Dielectrophoretically structured piezoelectric composites with high aspect ratio piezoelectric particles inclusions

Abstract

Piezoelectric composites were prepared by dielectrophoretic alignment of high aspect ratio piezoelectric particles in a thermosetting polymer matrix. A high level of alignment was achieved in the cured composite from a resin containing randomly oriented high aspect ratio particles. Upon application of an electric field during curing of the resin, the particles were found to rotate with their long axes in the direction of the electric field, before coalescing to form chains. The dielectric and piezoelectric properties of the structured composites are well described by an analytical model for composites containing particles arranged into chains. The influence of degree of rotation and aspect ratio of the individual particles as well as their spacing is described with this model. The results correlate with the experimental values for both permittivity and piezoelectric constants in the poling direction. Dielectric and piezoelectric properties were significantly improved with respect to randomly dispersed piezoelectric ceramic powder-polymer composites and the maximum g 33 was shifted to a lower volume fraction. The results could have implications for development of dielectric and piezoelectric (nano-)fiber composites for dielectrics such as embedded capcitors, as well as piezoelectrics for sensing and energy harvesting applications. V C 2012 American Institute of Physics.

Flexible Lead‐Free Piezoelectric Composite Materials for Energy Harvesting Applications

“…Piezoelectric-and dielectric constants of the capacitors were measured as a function of volume fraction. The same trend is supported by reported data on PZT composites, [32] which clearly demonstrates that piezoelectric properties can be optimized by using aligned fiber composites. Blue circles refer to structured quasi 1-3 fiber composites, and red squares refer to random 0-3 fiber composites.…”

“…The figure of merit peaks at about 5-10 vol % due to the steep increase of the charge coefficient at low filler volume fractions. The maximum value of d 33 g 33 increases with decreasing interparticle distance, from quasi 1-3 particle composites, through quasi 1-3 fiber composites, [32] to 1-3 composites. Figure 1b clearly shows that, due to the decreased inter-particle distance, the fiber composites are preferred over particle composites.…”

Future of the Particle Replication in Nonwetting Templates (PRINT) Technology

“…[53] While most examples of electrophoretic assembly of monodisperse colloidal systems have used spherical particles, the electrophoretic assembly of nonspherical particles has recently garnered attention for the ability to enable alignment in directions which may improve mechanical and electrical performance. [54,55] …”

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“…[53] In den meisten Beispielen für eine elektrophoretische Organisation wurden sphärische Partikel angeordnet, jedoch hat man in jüngerer Zeit auch nichtsphärische Partikel betrachtet, deren gezielte Anordnung in spezifische Richtungen vielversprechend ist, um verbesserte mechanische und elektrische Eigenschaften zu erhalten. [53] In den meisten Beispielen für eine elektrophoretische Organisation wurden sphärische Partikel angeordnet, jedoch hat man in jüngerer Zeit auch nichtsphärische Partikel betrachtet, deren gezielte Anordnung in spezifische Richtungen vielversprechend ist, um verbesserte mechanische und elektrische Eigenschaften zu erhalten.…”