The crystal growth of hydroxyapatite (HAP) in the presence of hexadecylamine was investigated by the patterns of X-ray diffractions (XRD), Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected-area diffraction (SAD). Results showed that the organic film could increase the ions supersaturation on its surface, thus leading to a fast growth of pure HAP crystals. Moreover, the positive headgroups in the organic film could act a...