Processing of nanocrystalline hydroxyapatite particles via reverse microemulsions

• DOI: 10.1007/s10853-007-2182-9
• Publication Date: 2007-10-05T09:18:33Z
• Authors: Hong Li; MinYing Zhu; LiHua Li; ChangRen Zhou
• Keywords: 02 engineering and technology; 0210 nano-technology

Nanocrystalline hydroxyapatite (HAP) particles were synthesized at room temperature using reverse microemulsions, in which cyclohexane was used as the organic phase, mixed surfactant with TX-100 and 1- pentanol, and CaCl2 solution as aqueous phase. The reactor systems with aqueous/organic volumetric ratios 1:10, 1:5, 2:5, and 1:2 were carefully selected for the microemulsion processing by the pseudo-ternary phase diagram and the electric conductivity measurement of the emulsion. The as-obtained HAP nanoparticles with carbonate substitution and broadening X-ray diffraction (XRD) traces were similar to the fine powder of human bone, despite of the aqueous/organic volumetric ratio in the emulsion. No obvious other’s phase occurred after as-obtained particles calcined under different temperature till 700 °C. In the emulsion-derived precursors, the HAP particles based on spherical morphology were prepared into the size between 15 ∼ 30 nm as a low volumetric ratio of 1:10 or 1:5 was applied. As the volumetric ratio increased to 2:5, the HAP particles with rod-like shape of (140∼280) × (10∼80) nm were formed. Practical implication of the results is that the nanocrystalline bone-like hydroxyapatite can be obtained via the emulsion processing at room temperature without further calcinations.