Determination of menthol kinetic constants with Love-wave device

Abstract

Love-wave devices gained enormous interest for sensor applications which need real time analyses and high sensitivity. These devices proved to be suitable for sensing physical quantities like mass. This effect is known as the main sensing mechanism in acoustic sensors and thanks to their high sensitivity, Love-wave can detect a small mass loading on the surface of the acoustic propagation medium. In this study, we present a new method to characterize in quasi real time evaporation of volatile compounds instead of several weeks for current experiments. A Love-wave device is used to determine menthol evaporation kinetic constant when menthol is associated with a polymer called ethyl cellulose (EC). For that, menthol and ethyl cellulose mixture were deposited as sensitive coating with a spray coating system. Experiments consisted in recording of frequency shifts during deposition of menthol and ethyl cellulose thin film. The evaporation of the volatile compound was followed in real time through mass variations of the film. A fit of the Love-wave sensor response allowed to determine characteristic constants associated to the evaporation kinetic of volatile compound in a few minutes.