Dielectric breakdown model for conductor-loaded and insulator-loaded composite materials

Significantly Enhanced Breakdown Strength and Energy Density in Sandwich-Structured Barium Titanate/Poly(vinylidene fluoride) Nanocomposites

Sandwich-structured BaTiO3 /poly(vinylidene fluoride) (PVDF) nanocomposites are successfully prepared by the solution-casting method layer by layer. They possess both high breakdown strength and large dielectric polarization simultaneously. An ultra-high energy-storage density of 18.8 J cm(-3) can be achieved by adjusting the volume fraction of ceramic fillers: this is almost three times larger than that of pure PVDF.

Nanostructural anisotropy underlies anisotropic electrical bistability

Regular arrays of nanorods having asymmetric cross-sections are fabricated by a combination of electrodeposition and glancing-angle deposition (GLAD). When these nanorods are embedded in a polymer matrix, they give rise to composite materials in which the structural anisotropy at the nanoscale translates into functional anisotropy in the form of direction-dependent electrical bistability. The degree of this directional bistability depends on and can be controlled by the spacing between the nearby nanorods.

Controlling reversible dielectric breakdown in metal/polymer nanocomposites

Composites comprising metal nanorods encased in a polymer matrix exhibit reversible electric breakdown and can be cycled between low- and high-conductance states multiple times without permanent damage to the material. The voltage at which the breakdown occurs can be adjusted by engineering the properties of the polymeric matrix, in particular by doping the polymer with dipole-possessing additives whose role is to screen the applied electric fields.

Field fluctuations and fractality in electrical breakdown trees

In the present paper, the discharge avalanche model, initially proposed by Dissado and co-workers, is modified to explore (by correlating its results with experimental information) the role of the space-charge characteristics in the fractal nature of electric trees. Stochastic fluctuations of the local electrical field in each site of the polymer sample (E(loc)) around the Laplacian field (E(lap)) are allowed and limited to intermediate values of E(lap). The major achievements of the modified model are the prediction of a nonmonotonic behavior in both the average time to failure and the average fractal dimension of the electrical trees, and the prediction of a transition from branched to runaway trees as the applied voltage is increased.