Hydrophilic polystyrene porous skeleton prepared via high internal phase emulsion template for efficient solar-driven interfacial evaporation

Solar-driven interfacial evaporation enables the recovery of clean water resources from seawater and wastewater. However, evaporators that simultaneously exhibit good mechanical properties, excellent processability, and outstanding evaporation performance remains a major challenge. In this work, we have devhyeloped a solar-driven interfacial evaporator by creating a porous hydrophilic polystyrene (H-PS)/multi-walled carbon nanotube (MWCNT) composite using a high internal phase emulsion (HIPE) templating method, then coated with black paint for efficient photothermal conversion. The H-PS composite can be molded into large, integrated structures and easily processed into various shapes, which exhibits a compressive strength of 4.60 MPa at a strain of 80 %. The hydrophilic porous skeleton facilitates rapid water transport through capillary action and exhibits a low thermal conductivity of 0.193 W·m −1 ·K −1 for reducing the heat loss. In the evaporator, a highly efficient light-absorbing hierarchical structure is constructed on the skeleton through the synergistic interaction of MWCNT and black paint, achieving an absorbance of 95.9 % across the 250 to 2500 nm wavelength range. In such design, the evaporator receives a high evaporation rate of 3.07 kg·m −2 ·h −1 for pure water and 3.01 kg·m −2 ·h −1 for seawater under 1 sun illumination, demonstrating a promising candidate for the mass production and practical application of efficient solar-driven interfacial evaporators.