The use of bulk acoustic wave devices as probes of material properties

This paper will describe the initial results of a study to apply acoustic wave devices for the non-gravimetric measurement of chemical sensor properties. The electrical impedance spectrum of a quartz crystal resonator coated with a polydimethylsiloxane (PDMS) layer have been measured and the viscoelastic material properties of the layer was calculated. This procedure was then repeated while exposing the resonator to different alcohol vapours. It is found that the values of the complex shear modulus of the film are significantly influenced by the in-diffusion of these molecules. This method has the potential to use a measurement of the complex shear modulus as an aid in analyte identification in chemical sensors.