We propose to develop a novel type of miniature chemical sensor utilizing very recent developments in microcantilevers. Sensors based on this technology will be up to 100 times smaller, considerably more sensitive, and less expensive than currently available chemical sensors. Microcantilevers that are 50-200 ?m long, 10-40 ?m wide, and 0.3-4 ?m thick and possessing resonance frequencies in the range 10-300 kHz, have recently been used in scanning force microscopy to detect extremely small changes in force in the range of 10-12-10-9 N. The resonance frequency and bending of the microcantilever varies reproducibly and sensitively due to adsorption of molecules on the cantilever surfaces making it an ideal chemical sensor with picogram sensitivity and parts per billion detection. Preliminary detection studies, have demonstrated detection of ppb of chemicals, Simultaneous bending measurements resulted in a sensitivity of 0.6 pg/mV. The recyclability of the chemical sensor will be demonstrated by removing the adsorbed chemical by heating of the sensor element. We also plan to demonstrate that the sensor can be vibrated in liquid environments with a good Q-factors, allowing it to be used to detect the presence of chemicals in liquid environments. Parasitic interferences can be accounted for by using reference microcantilevers, arrays of differentially coated sensors, thermal desorption rates and/or filters. Additionally, due to the extremely small size of the sensor, the development of a personal monitor that is highly sensitive may be possible. The proposed work will provide a highly significant advance in microcantilever sensor technology with possibilities of developing new sensors for many chemicals. Commercial applications of chemical sensors are numerous since these detectors will be extremely sensitive, miniaturized, and could be mass produced. Applications include industrial hygiene, air and water pollution control, mining industry, submarines, air quality monitoring, etc.
Keywords: SENSORS, MEMS, BENDING , MICROCANTILEVER, RESONANCE
