Imogolite: An aluminosilicate nanotube material

Abstract The analogy between carbon nanotubes and synthetic imogolite, an aluminosicate of stoichiometry (OH)3Al2O3SiOH, having a tubular structure of external diameter 2.4 nm and internal diameter 0.9 nm, is examined. High-resolution transmission electron microscopy, image matching and electron diffraction are used to examine the tube structure. Some interesting new results are obtained, concerning the various states of aggregation of the imogolite tubes, ranging from randomly oriented single tubes to essentially close-packed arrays. Both longitudinal and cross-sectional images were obtained. Some possible applications of imogolite as new materials are discussed. The various imogolite textures pose challenging problems for solid-state physicists, concerning for example the transport and optical properties of such fibre bundles.