Synthesis of Nanostructured Hydroxyapatites by the Mixed Surfactant Templating Method

抄録

This study was done to synthesize nanostructured calcium phosphate by the mixed surfactant templating method and clarify the pathway for nanostructure formation. The precursory mixture of Ca(NO₃)₂, KH₂PO₄, HNO₃ and H₂O containing both or either of polyoxyethylenealkylether (EO9) and polyoxyethylenesorbitanester (EO20) was treated with aqueous solution of ammonia. The EO9-based single surfactant system yielded platy apatite particles and the other EO20-based one led to rod-like apatite particles. In the EO9 and EO20 mixed systems, on the other hand, beads-linked chain-like apatite particles complexed with organic species were mainly formed, along with partial formation of a layered structure with a long period of 5.4 nm. On calcination at 500°C the chain-like particles were increased in specific surface area from ~10 to as large as more than 360 m²g^-1. The present result indicate that the mixed surfactant templating method is available for the synthesis of high-surface area apatite promising as implant materials.