A study of the mechanics of microcantilever sensors

Microcantilever sensors are being studied as a new platform for chemical vapor detection. It has been demonstrated by many groups that they have the potential to detect a wide range of chemicals with high sensitivity. Since these sensors do not offer any intrinsic chemical selectivity, immobilized chemical interfaces coupled with pattern recognition algorithms are often employed. Selectivity based on these chemical coatings often fails due to the lack of orthogonality in the chemical interactions. However, the use of adsorption-induced signals based on physical properties can offer additional complementary information. To successfully employ these versatile sensors, a comprehensive investigation of the mechanics of microcantilevers is necessary to understand their responses. Such an investigation is presented in this work. Both dynamic and static microcantilever theory is addressed as well as nonlinear dynamics resulting from large amplitude oscillations. Experimental data is presented and compared to modeled data for verification. Finally, an application of microcantilever sensors in photothermal deflection spectroscopy (PDS) is given. The detection of explosive compounds with PDS is demonstrated.