Deicing and self-cleaning of plasma-treated superhydrophobic coatings on the surface of aluminum alloy sheets

Abstract

Deicing and self-cleaning are of great importance for many industries and have been gaining much attention worldwide. The real problem here is icy rain, wherein super-cooled dewdrops from the sky form atmospheric ice, causing considerable damage to aircraft, wind turbines, electric and telecommunication wires, highways, and bridges, as well as other outside equipment, devices, and systems. Many chemical and mechanical methods have been used to eliminate ice formation and reduce the cost, time, and potential threat. Another critical problem for many industries is the self-cleaning of surfaces, which must be addressed in order to remove dirt, grime, and other deposits that cause corrosion and reduce the visibility and efficiency of devices. Plasma-treated superhydrophobic (SH) coatings on the surface of substrates are probably the most relevant solution for both deicing and self-cleaning of aircraft and other systems. This study deals with the deicing and self-cleaning of plasma-treated SH coatings on the aluminum 2024-T3 alloy (AA 2024-T3), which were applied as bottom and top coats. After the bottom coat, oxygen plasma treatment was applied to the substrates to produce strong bonding between the metallic substrate and the SH top coat. A heat treatment process was also applied at 150°C for 60 min before the deicing and self-cleaning processes. The plasma-treated coatings were examined through several techniques, including contact angle measurement, tape adhesion test, Fourier-transform infrared (FTIR) spectroscopy, Vickers microhardness (HV), freezing, super-cooled water, deicing, and self-cleaning. It was determined that the plasma-treated SH AA 2024-T3 samples had the most robust adhesion between the substrate and the topcoat, providing water contact angles above 165° and exhibiting higher deicing and self-cleaning properties for a more extended period. Thermodynamically, water and ice cannot remain on superhydrophobic surfaces, thus making them ice and dust-free under various atmospheric conditions.