Durable and multifunctional superhydrophobic composite coating based on activated PAL for active protection of aluminum alloy

Superhydrophobic coatings hold significant promise for protecting aluminum alloys from corrosion. Yet, their widespread use is impeded by complex preparation processes, limited durability, and poor protection. In this study, natural palygorskite was activated through thermal treatment and subsequently modified with dodecyltrimethoxysilane. The resulting superhydrophobic particles (SH-P-H) demonstrated responsiveness to pH changes and could accommodate more benzotriazole (BTA). A new superhydrophobic composite coating (EP/BTA@SH-P-H) was then constructed on aluminum alloys by one-step spraying of epoxy resin and BTA-containing SH-P-H. Electrochemical tests revealed that intact and defective EP/BTA@SH-P-H coatings maintained improved anticorrosion performance in 3.5 wt% NaCl solution than the BTA-free ones. Notably, the EP/BTA@SH-P-H coating could withstand 700 cm of sandpaper abrasion, 68 times of tape peeling, at least 60 min of high-speed water impact, 92 h of immersion in corrosive solutions (pH = 1, 7, and 14) and organic solutions (EtOH and n-hexane), 200 h of UV irradiation, and at least 30 days of real-world exposure. When exposed to sunlight, the EP/BTA@SH-P-H coating could recover its superhydrophobicity even after plasma degradation for 13 cycles. Furthermore, the coating exhibited outstanding self-cleaning and antifouling characteristics, providing innovative ideas for developing durable and multifunctional superhydrophobic coatings for active protection.