Simulation Studies Underlying the Influence of Filler Orientation on the Electrical Properties of Short Carbon Fiber Conductive Polymer Composites: Implications for Electrical Conductivity Regulation of Micro/Nanocomposites

The electrical properties of conductive polymer compositesarecritical in applications, and the electrical conductivity regulationthrough 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 SCFCPCswith different SCF orientations are analyzed with a numerical model.The results demonstrate that an increase in the degree of SCF orientationfrom 0 (SCFs perpendicular to conductivity direction) to 1 (SCFs parallelto conductivity direction) first leads to a corresponding increaseand then a decrease in the electrical conductivity of SCFCPCs. Thehighest electrical conductivity is achieved while the degree of SCForientation is increased to approximately 0.6, which is a higher SCForientation state compared to random orientation. Moreover, it isidentified that more SCFs in conductive networks do not necessarilyguarantee a higher electrical conductivity. The electrical conductivityof the SCF conductive networks also depends on the degree of SCF orientation.Evidently, the less-oriented SCFs tend to build in-layer conductivenetworks, while the highly oriented SCFs tend to build interlayerones, which apply a greater contribution to the electrical conductivity.Overall, the results of this study reveal why the highest electricalconductivity occurs at a higher SCF orientation rather than a randomSCF orientation. The clarified influence and mechanism provide indicationsfor the electrical conductivity regulation of micro/nanocompositesby adjusting the conductive filler orientation.