Smart polymer dielectrics enabling autonomous indication in response to electrical degradation

Introduction

In nature, animals adapt themselves to different states in response to environmental changes for the purposes of alarming danger, courtship, protection, and so forth, which are realized by altering in-body molecules or microstructures. For example, chameleons will change skin colors (Figure 1A) to attract the attention of mates or warn potential enemies, and the color variation is closely related to the molecules released by pigment cells. Inspired by these smart behaviors, scientists are endeavoring to explore and design smart materials for advanced applications, which are demanded to achieve an intelligent, sustainable, and comfortable human life in the future.

Numerous smart materials can imitate the intelligent responses in biological systems, exemplified by alterations in color and shape triggered under external stimuli or specific environmental conditions. Hence, smart materials, such as shape-memory alloys, biomimetic self-healing materials, photochromic materials, and mechanical-stress-responsive matters, etc., have been progressively developed for applications in energy, information, and biomedicines.1,2 It is recognized that rapid developments in modern communication, transportation, healthcare, artificial intelligence (AI), and other fields have led to a significant increase in the demand of electricity, ultimately overwhelming electrical grids. As a consequence, polymer dielectric materials, functioning as insulation to prevent electrical shorts and failures, are of importance in ensuring the stable operation of electrical grids. They are extensively used in electrical equipment such as capacitors, transformers, circuit breakers, and cables, etc. Therefore, the implementation of smart polymer dielectric materials in electrical fields is crucial to monitor the safe operation of power equipment as well as reduce the risks and maintenance costs of electrical grids.

Polymer dielectrics with a self-healing characteristic under electrical degradation have been documented in recent years.3 However, smart dielectric materials with the ability to autonomously indicate the initial degradation of polymer dielectrics in electrical systems are still missing even though this is significant for electrical safety. Currently, spectroscopic analysis has been employed to monitor the electrical degradation of polymer dielectrics, relying on the optical radiation generated by partial discharges.4 However, it suffers from complexity, high costs, susceptibility to environmental interference, and limited sensitivity, making the early detection and warning of electrical degradation more challenging. Therefore, developing smart materials with facile detectable signals for electrical degradation of polymer dielectrics is highly desirable in the electrical engineering field.