Tween-60 mediated synthesis of lamellar hydroxyapatite with worm-like mesopores

Lamellar hydroxyapatite with worm-like mesopores was successfully synthesized from the mixed ethanol solutions of Ca (NO3)2·4H2O and P2O5 in the presence of polyoxyethylene (20) sorbitan monostearate (Tween-60). The synthesized hydroxyapatite was characterized by means of wide angle X-ray diffraction (WAXRD), small angle X-ray diffraction (SAXRD), electron microscopes and gas absorption. It was found that the content of Tween-60 influenced the crystallinity and the size of lamellar hydroxyapatite, with the volume fraction of Tween-60 increasing the size of HAP lamellasomes increased. The mesopores, around 4 nm in diameter, have a high heat resistance. The mesopore forming templates were from the reactive products of P2O5 and ethanol.