Direct measurement of the percolation probability in carbon nanofiber-polyimide nanocomposites

We present the first experimental measurement of the geometric critical exponent {beta} associated with the percolation probability, the probability a metallic filler belongs to the conducting network, of an electrical composite. The technique employs conducting-tip atomic force microscopy to obtain...

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Bibliographic Details
Published in:Physical review letters 2008-11, Vol.102 (11)
Main Authors: Wang, David H., Trionfi, Aaron, Vaia, Richard A., Hsu, Julia W. P., Jacobs, J. David, Tan, L.-Seng
Format: Article
Language:English
Subjects:
CARBON
COMPOSITE MATERIALS
ELECTRIC CONDUCTIVITY
FIBERS
FILLERS
IMIDES
MATERIALS SCIENCE
NANOSCIENCE AND NANOTECHNOLOGY
NANOSTRUCTURES
ORGANIC POLYMERS
PROBABILITY
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Summary:We present the first experimental measurement of the geometric critical exponent {beta} associated with the percolation probability, the probability a metallic filler belongs to the conducting network, of an electrical composite. The technique employs conducting-tip atomic force microscopy to obtain a conducting areal density, and is demonstrated on polyimide nanocomposites containing different concentrations of carbon nanofibers. We find {beta} {approx} 1 and t (the exponent for bulk conductivity) {approx} 3. These values are consistent with the predictions for the Bethe lattice and larger than the values predicted in the 3D lattice percolation model. Hence, this electrical composite likely belongs to the same universality class as the Bethe lattice. The ability to measure geometric and transport critical exponents on the same material is critical to drawing this conclusion.
ISSN:0031-9007
1079-7114