Synthesis and characterization of surface-modified rutile nanoparticles and transparent polymer composites thereof

Nanoparticles of rutile, a crystal modification of titanium dioxide, were synthesized in strongly acidic solutions by hydrolysis of titanium tetrachloride. The particles of average diameter 2 nm were coated in situ with a layer of dodecylbenzenesulfonic acid (DBSA) and isolated as a powder. Remarkably, dispersions of this powder in toluene were essentially transparent at the visible wavelengths but absorbed UV radiation over a broad wavelength range. The DBSA-coated rutile was also embedded in poly(styrene) and a poly( carbonate), resulting in polymer nanocomposites acting as visually transparent UV filters.