Elastomers mechanically reinforced and toughened with CO2 gas

Abstract Gas-responsive polymers have recently attracted considerable interest as unconventional smart materials that provide a new path toward the utilization of specific gases including CO 2 . Herein, we report gas-responsive elastomers that enhance mechanical properties, such as modulus, strength, stretchability, and toughness with CO 2 gas. Various types of amine groups are introduced into polydimethylsiloxane elastomers to achieve the gas-induced mechanical reinforcement. In these elastomers, the amines form ionic crosslinks with CO 2 gas that mechanically strengthen the materials. Furthermore, nanodomains formed via microphase separation of the ionic components behave similarly to viscoelastic nanofillers that dissipate a large amount of energy during deformation, thereby remarkably toughening the elastomers. Surprisingly, the fracture energy of the elastomer with diamine increases ~35 times in CO 2 gas compared with that in N 2 gas. Furthermore, the elastomers sensitively respond even to CO 2 gas concentrations as low as 10 % and are remarkably toughened. Our design concept is widely applicable to the CO 2 reinforcement of other polymers, such as polyethylene.