Effects of dopamine-modified BaTiO₃ on breakdown strength of BaTiO₃/PVDF composites

In order to improve the breakdown strength of BaTiO₃/PVDF composites, first, dopamine was used to functionalize the surface of BaTiO₃, and dopamine modified BaTiO₃ (DoPa@BaTiO₃) was obtained. Then, it was compounded with polyvinylidene fluoride (PVDF), and Dopa@BaTiO₃/PVDF composites were prepared via solution casting method. Finally, breakdown strength and dielectric properties of Dopa@BaTiO₃/PVDF composites with different Dopa@BaTiO₃ addition were measured. The results show that compared with BaTiO₃/PVDF composites before modification, the breakdown strength of Dopa@BaTiO₃/PVDF composites improves significantly, while the dielectric constant is almost unchanged. When Dopa@BaTiO₃ addition is 3vol%, the breakdown strength is 210 kV/mm, which improves by 78% compared with the composites before modification; when Dopa@BaTiO₃ addition is 10vol%, the breakdown strength is 180 kV/mm, which improves by 88% compared with the composites before modification. The research solves the problem of low breakdown strength of BaTiO₃/PVDF composites, and can provide references to improve the dielectric constant and breakdown strength of composites at the same time.