Damage in elastomers: Healing of internally nucleated cavities and micro-cracks

Following on the work of Poulain et al. (Damage in elastomers: Nucleation and growth of cavities, micro-cracks, and macro-cracks, Int. J. Fract., 2017, 205, 1-21), this paper presents an investigation of the response of cavities/cracks internally nucleated within a transparent PDMS elastomer that is confined between two firmly embedded stiff beads and subjected to quasistatic cyclic loading-unloading. Specifically, it is observed that cracks that nucleate and propagate to reach tens of microns in length during the loading can heal completely upon unloading. They do so autonomously within a time scale of seconds. Furthermore, the regions of the elastomer that experience healing appear to acquire higher strength or toughness.