Small angle neutron scattering from single-wall carbon nanotube suspensions: evidence for isolated rigid rods and rod networks

Abstract

We report small angle neutron scattering (SANS) from dilute suspensions of purified individual single wall carbon nanotubes (SWNTs) in D 2O with added sodium dodecylbenzene sulfonate ionic surfactant. The scattered intensity scales as Q −1 for scattered wave vector, Q, in the range 0.005< Q<0.02 A ̊ −1 . The Q −1 behavior is characteristic of isolated rigid rods. A crossover of the scattered intensity power law dependence from Q −1 to Q −2 is observed at ∼0.004 A ̊ −1 , suggesting the SWNTs form a loose network at 0.1 wt% with a mesh size of ∼160 nm. SANS profiles from several other dispersions of SWNTs do not exhibit isolated rigid rod behavior; evidently the SWNTs in these systems are not isolated and form aggregates.