Composites based on micron-sized exfoliated graphite particles: Electrical conduction, critical exponents and anisotropy

• Published in: The Journal of physics and chemistry of solids Vol. 57; no. 6; pp. 715 - 718
• Main Authors: Celzard, A., McRae, E., Marêché, J.F., Furdin, G., Dufort, M., Deleuze, C.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-06-1996
• Subjects: A. non-crystalline materials; D. critical phenomena; D. electrical conductivity; A. non-crystalline materials; D. critical phenomena; D. electrical conductivity
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/0022-3697(95)00337-1

Electrically conducting composites, made of epoxy resin and micron-sized graphite platelets with diameter-to-thickness ratios of the order of 100 are presented. Samples of various volume percentages of graphite particles are characterized by X-ray diffraction and electron microscopy: orientation of the filler and porosity of the polymer matrix are observed. DC conductivity measurements have been made both within and perpendicular to the plane of the film. Use of percolation theory shows that taking into account the swelling effects of the composite occurring during reticulation yields quasi-universal values for the conductivity critical exponent in both directions and a low critical volume concentration of
Φ
c
= 1.3%.