Titanate nanotubes were synthesized via hydrothermal treatment of rutile TiO2. The reaction conditions were: particles sizes of TiO2 having diameter between 0.05 and 0.5 mm, 10 M NaOH solution and a temperature of 150 degrees C. The effect of reaction time on the morphology and the crystalline structure were investigated by X-ray diffraction (XRD), Raman spectroscopy and High Resolution Transmission Electron Microscopy (HRTEM). Results showed that the reaction products are composed of nanotubes having 3, 4 and 5 layers. All the three forms coexist together in each sample with different fractions. The number of layers of the major form increases from 3 to 5 layers when reaction time increases from 12 to 120 h. At the same time, internal and external diameters vary from 3 nm to 5 nm and from 7 nm to 11 nm respectively. Deformation of nanotubes as well as nanotubes assembling and the formation of nanoribbons appear clearly for high reaction times (120 h). (C) 2016 Elsevier B.V. All rights reserved.