SAW chemical sensing using poly-ynes and organometallic polymer films

We have investigated chemical sensing properties of three polymeric films (organic and organometallic poly-ynes) by a surface acoustic wave (SAW) and surface transverse wave (STW) sensor, at room temperature. The sensor system, consisting of an acoustic two-port resonator operating at 433.92 and 380.8 MHz, respectively, has been configured as a frequency oscillator, including an integrated electronic module. The polymeric membranes have been tested, at room temperature, toward gases (NO2, NO, NH3, CO, CH4, SO2, H2S in N2), relative humidity (RH), and vapours (ethanol, acetone, ethyl-acetate) by showing high sensitivity and low selectivity. A comparison of sensing performance of our SAW RH sensors with a commercial hygrometer has been realised. Principal component analysis (PCA) has been applied as pattern recognition technique achieving good separation for the examined vapours, at tested low concentrations.