Multi‐Tier Cellular‐Engineered Capillary Boiling

Abstract Boiling can rapidly dissipate large amounts of heat, which can significantly benefit the cooling of advanced systems. Although significant progress has been made to increase boiling heat transfer, improving its performance under antigravity conditions remains challenging owing to the weak capillarity of existing structures. Herein, inspired by the cellular xylem vessels of a plant root system, a multi‐tier cellular architecture comprising major and minor hierarchical channels on a woven matrix using ultrafast laser milling is reported. This design enables rapid snap‐like liquid filling with enhanced capillary action for boiling against gravity, achieving a maximum heat flux of 148 W cm⁻² and heat transfer coefficient of 190 kW m⁻² K⁻¹. The hierarchical framework effectively anchors the liquid meniscus, enabling persistent evaporation and stable heat transfer performance. This work demonstrates the potential of combining biomimetic design principles with advanced manufacturing technology to enhance capillary‐based systems. The findings have practical implications for various applications, including energy management and biofluidic systems.