Application of flexural mechanical resonators to high throughput liquid characterization

Abstract

Application of flexural mechanical resonators such as tuning forks, benders, etc. to liquid characterization is discussed. Additional complex impedance produced by a liquid environment to such resonators is considered. It was shown experimentally, that for the disk bender resonator this additional impedance can be represented by the sum of two terms: one that is proportional to liquid density and a second one that is proportional to the square root the of viscosity density product. Same model was earlier shown applicable to the tuning fork resonator. Interaction of a resonator of arbitrary shape oscillating in any mode with surrounding fluid is considered theoretically. The conditions on which this impedance model is applicable to any type of a resonator that directly displaces liquid are discussed. These conditions are satisfied for most of flexural resonators available, detailed consideration of tuning fork and disk bender is provided. Sensitivity of flexural resonator response to liquid electrical properties is discussed. Application of disk bender to density and viscosity measurements in strong electrolytes is considered.