Utilization of polymer viscoelastic properties in acoustic wave sensor applications.

摘要

The changes which occur in polymer viscoelasitc properties in response to cross-linking reactions and due to absorption of gas phase species have been used advatageously in several acoustic wave-based sensor applications. When a polymer film is present on the surface of an acoustic wave device, changes in the visoelastic properties of the film induce changes in wave porpagation velocity and attenuation, providing two sensor responses. Film changes which occur polymer cross-linking allow photopolymerization to be monitored in real time using acoustic devices. A photoaction spectrum of photoresist reveals the cross-linking wavelength with maximum quantum yield. Changes in the viscoelastic properties of a polysiloxane film induces by vapor absorption are found to be unique for each of several species, enabling differentiation of species with a single film. A Maxwell model for polymer viscoelasticity, in combination with mass loading effects, provides a sound theoretical basis for explaining observed results for both polysiloxane and polybytadiene/polystyrene copolymer films. 16 refs., 5 figs. (ERA citation 15:033008)