Vibrating Microcantilever used as Viscometer and Microrheometer

The aim of this paper is to demonstrate that vibrating microcantilevers can be used (1) to measure the viscosity of a Newtonian fluid for a wide range of viscosities and (2) to determine the viscoelastic properties of a Maxwellian fluid. To widen the viscosity measurement range of more classical microcantilever-based viscometers, the frequency spectrum of a vibrating microcantilever is studied instead of restricting the focus to shifts in resonant frequency and quality factor measurements. Results of experiments are presented to validate that, even if no resonant phenomenon occurs, viscosity measurements are possible. The same approach can be used for the determination of viscoelastic properties of complex fluids. To this end, a new analytical model has been developed and the preliminary measurements are encouraging for the development of a microrheometer on a chip.