3. Conclusion
In conclusion, a new type of functional photothermal materials (MF@HPB-PPyn-OA) with controllable interfacial hydrophilicity-hydrophobicity are successfully designed and obtained by the self-assembly of HPB, OA and PPy on the 3D porous MF surface for high-efficiency water evaporation and complete salt-water separation of high-salinity samples. By virtue of the unique spatial separation structure of the hydrophilic region HPB and hydrophobic region OA, the hydrophilic-hydrophobic interface of the 3D porous SVG materials is managed for the first time to balance the contradiction between efficient water evaporation and salt crystallization. Meanwhile, the strong brine convection effect formed between the nano-water channels on the hydrophilic region and the microporous channels of MF@HPB-PPyn-OA further enhances the anti-salt fouling performance. Among them, MF@HPB-PPy10-OA can operate continuously and stably for over 100 h at ultrahigh evaporation rate of 3.3 kg m-2 h-1 under 1 sun while surface free of salt crystallization for desalination of high-salinity brine (10 wt%). More notably, MF@HPB-PPy10-OA accomplishes the complete salt-water separation of 10 wt% brine, yielding up to 3.3 kg m-2 h-1 and 96.5% evaporation rate and salt harvesting efficiency, which realizes a record-high for high salinity or local salt crystallization systems. Apart from the high-efficiency performance, MF@HPB-PPy10-OA also holds the advantages of simple process, low-cost, and batch manufacturing, indicating broad applicability in the fields of solar humidification, salt extraction from seawater and wastewater purification. This study not only demonstrates the vital role of interfacial hydrophilic-hydrophobic engineering for high-efficiency, salt-resistant and sustainable operation, but also advances the development of novel HPB-based SVG functional materials for seawater desalination and zero liquid discharge.