graphene content. One realizes the well-known increase of the electrical conductivity
with increasing graphene volume content. As displayed in Figure 10.35b, this
graphene composite follows Eq. 10.9 with good precision. This is insofar remarkable
as this equation was, originally, derived for one-dimensional fillers. At comparably
low concentrations the electrical conductivity of the carbon nanotubes composite is
better than that of the composites using graphene The percolation threshold is in the
case of carbon nanotube composites in the range of 10
À8 , whereas this threshold was
found in the described example as to be in the range of 10
À3
.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
graphene content [vol%]
10
-8
10
-7
10
-6
10
-5
10
-4
10
-3
10
-2
10
-1
electric
conductivity
[Sm
-1 ]
(a)
0.001
0.01
0.1
1
log(reduced graphene content p - p c )
10
-4
10
-3
10
-2
10
-1
electric
conductivity
[Sm
-1 ]
0.07 vol%
1.26 0.06
c
p
α
=
=
±
(b)
Figure 10.35 Electrical conductivity of a
polyethylene graphene composite as a function
of the graphene content [21]. Also this
composite follows the law given in Eq. (10.9).
Therefore the double logarithmic plot depicted
in Figure 10.35b is well approximated by a
straight line.
10.4 Electrical Conductivity of Nanocomposites j295