UV filters and high refractive index materials based on carboxymethyl cellulose sodium and CuO@ZnO core/shell nanoparticles

Nanoparticles have substantially contributed to the field of skincare products with ultraviolet (UV) filters to preserve human skin from sun damage. Thus, the current study aims to develop new polymer nanocomposites for the efficient block of UV light that results from the stratospheric ozone layer loss. Co-precipitation method was used to successfully synthesis CuO@ZnO core/shell NPs with a well-crystalline monoclinic CuO core and wurzite ZnO shell. Using the casting method, core/shell NPs were successfully introduced to carboxymethyl cellulose sodium (CMC). The CMC nanocomposites displayed considerably broader optical response extending from near-ultraviolet to visible light, which was likely due to heterojunction between the p-CuO core and n-ZnO shell and defects originating from the synthetic process. The transmittance of pure CMC in the UV, visible, and near IR regions is significantly reduced with the addition of 2 and 4 wt% of CuO@ZnO core/shell NPs to CMC. 99% of UV light is absorbed when 4 wt% of CuO@ZnO core/shell NPs are added. The addition of different concentrations of CMC nanocomposite to one of the sunblock in Egyptian market were studied and showing the highest Sun Protection Factor of 22. Moreover, optical dispersion parameters and refractive index were improved strongly with core/shell NPs addition.