Title

Damping and Mass Sensitivity of Laterally Vibrating Resonant Microcantilevers in Viscous Liquid Media

Document Type

Conference Proceeding

Language

eng

Publication Date

5-2011

Publisher

Institute of Electrical and Electronics Engineers (IEEE)

Source Publication

2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum

Source ISSN

978-1-61284-111-3

Original Item ID

doi: 10.1109/FCS.2011.5977838

Abstract

The effect of liquid viscosity and density on the characteristics of laterally excited microcantilevers is investigated and compared to transversely excited microcantilevers. When immersed into a viscous liquid medium such as water from air, the resonant frequency of laterally (in-plane) vibrating microcantilevers is shown to decrease by only 5-10% as compared to ~50% reduction for transversely (out-of-plane) vibrating microcantilevers. Furthermore, as the viscosity of the medium increases the resonant frequency of a laterally vibrating beam is shown to decrease at a slower rate than that of a transversely vibrating beam. The decreased viscous damping also leads to increases in the quality factor of the system by a factor of 4-5 compared to beams vibrating transversely. The mass sensitivities of laterally vibrating beams are also theoretically predicted to be roughly two orders of magnitude larger in water for some cantilever geometries. The increase in the quality factor and mass sensitivity indicate that operating in the in-plane flexural mode (lateral vibration) will decrease the limit of detection compared to operating in the more common out-of-plane flexural mode (transverse vibration). These improvements in device characteristics indicate that microcantilevers excited laterally are more suited for operating in media of high viscosities.

Comments

Published as part of the proceedings of the conference, 2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum, 2011: 1-6. DOI.