Two-step electrical percolation in nematic liquid crystal filled by multiwalled carbon nanotubes

Percolation of carbon nanotubes (CNTs) in liquid crystals (LCs) opens way for a unique class of anisotropic hybrid materials with a complex dielectric constant widely controlled by CNT concentration. Percolation in such systems is commonly described as a one-step process starting at a very low loading of CNTs. In the present study the two-step percolation was observed in the samples of thickness 250 \(\mu\)m obtained by pressing the suspension between two substrates. The percolation concentrations for the first and second percolation processes were \(C_n^{p_1}\approx 0.0002\) wt. \% and \(C_n^{p_2}\approx 0.5\) wt. \%, respectively. The two-stage nature of percolation was explained on a base of mean field theory assuming core-shell structure of CNTs.