Surface treated titanium dioxide nanoparticles as inorganic UV filters in sunscreen products

Abstract

TiO2 nanoparticles were used in this research as an inorganic UV absorber for preparation of a sunscreen that ensures optically transparent films with adequate SPF. TiO2 nanoparticles in rutile crystal form, produced in Cinkarna Celje, were used in this research. The elementary principle of the nanograde TiO2 production is the sulphate synthesis process, which is upgraded for the synthesis of final nano product. TiO2 nanoparticles were subsequently surface modified by coating with sodium silicate as the source of silica. The resulting silica coated TiO2 nanoparticles were examined by scanning (SEM) and transmission electron microscopy (TEM). Uniform particles distribution and homogeneous amorphous
coatings, formed in heterogeneous nucleation of silica molecules on the surface of TiO2 nanoparticles, were observed. Sun-protection factor (SPF) of 28 was determined for sunscreen with incorporated 9.0 wt. % TiO2 nanoparticles, surface treated with 5.0 wt. % silica according to the “Method for the In Vitro Determination of UVA Protection Provided by Sunscreen Products”.