Strong and tough self-healing elastomers enabled by dual reversible networks formed by ionic interactions and dynamic covalent bonds

A strong and tough self-healing elastomer is prepared based on double reversible networks consisting of ionic interactions and Diels-Alder (D-A) crosslinks. The elastomer is synthesized through one-pot copolymerization of a pair of oppositely charged monomers and furan functionalized methacrylate (FMA), which is then crosslinked with 1,1'-(Methylenebis(4,1-phenylene))bis(1H-pyrrole-2,5-dione) (BMI) via Diels-Alder (D-A) reaction. The oppositely charged monomers form ionic bonds which can segregate into aggregates with a wide distribution of size. Under heating or external force, the aggregates can dissociate from small to big ones to dissipate amount of energy and endow the materials with high mechanical properties (13 MPa in strength, 480% in stretchability). While the D-A crosslinks act as covalent bonds at room temperature and endow the materials with high elasticity and fast shape recovery ability. These two reversible networks with different dynamics contribute to the multiscale self-healing properties of the elastomer. As a result, the self-healing efficiency of the elastomer is as high as 86%.