Figure 5: | Scientific Reports

Figure 5

From: Role of the particle size polydispersity in the electrical conductivity of carbon nanotube-epoxy composites

Figure 5

(a) Natural logarithm of the conductivity measured in CNT-SU8 nanocomposites as a function of 1/L n for the as-milled (filled squares) and the bi-modal (filled circles) CNTs. Both sets of data follow a common curve, which evidences a quasiuniversal behaviour that is independent of the particular distribution of the CNT lengths. The dashed line is a linear fit to equation (6) where the clustering factor \({{\rm{Z}}}_{{\rm{cl}}}\) is assumed to be a constant. The solid line is a non-linear fit obtained by assuming that \({{\rm{Z}}}_{{\rm{cl}}}\) scales as \(\mathrm{1/}{L}_{n}^{\beta }\), with \(\beta =1/10\). (b) Schematic representation of the CNT network: the nanotubes form local clusters in the epoxy matrix. (c) Values of the localisation length ξ obtained from nonlinear fits of the conductivity for different values of the exponent β. (d) Clustering factor as a function of \(\mathrm{1/}{L}_{n}\) for β ranging from 0.05 to 0.3 (from top to bottom).