Rutile microtubes assembly from nanostructures obtained by ultra-short laser ablation of titanium in liquid

Pulsed laser ablation of a titanium target in water was performed by an ultra-short laser source (Ti:sapphire, @=800nm, 1kHz, 100fs). The obtained structures were characterized by Atomic Force Microscopy, Scanning Electron Microscopy, X-Ray Photoelectron Spectroscopy, micro-Raman spectroscopy and X-ray Diffraction, revealing the presence of non-stoichiometric titanium oxide nanoparticles with a certain amount of crystalline rutile phase. Upon remaining in water the ablated species, the formation of a lamellar phase has been observed. This lamellar phase rolls up to microtubes by remaining in water for a month, through a self-assembling process. The formed microtubes, with an inner diameter of about 2 um and an outer diameter of 4 um are characterized by a smooth interior surface and aggregation of nanoparticles on the outer surface.