Studying particulate adsorption by drying droplets on a microfabricated electro-acoustic resonator

Microfabricated in-plane bulk acoustic resonators can be configured as gravimetric sensors wherein the mass of surface-bound species is transduced as a shift in the resonant frequency. Using this principle, we examine the adsorption of spherical polystyrene latex particles on the resonator surface by drying particulate laden droplets. Distribution of particles on the surface is governed by the coffee-ring effect which is correlated to the observed frequency response of the resonators. We also present an analytical approach to describe the spatial dependence of adsorbed mass on the induced frequency shift for square plate resonators which can be extended to model other resonator geometries.