Multi-nozzle electrospray method for high-throughput uniform superhydrophobic coating

Abstract

Electrospray is an effective method to fabricate functional layers on substrates. With electrospray, uniform and fine droplets can be created and attracted to the substrate without being blown away using the electric field formed by the nozzle and the substrate. The uniformity of coated layer is seldom affected by the fluid drying process (such as Marangoni flow on substrates) since the size of droplets could reach micron level and the solvents in the droplets could evaporate quickly. That is why the electrospray process is often referred to as ‘dry deposition’. However, when a multi-nozzle electrospray system is considered for a faster fabrication process of large substrates, the drying process could be completely different from that of a single nozzle system. In addition, crosstalk and non-uniform spray volume from each nozzle could be an additional issue to be addressed. In this study, we proposed a multi-nozzle electrospray system and process to average out the non-uniformity of the spray amount and obtain the uniformity of the layer through a fast-drying process. Finally, we demonstrated the effectiveness of our proposed methods by fabricating superhydrophobic layers on a highly insulating substrate.