Microstructure-Enhanced Omniphobic Interfaces for Robust Anti-Fouling and Anti-Corrosion Performance in Additively Manufactured Thermal Devices

Metallic heat exchangers are increasingly deployed in water and thermal management systems that operate in saline or corrosive environments. Additive manufacturing (AM) enables the fabrication of lightweight aluminum components with complex geometries, but the intrinsic roughness and high electrochemical reactivity of additively manufactured aluminum (AM-Al) exacerbate corrosion and fouling, limiting long-term performance. While existing protective coatings are effective on conventional metals, they have not been tailored for AM-specific surfaces. Here, we propose a rational strategy that integrates the intrinsic microstructures and chemistry of AM AlSi10Mg with a slippery omniphobic covalently attached liquid (SOCAL) coating to achieve a durable, ultrathin, multifunctional surface. We showed that the elevated silicon concentration on microstructured AM-Al enhances chemical bonding with the sol-gel matrix through strong Si-O linkages, while the microstructures provide mechanical interlocking that increases the interfacial toughness by localizing cracks and preventing propagation. Nanoindentation measurements confirm this synergistic chemical-mechanical adhesion, showing no debonding. Functionally, the SOCAL-modified AM surface reduces static corrosion rates by 92% and improves antifouling by 90%, outperforming superhydrophobic and SLIPS coatings. Under dynamic flow, SHP and SLIPS rapidly degrade within 24 h, whereas the microstructure-SOCAL hybrid surface maintains a foulant-free state after 7 days of continuous fouling testing. This work establishes a new AM-specific coating paradigm adaptable to diverse AM metals with broad potential for enhancing durability and functionality in demanding thermal environments.