Toward a Miniaturized Low-Power Micromechanical Electronic Nose

An electronic nose based on an array of vibrating doubly clamped beams is proposed. These very high aspect ratio (length/thickness) suspended resonators can be individually functionalized by applying polymer coatings with an inkjet printing approach. The absorption of volatile compounds induces a swelling of the polymers that result in axial stress formation and a shift of the resonance frequency. Furthermore, integrated piezoelectric transducers are used for both actuating the resonators, as well as monitoring their resonance frequency in an oscillator loop. This allows for detection at ppm-level concentrations of low molecular weight volatiles. More importantly, the generic resonant transducers can be individually coated with different polymers to allow for selective detection of volatile compounds. Here, we present the first results demonstrating the obtained selectivity by varying the coating chemistry on identical resonators.