Diffusion of acetone at the interface of a bonded pressure sensitive adhesive tape was measured using single frequency capacitance measurements (SFCM) and a novel interdigitated electrode sensor design. The relative concentration of acetone at the bondline as a function of distance from the edge of the specimen and exposure time was correlated to adhesion loss measured by the 90° peel test. This work suggests that these novel sensors are applicable for the study of interfacial diffusion processes. and could be extended to other coatings or adhesives in a variety of environments.