Four-Channel QCA Using Mesoporous Silica Films for Gas Sensing Applications

A four-channel quartz crystal microbalance array (QCA) coated with silica hybrid films is tested as a gas sensor to identify and quantify target analytes. Plasma calcined mesoporous silica films have been used to form hybrids for gas sensing applications. Silica hybrids are obtained by incorporating various receptor molecules in the porous network through physiosorption and/or chemical bonding between the silica matrix and receptor molecules. Field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, secondary ion mass spectroscopy, and nitrogen adsorption analysis are used to characterize the obtained films. The frequency interference between the individual quartz crystal microbalance in the QCA has been eliminated by appropriate positioning of the electrodes. It is concluded that the sensitivity and selectivity of the four-channel QCA could be enhanced by depositing plasma calcined mesoporous hybrids on the electrodes