Stresses dominate pulsated electrohydrodynamic spraying modes in near field

Polymeric solution pendant at the outlet of a capillary can spray in the forms of single-jet, multi-jet, drop, and atomization under an actuated pulse voltage in near field. The electrohydrodynamic (EHD) spraying mode depends on electric and mechanical stresses, which are related to physical properties of applied solution and collector, on the liquid meniscus. Experimentally and analytically, the liquid meniscus emits the jet preferably under a solution with low electrical conductivity over a conducting or semi-conducting collector. Furthermore, the multi-jet comes from an applied solution with low surface tension; the atomization happens under the applications of a solution with high electrical conductivity and/or an isolated collector; and the big drop occurs under an applied solution with high viscosity. The results provide a significant instruction for modifications of solution and collector in pulsated EHD printing.