Electrophoresis and orientation of multiple wall carbon nanotubes in polymer solution

This paper contains an in-depth analysis of the electrophoresis of multi-wall carbon nanotubes (MWNTs) in liquid epoxy where electrophoresis experiments under DC and AC fields were carried out for five different types of multi-wall carbon nanotubes (MWNTs). DC electrophoresis and particle image velocimetry were used to determine the electrophoretic particle mobility and zeta potential, where the MWNTs with the largest outer diameter and length led to the highest mobility values. The orientation and agglomeration of MWNTs into striation lines under AC electrophoresis were investigated by analysing the hue, saturation and intensity of the transmitted polarised light under microscope, following a schedule of step-wise applied voltage in the range of 0 to 100 V. Plots of hue and saturation as a function of the applied voltage were used to assess the degree of orientation and density of orientated MWNT structures, respectively, and to determine an optimum AC electric field value for the orientation of a specific MWNT type by electrophoresis.