Characterization of electro-adhesion using surface waves generated and detected by Laser-Ultrasonics

Studying and understanding adhesion characteristics between a coating and its substrate is important for improving the reliability of a thin film's adhesion. To the best of the authors' knowledge, this work studies for the first time a specific electro-adhesion process using Laser-Ultrasonics. An electric field source is applied to a convenient sample composed of a polyvinyl chloride (PVC) layer on an aluminum (Al) substrate. The aim is to investigate the impact of different electro-adhesion levels on the propagation of surface acoustic waves (SAW), which are generated by a pulsed laser and detected using an interferometer. This non-destructive and non-contact experimental setup allows us to determine the surface modes dispersion curves for each adhesion level. A theoretical model is developed to numerically solve the dispersion relation in order to analyze the influence of the interface quality on the dispersion curves. These ones have also been obtained by the finite element method (FEM) allowing us to predict the shape of the experimental signals. This research paves the way for future studies of specific adhesion phenomena across different materials.