Nanotubes with well-defined structure: imogolites

Imogolites (aluminosilicate and aluminogermanate) are nanotubes (NTs) with well-defined diameter and chirality that can be synthesized in aqueous solution in mild conditions. It has been shown that the diameter and the single- or double-walled NT formation can be controlled depending on the synthesis parameters such as anionic ligands, temperature, pH and reactant concentration. In this chapter, the advances for understanding at a molecular level the remarkable properties of imogolites, their stability and formation mechanism are reviewed highlighting the computational chemistry contribution. Different theoretical methods have been used, in special the Self-Consistent-Charge Density-Functional Tight-Binding method (SCC-DFTB), the most used for investigating imogolites, is here briefly described.