title: Electroemulsification in a Uniform Electric Field.
abstract: Emulsification using electric fields is an easy alternative to flow-induced drop breakup, and the former is reported to be more effective and economical than the latter, especially when the medium phase is poorly conducting and highly viscous. The emulsification of a coarse water-in-oil emulsion in a uniform electric field is studied. We perform a detailed experimental analysis of the effect of applied electric field strength and the duration of applied electric field on the drop size distribution. The average diameter as well as the time for emulsification decreases with an increase in the intensity of the electric field. Moreover, a narrow size distribution is observed. An average size of a few microns of the dispersed phase could be achieved. New breakup mechanisms at play in the emulsification process are discussed. Identified mechanisms involve charged lobe disintegration, charged drop breakup, chain formation in which several water droplets are interconnected by thin water bridges, electrospraying and charge transfer, and coalescence. The study shows that charged drop disintegration could be the key mechanism of fine emulsification of an initially electrically neutral coarse emulsion.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Bombay , Powai, Mumbai - 400 076, Maharashtra, India.
authors.forename: Rahul B
authors.initials: RB
authors.lastname: Karyappa
authors.affiliation: Department of Chemical Engineering, Institute of Chemical Technology , Nathalal M. Parekh Marg, Matunga (East), Mumbai 400 019, Maharashtra, India.
authors.forename: Ankita V
authors.initials: AV
authors.lastname: Naik
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Bombay , Powai, Mumbai - 400 076, Maharashtra, India.
authors.forename: Rochish M
authors.initials: RM
authors.lastname: Thaokar