Surface Acoustic Waves (SAW) are acoustic waves travelling along the surface of a solid. There are created by depositing the interdigitated transducers (IDT) on a piezoelectric layer. When an AC voltage is applied on the IDTs, the electric field created in the piezo layer will produce a periodic deformation at the surface which will generate the acoustic wave.
On one hand, SAWs can be used to induce forces at the interface between the solid and another media like a droplet and play the role of an actuator. On the other hand, the highly localized nature of the wave at the surface of the material makes it a sensitive tool for sensing changes in the material's surface or the adjacent medium. Therefore, the SAW phenomenon opens-up a broad range of applications. SAW-devices have already proven their commercial success as acoustic wave filters for mobile phones and gas-sensors for detecting hazardous gasses. During the past years, more research effort was invested in SAW steered droplet manipulation for lab-on-chips systems and chemical bio-sensing.
Figure 1 Typical SAW device used for sensing.
In this work, the student will design and characterize a SAW-device capable of atomizing a droplet into a vapor as depicted in the picture below . More specifically, this master thesis will involve
- Simulations in COMSOL in order to maximize the force to atomize the droplet. The simulations will couple several physics as electrics, mechanics, acoustics and fluidic.
- Fabrication of the optimized design
- Characterization of the spraying system. The vapor content and formation could be analyzed to investigate different liquid constitutions.
Figure 2 Conceptual sketch of the proof-of-concept device.
 Yabe, A. et al, A self-converging atomized mist spray device using surface acoustic wave. Microfluid Nanofluid (2014) 17:701–710
Type of project: Thesis
Duration: 6-12 months
Required degree: Master of Engineering Technology, Master of Science, Master of Engineering Science
Required background: Electromechanical engineering, Electrotechnics/Electrical Engineering, Materials Engineering, Mechanical Engineering, Nanoscience & Nanotechnology, Physics