Formation of TiO₂ nanopattern using reverse imprinting and sol-gel method

TiO₂ and its nanopattern fabrication have been studied intensively because of its wide band gap and photocatalystic nature. TiO ₂ nanopatterns can be made by conventional patterning techniques, consisting of deposition, photolithography, and etching processes. However, these processes include complicated and expensive process steps, such as photolithography. Therefore, a simpler and more economic process is needed. In this work, TiO₂ nanopatterns were fabricated using reverse-imprint lithography and the sol-gel method. Ethanol based TiO₂ sol was prepared using tetrabuthylorthotitanate (C₁₆H₃₆O ₄ Ti) and diethanolamine (C₄H₁₁NO₂). TiO₂ sol was then coated on the surface of the replicated polymer mold of hard-polydimethylsiloxane and polydimethylsiloxane by spin coating and transferred to the substrate by the reverse imprinting process at 200 °C. A postimprint annealing process was subsequently carried out to form the TiO ₂ polycrystalline phase. The x-ray diffraction and x-ray photoelectron spectroscopy results confirmed that the transferred TiO ₂ nanopattern was chemically pure polycrystalline TiO₂.