Method for electrostatic atomization of emulsions in an EHD system

In order to atomize oil in an electrohydrodynamic (EHD) system, the conductivity must be in the optimum range. The conductivity of pure oil is too low, requiring the addition of 3-20% surfactant to reach the correct conductivity. Adding water increases the conductivity too much, so emulsions cannot be atomized. In this study, a liposome-containing, water-in-oil emulsion was developed which allows water to be added to oil without greatly increasing the conductivity, and also allows oil to be atomized with minimal additives. Oil was emulsified with 0.01% lecithin and 0.3-50% water and atomized electrostatically. Extra virgin olive oil, soybean oil, sunflower oil, corn oil, butter and peanut oil with added aspartame, GDL, Folic acid, B12, Dijon flavor and Red 3 were sprayed onto six kinds of crackers and glass cover slides to demonstrate that reproducible, efficient coatings can be produced using this method. Emulsions up to 20% water produce good atomization. Over 25% water, the droplet-size increases and reproducibility decreases. A liquid crystal phase in the emulsion restricted the conductivity of the water phase to keep the overall conductivity low. Under high electric fields, elongation, chaining, coalescence or breaking of the droplets increases the conductivity enough to permit atomization. (c) 2004 Elsevier B.V. All rights reserved.