Electrical treeing, which causes tiny dendritic hollow channels generated inside solid dielectrics, is typically regarded as an irreversible degradation and usually results in catastrophic breakdown. Here, using in situ electroluminescence during electrical treeing, autonomous self-healing of electrical degradation in dielectric polymers is achieved. The encapsulated healing agents and the UV-shielding shell of the microcapsules enable attraction of tree trajectories and repeated repair of treeing damage. This work provides opportunities to significantly improve the reliability of electronics and electrical power systems.

The self-healing of large scale electrical tree damage in a bulk thermoset polymer is achieved through an anionic polymerization-based microcapsule approach.

Mechanically robust polymers are broadly-applied engineering materials, in which internal, hidden defects resulted from mechanical, electrical and thermal fatigues are one of the major factors threatening their long-term stability. Self-healing...

Repeatable self-healing of multiscale damage ranging from nanometer to millimeter is achieved in thermoplastic polymers through defect-targeted magnetic heating.

Dielectric polymers are playing important roles in electrical and electronic industries. However, aging under high electric stress is a main threat to the reliability of polymers. In this work, we demonstrate a self-healing method for electrical tree damage based on radical chain polymerization, which is initiated by in situ radicals that are generated during electrical aging. Acrylate monomers contained in microcapsules will be released and flow into hollow channels after the capsules are punctured by electrical trees. Autonomous radical polymerization of the monomers will heal the damaged regions, which is triggered by radicals resulting from polymer chain scissions. After optimizing the healing agent compositions by evaluating their polymerization rate and dielectric properties, the fabricated self-healing epoxy resins showed effective recovery from treeing in multiple aging–healing cycles. We also expect the great potential of this method to heal tree defects autonomously without the need to switch off operating voltages. This novel self-healing strategy will shed light on building smart dielectric polymers with its broad applicability and online healing competence.