Radio frequency thin film characterization with polymer-coated Love-wave sensor

Among acoustic wave sensors, Love-wave presents a high sensitivity for gas and liquid detection. These devices are sensitive to all propagation perturbations types including mass loading and mechanical properties changes (e.g. viscoelasticity) of the sensitive coating. High selectivity is achieved with a polymer coating chosen for its affinities towards target compounds. Experimental results allow to characterize thin film materials in radio frequency domain. An accurate knowledge of dynamic polymer parameters will allow a better sensors responses analysis, thus leading to a better choice of the sensitive coating. For experiments, the sensitive layers are made of poly(etheruretane) and poly(dimethylsiloxane). Measurements of insertion losses and frequency shifts confirm the influence of polymers viscoelastic properties in the Love-wave sensors responses. Results allow to confirm the glassy-like state of these polymers at Love-wave device frequency. (c) 2005 Elsevier B.V. All rights reserved.