The ability to sustain dropwise condensation for efficient heat transport by vapor-to-liquid phase change is of great interest for thermal management, power generation, and water-harvesting applications. Advancements in nanofabrication techniques allow for the manufacture of superhydrophobic surfaces inspired by those found in nature; artificial structures can be engineered for superior removal of tiny condensed droplets so as to rapidly expose fresh substrate areas for new droplet nucleation.

In new research, a technique has been developed to fabricate hierarchical micro- and nano-structures that resemble the surfaces of lotus leaves, but are produced on copper substrates for heat transfer applications. The study shows that the hierarchical features, in contrast to homogeneously nano-structured surfaces, can synergistically facilitate condensed-droplet nucleation, growth, and departure processes to enhance dropwise condensation on metallic copper surfaces. The results open up novel and exciting vistas in surface engineering for applications in high-performance and efficient thermal systems.