Abstract
Harmful volatile organic compounds (harmful VOCs), e.g., lacquer, thinner, solvent for paint, are used in a painting process in factories. Two kinds of organic thin films were deposited onto a quartz crystal by an r.f. sputtering with poly(tetrafluoroethylene) (PTFE) and poly(ethylene terephthalate) (PET) targets (sputtered PTFE thin film and sputtered PET film), and we evaluated detection sensitivities for the VOCs using quartz crystal microbalance (QCM) method. The frequency shift of the sputtered PTFE thin film due to the adsorption of the VOCs was larger than that of the sputtered PET thin film when acetaldehyde or toluene was used for the VOC. It suggests that the adsorption mass of these VOCs to the sputtered PTFE thin film was higher than that to the sputtered PET thin film. In addition, the adsorption masses of these VOCs decreased with increase of the environmental temperature at both of the sputtered thin films, which suggests that desorption velocities of these VOC molecules increase compared to the adsorption velocities at higher temperature. The adsorption amount of water of the sputtered PET thin film was higher than those of other VOCs, and response to the detection of water was excellent. Therefore, it is considered that the sputtered PET thin film can be used for reference sensor for water.
