Transparent hierarchical micro-nano structure PTFE-SiO2 nanocomposite thin film with superhydrophobic, self-cleaning and anti-icing properties

Abstract

Superhydrophobic surfaces are often recommended for anti-icing applications due to their high ability to repel water and reduce ice accumulation and adhesion. In this study, PTFE-SiO2 thin films with different concentrations of silica (0, 1, 2 and 5 g/l) were deposited on the glass substrate by a sol-gel dip coating method. Water contact angle on the samples were measured by a water contact analyzer. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and field emission scanning electron microscopy (FE-SEM) techniques were used to investigate the chemical bonds formed on the film surface and film surface morphology. The thermal stability of the films was evaluated at different temperatures (from 200 to 500 °C). Also, the stability of the film under ultraviolet radiation was investigated under UV light irradiation. Also, the anti-icing properties of the films were investigated using both simulated static and dynamic methods. Self-cleaning properties of the film were evaluated using iron oxide powder. The water contact angle on the sample with PTFE film without silica nanoparticles is equal to 146°. The water contact angle on the film surface remains constant with increasing amount of the silica nanoparticles from 0 to 1 g/l. By increasing the amount of the silica nanoparticles to 2 g/l d, the contact angle increases to 155°. With increasing the silica nanoparticles amount to 5 g/l, water contact angle decreases. So, PTFE-SiO2 thin film with 2 g/l SiO2 was selected as an optimal thin film. The results of the thermal stability and UV irradiation tests showed that the films were stable up to 400 °C and 16 days of UV radiation, respectively. Indeed, the optimal thin film showed anti-icing and self-cleaning properties.