Role of surface roughness in controlling the adhesion of a soft adhesive on a hard surface

Debonding of a soft adhesive from a hard Aat surface is initiated by the formation of cavities which extend in the volume of the adhesive. Often these cavities nucleate at or in the immediate vicinity of the interface. Adherent's surface properties, surface topography and chemical composition have an important influence on these associated micromechanisms. We performed flat probe tests using a model acrylic latex (pressure sensitive adhesive, PSA) against various rough stainless steel surfaces, prepared by varying their degree of polishing, and we observed a dual effect of increasing the amplitude of surface roughness on the micromechanisms: a decrease of the level of stress at which cavitation occurs at the beginning of the debonding, and a decrease in the rate of expansion of the cavities in a later stage of the test. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.