Alignment of MWCNTs in Polymer Composites by Dielectrophoresis

Successful structural reinforcement of polymer matrices by carbon nanotube has been shown where significant improvement of mechanical properties was achieved at very low carbon nanotube loading. Due to the mechanical properties of aligned composites is better than random has been demonstrated; the conception is not easy to perform in carbon nanotube polymer composites via conventional techniques. Here, we report a novel operation to actively align and network multi-wall carbon nanotubes (MWCNTs) in a polymer matrix. In this process, MWCNTs were aligned via AC electric field induced dipolar interactions among the nanotubes in a viscous matrix followed by immobilization by curing polymerization under continued application of the anisotropic electric field. In situ SEM verified the electrostatic stabilization of the MWCNTs in the dispersion and the orientation and agglomeration caused by the dielectrophoretic force. Alignment of MWCNTs was controlled as a function of magnitude, frequency, and application time of the applied dielectrophoresis. In the present work, MWCNTs are not only aligned along the field, but also migrate laterally to form thick. The actively aligned MWCNTs amplify the flexural modulus and wear-resisting property.