Integration of conducting polymers with MEMS lateral comb-drive resonator via electrodeposition for VOCs detection

Micro-electro-mechanical systems (MEMS)-based resonators have a wide range of current applications such as the detection of chemical and biological substances. Up to now, several studies have been done in the literature about the integration of conducting polymers with MEMS to design a sensing layer for the applications mentioned above. However, all studies have been carried out on the coating of MEMS cantilever which has some disadvantages for the mass sensor like position-depended sensing as a result of being not only a mechanical spring structure but also a proof mass. In this study, conductive polymers (CPs) have been coated on different MEMS lateral comb-drive resonator designs by an effortless and effective solution provided by the electrochemical polymerization technique for the first time in the literature. An aqueous dispersion of carboxymethyl cellulose (CMC) and pyrrole has been formed, and the PPy/CMC composite film has been homogeneously coated on the MEMS resonators by electrochemical polymerization. The integration of CPs with MEMS has not only benefited the mechanical advantages of the lateral resonator but also used optical, electrical, and functional properties of the CPs. To examine its utilization as a sensor, the designed resonators have been used in the detection of volatile organic compounds in open-air conditions. Due to the differences in intermolecular interaction according to the polymer and VOCs structure, discrimination and detection of the VOCs have been performed even in uncontrolled air conditions.

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