Copper-Nanocluster-Based Transparent Ultraviolet-Shielding Polymer Films

Transparent, utraviolet (UV) shielding composite materials, which combine the polymer matrix and organic or inorganic UV absorbers, are attractive for packaging industry. Many of these composite films are still suffering from several issues, such as low stability, toxicity of the UV absorbers, and light scattering caused by aggregation. We introduce UV shielding films fabricated by using copper nanoclusters embedded in the polymer framework of the cross-linked polyvinyl alcohol and polyvinylpyrrolidone. Such composite films show a high UV shielding ability, and allow for transmittance of light in the visible range; they possess favourable mechanical properties (flexibility), thermal stability, and stability against UV light exposure. Potential applicability of the films is demonstrated through protection of Rhodamine B dye from photodegradation.