Direct measurement of the percolation probability in carbon nanofiber-polyimide nanocomposites.
- Air Force Research Laboratory, Wright-Patterson AFB, OH
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.
- Research Organization:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 967789
- Report Number(s):
- SAND2008-7732J; PRLTAO; TRN: US200924%%25
- Journal Information:
- Proposed for publication in the Physical Review Letters., Vol. 102, Issue 11; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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