Room temperature self-healing and reprocessing elastomer with dynamic bonds for flexible wearable sensor

Abstract

The production of room-temperature (RT) self-healing elastomers with good mechanical properties is significant for application in soft electronics, yet remains a challenge in material design. Herein, we present an effective and feasible approach to create RT self-healing cross-linked elastomers (CEs) through photo-initiated copolymerization. A key feature is the incorporation of 2,7-dihydroxynaphthalene and alicyclic diisocyanate into the polymer backbone as hard domains, along with the rational optimization of the soft segments. In addition, urethane-based H-bonding interactions, acting as sacrificial bond, contribute to the high toughness of the CEs. The resulting CEs exhibit desirable mechanical performances, including a tensile strength of 12.9 MPa, an elongation at break of approximately 1243 %, and a high toughness of 68.64 MJ m–3. Furthermore, by integrating a flexible PTMEG-based polymeric chain and hindered urea bonds into the backbone, the chain mobility and dynamic nature of the CEs are improved. The CEs are capable of reprocessing and self-healing at RT within 30 min upon scratching, with a self-healing efficiency in toughness reaching 99.64 %. The dynamic networks are evidenced by rheological test, stress relaxation analysis, as well as creep and recovery experiments. These CEs, characterized by their superior properties, hold promise for applications in flexible wearable electronics.