Titanate nanotubes

Titanium-dioxide is widely used in several industrial sector such as paint industry or cosmetics due to its favorable properties. Beside the titanium-dioxide unique properties titanate nanotubes have wide-ranged possibility coming from their unique nanostructure.

Titanate nanotubes produced by an alkali hydrothermal nanotechnological process have a diameter and length commensurable with one-thousandth of the human hair and one-tenth of a typical bacteria, respectively. Such nanostructures has tubular morphology with a diamter of 5-8 nm and a length upto 100-500 nm (fig. 1.).


Fig. 1. Transmission electron microscopic images present titanate nanotubes with tubular morphology. Such nanostructures has tubular morphology with a diamter of 5-8 nm and a length upto 100 nm.

These tiny nanotubes are not closed structure but look like small, rolled-up carpets with a few atomic layer thickness (Fig. 2.). The layered structure coming from the rolling-up mechanism resulted in such “nanocarpets” with 4-5 layers.


Fig. 2. TEM images show the layered, roll-up structure of the titanate

They are promising base materials for different sensors (e.g. lambda sensors), catalysts or catalyst support due to their semiconducting behaviour.

Titanate nanotubes has unique ion exchange properties due to the special surface chemistry and the layered structure. Exploiting such possibilities led to water softing or removal of other unwanted ions (e.g. heavy metal ions).

The unique nano-construction, tiny dimension, relatively huge specific surface area and the one dimensional structure make titanate nanowires as a promising filler for polymers. Several titanate naowire/polymer (e.g. polyethylene, polystryrene, polyurethane, epoxy resins) nanocomposites have increasing tensile stregth, Young modulus, wearing resistance. Beside the enhanced mechanical properties titanate nanowire also endow polymeric composites with burning resistance and antistatic effect.

Titanate nanowire based paints have outstanding hiding power and white color due to the one-dimensional construction and th enhanced light reflectiveness and whiteness coming from the chemical structure. Hiding power can be combined with superhydrophobic, antimicrobial or photocatalytic properties resulted in germ- and funghi-killer self-cleaning paints.