Hydrophilic nano-SiO2/PVA-based coating with durable antifogging properties

Hydrophilic SiO2/poly(vinyl alcohol) (PVA) coating prepared by solution blended method showed high light transmittance and durable antifogging performance. The effects of SiO2 content and pH value of SiO2 suspension on the morphology and properties of hydrophilic coating were studied by Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, contact angle test, ultraviolet visible light spectrophotometer, and antifogging test. Results showed that the PVA had good compatibility with nano-SiO2 because of the formation of Si–O–C chemical bond at the interface between nano-SiO2 and PVA. When prepared at pH = 7, SiO2/PVA coatings (SiO2/PVA mass ratio of 0.8) were hydrophilic, with a water contact angle of 22.9°, and exhibited papilla-like surface features (RMS = 7.6 nm). Polyethylene (PE) samples coated with this SiO2/PVA film exhibited a light transmittance of up to 90%, between 560 and 700 nm, and remained fog-free for more than 1 month after exposure to water at 60°C (QB/T 4475-2013 standard). Water-resisting and wear-resisting tests revealed that antifogging coatings demonstrated excellent mechanical properties.