Simultaneous determination of density and viscosity of liquids based on resonance curves of uncalibrated microcantilevers

The response of magnetically driven noncalibrated atomic force microscope cantilevers was measured in water/ethanol mixtures. Data recorded in pure water and in pure ethanol were used independently to extract parameters characteristic of the resonance behavior of the system. These parameters were then employed to determine the viscosity and density values of the mixtures. The values obtained are within $∼5%$ of those published in the literature. The procedure presented allows small volumes (approximately microliters) of liquids to be investigated and does not require any knowledge of the spring constant or the geometry of the microcantilever.