Recyclable Ctenophore-Inspired Field-Coupling Microspheres for Precise Detection of Microscopic Defects and Electric Field Distortions in Dielectric Materials

Microscopic defects within dielectrics can distort the local electric field at the operating voltage, inducing electrical aging or even insulation failure. These defects are only a few hundred micrometers, and the corresponding distorted electric fields are extremely weak. Consequently, it is challengeable for existing sensing methods to detect these defects and distorted electric fields accurately, in situ, and nondestructively under electrically charged conditions. Inspired by the warning bioluminescence of ctenophores, we designed a field-coupling microsphere (FCM) with high sensitivity of microscopic defects and distorted electric fields. When the FCM is located in a distorted electric field, the micron-scale luminescent units on its surface precisely sense this distorted electric field and emit in situ electroluminescence, thus exposing defects and distorted electric fields. Furthermore, we prepared a recyclable electrosensitive coating (REC) by compounding FCMs into phase-change matrix materials that are applicable to the surfaces of electrical and electronic equipment to accurately sense microscopic defects and distorted electric fields. To the best of our knowledge, this is the first smart coating material to visualize invisible distorted electric fields using field-coupled electroluminescence, which provides a novel method to study electric field evolution inside dielectrics and to detect microscopic defects in electrical and electronic equipment.