Electric-field-assisted fabrication of linearly stretched bundles of microdiamonds in polysiloxane-based composite material

Abstract

A field-inducement methodology for building self-assemblies of microdiamonds (MD) in a pre-polymer of polysiloxane has enabled their asymmetric polarization. The MDs are readily suspended in the pre-polymer; under the influence of diverse electric fields, the MDs can assemble as linearly stretched, linear network, or linearly stretched bundle structures, anchored at both electrodes before the mixture becomes cross-linked and forms a composite film. Linear assemblies of MDs (LAMDs) were successfully incorporated and stretched out within the polysiloxane matrix and oriented themselves perpendicular to the plane of the composite film. The thickness of the LAMDs and population of MDs composing LAMDs can be modulated according to the applied electric field condition and the MD content. The functional composites with assemblies of LAMDs exhibited enhanced thermal conductivity while maintaining high electric resistivity similar to that of the polysiloxane. Mechanisms are proposed to explain the fabrication and heat transfer through the bridge-like structure of the LAMDs. (c) 2012 Elsevier B.V. All rights reserved.