Self-Assembly of Dandelion-Like Hydroxyapatite Nanostructures Via Hydrothermal Method

Self-assembled dandelion-like hydroxyapatite (HAp) nanostructures; were successfully synthesized via a mild template-free hydrothermal process, using ethylenediaminetetraacetic acid (EDTA) as the surfactant. The obtained dandelion-like HAp nanostructures were between 5 and 8 pin in diameter and were composed of radially oriented nanorods with an average diameter of about 200 nm. The X-ray diffraction analysis and Fourier transform infrared spectroscopy were used to characterize the crystalline phase and purity of the synthesized nanostructures. The Brunauer-Emmett-Teller surface area of the dandelion-like nanostructures was measured to be about 39 m(2)/g. The results of thermal analysis revealed that dandelion-like HAp nanostructures have appropriate thermal stability up to 1200 degrees C. Scanning electron microscopy and transmission electron microscopy analyses showed that EDTA plays an important role in obtaining the dandelion-like morphology, because without it, only mono-dispersed HAp nanoparticles with an average diameter of about 125 nm were formed. The mechanism for the formation of dandelion-like HAp nanostructures was suggested based on the radial self-assembly of Ca-EDTA molecular complexes.