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

Abstract

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 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 .

Morphology Control of Metal Oxide Nanocrystals

“…Reprinted with permission from Ref. 180 185,186 or self-assembled monolayers 20,113,187,188 . However, metal oxide formation on polytetrafluoroethylene (PTFE) was difficult compared to PET films.…”

Nanofabrication of Metal Oxide Nanostructures in Aqueous Solutions

“…These results suggest that acicular TiO 2 grew along the c-axis to enhance the diffraction intensity from the (004) planes. Crystal growth of anatase TiO 2 along the c-axis was previously observed in TiO 2 films 113 . Anisotropic crystal growth is one of the features of liquid phase crystal deposition.…”

Nano/Micro-Patterning of Metal Oxide Nanocrystals

“…The orientation and crystal growth mechanism are further discussed in a separate article. 49 Thin films were further evaluated by X-ray photoelectron spectroscopy (XPS; ESCA-3200, Shimazu Corporation, 1 × 10 -5 Pa). The X-ray source (MgKα, 1253.6 eV) was operated at 8 kV and 30 mA.…”