Longitudinal vibration mode of piezoelectric thick-film cantilever-based sensors in liquid media

We report on the fabrication of a self-actuated resonant-microsensor, based on a thick-film piezoelectric cantilever, dedicated to either (bio)chemical detection in gaseous or liquid media or fluid characterization. The aim of this paper is to demonstrate that longitudinal modes can be used in highly viscous environments. Lower levels of fluid-solid interaction in comparison with classical flexural modes are expected from the results of our analytical model of a cantilever oscillating in a fluid. For example, in various fluid ranging from air to a Newtonian fluid of 300 cP viscosity, measured quality factors for the first longitudinal mode range from 300 to 20.