High field dielectric properties of anisotropic polymer-ceramic composites

Abstract

Using dielectrophoretic assembly, we create anisotropic composites of BaTiO3 particles in a silicone elastomer thermoset polymer. We study a variety of electrical properties in these composites, i.e., permittivity, dielectric breakdown, and energy density as function of ceramic volume fraction and connectivity. The recoverable energy density of these electric-field-structured composites is found to be highly dependent on the anisotropy present in the system. Our results indicate that x-y-aligned composites exhibit higher breakdown strengths along with large recoverable energy densities when compared to 0-3 composites. This demonstrates that engineered anisotropy can be employed to control dielectric breakdown strengths and nonlinear conduction at high fields in heterogeneous systems. Consequently, manipulation of anisotropy in high-field dielectric properties can be exploited for the development of high energy density polymer-ceramic systems.

Improving the d33 and g33 properties of 0-3 piezoelectric composites by dielectrophoresis

“…[19][20][21][22][23][24] When an electric field is applied to an uncured thermosetting polymer, the dispersed particles form chains, which are fixed in place when the matrix is cured. Several studies reporting an increase in the permittivity of a composite material in the direction of these chains have been published, [25][26][27][28][29] However, the effect of the dielectrophoretic alignment on the piezoelectric properties, such as d 33 and g 33 , of piezoelectric particle-polymer matrix composites has not been explored yet, with the exception of one preliminary study. 30 In this paper, the effect of several key processing parameters on these piezoelectric properties and a quantitative coupling of these properties to the structured composites are investigated.…”

A model for the dependence of the electrical conductance with the applied stress in insulating-conducting composites

“…These systems are usually considered as isotropic percolating networks where the dependence of transport properties, like the dc-electrical conductance, G, are expressed as functions of the percolation probability between neighboring particles. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] Many experimental works have been reported concerning the effect of mechanical stress on G ͑Refs. 9, 19, and 28-39͒ and the ac-impedance of composites, [38][39][40][41][42] but the systematic theoretical investigation of the dependence of G with the external applied stress has been initiated in a few relevant works in recent years.…”

Static magnetic solution in magnetic composites with arbitrary susceptibility inhomogeneity and anisotropy

“…For example, it has been shown in experiments that the effective susceptibility and breakdown strength (for dielectric composites) can be greatly affected by the alignments of the inclusion particles. [28][29][30][31] In this work, two different structures, an isotropic structure with well-dispersed inclusion particles and an anisotropic structure with chain-dispersed inclusion particles, are used to study the effects of the susceptibility mismatch on the effective susceptibility and local magnetic field concentration. Figure 5(a) shows the effective susceptibility affected by the susceptibility mismatch for a two-phase composite with two different inclusion particles arrangements.…”