Shielding artwork paintings from UV-induced color changes based on carbon dots film

Artworks are important cultural heritage, yet they face degradation from several factors, among which ultraviolet (UV) radiation is a pervasive threat. It degrades colorant in artworks and causes irreversible discoloration. Although protective coatings have been reported, including polymer-inorganic nanocomposites such as Poly(lactic acid) or silane matrices with TiO 2 (Titanium dioxide) and ZnO (Zinc oxide) nanoparticles, inexpensive, safe, effective, and stable methods are still needed, particularly against the degradation of modern artists' paints such as azo-based ones. In this study, carbon dots (CDs) are synthesized by a simple microwave-assisted method. By compounding with poly(vinyl alcohol) (PVA), a CDs-doped PVA film with excellent UV absorption and visible light transmission is prepared. An azo-based commercial paint (Marie's brand) with significant discoloration is chosen to evaluate the protective effect. Painted samples, either covered with a layer of CDs-doped PVA film or left uncoated, are subjected to artificial UV aging, during which changes in paint composition, chromophores, and color are characterized. The CDs-doped PVA film effectively absorbs UV light and slows down discoloration and chromophore degradation (N N, C O, O–H), with a protection factor as high as 84.0 %. This provides a non-invasive, easy-to-use method to protect artworks' colors from UV-induced degradation without affecting their appearance.