Novel Smart Insulating Materials Achieving Targeting Self-Healing of Electrical Trees: High Performance, Low Cost, and Eco-Friendliness

Abstract

It remains challenging to promptly inhibit and autonomically heal electrical trees inside insulating dielectrics, which are caused by sustained strong electrical fields and substantially shorten electronic device lifetimes and even cause premature failure of electrical equipment. Therefore, we demonstrate a magnetically targeted ultraviolet (UV)-induced polymerization functional microcapsule (MTUF-MC) to endow insulating materials with physical and electrical dual-damage self-healing capabilities. Specifically, Fe3O4@SiO2 and TiO2 nanoparticles, which serve as magnetic targets and UV shields (thereby preventing the healing agent from prematurely triggering), constitute a functional microcapsule shell, ensuring a low dopant concentration and excellent self-healing ability of the epoxy composites without affecting the intrinsic performance of the matrix. By exploiting in situ electroluminescence originating from electrical trees, UV-induced polymerization of healing agent is handily triggered without any applying external stimuli to intelligently, contactlessly, and autonomously self-healing electrical trees inside insulating dielectrics.

Self-Healing Polymers for Electronics and Energy Devices

“…Sima et al further developed this method and introduced magnetic targeting functionality to the microcapsules by incorporating Fe 3 O 4 @SiO 2 magnetic nanoparticles into the shell of the microcapsules. 344 The Fe 3 O 4 nanoparticles were coated with SiO 2 to prevent the negative effect of low electrical resistivity of Fe 3 O 4 on the breakdown strength and dielectric loss of the polymer dielectrics. Driven by the directional highintensity magnetic fields, Fe 3 O 4 nanoparticles guided the microcapsules to the vulnerable regions (e.g., regions with high local electric field) of the polymer dielectrics (Figure 43a).…”

“…Sima et al further developed this method and introduced magnetic targeting functionality to the microcapsules by incorporating Fe 3 O 4 @SiO 2 magnetic nanoparticles into the shell of the microcapsules . The Fe 3 O 4 nanoparticles were coated with SiO 2 to prevent the negative effect of low electrical resistivity of Fe 3 O 4 on the breakdown strength and dielectric loss of the polymer dielectrics.…”

“…(b) Optical images of initiation and self-healing of electrical trees in epoxy. Reprinted from ref . Copyright 2021 American Chemical Society.…”

Smart dielectric materials for next-generation electrical insulation

“…Various kinds of light can be produced when excited molecules return to ground states and when recombination of opposite charge carriers happens [9] . Partial discharges can also generate light emissions that peak in the UV range [231] .…”

Microcapsule-Based Autonomous Self-Healing of Electrical Damage in Dielectric Polymers Induced byIn SituGenerated Radicals

“…Recently, designing self-healing approaches for electrical damage using microcapsules has also been heatedly discussed. Ultraviolet (UV) light originating from excited molecules or recombination of charge carriers during electrical aging , has been used to trigger the polymerization of epoxy monomers with the aid of photoinitiators. , However, the efficiency of healing is likely to suffer from the UV absorbance of the polymer matrix, especially for some UV-opaque composites. In another technical route, a latent hardener was incorporated in the matrix and would initiate the polymerization of monomers from microcapsules at an elevated temperature, which restricts its applications in temperature-sensitive scenarios.…”