2005 Volume 19 Pages 288-293
Acidic aqueous solution of calcium phosphate was mixed with both or either of nonaethyleneglycol monododecylether (C12EO9) and polyoxyethylene (20) sorbitan monostearate (Tween60) and then treated with aqueous ammonium at 25°C. In contrast to both single surfactant systems, the TEM image of the resulting solid in the mixed surfactant showed an aggregate of lath-shaped particles 4-8 nm wide and above 100 nm in length,consisting of 2-3 nm wide core particles encapsulated with calcium-stearate (Ca-St) films. On calcination at 500°C, the Ca-St encapsulated solid was converted into HAp nanoarticles with a surface area of as high as 364 m2g-1.