The effect of the intrinsic electrical matrix conductivity on the piezoelectric charge constant of piezoelectric composites

Abstract

Polymer-piezoceramic composites have drawn a lot of attention for sensor and energy harvesting applications. Poling such materials can be difficult due to the electric field getting mostly distributed over the low dielectric constant matrix. During this process, the electrical matrix conductivity plays a vital role. This work shows how two different polymer materials, loaded with various piezoelectric ceramic fillers, have very different poling efficiencies simply due to their intrinsic matrix conductivity. It is shown how temperature increases the matrix conductivity, and hence, increases the piezoelectric charge constant of the composites. By choosing the proper matrix material under the proper conditions, piezoelectric composites can be poled at electric fields as low as 2 kV mm −1 , which is identical to that of bulk ceramic fillers. In addition, the matrix conductivity can be altered by aging the composites in a high humidity atmosphere, which can increase the piezoelectric charge constant in similar fashion. This is a simple method to increase the matrix conductivity, and hence the piezoelectric charge constant, without the need to add any conductive fillers into the composites, which increase complexity, and leads to an increased dielectric losses.

Boundary layer state detection using piezoelectric sensors

“…Our in-house knowledge of piezoelectric materials enabled us to design our own piezoelectric bimorphs, providing excellent control over layer thicknesses, materials and poling conditions [31][32][33][34][35][36]. The procedure followed is typically used in industry to manufacture piezoelectric bimorphs.…”

Dielectric and Mechanical Properties of PDMS–La2Ba2XZn2Ti3O14 (X = Mg/Ca/Sr) Nanocomposites

“…In the past decades, polymer–ceramic composites/nanocomposites have been of great interest to researchers for their novel applications. There are various ceramic oxides/particles which have been used by different research groups in making polymer composites for various applications. − However, there is an increase in demand for electroceramic oxide fillers in making polymer composites due to their various electrical properties. − Technically, these special classes of ceramic oxides have been explored for their ferroelectric, piezoelectric, and dielectric responses and have been used in nonvolatile memories [dynamic random access memories (DRAMs)], high-capacity dielectric devices, and materials for energy storage and conversion. − The incorporation of these electroceramic fillers in the matrix polymer has become a common practice to improve the electrical, mechanical, and other properties. These polymer–ceramic composites/nanocomposites can be effectively used as flexible electronic and electrical materials …”

“… 21 − 23 24 25 26 However, there is an increase in demand for electroceramic oxide fillers in making polymer composites due to their various electrical properties. 27 − 29 30 31 32 Technically, these special classes of ceramic oxides have been explored for their ferroelectric, piezoelectric, and dielectric responses and have been used in nonvolatile memories [dynamic random access memories (DRAMs)], high-capacity dielectric devices, and materials for energy storage and conversion. 33 − 35 The incorporation of these electroceramic fillers in the matrix polymer has become a common practice to improve the electrical, mechanical, and other properties.…”

Influence of Matrix and Surfactant on Piezoelectric and Dielectric Properties of Screen-Printed BaTiO3/PVDF Composites

“…Actually, the choice of the matrix significantly contributes to the efficiency of the poling process; the electrical conductivity of the matrix should be as high as possible. In such a case, at a fixed poling field, a higher d 33 is observed [ 17 ]. Another parameter that must be taken into account is the permittivity of the matrix; a higher permittivity results in a more uniform penetration of the electric field within the material [ 18 ], resulting in an improved poling process.…”