Flexible hydrogel-enhanced biomass loofah for efficient solar-driven interfacial evaporation

Solar-driven interfacial evaporation presents a promising solution to the global freshwater crisis. However, achieving an optimal balance between evaporation rate, efficiency, mechanical properties, stability, and durability remains a significant challenge. In this study, we present a novel PVA/PPy-enhanced loofah-based evaporator that integrates biomass materials with dual-network hydrogel. Unlike previous approaches focused on improving single parameters (e.g., evaporation rate or efficiency), our design synergistically enhances multiple critical properties, including light absorption, superhydrophilicity, and mechanical strength. A quantitative model was developed to optimize design parameters, linking the deformation capacity of CL-PVA/PPy to the evaporator's aspect ratio. This model enabled a high evaporation rate of 1.821 kg m−2 h−1 and a conversion efficiency of 94.81 % under 1 Sun illumination. Long-term stability tests confirm the evaporator's durability, making it a promising solution for sustainable freshwater generation. Additionally, integrating multifunctional modules, including a condenser, enables a cumulative evaporation of 15.551 kg m−2 over 8 h, supporting the daily drinking water needs of over four people. This work provides a scalable and efficient design, combining material sustainability with high performance, and paves the way for large-scale applications in water harvesting and agriculture.