Nozzleless Electrostatic Atomization Process for Crystallization via Liquid-Liquid Interfaces

The present study has an object of developing a crystallization process by nozzleless electrostatic atomization. This process could control the fine particle size independent of the nozzle diameter. The behavior of liquid-liquid interfaces formed using different organic solvents was observed. A Taylor cone appeared near the interface, particularly in the case where 1-decanol was used as the solvent, resulting in the generation of numerous droplets from the electrode's tip. This process was applied to the production of taurine particles; as a result, spherical taurine particles were formed along the droplet interface almost without loss. The crystal structure of taurine particles was characterized by powder X-ray diffraction (PXRD). The intensity and position of peaks in the PXRD pattern of the prepared taurine particles were identical to those in the pattern of the untreated taurine particles, where the crystalline structure of the spherical particles was independent of the droplet shape. The yield of precipitated particles was almost 100% since this method was performed in a liquid-liquid system. The influences of the applied voltage and interfacial tension on the particle size of taurine were examined. The particle size decreased with increasing applied voltage or decreasing interfacial tension between the taurine aqueous solution and organic solvent. The developed electrostatic atomization process without a nozzle is a promising method for creating particles whose physical properties are independent of the nozzle diameter. Furthermore, this method has a possibility of being able to control the particle morphology independent of the nozzle. This method would continuously produce the particles in the absence of nozzle clogging.