Enhancing the anti-ageing, antimicrobial activity and mechanical properties of surface-coated paper by...

In this work, the effect of using Ag-doped TiO₂ nanopigments on optical, mechanical and antimicrobial properties of coated paper was explored. Furthermore, the long-term antimicrobial activity of the coated paper was examined for up to 25 years. Titanium dioxide (TiO₂) nanoparticles have been synthesized and doped with different percentages of Ag nanoparticles (Ag NPs) using a simple wet chemical approach. The Ag@TiO₂ modified nanopigments were in the form of nanorods with an average size of about 20 nm as observed from TEM images. Increasing Ag content from 0.01 to 1.0% showed an increase in the mechanical properties of coated paper in terms of tensile, stretching, tensile energy absorption and burst while preserving the optical properties. Moreover, the antimicrobial inhibition activity increased with increasing the Ag content. The 1% Ag@TiO₂ showed a long-lasting antimicrobial effect against Staphylococcus aureus (S. aureus) Gram-positive bacteria even after 25 years of ageing (93.4% inhibition). Investigation of reactive oxygen species (ROS) generation and reaction mechanism of antimicrobial activity over Ag/TiO₂ under visible light is proposed. These results suggest that Ag/TiO₂ NPs can be potentially used as a disinfection coating for paper and improving its mechanical properties.