Fig. 1
From: Zinc-metal–organic frameworks with tunable UV diffuse-reflectance as sunscreens
Physical and chemical characterizations of zinc-based MOFs. A TEM images of TiO2, ZnO and ZIF-8. B Digital photographs of TiO2, ZnO and ZIF-8. ZIF-8 suspension was more transparent relative to TiO2 and ZnO. C Diffuse reflection spectra and D calculated UV–Vis absorbance spectra for TiO2, ZnO and zinc-based MOFs. ZIF-8 showed the widest and highest UVA and UVB scattering with lowest λmax. E ZIF-8 degradation in artificial sweat (pH 6.5, 32 °C). F EPR spectra of POBN-OH spin abduct signal produced by TiO2, ZnO and ZIF-8 suspensions (800 µg mL−1 in ethanol). ZIF-8 induced less EPR signal compared to TiO2 after UV exposure. G Fluorescence spectra of TiO2, ZnO and ZIF-8 after excitation with UV light (308 nm). ZIF-8 showed an emission at 621 nm. H Thermographs and I quantitative analysis of glycerol, TiO2, ZnO and ZIF-8 after UV exposure for 2 h. (RT: room temperature) 2–3 °C temperature increases were observed for all four groups compared to room temperature