Deposition behaviors and patterning of TiO2 thin films on different SAMs surfaces from titanium sulfate aqueous solution

Patterning of TiO2 thin films was successfully obtained on different self-assembled monolayers (SAMs) in aqueous solution by micro-contact printing (μCP) method. The substrates were immersed in an aqueous solution containing titanium sulfate (Ti(SO4)2) and hydrogen peroxide for deposition at 80 °C. The growth rates on various surfaces were as follows: sulfonic (–SO3H) > amino (–NH2) > methyl (–CH3) > hydroxyl (–OH). According to the XPS results, SAMs with the terminal groups of –SO3H and –NH2 were favorable for the deposition. The TiO2 film deposited on the SAM with the terminal group of –CH3 could be easily peeled off. Clearly, TiO2 patterns were obtained on the prepatterned surfaces of –SO3H/–CH3 and –NH2/–CH3 SAMs. The deposition mechanism might be relevant to electrostatic interaction, Stern layer, lone pair electrons and Van der Vaals forces. The TiO2 film was anatase after annealing at 500 °C and comprised particles with an average diameter of ca. 10 nm.