Percolation Studies of Single- and Multi-Walled Carbon Nanotubes/Poly(methyl methacrylate) Nanocomposites

Abstract

Using an ultrasonication method, the dispersion of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) in a polymer matrix, poly(methyl methacrylate) (PMMA), were used to produce SWCNT/PMMA and MWCNT/PMMA composites. Composites were made using purified SWCNTs and MWCNTs with different SWCNT and MWCNT loadings (ranging from 0.2 % to greater than 2.0 % by weight) and viscous Plexiglas® (PMMA) solutions. DC electrical conductivity measurements were performed on high quality samples, attaining conductivities of the order of 103 S/m for high loading. The electrical percolation threshold (φ c ) and the critical exponent, t, for SWCNT/PMMA and MWCNT/PMMA samples have been obtained. Our measured values are consistent and within the range reported in the literature. The t values obtained by our method are consistent with a quasi-two dimensional network for MWCNT nanocomposites and three-dimensional network for SWCNT nanocomposites.