Titanium Oxide Nanoparticles Precipitated from Low‐Temperature Aqueous Solutions: I. Nucleation, Growth, and Aggregation

Abstract

Titanium oxide (TiO2) thin films can be prepared by controlled hydrolysis of a titanium tetrachloride (TiCl4) precursor in an aqueous solution at temperatures below 100°C. As part of an effort to understand the formation of such TiO2 films, the kinetics of the nucleation, growth, and aggregation of TiO2 nanoparticles in aqueous solutions of TiCl4 were studied using dynamic light scattering and a transmission electron microscope (TEM). A higher degree of supersaturation, produced by a higher solution temperature, a higher concentration of TiCl4, or a higher pH, results in a shorter nucleation induction time, a faster initial growth/aggregation rate, and a larger aggregate size. The interfacial energy of TiO2 nanoparticles was found to be 0.072 J/m2 from the homogeneous nucleation theory. Further investigations by a high‐resolution scanning electron microscope (SEM) and TEM for the as‐deposited films showed the structure hierarchy organized from nanocrystalline particles precipitated in the supersaturated solution. As a result, the effect of solution conditions on the nucleation, growth, and aggregation of TiO2 nanoparticles can provide useful guidance for tailoring of microstructures of the TiO2 films.

Titanium Oxide Nanoparticles Precipitated from Low‐Temperature Aqueous Solutions: III. Thin Film Properties

“…In short, desired amount of hydrochloric acid (HCl, 36.5%–38%, J. T. Baker, Phillipsburg, NJ) was first dissolved in ice‐cold DI water (Barnsted E‐pure, resistivity 18–20 MΩ‐cm) followed by slow injection of adequate amount of titanium chloride (TiCl 4 , 99.99%, Alfa‐Aesar, Ward Hill, MA) in a parafilm‐covered glass bottle. The method for calculating supersaturation at the deposition temperature (70°C) has been addressed in Part I . Table indicates the amount of chemicals added to achieve different supersaturation levels investigated in this study.…”

High-Rate Li+Storage Capacity of Surfactant-Templated Graphene-TiO2Nanocomposites

“…27 For the other three samples, the TiCl 3 precursor concentration ([TiCl 3 ]), reaction temperature (T rxn ), and reaction time (t rxn ) were reduced, which act to decrease the extent of TiO 2 formation. 40 Between the M-6.5, M-0.65, and M-0 samples (collectively, the M-samples), the [SDS] was altered, which influences the adsorption of SDS onto FGSs 37 and thus the dispersion behavior of FGSs, 33 as well as the nucleation and growth of TiO 2 . 35,41 At the ionic strengths of the aqueous reaction mixtures, the cmc for SDS is ∼0.8-1 mM.…”

Analytical solutions of gas transport problems in inorganic/organic hybrid structures for gas barrier applications

“…The barrier film is coated on the substrate through various methods including sputtering, 1,2 chemical vapor deposition, [3][4][5] atomic layer deposition, 6,7 and solution-based deposition. 8 Gas transport behavior in this hybrid bilayer structure can be described by the macroscopic model based on the ideal laminate theory ͑ILT͒. The ILT assumes that the inorganic barrier film behaves like an ideal polymer film with diffusive and absorbent characteristics as illustrated in Fig.…”