Multiplexed electrospraying of water in cone-jet mode using a UV-embossed pyramidal micronozzle film

摘要

The electrospraying of water in the cone-jet mode is difficult in practical applications owing to its low throughput and the electrical discharge caused by the high surface tension of water.A film with multiple dielectric micronozzles is essential for multiplexed electrospraying of water in cone-jet mode without electrical discharge.Thus,a pyramidal micronozzle film with five nozzles was fabricated using the UV-embossing process.The pyramidal micronozzle film consisted of pyramidal micronozzles,a micropillar array,and an in-plane extractor,which were proposed to minimize wetting and concentrate the electric field to the water meniscus at the tip of the pyramidal micronozzle.The electrospraying of water using a single pyramidal micronozzle was visualized by a high-speed camera at a flow rate of 0.15-0.50 ml/h with voltages of 0.0-2.3 kV,-1.6 kV,and-4.0 kV at the water,guide ring,and collector,respectively.Three distinct modes,the dripping,spindle,and cone-jet modes,were observed and distinguished according to the motion of the water meniscus at the nozzle tip.The steady Taylor cone and jet were observed in a voltage range of 1.3-2.0 kV in water,particularly in cone-jet mode.Multiplexed electrospraying of water in cone-jet mode at a flow rate of 1.5 ml/h was performed using a pyramidal micronozzle film,demonstrating the potential for a high-throughput electrospraying system.