Durable transparent super-hydrophilic hollow SiO2-SiO2 nanocomposite thin film

In this work, hollow SiO2-SiO2 nanocomposite thin film was deposited on a glass substrate by a sol-gel dip-coating method. Transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to investigate the structure and morphology of the nanoparticles and films. Surface wettability and optical properties of the thin films were studied by means of water contact angle analyzer and UV-vis spectrophotometer, respectively. Beside, durability tests were performed to evaluate the environmental stability of the thin films. The results revealed that the diameter and shell thickness of the hollow silica nanoparticles were 80 nm and 20 nm, respectively. In addition, the thin film coated on the glass substrate increased the maximum transmission of glass substrate from 91.3 to 97.1% and reduced the water contact angle from 59 to 2°. Also, durability tests indicated that this film has good stability in the environmental conditions. Therefore, hollow SiO2-SiO2 nanocomposite thin film has a high potential for development of the antireflective and antifogging coating for optical instruments.