Evaluation of a vibrating micromachined cantilever sensor for measuring the viscosity of complex organic liquids

A novel micromachined viscosity sensor is evaluated in particular for measuring complex organic liquids with non-Newtonian behavior. The sensor contains a micromachined cantilever, which is electromagnetically driven by an ac current in a permanent magnetic field utilizing the Lorentz force. The change in the resonance frequency is monitored when the oscillating cantilever is immersed in a viscous liquid. This procedure can be used to determine the viscosity of the liquid. We evaluate the sensor for a series of test liquids in a wide viscosity range from 10 to 500 mm2/s and compare its performance to a conventional viscometer and to a microacoustic thickness shear mode (TSM) viscosity sensor. In particular, its behavior for non-Newtonian oil mixtures containing polymer-additives is considered.