Calcium phosphate precipitation in catanionic templates

For samples with low amount of surfactant and an excess of anionic component, TOC analysis shows more than 80% of the added surfactant is trapped in the precipitate. These samples display in SAXS three peaks that are characteristic of a hexagonal structure. Such structure, where the repetition distance is much lower than twice surfactant chain length, has not yet been described in surfactant self-assembly. This must be a monolayer microstructure, but symmetry group is not known since higher orders cannot be detected. The HAP-template hybrid structure disappears after calcination, and the BET surface of calcined powders is smaller than for HAP particles synthesized in homogeneous conditions.