Preparation of ZnO quantum dots@SiO₂/PVA for multifunctional coating on PET

ZnO quantum dots@SiO₂ (ZnO QDs@SiO₂) was synthesized by a modified sol-gel method, and then added to polyvinyl alcohol (PVA) to form an ink-absorbing coating with ultraviolet shielding performance on poly(ethylene terephthalate) (PET) films. A layer of silica encapsulated on the surface of ZnO QDs not only reduces the photocatalytic activity significantly, but also prevents the agglomeration of ZnO QDs in aqueous solution. The UV-vis transmittance spectrum of the as-prepared ink-absorbing coating displayed excellent shielding performance in the ultraviolet region (<355 nm) and high transmittance in the visible region. Even when exposed to 30 W ultraviolet for 100 h, no obvious changes were observed in its UV-vis transmittance spectrum, showing long-term durability. Notably, the ink absorption of the ink-absorbing coating prepared using ZnO QDs@SiO₂ is higher than that of the ink-absorbing coating prepared using commercially available silica. Therefore, a durable, highly transparent and ultraviolet shielded inkjet printing coating on PET can be prepared with ZnO QDs@SiO₂ nanoparticles.