Quantitative analysis of the debonding structure of soft adhesives.

We experimentally investigate the growth dynamics of cavities nucleating during the first stages of debonding of three different model adhesives. The material properties of these adhesives range from a more liquid-like material to a soft viscoelastic solid and are carefully characterized by small strain oscillatory shear rheology as well as large strain uniaxial extension. The debonding experiments are performed on a probe tack set-up. Using high contrast images of the debonding process and precise image analysis tools, we quantify the total projected area of the cavities, the average cavity shape and growth rate and link these observations to the material properties. These measurements are then used to access corrected effective stress and strain curves that can be directly compared to the results from the uniaxial extension.