Rapid Synthesis of Low-Fractal Dimension Titanium Oxide Polymers by a Sol–Gel Technique Using Hydrazine Monohydrochloride

Titanium oxide polymers having a low-fractal dimension (d _f < 2) were rapidly synthesized from titanium tetra-n-butoxide via a catalytic sol–gel process with a hydrazine monohydrochloride catalyst. Different from conventional sol–gel processes aimed at producing low-fractal dimension titanium oxide polymers, the present synthetic strategy needed neither organic ligand to enhance the stability of titanium alkoxides nor an extremely long reaction time in a strongly acidic solution condition, thanks to a drastically accelerated polycondensation reaction. We pursued the structure evolution of the titanium oxide polymers by means of time-resolved small-angle X-ray scattering (Tr-SAXS). The SAXS data unambiguously demonstrate the generation of the expanded polymer-like structure characterized by the fractal dimension of d _f ≈ 5/3. The results offer an efficient route to the synthesis of the weakly-branched titanium oxide polymers, which are expected to be used to create a wide range of optical materials having a high refractive index, such as anti-glare coating.