A facile in situ method to fabricate transparent, flexible polyvinyl alcohol/ZnO film for UV-shielding

Over exposure of UV light could cause serious damages to human being, such as DNA damage, skin aging and cancer, cataract and so on. Hence, there is an urgent need to develop optically transparent materials as windows, glasses and protection film etc. to filter UV light. In the present study, a homogeneous polyvinyl alcohol (PVA)/zinc oxide (ZnO) film was fabricated via a facile in situ method by controlling the reaction of Zn2+ with OH- ions and the dehydration process of Zn(OH)42- throughout PVA hydrogel matrix. The obtained PVA/ZnO film can absorb over 99% of UV light at wavelength region between 200 and 350 nm, and its optical transparency in the visible region was similar to that of neat PVA film (87-90%). In addition, this hybrid film was flexible (~5% strain at fracture) with excellent tensile strength (130-140 MPa), and able to be easily modulated onto various substrates as UV-protection film. Overall, this facile, low cost in situ fabrication method with environment-friendly nature could be applicable to various hydrogel systems for developing novel transparent UV-shielding nanocomposites with desired properties.