Coupled determination of gravimetric and elastic effects on two resonant chemical sensors: love wave and microcantilever platforms

The field of chemical microsensors for both gas and liquid sensing has been widely investigated in recent years. Several technologies have been utilized which include love-wave acoustic sensors and silicon microcantilevers. Those structures are both used as chemical sensors by adding a sensitive coating to the device surface. Perturbations of the sensitive coating properties induce frequency drift in both devices, thus making chemical detection possible. Microcantilevers are essentially sensitive to the coating mass changes which modify the resonant frequency of the structure. However, the acoustic wave device is sensitive to all types of propagation perturbations which include mass loading and mechanical properties changes of the coating. One of the difficulties in acoustic sensor field is to separate each contribution from the induced frequency shifts. The aim of this paper is to couple experimental results from microcantilevers and love-wave devices in order to identify and separate the two effects. At last, this coupled study is also interesting for gas and liquid phase detection applications, as it will permit to determine the elasticity evolution during the detection process, i.e. the analyte sorption.