Diluent-Induced Liquid Crystalline Domain Ordering Synergistically Enhances Thermal Conductivity and Electrical Insulation of Polymers

With the increasing demand for high-performance electrical equipment, particularly in power semiconductors, it is crucial to develop packaging materials with excellent insulation, thermal conductivity, and thermal stability. However, achieving simultaneous enhancement of the thermal conductivity and dielectric strength remains a significant challenge. In this work, a phenyl glycidyl ether diluent was introduced to induce ordered liquid crystalline epoxy films, yielding substantial electro-thermal improvements. At a 7 wt % diluent loading, the breakdown strength reached 144.43 kV·mm –1 ─20.85% higher than the control. Remarkably, the breakdown strength at 150 °C decreased by only 16.94% compared to that at room temperature. The thermal conductivity and glass transition temperature also increased to 0.393 W·m –1 ·K –1 and 152.3 °C, with respective gains of 24.37% and 4.6%. This approach offers a scalable strategy for designing high-performance epoxy encapsulants for demanding electrical applications.