Determination of Liquid Density and Viscosity Using a Self-Actuating Microcantilever

A sensor for determining liquid density and viscosity using a self-actuating microcantilever is proposed. A microcantilever incorporating piezoelectric thin films with seven multilayers was fabricated in order to acquire a direct electrical signal. As proof of the operating principle and sensitivity, the change in resonant frequency peak (f(res)) and full width at half maximum (FWHM; Delta f) values with liquid viscosity and density were we measured using the glycerol-water solutions with various glycerol concentrations. With increasing liquid viscosity from 1 to 600 cP, an increase in FWHM from 2920 to 10314 Hz was observed. Also, it was observed that shifts in the resonant frequency decreased with increasing liquid density. Using nonlinear regression fitting between liquid density and f(res)(2), the presented self-sensing microcantilever could potentially provide a solid platform for real-time monitoring of liquid density. (C) 2013 The Japan Society of Applied Physics