Synthesis of hydroxyapatite nanoparticles trough polyelectrolyte-modified microemulsions

The paper is focused on the formation of hydroxyapatite nanoparticles (HAp) in polyelectrolyte-modified microemulsions, in a microemulsion template phase consisting of cyclohexane, water, cationic surfactant and cosurfactant, in the presence of Na-polyacrylate (PAA) as an anionic polyelectrolyte. It is shown that PAA, can be incorporated into the individual inverse microemulsion droplets. The microemulsion droplets and PAA-filled microemulsion droplets can be successfully used as a template phase for the nanoparticles formation. Prepared HAp in presence of polyelectrolyte has a different morphology from samples which are synthesized in absence of polyelectrolyte. PAA leads to formation of needle-like HAp (20-30nm in diameter and 100-200nm in length). Formation of HAp at room temperature was confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Size and morphology of the HAp samples were characterized using transmission electron microscopy (TEM).