Synthesis of hydroxyapatite nanoparticles through inverse microemulsions

This study is focused on the formation of hydroxyapatite (HA) nanoparticles in an inverse microemulsion processing route, in which cyclohexane is used as the organic phase, cetyltrimethylammonium bromide as surfactant phase, n-pentanol as surfactant, and a solution of Ca(NO3)2 and (NH4)2HPO4 is used as the queous phase. The influence of polyelectrolyte sodium salt of poly acrylic acid (PAA) and a reactant concentration on the final structure of HA nanoparticles were investigated. A wide variety of morphologies were encountered in synthesis which produced rod-like particles (10-15 nm in diameter and 40-50 nm in length), nanosphere particles (5-15 nm in diameter), and needle-like particles (20-30 nm in diameter and 100-200 nm in length). A great structural diversity resulted in the presence of PAA and by reactant concentration alteration. Finally, the synthesized nanoparticles were visualized by transmission electron microscopy (TEM) and identified by FT-IR and X-ray.