Rapid and sustainable surface acoustic wave atomizer

Abstract

Surface acoustic waves have considerable potential to rapidly generate micron to submicron sized aerosols due to the capillary wave at the liquid-air interfacial boundary. The atomization process, however, is often found to be unstable and discontinuous due to the inconsistency of the droplet position and the lack of accuracy of resonance frequency, resulting in less efficient atomization performance. We developed a rapid and sustainable surface acoustic wave (SAW) atomizer to generate aerosols in a robust, straightforward, and stable mechanism for a continuous, consistent, and reliable deposition of a functional material (i.e., poly(3,4-ethylenedioxythiophene) polystyrene sulfonate [PEDOT:PSS]). Two identical progressive focused surface acoustic wave devices were arranged in angles and in opposite directions with 1 mm wide opening to regulate appropriate amount of liquid sample to be atomized. Several parametrical studies (i.e., on the design of the SAW device, liquid flow rate, applied voltage, and deposition distance) were conducted to quantitatively characterize the performance of the atomizing system. Furthermore, the aerosol size was quantitatively measured and presented as the particle size distribution based on field emission scanning electron microscope (FESEM) images using an image processing method. The results showed that the atomizer is conclusive in demonstrating a continuous, rapid, and consistent atomization performance as an alternative and promising spray method.