the TCL.