Modeling and data analysis of a multimode resonator sensor loaded with viscous and viscoelastic fluids

In this contribution, we present a novel data-analysis scheme for resonant sensors loaded with viscous and viscoelastic fluids. The suspended-plate resonator has integrated electrodynamic excitation and readout, exhibiting three well-defined modes of vibration below 1 kHz - one uniformly out-of-plane, one translational in-plane, and one out-of-plane wagging, identified by stroboscopic microscopy. Measurements were performed with 20 μl of water, ethanol and silicone fluids with up to 98 mPa.s steady-shear viscosity, resulting in sufficiently high Q-factors. The interaction of the liquid droplet with the resonator is modeled by finite elements analysis (FEA). The dependence of the resonance parameters on the mass-density and viscoelastic moduli is investigated. The material parameters of small sample volumes can be measured with this fast and sensitive method.