Synthesis of mesoporous calcium phosphate using hybrid templates

Mesostructured calcium phosphate was synthesized by means of the combination of a soluble metal salt with an aqueous phenylphosphonic acid solution containing sodium dodecyl sulfate (SDS). Phenylphosphonic acid (PhP) was selected as the template to pattern the materials with pores generated by the formation of a lamellar calcium PhP phase. SDS was introduced to improve the thermal stability of the pore structure. The resulting materials were characterized by means of X-ray diffraction (XRD), small-angle X-ray diffraction (SAXS), electron microscopes and BJH gas absorption method. With the aid of SDS, calcium phosphate materials with the surface area and pore volume as 72 m²/g and 569 cm³/g, respectively, were successfully developed at the SDS:PhP molar ratio of 0.3:1. It was found that the addition of SDS could effectively improve the thermal stability of the pore structure. A possible mechanism was proposed to interpret the formation procedure and the improved thermal stability of the mesoporous structure.