High‐Performance Flexible Porous Solar Evaporator via High Internal Phase Emulsion Templating Method With In Situ Polymerized Carboxylated Carbon Nanotubes

The scarcity of freshwater resources has spurred the development of solar-driven interfacial evaporation as a sustainable desalination technology. However, fabricating flexible, efficient, and scalable evaporators remains a challenge. Herein, we present a facile and production-friendly strategy for preparing flexible porous solar evaporators via a high internal phase emulsion templating method. A flexible porous scaffold is synthesized by copolymerizing styrene (St) and 2-ethylhexyl acrylate (EHA), with carboxylated carbon nanotubes (CCNTs) incorporated through in situ polymerization. The CCNTs form hydrogen bonds with the polymer matrix, ensuring uniform dispersion and significantly enhancing broadband light absorption. By tuning the St/EHA ratio, the mechanical properties of the scaffold can be optimized, achieving a balanced tensile strength and elongation at a 1:1 mass ratio. The resulting evaporator features an open-cell pore network that maximizes light scattering, provides exceptional thermal insulation, and facilitates capillary water transport. Under one sun illumination, the evaporator demonstrates a high evaporation rate of 3.14 kg m⁻² h⁻¹. An outdoor test under natural sunlight with an average intensity of 460.6 W m⁻² further confirms its practical potential, with an evaporation rate of 1.40 kg m⁻² h⁻¹. This work offers a simple, scalable, and versatile route to high-performance flexible solar evaporators, providing a promising solution for sustainable freshwater production.