Design and fabriction of micro-viscometer using the propagation of acoustic waves in micro-channel

A micro-viscometer for measuring viscosity changes in small amount of liquid in real time is designed and fabricated. The merits of the device are to use minimal liquid and to increase the sensitivity for measuring the viscosity. The micro-viscometer is composed of two chambers connected by several micro-channels. Each chamber has a unimorphic piezoelectric diaphragm for driving and sensing sound waves. The micro-channel plays a role as a waveguide and an attenuator of sound waves. Attenuation of sound wave is a function of the viscosity of the liquid. So, the output voltage of sensor is also changed as the viscosity of liquid is changed. After fabrication through micromachining, the device was tested on several viscous liquids, and then it was demonstrated that the device can play a role of a viscometer with high sensitivity. In this paper, we mainly discuss on the comparison between experimental results and newly simulated results.