Optimal synthesis of mesostructured hollow titania nanotubes templated on CaCO3 nanoparticles

Approximate 10 µm length of mesostructured hollow titania nanotubes with intact configuration was successfully prepared by using needle-like calcium carbonate and octadecylamine as double templates at room temperature in nonaqueous system. During the whole preparation, two parameters i.e. tetrabutoxytitanium/calcium carbonate molar ratio and annealing temperature, were optimized to obtain titania nanotubes with well-defined tubular morphology and mesoporous structure in tube walls. The as-prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, broad-angle X-ray diffraction, pore size distribution and Brunauer–Emmett–Teller. The results showed that under optimal experimental conditions i.e. tetrabutoxytitanium/calcium carbonate molar ratio (50 wt.%) and annealing temperature (773 K), the tube materials exhibited uniform tubular structure with a length of 8–15 µm and an inner diameter of ∼ 400 nm, a wall thickness of ∼ 40 nm, a surface area of 112.2 m2/g and a pore volume of 0.18 cm3/g. The optimized titania nanotubes were utilized as a carrier for the immobilized of ibuprofen via a simple adsorption method. It was found that the loaded drug presented good sustained release property in three release media, i.e. simulated body fluid, normal saline and pure water.

Graphical abstractUnder optimal experimental conditions in this study, mesostructured hollow titania nanotubes with intact configuration were successfully synthesized by using needle-like calcium carbonate and octadecylamine as double templates at room temperature. This novel kind of TiO2 nanotubes with unique structure and morphology could be potentially applicable in many fields such as drug delivery, biologically active agents' protection, separation, catalysts and adsorbents.Figure optionsDownload full-size imageDownload as PowerPoint slide