A role of van der Waals interactions in DC anhydrous electrodeposition and dielectric constant of carbon nanotubes

Electrodeposition of single-walled carbon nanotubes (SWCNTs) from anhydrous organic solvents by dc electric field shows characteristic properties: water inhibits deposition, only thin straight bundles lying parallel to the substrate surface are deposited, and only semiconducting SWCNTs are found in the deposited film. To understand the mechanism of this dc anhydrous electrodeposition, deposition efficiencies were measured for various organic solvents having different dielectric constants. The results were analyzed by the Lifshitz theory of van der Waals interaction, which indicates that the van der Waals force is mainly responsible for the adhesion. The static dielectric constant of semiconducting SWCNTs in a form of thin straight bundles is estimated to be ∼4.5.