A chemical sensor based on internal friction

This study demonstrates the detection of and differentiation between airborne chemicals using high resolution internal friction and frequency measurements. In essence, we determine the loss (1/Q) per unit mass of analyte absorbed by a chemoselective polymer deposited on a resonator. We report the selectivity and sensitivity of this sensing technique for AT-cut quartz resonators coated with two different chemoselective polymers exposed to each of six different analytes. We also used spectra subtraction to extract the mechanical response changes of the thin film polymer coating from that of the coated resonators both with and without an analyte present.