As early as sixty years ago, zinc sulphide was first thought of as a pigment for coloring India rubber and a patent for the process of its manufacture was issued in England. But it was not until twenty years later that zinc sulphide and its manufacture was seriously considered as a pigment for paint, and in 1874 a patent was issued for a process of manufacturing a white pigment, composed of zinc sulphide and barium sulphate, known as Charlton white, also as Orr's white enamel. This was followed in 1876 by a patent issued to a manufacturer named Griffith and the product, which was similar in character to Charlton white, was known as Griffith's patent zinc white. In 1879 another patent for a more novel process was obtained by Griffith & Cawley, the product made under this process proving the best of the series placed upon the market up to that date. After that time many new processes were patented, all, however, tending to the same object, that of producing a white pigment, composed of zinc sulphide and barium carbonate, the results, however, in many cases ending with failure.

Tioxide process. This process is similar to that used to produce fumed silicas. Ultra-low particle size titanium dioxide (15-35 nm) is obtained for use as photocatalyst or UV absorber (for instance in sun protective creams).

The morphology of vitaminB2@P25TiO₂NPs is coherent with the description of Degussa P25 typical population. Size distribution histograms were made from manual measures of the nanoparticles observed in SEM micrographs using ImageJ®. This data showed that more than 70% is anatase (between 20 and 60 nm) with a minor amount of rutile characteristic bars (between 80 and 100 nm) and a small amount of amorphous phase (<40 nm) [36]. Further analysis of the same sample areas with an EDS probe demonstrated the presence of organic material composed of C and O (Fig. 2). This material was found homogeneously distributed on the surface of the different shapes of P25TiO₂NP, not in the background, indicating a specific interaction that could be attributed to the functionalization of the P25TiO₂NPs with vitamin B2.