Topotaxial nucleation and growth of TiO₂ submicron-scale rod arrays on titanium substrates via sodium tetraborate glass coating

A novel approach to fabricate sub-μm scale arrays is demonstrated with the growth of rutile TiO₂ on titanium substrates. The fabrication process is template-free, simply involving coating of the titanium substrate with sodium tetraborate glass, Na₂O · 2B₂O ₃: when the glass coating was removed by dissolution in distilled water at 80°C for about 5 h, random or well-ordered submicron-scale rod arrays of rutile were left on the substrate. A glass phase topotaxial (GPT) nucleation and growth mechanism is thought to operate in the crystal growth process.