Titanium Oxide Thin Films on Organic Interfaces through Biomimetic Processing

Abstract

Titanium oxide (TiO 2 ) thin films have been deposited on silicon, glass, and plastic substrates by destabilization of an aqueous titanium lactate solution at low temperatures (<100°C). The process uses a commercially available, lowcost precursor and is simple to perform; it involves only control of pH in aqueous, chelated titanium solutions. With this solution technique, high deposition rates (>50 nm/min), film thickness (>100 nm), and excellent film uniformity have been obtained. Uniform coatings can be applied on complex-shaped polymeric substrates and porous membranes. Films can be formed on both sulfonated and untreated polymeric surfaces. As-deposited films on plastic substrates consist of amorphous, hydrated TiO 2 . On sulfonated self-assembled monolayers on silicon substrates, nanocrystalline TiO 2 films have been formed. The deposited films exhibit strong ultraviolet (UV) absorption with excellent transmission in the visible wavelength range, which indicates that the coatings may be useful as protective UV blockers for polymeric materials.

Site selective micro-patterned rutile TiO2 film through a seed layer deposition

“…The films were prepared by chemical bath deposition in a rather low acidity and environmental friendly solution. The inorganic oxides were deposited on the methyl region, not on the bare Si area, this was consistent with some other reports [49]. The modification of surface with OTS SAM promoted the nucleation of SnO 2 .…”

Fabrication and characterization of TiO2 thin film prepared by a layer-by-layer self-assembly method

“…In this figure, the frequency shift of QCM coated with PDDA that has a remarkably larger charge density [28] than that of colloidal particles was saturated in short time and then there is no large change of frequency shift, however the frequency shift of QCM deposited TiO 2 nanoparticles was saturated after about 30 s and then decreased significantly. This decrease of frequency shift after 30 s in TALH may be derived from the separation of precipitated TiO 2 on QCM because at low pH, the destabilization of chelate results in TiO 2 precipitate or films and the TiO 2 precipitates formed from titanium lactate solution are charged positively [19], which has resulted in the separation from TiO 2 nanoparticles deposited during previous procedure. We assume that this phenomenon is gradually carried out after deposition for 30 s with TiO 2 nanoparticles.…”

“…On the other hand, although the TiO 2 thin film comprising polyelectrolyte and TALH solution which is stable and double negatively charged inorganic precursor [21] shows high refractive index (n = 1.68¨1.8), this film has a small film growth with the average thickness (ca.1.5¨5 nm) of a bilayer [22,23]. In addition, the film growth phenomenon between TALH and polyelectrolytes or nanoparticles has not been sufficiently explored as functions of the immersion time or the pH of solution [19].…”

“…In previous reports, TiO 2 thin films composed of positively charged TiO 2 nanoparticles [17] and oppositely charged polyelectrolyte [18] or consisted of polyelectrolyte and negatively charged titanium (IV) bis(ammonium lactato) dihydroxide (TALH) [19] have been successfully fabricated by a LBL self-assembly method. However the refractive index of the film composed of TiO 2 nanoparticles and polyelectrolytes is significantly decreased because of the presence of pores and polyelectrolyte with low refractive index relatively [20].…”

Tubular Titania Nanostructures via Layer‐by‐Layer Self‐Assembly

“…The length and diameter of the tubes are controlled by the template while the wall thickness is dependent on the LbL deposition cycle. Unlike other titanium alkoxides which hydrolyze rapidly in the presence of water, TALH is relatively stable at ambient temperature in neutral solution [26][27][28] which makes it an ideal precursor for the construction of titania-based thin films from aqueous solution. [29][30][31] The current method provides a promising way for producing PE/ TiO 2 composite and pure anatase or rutile titania tubular structures with defined diameters and wall thicknesses.…”