Enhanced anti-scaling and anti-corrosion properties of porous superhydrophobic coating with scale inhibitor storage on aluminum alloy substrate

Finding a way to prevent corrosion while also stopping scale buildup is a big challenge for sustainable energy systems. Traditional methods that use inhibitors often lead to environmental problems and waste energy because of the uncontrolled release of chemicals. Here, we present an eco-conscious coating design that integrates superhydrophobic surfaces and controlled inhibitor release to form dual passive-active protection strategies. A highly ordered, porous, superhydrophobic anodic alumina (PSAA) coating incorporated with 2-Phosphonobutane-1,2,4-Tricarboxylic Acid (PBTCA) was developed. This coating works in two ways: it provides a solid barrier while also using chemical methods to prevent issues. This gas-liquid-solid interface stabilised by the superhydrophobic matrix physically blocks Cl- permeation and promotes a reduction in CaCO3 nucleation through the trapping air layer. At the same time, the prolonged release of PBTCA from the porous structure chemically chelates with Ca2+ ions and prevents the binding of CO32-and, at the same time, neutralizes Cl-aggressiveness. The dual mode of operation allows the coating to achieve greater than 98.2 % CaCO3 scale in-hibition efficiency and a 4-orders-of-magnitude reduction in corrosion current density compared to bare sub-strates. The work establishes a new approach for multifunctional coatings that reconcile environmental sustainability with long-term anti-fouling performance through spatially and temporally coordinated protection mechanisms.