- Abstract Single walled carbon nanotubes (SWNTs) with an anisotropic morphology (rod) are currently being employed as fillers in polymer matrix to produce novel nanocomposites with enhanced properties and performance in a wide variety of applications. We investigate the effect of the addition of second isotropic (spherical) filler, antimony tin oxide (ATO) particles to the anisotropic SWNT-polymer composites. Cryogenic transmission electron microscope (cryo-TEM) and scanning electron microscope (SEM) were employed to image the aqueous dispersions of the SWNTs–ATO–Latex solution and composite thin films respectively. The SEM imaging of these films shows that SWNTs (rods) tend to aggregate in the presence of ATO clusters, indicating depletion interactions between the rods and the spheres. The difference in the value of electrical conductivity of the films measured along the radial and the tangential directions to the spinning lines is probably due to the preferred orientation of the SWNTs in the matrix during the spin coating process.