Mechanochemistry as a Tool to Study Cavitation in Multiple-Network Elastomers

Elastomers are often used as seals in connecting hardware for gas transport. Upon saturation with a gas followed by rapid decompression, elastomers suffer from cavity nucleation and growth. This phenomenon, known as rapid decompression, is well-known to damage elastomers and hamper their lifetime in use. As such, a method to non-destructively visualize this damage, particularly when the elastomer looks as-pristine, would enable the timely replace seals prior to failure.
Here, by incorporating mechanofluorescent damage-activated probes in elastomers, we are able to visualize cavitation-induced damage by polymer chain scission at the early stages of fracture. We nucleate cavities by rapid decompression of hydrogen-saturated elastomers and then examine damage via fluorescence microscopy. Using this tool, we demonstrate that cavity expansion is an irreversible fracture process that occurs via nucleation and propagation of randomly oriented penny-shape cracks. As a result, energy dissipation mechanisms that lead to toughening, like sacrificial bonds in multiple-networks, also improve cavitation resistance.