Ultrahigh Mechanical Strength and Robust Room-Temperature Self-Healing Properties of a Polyurethane–Graphene Oxide Network Resulting from Multiple Dynamic Bonds

摘要

Addressing the conflict between achieving high mechanical properties and room-temperature self-healing ability is extremely significant to achieving a breakthrough in the application of self-healing materials. Therefore, inspired by natural spider silk and nacre, a room-temperature self-healing supramolecular material with ultrahigh strength and toughness is developed by synergistically incorporating flexible disulfide bonds and dynamic sextuple hydrogen bonds (H-bonds) into polyurethanes (PUs). Simultaneously, abundant H-bonds are introduced at the interface between graphene oxide nanosheets with dynamic multiple H-bonds and the PU matrix to afford strong interfacial interactions. The resulting urea-containing PU material with an inverse artificial nacre structure has a record mechanical strength (78.3 MPa) and toughness (505.7 MJ m–3), superior tensile properties (1273.2% elongation at break), and rapid room-temperature self-healing abilities (88.6% at 25 °C for 24 h), forming the strongest room-temperature self-healing elastomer reported to date and thus upending the previous understanding of traditional self-healing materials. In addition, this bionic PU–graphene oxide network endows the fabricated flexible intelligent robot with functional repair and shape memory capabilities, thus providing prospects for the fabrication of flexible functional devices.