Development of fast resettable gravimetric aromatic gas sensors using quartz crystal microbalance

Abstract

A surface molecular imprinting technique was applied for fabricating a porous aromatic gas sensing structure on the surface of a quartz crystal chip. A modified layer by layer process between poly (sodium, styrene sulfonate) (PSS) and poly (allylamine hydrochloride) (PAH) in the presence of aromatic compounds was carefully performed to obtain firm and selective films. In the obtained films, two functional areas of the phenyl rings in PSS molecules and hydrophilic static charge interaction sites between PSS and PAH were worked as sensing principles in the gas sensor applications. In the toluene or phenol imprinted film condition, the sensitivities reached to 0.1 ppm and 6.6 ppb (LOD) for the toluene and the phenol gases, and the selectivity value of the phenol to the toluene reached to 67 with our standard. The obtained selectivity and sensitivity were explainable by the nature of the film components and the surface molecular imprint effect. The sub-min level reset time was normally obtained in these measurements.