Abstract
Dielectrophoresis (DEP) is a phemomenon of induced particle motion in non-uniform electric fields. The effect is frequency dependent; by monitoring the motion of particles in AC fields and ananlysing the change in motion with frequency, it is possible to determine the electrical properties of nanoparticles in lab-on-a-chip systems. In this paper, we demonstrate how DEP can be used to determine the ratio of semiconducting and metallic carbon nanotubes in solution, by monitoring the frequency-dependent impedance change between two electrodes as a function of energising frequency.