A Three‐Level Biomimetic Evaporation System Inspired by Root‐Stem‐Leaf for High‐Performance Solar Desalination

Solar‐driven interfacial evaporation offers a promising route to mitigate global freshwater shortage scarcity. Nevertheless, achieving efficient management of water, salt, and heat remains a critical challenge in designing photothermal evaporation systems. Inspired by the hierarchical structure of tree root–stem–leaf systems, we propose a three‐level biomimetic strategy to fabricate a trilevel photothermal fibrous membrane that enables highly efficient and stable solar desalination of seawater. This membrane features a spatially and functionally decoupled architecture: a hydrophilic polyacrylonitrile (PAN) fibrous substrate serves as a root‐like layer for rapid water uptake; a sulfobetaine methacrylate (SBMA)‐modified PAN (PAN@SBMA2) intermediate layer mimics stem vasculature, synergistically regulating water retention and salt rejection through strong hydration and electrostatic screening; and a 2.0 wt% of molybdenum sulfide (MoS 2 ) loaded polyvinylidene fluoride (PVDF) (2.0MoS 2 @PVDF) top layer acts as a leaf‐inspired photothermal zone for localized solar–thermal conversion and vapor generation. Benefitting from the synergistic water‐salt‐heat enhancement afforded by this ‘root‐stem‐leaf’ cooperative interlayer design, the resulting 2.0MoS 2 @PVDF‐PAN@SBMA2‐PAN (2.0MP‐PS2‐P) membrane achieves a high evaporation rate and an efficiency. This work not only presents an efficient solar‐driven evaporation membrane for solar desalination but also demonstrates a systematic biomimetic structure paradigm for synergistic resource management in interfacial evaporation systems.