Eur. Phys. J. E (2015) 38: 119
https://doi.org/10.1140/epje/i2015-15119-y

Regular Article

Liquid-body resonance while contacting a rotating superhydrophobic surface

¹ Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, VIC3800, Clayton, Australia
² Biomechanics and Biomaterials Laboratory, Department of Mechanics, School of Aerospace Engineering, Beijing Institute of Technology, 100081, Beijing, China
³ Centre for Translational Medicine, Cardiovascular Research Institute, 14, Medical Drive, 117599, Singapore, Singapore

^* e-mail: engngtw@gmail.com

Received: 9 June 2015
Accepted: 20 October 2015
Published online: 20 November 2015

Abstract

We advance a scheme in which a liquid body on a stationary tip in contact with a rotating superhydrophobic surface is able to maintain resonance primarily from stick-slip events. With tip-to-surface spacing in the range mm for a volume of 10 μL, the liquid body was found to exhibit resonance independent of the speed of the drum. The mechanics were found to be due to a surface-tension-controlled vibration mode based on the natural frequency values determined. With spacing in the range mm imposed for a volume of 10 μL, the contact length of the liquid body was found to vary with rotation of the SH drum. This was due to the stick-slip events being able to generate higher energy fluctuations causing the liquid-solid contact areas to vary since the almost oblate spheroid shape of the liquid body had intrinsically higher surface energies. This resulted in the natural frequency perturbations being frequency- and amplitude-modulated over a lower frequency carrier. These findings have positive implications for microfluidic sensing.