Deformation of Impacting Interface of Electrically Charged Drops on Solid Surfaces

Predicting the dynamics of an electrically charged drop impacting a solid surface is great importance in various industrial applications such as spray coating and painting. An decelerates immediately before touch-down by lubrication pressure intervening air. The build-up forms dimple resulting entrapment bubbles under drop. We measured visualized bubble formations using high-speed interferometry back-light imaging techniques focusing on effect electrostatic charge deformation. clarified that size decreased, kink became more flattened with increasing charge, which resulted forming micro-bubble band around central bubble. By comparing profile obtained images, we revealed air layer, thinner than 266 nm, raptures into small pieces microbubble while thicker layer collapses Replacing substrate from conductive to dielectric hinders decrease volume, confirming Maxwell stress acting between bottom plays crucial role determining entrapment.