Multistep crystal growth of oriented fluorapatite nanorod arrays for fabrication of enamel-like architectures on a polymer sheet

Enamel-like fluorapatite (FA) films were produced on a conventional polyvinyl alcohol (PVA) sheet in an aqueous solution system based on simulated body fluid containing fluoride ions. We obtained FA films thicker than 100 μm by multistep crystal growth on the polymer sheet. High-density nucleation of the FA crystals was achieved on the polymer surface having OH groups at a relatively high degree of supersaturation. Crystal growth of the FA nanorods along the c direction was then promoted through geometric selection at a relatively low degree of supersaturation. Multistep epitaxial growth produced enamel-like architectures consisting of c-axis-oriented nanorods with a controlled diameter below 300 nm.