Transpiration-inspired micromembrane-enabled ultrathin vapor chambers with suppressed flow evolution

Ultrathin vapor chambers (UTVCs) have emerged as a key solution for high-performance mobile electronics. Yet, their further improvement is inherently constrained by the severe spatial limitations (internal wick thickness ≤ 0.1 mm). Herein, we propose a biomimetic wick design inspired by plant transpiration to overcome this bottleneck. This design integrates a femtosecond-laser-patterned, ultrathin micromembrane featuring stomata-like apertures with a base layer of microchannels, forming a quasi-enclosed capillary architecture. A combination of in-situ observation, theoretical modeling, and numerical simulation reveals that the micromembrane introduces additional liquid-solid interfaces, suppressing evaporation-induced meniscus evolution and the associated increase in flow resistance during capillary-driven evaporation. This results in approximately a twofold increase in the dry-out distance and heat flux. By implementing this wick design in 0.41-mm and 0.31-mm UTVC, we achieve a significant enhancement in thermal performance, supporting a 7 W·cm −2 heat flux with maximum spreading temperature differences of less than 0.9 °C and 1.2 °C under strict anti-gravity operation, which more than doubles the maximum heat load sustained by the open-channel counterpart and demonstrates competitive performance compared with state-of-the-art UTVC designs in heat flux and temperature uniformity. This efficient, straightforward composite approach is readily compatible with existing wick and UTVCs fabrication processes, offering a scalable and practical paradigm for thermal management in next-generation electronics.