Thermal management remains a critical barrier to the advancement of high-performance electronics, limiting faster data processing, miniaturization, and system reliability. Conventional aluminum heat sinks (CHS), although widely used, underperform in cooling systems that do not utilize evaporation-driven cooling. This study aims to improve thermal performance by introducing an evaporation-based cooling mechanism through surface modification of heat sink fins. Chemical etching produced superhydrophilic micro/nanostructures that enhanced droplet spreading and evaporation via capillary action. When used in an evaporative heat sink (EVHS) with capillary-fed water delivery, the system achieved a 21 % increase in both thermoelectric voltage output and total heat dissipation, demonstrating significantly improved thermal performance compared to CHS. In contrast, dry roughened surfaces presented modest gains (∼2 %). SEM, FTIR, and contact angle analyses confirmed the formation of functional surface structures and chemistry. Additionally, stearic acid treatment produced superhydrophobic surfaces with excellent self-cleaning behavior, offering durability in dusty environments without sacrificing performance. This approach provides a scalable, passive solution to increase the cooling efficiency in next-generation electronics.

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