| Abstrakt: |
Polystyrene (PS) is widely used in sensors. It has high sensitivity, particularly to aromatic compounds, room temperature operation, has a relatively large surface area; allows more analytes to interact with the film, and enhances the sensor's stability. PS film was deposited on one side of Quartz Crystal Microbalance (QCM) using the spin coating. PS was dissolved in various concentrations of the organic solvent toluene to produce various film thicknesses. The concentration of the solution was determined by calculating the mass of PS to the volume of toluene. PS solution concentrations were 7%, 9%, and 11%. After deposition, the film was annealed at 100, 150, and 200 °C for one hour. The Thickness of PS films was calculated using the Sauerbrey equation. According to the Sauerbrey equation, the measured frequency shift is proportional to the film thickness. The coated QCM sensor detected chloroform concentrations of 5ppm, 10ppm, and 15ppm at room temperature. The repeatability of PS film as a gas sensor was investigated over several measurement cycles, each cycle lasting for 30 minutes. The sensor was flushed for 500s before being tested for the next cycle to release the chloroform molecules that interacted with PS film. However, some molecules remain in the PS film, as indicated by the sensor's frequency response, which differs from its initial condition. QCM sensor coated by PS film has good sensitivity towards chloroform because it distinguishes different concentrations of chloroform. The frequency shift is proportional to the chloroform concentration. [ABSTRACT FROM AUTHOR] |
