Van der Waals interactions of parallel and concentric nanotubes

Abstract

For sparse materials like graphitic systems and carbon nanotubes the standard density functional theory (DFT) faces significant problems because it cannot accurately describe the van der Waals interactions that are essential to the carbon-nanostructure materials behavior. While standard implementations of DFT can describe the strong chemical binding within an isolated, single-walled carbon nanotube, a new and extended DFT implementation is needed to describe the binding between nanotubes. We here provide the first steps to such an extension for parallel and concentric nanotubes through an electron-density based description of the materials coupling to the electrodynamical field. We thus find a consistent description of the (fully screened) van der Waals interactions that bind the nanotubes across the low-electron-density voids between the nanotubes, in bundles and as multiwalled tubes.

Size‐Dependence and Elasticity of Liquid‐Crystalline Multiwalled Carbon Nanotubes

“…Apparently, the issues concerning liquid-crystalline properties and molecular chain rigidity have been quantitatively analyzed in the polymeric and biological systems. [19][20][21][22][23][24][25][26] However, the following specific issues of scale and mechanical elasticity raised in the liquid-crystalline nanoparticles with large crystalline structure units challenge the well-established liquid-crystal field. Because of the tubular nanocrystalline structure as building blocks, the intrinsic characteristics of liquid-crystalline nanotubes are the higher hierarchically ordered structures compared to molecular liquid-crystalline systems, as shown schematically in Figure 4.…”

“…[10] Carbon nanotubes are a class of nanomaterials that show a strong relationship between their exceptional physical properties and their dimensions in a wide size range; from nano-to microdomains. [11][12][13][14][15][16][17][18][19] Such a wider range of the dimensions of the nanoparticles raises fundamental questions about the size threshold for liquid crystallization of 1D nanoparticles and the effects of 1D nanoparticles as mesogens (structure units) in liquid-crystalline alignment. It is envisaged that some profound differences are related to nanoparticle mesogens, larger structure units with a short-range-ordered lattice structure, in comparison with classic mesophase systems.…”

Phonon Dispersion Relation of Carbon Nanotube

“…Indeed, the calculations are performed on graphene sheets, which is a good approximation if the radius of the CNT is much greater than the distance between two neighboring nuclei of the carbon atoms in the CNT. As we know from the literature like [3,6,7], the diameter of most CNTs is between 0.7 nm and 2 nm, whereas the distance between the nuclei of the atoms is 1.42Å.…”

“…These materials have been hailed for their material properties and the applications that these properties promise. Their high electrical and thermal conductivity, remarkable strength, elasticity and anisotropic shape suggest numerous possibilities of nanoscale biological probes and structural elements in many electronic devices [3][4][5].…”

About Grafting of Single-Walled Carbon Nanotubes on the Oligo-N-Vinyl Carbazole and Copolymer Involving N-Vinylcarbazole and Hexylthiophene

“…Thus the uniformity of the dispersion process is not optimized and the resulting nanocomposite is often inhomogeneous and has undesirable properties. Among the factors innhibing the dispersion process is the shearing cohesiveness between SWNTs, which is governed by van der Waals interactions (Byron et al, 2006;Schroder et al, 2003). Different procedures have been applied in order to obtain more dispersed SWNTs.…”