High-strength, stretchable, and NIR-induced rapid self-healing polyurethane nanocomposites with bio-inspired hybrid crosslinked network

Stretchable and self-healable materials with excellent mechanical performance hold great promise for applications in flexible functional devices. Despite rapid developments, achieving high mechanical strength, extreme stretchability, and rapid self-healing capability in self-healing materials remains challenging. Here, inspired by the hierarchical structure and unique network of connective tissue, we fabricated a class of bionic nanocomposites with high stretchability, outstanding mechanical strength, and rapid self-healing ability by integrating the bottlebrush copolymer functionalized graphene oxide (BCP@GO) into a polyurethane (PU) matrix via in-situ polymerization. The bottlebrush copolymer (BCP) acted as a bond bridge for linking the GO nanosheets (noncovalent interaction) and PU chains (covalent and hydrogen-bond interaction). The covalent interactions were responsible for providing high mechanical strength, and the abundant hydrogen-bond-based cross-links realized extreme stretchability and rapid self-healing capability. The resultant BCP@GO/PU nanocomposite with only 0.5 wt.