On the self-assembly of TiO_x into 1D NP network nanostructures

Here, we report for the first time a 'ligand free' method of designing 1D TiO_x supramolecular network materials, which starts from Ti bare metal powder. Each TiO_x oxidation step has been carefully investigated with different analytical techniques, including high resolution transmission electron microscopy/high resolution scanning electron microscopy (HRTEM/HRSEM), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy and superconducting quantum interference device (SQUID) measurements. The self-assembly of TiO_x nanoparticles (NPs) into 1D supramolecular nanoparticle networks is induced by the formation of mixed valent Ti^II,III species. The synthesis starts with etching a bare Ti surface, followed by a continuous oxidation of TiO_x clusters and NPs, and it finally ends with the self-assembly into rigid 1D NPs chains. Today, such self-assembled 1D NP TiO_x network materials are bridging the gap between the nanoscale and the macroscopic material world and will further provide interesting research opportunities. (fast track communication)