A Tough Self-Healing Elastomer with a Slip-Ring Structure

Tough self-healing elastomers with excellent comprehensive performance are extremely demanding and fascinating for future product development, such as wearable devices and robots. However, the deformation of conventional elastomers is dependent on the cross-link density, and there is a trade-off between toughness and stretchability. Therefore, it is a challenge to solve the contradiction between toughness and stiffness. Here, we prepared a tough and stiff rotaxane cross-linked (RC) elastomer with a self-healing property by a one-pot rotaxa-polymerization method in which inclusion complexes of β-CD-trimer@isoprene were copolymerized with isoprene monomers and 2-hydroxyethyl acrylate (HEA) monomers. The rigid β-CD-trimers not only form intermolecular hydrogen bonds with the HEA chains but also can move along the PI segments, leading to good comprehensive mechanical properties. This one-pot synthesis of RC elastomers is facile, and the material simultaneously has good stiffness and toughness. The fracture energy and Young’s modulus materials could reach 43.40 MJ/m3 and 1.40 MPa, respectively. Furthermore, the PI-PHEA RC elastomer showed self-healing ability due to a large amount of hydrogen bonds (PI stands for polyisoprene). The self-healing efficiency can reach 84.34% at 60 °C.