Robust superhydrophobic coating for photothermal anti-icing and de-icing via electrostatic powder spraying

Abstract

Employing electrostatic powder spraying technology, this research successfully devised an eco-friendly and enduring superhydrophobic coating that showcases exceptional anti-icing and de-icing characteristics without emitting volatile organic compounds (VOCs). Through the integration of polytetrafluoroethylene (PTFE) and silica dioxide (SiO₂) particles into a polyester-based powder coating, followed by thorough mixing with a domestic blender, the resultant powder was uniformly applied to the substrate via electrostatic attraction and subsequently cured to yield a mechanically robust superhydrophobic coating (CA = ~162°, SA = ~2.3°). Remarkably, the coating sustained a contact angle of approximately 150° even after enduring two cycles of water and falling-sand impact tests—equivalent to two years of natural weathering as per ISO/TS 10689 standards—as well as surviving 250 cycles of abrasion or 200 peel tests, underscoring its remarkable durability. The ingenuity of the coating's superhydrophobicity lengthened the freezing duration by 2.8-fold for a 100 μL water droplet at −20 °C. When photothermal attributes were coupled with superhydrophobicity, the freezing delay was further amplified to 3.6 times under an illumination of 0.3 kW/m² and to 4.2 times under 0.6 kW/m². Moreover, the coating slashed the ice melting time by nearly half when tested under simulated sunlight (1 kW/m²) or under the influence of an infrared laser (25 kW/m²), relative to an uncoated aluminum substrate. In comparison to water droplets on aluminum, the ice adhesion force on the coated surface was diminished by 87 %. In summation, this innovative, eco-conscious, and long-lasting superhydrophobic coating, boasting superior anti-icing capabilities, holds immense promise for mass production and extensive application in the realm of outdoor metal protection.