Kinetics of single-walled carbon nanotube migration in epoxy resin under DC electric field

Carbon nanotubes (CNTs) orient in a polymer matrix under electric field due to their highly anisotropic electric polarizability. Under direct current (DC) electric field, CNT also migrates toward electrodes resulting in a non-uniform CNT concentration which can affect the properties gained from CNT alignment. In this study, DC electric field was applied across a CNT/epoxy mixture and the kinetics of CNT migration were studied in real time as a function of electric field strength, CNT concentration and length distribution. The rate constant k of CNT migration was found to be linearly proportional to the electric field strength, while varying the CNT concentration and length distribution exhibited a minimal effect on the migration velocity. Combined with our previous study of the temperature dependence of CNT migration, the relationship between the rate constant k of CNT migration and electric field strength, CNT concentration and length distribution was established. The resulting relationship can be used to manipulate the spatial distribution of CNT to selectively enhance the mechanical, thermal and electrical properties of CNT/polymer composites.