Shape-Controlled Synthesis of Hydroxyapatite in Organic Media

Abstract

AbstractWe have examined the effect of organic solvent on the microstructures of hydroxyapatite (HAp) formed by hydrolysis of α -tricalcium phosphate ( α -TCP) in heterogeneous solvent system (water-hydrophobic organic solvent). The shape of HAp was like ultrafine whisker (length : about 1 ∼- 4 µ m) and its size depended on the used organic solvent.As a simple hybridization, incorporation of fluoride anion (F−) into HAp was attempted in similar system to obtain fluoridated apatite [Ca10(PO4)6(OH)2−x Fx.]. The formation rate was strongly affected by the concentration of F− and reaction temperature. Although the product in water (in the absence of organic solvent) consists of fine particles less than 1 µ m, the product prepared in the heterogeneous solvent system was mixture of ultrafine particles ( ∼ 0.1 µ m) and needle-like particles (length : about 1 ∼ 4 µ m, width : ∼ 0.5 µ m). The microstructures of HAp and FHAp were controlled by hydrophobicity of organic solvent.