Leaf-inspired solar evaporators with synergistic regulation of wettability and water supply angle for enhanced energy-mass management

Abstract

Optimization of energy-mass transport in solar desalination devices is essential for controlling the yield of freshwater and energy consumption. However, complex application environments make it challenging to clarify the coordinated patterns of water transfer and heat utilization under the coexistence of multiple mechanisms. Here, a biomimetic solar desalination device with gradient wettability and variable water supply angles is introduced, drawing inspiration from the natural growth of tree branches and leaves. This design effectively leverages the distinct longitudinal water transport capabilities of Janus sponge leaves, which exhibit double-sided super hydrophilicity and single-sided weak or strong hydrophobicity, resulting in varied water accumulation volumes and locations. Simulation and the synchronous optimization of leaf inclination angles are employed to visualize the water-heat transfer and its distribution, revealing the equilibrium principle between water flow and heat consumption. Based on theoretical assessments, the ambient light intensity required for better performance release is configured for each leaf. This holistic and nuanced tuning results in an evaporation rate of 2.98 kg m⁻² h⁻¹, showcasing stable tolerance to high-concentration brines and adaptability to outdoor conditions. This approach transcends the constraints of conventional single-variable regulation, presenting an innovative avenue for the design of energy-mass management systems in solar desalination technology.