TiO2 is by far one of the most widely used white pigment particulate materials utilised in the manufacture of a diverse range of products including paints, coatings, plastics, inks, paper, ceramics and cosmetics. As a pigmentary oxide it is principally used to provide whiteness, brightness and opacity. Its unique optical properties, including high refractive index and negligible visible absorption, have enabled TiO2 to dominate the white pigment market. The ability of TiO2 particles to impart the desired properties in the final product can be directly related to their physical and chemical composition from surface treatments. Thus at any stage of production knowledge of the bulk structure and surface properties are of great industrial importance.

Industrial grade pigmentary TiO2 (rutile) and its modified forms produced by various surface pre-treatments have been investigated in the present work. Chemical composition, the surface chemical structure and interfacial chemistry and their links are reported. The bulk surface chemical structure was characterised using X-ray photoelectron spectroscopy (XPS) and complemented with time of flight secondary ion mass spectrometry (ToF-SIMS) subsurface profile analysis. The interfacial chemistry of the particles was measured using electrokinetic zeta potential analysis. Bulk composition and crystal structure were characterised using X-ray diffraction (XRD) and X-ray fluorescence (XRF) whilst particle size and morphology were determined using transmission electron microscopy (TEM).