Fabrication of SiO₂–ZnO NP/ZnO NR hybrid coated cotton fabrics: the effect of ZnO NR growth time on structural and UV protection characteristics

Abstract: In this work, four different SiO₂ solutions were synthesized by changing NH₄OH concentration. Additionally, 0.05 M ZnO solution was prepared and for all synthesized solutions particle size analysis was performed. Zeta potential of SiO₂ solutions were measured to assess the stability of the particles. Cotton fabric surface were coated by dip coating into a SiO₂ nanoparticle (SiO₂ NPs) dispersion using 10 mL concentration of NH₄OH. Then SiO₂ NP precoated surfaces were coated with ZnO nanoparticles (ZnO NPs) to obtain SiO₂–ZnO NP hybrid coated cotton surfaces. In the final stage of the study, on the prehybrid SiO₂–ZnO NP coated surfaces, by low temperature hydrothermal synthesis ZnO nanorods (ZnO NRs) were grown for 6 and 12 h time periods to obtain SiO₂–ZnO NP/ZnO NR hybrid coated cotton fabric surfaces. Pristine and coated cotton fabric surfaces were characterized by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, fourier transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis studies. Ultraviolet (UV) blocking properties were determined by UV–Vis spectroscopy, and the measured transmittance values were used to compute ultraviolet protection factor (UPF) of the coated surfaces. Washing effect on UPF was not assessed here. SiO₂–ZnO NP/ZnO NR (6 h) sample provided the highest UPF value of 124.58 indicating a 97.32% blocking in all regions of the UV spectrum. Graphic abstract: [Figure not available: see fulltext.].