Synthesis of imogolite fibers from decimolar concentration at low temperature and ambient pressure: a promising route for inexpensive nanotubes.

To date, the successful low-temperature synthesis of the aluminosilicate imogolite nanotubes always involved initial concentrations of the reagents in the millimolar range, higher concentrations being reported to lead to the formation of the less well characterized allophane phase. The present work shows that reaction kinetics and not initial concentration control the formation of the nanotubes: substantial amounts of well formed imogolite were obtained from a decimolar initial concentration, i.e. 100 times higher than the "standard" protocol. The allophane-like spheroids expected from the high reagent concentration were not observed in this work, and proto-imogolite was obtained instead.