Microscale sessile drop breakup by acoustically-driven ultrahigh frequency piezoelectric actuation

In this thesis, we highlight proficient control over lithium niobate acoustofluidic actuation of two microscale sessile drop destabilizing phenomena of planar splitting and atomization, by elucidating the governing fluidic physics with a dependency on the applied excitation energy. In particular, this work introduced a new mode of actuation as planar drop splitting, characterized both symmetrically and asymmetrically by respective energy schema. For atomization, a more efficient handheld lithium niobate microactuator was pioneered and accompanied by a review of capillary wave atomization, which identified a longstanding 150 year old misconception in the underlying physics responsible for the droplet breakup. Having identified a means of quantifying the critical frequency responsible for capillary wave destabilization in atomization, new expressions for the droplet volume and flow rate were derived based on a more realistic model of the effect of the ultrasound bulk jet turbulence to capillary wave turbulence. Lastly, separation of suspended microparticles was induced by acoustically-driven drop breakup.