The electrical properties of conductive polymer composites
are
critical in applications, and the electrical conductivity regulation
through micro/nanofiller orientation is attracting broad attention.
For short carbon fiber (SCF) conductive polymer composites (SCFCPCs),
the electrical properties and SCF conductive network topology of SCFCPCs
with different SCF orientations are analyzed with a numerical model.
The results demonstrate that an increase in the degree of SCF orientation
from 0 (SCFs perpendicular to conductivity direction) to 1 (SCFs parallel
to conductivity direction) first leads to a corresponding increase
and then a decrease in the electrical conductivity of SCFCPCs. The
highest electrical conductivity is achieved while the degree of SCF
orientation is increased to approximately 0.6, which is a higher SCF
orientation state compared to random orientation. Moreover, it is
identified that more SCFs in conductive networks do not necessarily
guarantee a higher electrical conductivity. The electrical conductivity
of the SCF conductive networks also depends on the degree of SCF orientation.
Evidently, the less-oriented SCFs tend to build in-layer conductive
networks, while the highly oriented SCFs tend to build interlayer
ones, which apply a greater contribution to the electrical conductivity.
Overall, the results of this study reveal why the highest electrical
conductivity occurs at a higher SCF orientation rather than a random
SCF orientation. The clarified influence and mechanism provide indications
for the electrical conductivity regulation of micro/nanocomposites
by adjusting the conductive filler orientation.