Experimentally fitting the attraction strength of an interface by the response of the thickness shear-mode acoustic wave sensor

The thickness shear-mode (TSM) sensor is extended for operating in a liquid environment for application in biological engineering. The interfacial effect between the sensor surface and the attached medium is one of the major controversies in modelling of the TSM resonator in a liquid environment. Several slip models have been proposed to describe the interfacial mechanism of a TSM resonator in a liquid environment. In this paper, the correlation between the spring-damper model and other slip models is presented. Three TSM sensors with different surface modifications were fabricated to verify the models. The results of the measured experimental frequency shifts are found to deviate from theoretical results evaluated using a non-slip model. By adjusting the attraction strength between the contacted interfaces, the results can be fitted by the spring-damping interface model