Electrically conductive bulk composites through a contact-connected aggregate

PLoS One. 2013 Dec 9;8(12):e82260. doi: 10.1371/journal.pone.0082260. eCollection 2013.

Abstract

This paper introduces a concept that allows the creation of low-resistance composites using a network of compliant conductive aggregate units, connected through contact, embedded within the composite. Due to the straight-forward fabrication method of the aggregate, conductive composites can be created in nearly arbitrary shapes and sizes, with a lower bound near the length scale of the conductive cell used in the aggregate. The described instantiation involves aggregate cells that are approximately spherical copper coils-of-coils within a polymeric matrix, but the concept can be implemented with a wide range of conductor elements, cell geometries, and matrix materials due to its lack of reliance on specific material chemistries. The aggregate cell network provides a conductive pathway that can have orders of magnitude lower resistance than that of the matrix material--from 10(12) ohm-cm (approx.) for pure silicone rubber to as low as 1 ohm-cm for the silicone/copper composite at room temperature for the presented example. After describing the basic concept and key factors involved in its success, three methods of implementing the aggregate into a matrix are then addressed--unjammed packing, jammed packing, and pre-stressed jammed packing--with an analysis of the tradeoffs between increased stiffness and improved resistivity.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Computer Simulation
  • Elastic Modulus
  • Electric Conductivity*
  • Materials Testing*
  • Silicone Elastomers / chemistry*
  • Stress, Mechanical

Substances

  • Silicone Elastomers

Grants and funding

This work received support from the United States Air Force Office of Scientific Research under Grant #FA9550-11-1-0093 URL of grant agency. http://www.wpafb.af.mil/afrl/afosr/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.