A quartz crystal microbalance (QCM) chemical sensor coated with superhydrophobic film for detecting volatile organic compounds (VOCs) such as formaldehyde and toluene under ambient conditions was developed. The superhydrophobic film was deposited by means of microwave plasma enhanced chemical vapor deposition (MPECVD). The sensitivities of QCM sensor coated with superhydrophobic film to VOCs such as formaldehyde and toluene were investigated under ambient conditions. The sensitivity of the sensor to formaldehyde and toluene was considerably improved by the superhydrophobic surface modification. The surface modification promoted microscopic texturing to the film surface and thus increased the effective specific surface area of the sensor for the adsorption of formaldehyde and toluene. In addition, the adsorption of water molecules was minimized due to the superhydrophobic film deposited on the sensor surface, thus promoting the preferential adsorption of formaldehyde and toluene molecules on the QCM sensor coated with superhydrophobic film, compared to the conventional QCM sensor. Moreover, the adsorption mechanisms of formaldehyde-water and toluene-water molecules to the superhydrophobic film were discussed.
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