-----Original Message-----
From: David Bowman
Sent: Wednesday, February 27, 2002 11:11 AM
Subject: Re: Flat conductors (was I need help).
I suspect that the conduction process through and across the paper
may probably be modeled adequately by some version of a percolation
theory model. In addition, it might be the case that the overall
resistivity of the paper is dominated by the junction resistance
across touching adjacent carbon-coated fibers rather than the
bulk resistivity of the carbon itself.
David Bowman
David_Bowman@georgetowncollege.edu
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I do a number of experiments with graphite lines on a piece of paper and
have looked at the lines using a scanning electron microscope. They are
certainly of non-uniform thickness, consisting of many touching flakes. I
agree with David that there is likely significant junction resistance
between carbon coated material, as well as between the metallic electrode
and the carbon material. So the measured resistance would be expected to be
much higher than expected from the carbon material resistivity, cross
sectional area, and length.
To complicate issues further, don't forget that graphites and carbons are
anisotropic, with conductivities much higher in the graphitic planes
compared to perpendicular to the planes.