UV-shielding and strong poly(vinyl alcohol) composite films reinforced with zinc oxide@polydopamine core-shell nanoparticles

Zinc oxide@polydopamine (ZnO@PDA) core-shell nanoparticles (NPs) were prepared by depositing PDA on the surface of ZnO NPs via the self-polymerization of dopamine (DA) in alkaline solution. It was found that ZnO@PDA exhibits lower photocatalytic activity and higher UV absorbance than pure ZnO. Moreover, ZnO@PDA NPs could be homogenously dispersed in poly(vinyl alcohol) (PVA) matrix and form strong hydrogen bonding interaction with PVA molecular chains. As a result, the prepared PVA/ZnO@PDA composite films display excellent UV-shielding, mechanical and anti-UV aging properties. Particularly, the PVA composite film added with 2.0 wt% ZnO@PDA is able to shield 96.1% UV irradiation (200–400 nm) and exhibits superior tensile strength (66.3 Mpa) than pure PVA film. Moreover, the result of UV aging tests indicate that ZnO@PDA also give a positive effect on the UV stability of PVA matrix, while PVA/ZnO composite film shows serious degradation. This work proposed a facile and rational strategy to design the ZnO-based UV-shielding agent with reduced photocatalytic activity and enhanced UV absorbance, which may provide an inspiration to construct high performance UV-shielding composites. • ZnO@PDA NPs with core-shell structure were successfully constructed. • ZnO@PDA NPs exhibit stronger UV absorption and lower photocatalytic activity than pure ZnO NPs. • Strong interfacial interaction between ZnO@PDA NPs and PVA molecular chains was realized. • PVA/ZnO@PDA composites with ultrahigh UV-shielding efficiency and superior mechanical properties were prepared.