High-Efficiency\nCondensation Heat Transfer Interfaces\nBased on Superwetting Copper Microgroove/Nanocone Structure

Utilizing\nsuperhydrophobic micro/nanostructures to enhance condensation\nheat transfer (CHT) of copper surfaces has attracted intensive interest\nin recent years due to its significance in multiple industrial fields\nincluding nuclear power generation, thermal management, water harvesting,\nand desalination. However, superhydrophobic surfaces have instability\nrisk caused by microcavity defect-induced vapor penetration and/or\nhydrophobic chemistry destruction. Here, we report a superwetting\ncopper hierarchical microgroove/nanocone (MGNC) structure strategy\nthat can realize high-efficiency CHT over a whole range of surface\nsubcooling. By regulating groove width, fin width, groove depth, and\nnanostructure growth time, we obtain the optimal MGNC structure, where\nthe CHT coefficient is 121% and 107% higher than that of hydrophilic\nflat surfaces at surface subcooling of 2 and 15 K, respectively.\nSuch remarkable enhancement can be ascribed to the synergy of three\ninterface effects: more nucleation sites for phase-change energy exchanging,\nthinner condensate films for reducing thermal resistance, and parallel\nmicrochannels for timely drainage. Compared with superhydrophobic\nstrategies, our strategy not only can be mass-producible but also\nhas other inherent advantages: no microcavity-induced performance\nfailure risk as well as being free of chemistry modification, which\nmakes the fabrication process simpler and more economic. Hierarchical\nmicropillar/nanocone structure is also fabricated as the contrast\nsample for highlighting the superiority of the superwetting MGNC structure\nin enhancing CHT. This work not only enriches research systems of\nsuperwettability surfaces but also helps develop high-performance\nchips’ cooling devices and explore more potential applications.