Aerosol generation out of thin fluid films using surface acoustic waves

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This proposal concerns the continuative research for the physical fundamentals of the aerosol generation out of thin fluid films during their interaction with surface acoustic waves (SAW), which are excited via interdigital transducers (IDT) on piezoelectric substrates. The main focus of this proposal is the experimental and theoretical investigation of the interaction of SAW with a small fluid volume located outside of the IDT aperture. This comprises the generation of a thin fluid film, its lateral transition in the direction of the IDT aperture and the generation of aerosol droplets out of the thin fluid film. Thereby, the target is the determination of properties of the fluid film and the aerosol as functions of the material properties (e.g. viscosity) and the experimental boundary conditions (e.g. acoustic wavefield) of the SAW. Already established models for these parameters should be evaluated and extended for a new, promising fluid supply method and the application of standing wavefields. Additionally, new models should be formulated for the onset of fluid thin film translation and aerosol generation, as well as for the temperature in the atomization zone. The continuous fluid supply using glass capillaries or microchannels located outside of the IDT aperture, as evaluated by the proposer, thereby serves as experimental base. It improves process control and reproducibility, optimizes the droplet size distribution and simplifies the mathematical description of the complex, nonlinear interaction of SAW and fluid by spatially separating fluid supply and atomization zone. Furthermore, it enables a reliable technical use and the future integration in hand-held devices for medicine or biotechnology.