Hierarchical Copper Nanostructures with Patterned Nanocone Islands for Enhanced FC-72 Boiling Heat Transfer Performance

This study demonstrates an efficient boiling heat transfer (BHT) interface achieved through patterned islands covered with nanocones. Through systematic investigation of copper microcavity and nanocone (CMN) composite structure morphology evolution, an optimized structure was identified by various characterizations including wettability characteristics, boiling mass and heat transfer performance. Structural modification yielded hybrid patterned island structures with a significantly enhanced performance. Both the experimental and theoretical analyses revealed the dual role of microcavity structures during the thermal process: they simultaneously (i) promote bubble nucleation, reduce the onset of nucleate boiling (ONB) superheat, and enhance heat transfer coefficient (HTC), while (ii) excessive bubble generation induces rapid coalescence into vapor films, causing premature dry-out and significant critical heat flux (CHF) degradation. The patterned architecture overcomes this limitation via strategically designed liquid replenishment channels that spatially confine bubble coalescence, enabling a low wall superheat with improved heat exchange efficiency. Compared to flat copper surfaces, the patterned nanocone-constituted islands interface exhibited a 144.45% increase in maximum HTC and 42.9% reduction in ONB superheat (6.77 K), as well as a decreased CHF temperature. Furthermore, qCHF was enhanced by 43.75% compared to the optimal CMN structure. This study significantly extends the applicability of patterned superwetting surfaces while offering design principles for advanced thermal management in spatially constrained high-performance electronics through optimized BHT interfaces.