The aluminosilicate mineral imogolite is composed of single-walled nanotubes with stoichiometry of (HO)3Al2O3SiOH and occurs naturally in soils of volcanic origin. In the present work we study the stability and the electronic and mechanical properties of zigzag and armchair imogolite nanotubes using the density-functional tight-binding method. The (12,0) imogolite tube has the highest stability of all tubes studied here. Uniquely for nanotubes, imogolite has a minimum in the strain energy for the optimum structure. This is in agreement with experimental data, as shown by comparison with the simulated X-ray diffraction spectrum. An analysis of the electronic densities of states shows that all imogolite tubes, independent on their chirality and size, are insulators.
ACS Nano, 2007, V. 1, № 4 , P. 362-368.

Inorganic MoS2 nanotubes under high pressure have been investigated at the atomistic scale using Born−Oppenheimer molecular dynamics simulations. We show that the low friction coefficient at high loads is not due to the ball-bearing effect. Instead the nanostructures burst under high loads and form nanoplatelets which attach themselves at the material surfaces of closest contact, effectively leading to local “nanocoating” which results in friction coefficients identical to those of lubricants based on MoS2 platelets. The breakup process always starts from the innermost tube, which opens the possibility to tune the nanomaterials to be effective at well-defined loads.
J. Phys. Chem. C, 2008, V. 112, № 46, P. 17764-17767.

We present the results of molecular dynamics simulations for the capillary imbibition of a drop of an ionic PbI2 melt into inorganic BN, MoS2, and carbon nanotubes. Radial atomic distribution functions are used to characterize the structure of the liquid inside of nanotubes and the kinetics of the penetration. We find that in all cases the PbI2 melt remains liquid but a shell-like structure of the melt along the nanotube axis becomes visible. The filling of MoS2 nanotubes obeys the Lucas−Washburn equation within each shell, whereas the filling of carbon and BN nanotubes follows a modified expression. Both the chemical nature and roughness of the nanotube walls play an important role in the capillary kinetics and the habitus of the embedded liquid.
J. Phys. Chem. C, 2009, V. 113, P. 13664-13669.

Atomic models of nanotubes of a family of polytitanic acids H2TinO2n+1 (n = 2, 3, and 4) are proposed, and their properties are studied by means of the density functional theory based (DFTB) method as a function of their chemical composition and radii in comparison with the related dehydrogenated lepidocrocite TiO2 nanotubes. We find that these nanotubes have very similar structural properties, which are difficult to distinguish with the commonly applied XRD technique. The variable composition can be attributed to the nanotubes of titanic acid obtained experimentally due to thermodynamic dehydration ↔ hydration equilibrium.
J. Phys. Chem. C, 2009, V. 113, P. 20837-20840.