Growth Kinetics of the Hydroxyapatite (0001) Face Revealed by Phase Shift Interferometry and Atomic Force Microscopy

The relationship between the growth rate of the hydroxyapatite (0001) face and bulk supersaturation of a simulated body fluid was measured by real-time Moire phase shift interferometry. It was found that the (0001) face grew in the multiple two-dimensional nucleation mode, from surface observation by atomic force microscopy, and the growth rate data were fitted by the theoretical equation of multiple two-dimensional nucleation. The edge free energy of an island nucleated on the (0001) face, the most important parameter for two-dimensional nucleation, could be directly estimated as γ = 3.3 kT, which was almost the same order as that on the (110) or (101) face of a lysozyme protein crystal.