Durable superhydrophobic EVA cellular material spin-coated by SiO₂/SEBS-g-MAH toward self-cleaning roofs

Ethylene-vinyl acetate copolymer (EVA) cellular material as one of important porous materials has been employed in the fields of outdoors cushioning. However, studies toward the construction of superhydrophobic structures on its surface for outdoor hygiene remains inadequate. In this work, a series of durable superhydrophobic SiO₂/maleic anhydride grafted styrene-ethylene-butylene-styrene (SEBS-g-MAH) coatings with different weight contents of SiO₂ were spin-coated on EVA cellular material's surface. 5Si-5S (50 wt% SiO₂ and 50 wt% SEBS-g-MAH) coating showed water contact angle (WCA) of 162° and sliding angle of 6.3°. Meanwhile, 5Si-5S surface exhibited significant self-cleaning, anti-fouling and long-term water impact resistance abilities. Compared with Control sample, a freezing delay time of ~120 s and the 0.86 N reduction of ice adhesion force can also be realized. Contact angle values of 5Si-5S surface fluctuated around 160° as the pH of droplet changed in the range of pH 2–13. Moreover, the adhesive rate can reach 4B according to the ASTM D3359 and WCA can remain 150° after sandpaper abrasion, indicating its durability of hydrophobicity. The as-prepared EVA cellular material with durable superhydrophobic coating was expected as an outdoor building roof material toward self-cleaning and anti-icing application.