Deposition Mechanism of Anatase TiO₂ on Self-Assembled Monolayers from an Aqueous Solution

The nucleation and growth process of anatase TiO 2 on several kinds of self-assembled monolayers (SAMs) in an aqueous solution has been evaluated in detail. Homogeneously nucleated TiO 2 particles and amino groups of SAM showed negative or positive ζ potential in the solution, respectively. The adhesion of TiO 2 particles to the amino group surface by attractive electrostatic interaction caused rapid growth of TiO 2 thin films in the supersaturated solution at pH 2.8. On the other hand, TiO 2 was deposited on SAMs without the adhesion of TiO 2 particles regardless of the type of SAM in the solution at pH 1.5 whose degree of supersaturation is low as a result of a high concentration of H + . Additionally, the orientation of films deposited on all SAMs was shown to be improved by enlarging the reaction time regardless of the kind of SAM or pH. It is conjectured that the adsorption of anions to specific crystal planes caused c -axis orientation of anatase TiO 2 .