Surfactant-assisted preparation of fluoride-substituted hydroxyapatite nanorods

Fluoride-substituted hydroxyapatite (FHAp) nanorods have been successfully prepared by adding Tween80. As compared to the spheroidal morphology without any surfactant, the FHAp nanorods prepared with Tween80 were elongated along the c-axis. The reason was attributable to the enlarged difference between the growth rates of crystal surfaces due to the adsorption of Tween80. The effects of the pH value on the apatite formation were investigated by calculating the solubility isotherms of the Ca2+–PO43−–F−–H2O system in conjunction with experimental results, and it was found that acidic solutions were unfavorable to FHAp preparation and the proper pH should be controlled at about 9 when preparing the FHAp nanorods with the addition of Tween80.