Enhanced dielectric performance of polypropylene films via plasma-fluorinated MMT@TiO2@SiO2 nanohybrids

The safety and reliability of dry-type film capacitors depend critically on the insulation performance of their dielectric films. Polypropylene (PP) films serve as primary dielectric materials due to their superior insulation properties, high mechanical strength, and excellent heat resistance. With increasing transmission voltages and equipment miniaturization trends, enhancing dielectric film insulation is crucial to ensure ultra-high-voltage (UHV) transmission security. This study incorporates a fluorinated functional layer–modified nanofiller, MMT@T@S-F (MMT@TiO 2 @SiO 2 -F), into PP films via bulk modification. Film breakdown tests demonstrate that at 25 °C, 50 °C, and 75 °C, PP/MMT@T@S-F films exhibit DC breakdown strength increases of 41.26%, 36.26%, and 32.98% respectively, compared to pure PP films. Micro-nano structural analysis reveals elevated interfacial energy levels in MMT@T@S-F nanoparticles. Simultaneously, the organic fluorine modification introduces high-energy charge traps into PP films, further reducing free-moving carriers while maintaining functional effectiveness at elevated temperatures. Graphical abstract