Engineering of core@double-shell Mo@MoO3@PS particles in PVDF composites towards improved dielectric performances

Polymer composites with high dielectric permittivity (epsilon ') and breakdown strength (E-b), low loss, have significant applications in electronics device and electrical equipment. To harvest excellent integrated dielectric properties in molybdenum (Mo)/polyvinylidene fluoride (PVDF), in this study, raw Mo particles were calcined at high temperature to obtain molybdenum oxide (MoO3), followed by the encapsulation of a layer of polystyrene (PS) shell, and the fabricated core@double-shell structured Mo (Mo@MoO3@PS) particles were incorporated into PVDF. The measurement outcomes demonstrate the coexistence of the MoO3 and PS double shells on the surface of raw Mo particle. The first inorganic MoO3 interlayer massively suppresses the dielectric loss and leakage current of Mo/PVDF because it effectively prevents the direct contact between raw Mo particles. The second organic PS shell not only greatly strengthens the interfacial compatibility with PVDF thereby enhancing the fillers' homogeneous dispersibility in the matrix, but also further suppresses the conductivity and loss, and improves the E-b of the composites owing to its high electrical resistivity. The PVDF with 40 wt% of Mo@MoO3@PS exhibits good comprehensive dielectric performances: epsilon ' of 100 and E-b of 7.89 kV/mm, loss factor of 0.058 at 100 Hz. Consequently, the obtained Mo@MoO3@PS/PVDF with concurrently high-epsilon ' and E-b but low loss shows promising potential applications in microelectronics and electrical industries.