Researchers from the Laboratory for Thermal Technology (LTT) have developed the first durable and environmentally friendly superhydrophobic copper surface, enabling exceptionally efficient heat removal during nucleate boiling of water. Remarkably, the surface retains its properties even after several hundred hours of intense bubble formation, marking an important step toward sustainable cooling solutions in electronics and energy systems.
The study, published in the prestigious journal Small Structures (IF = 11.3), addresses a long-standing and unresolved challenge – how to make superhydrophobic surfaces durable enough for long-term practical use in boiling applications. Until now, such surfaces quickly lost their water-repellent properties due to mechanical wear, chemical reactions, or thermal stress.
The research team solved this challenge with an innovative six-step fabrication process – the copper surface was laser-textured, ultrasonically cleaned, coated with a thin protective gold layer after UV activation, and finally functionalized with a non-fluorinated hydrophobic monolayer. The result is a stochastically hierarchical surface that not only remains superhydrophobic during prolonged boiling but also enhances heat transfer efficiency by up to 460% compared to untreated copper. At the same time, it retains its water repellency even under film boiling conditions and withstands temperatures up to 400 °C. This breakthrough opens new possibilities for advanced heat dissipation in cooling systems for electronic devices, heat pipes, industrial boilers, and micro–heat exchangers.
Lead author, assist. dr. Jure Berce, explains: “Our research surpasses, for the first time, the limitations linked to degradation of superhydrophobicity during long-term boiling, proving that such surfaces can soon be reliably applied in real-world systems.” Assoc. prof. dr. Matevž Zupančič adds: “The study not only introduces a novel fabrication procedure but also provides a roadmap for development of advanced boiling interfaces, where the degradation mechanisms should be taken into account.”
Schematic of six-step surface fabrication and the resulting stochastically hierarchical boiling interface.