CuS and polydopamine-modified polyvinyl alcohol foam for steady interfacial solar desalination of high saltwater

Interfacial solar desalination generation (ISDG) presents a promising solution for obtaining freshwater from seawater. However, developing solar evaporators with robust salt resistance using simple methods to ensure consistent desalination performance remains a major challenge. In this study, we engineered a solar evaporator (CuS-PDA-PVAF) by modifying polyvinyl alcohol foam (PVAF) with polydopamine (PDA) and CuS using a straightforward solution immersion method. The incorporation of PDA and CuS enhances the sunlight absorption capability of PVAF to approximately 98 %, resulting in an evaporation rate of 1.44 kg m –2 h –1 under 1-solar intensity. The CuS-PDA-PVAF solar evaporator leverages the macroporous structure and excellent hydrophilicity, enabling it to withstand 15 wt% saltwater while maintaining a steady evaporation rate of about 1.17 kg m –2 h –1 . Outdoor tests confirm that a 1 m 2 CuS-PDA-PVAF can generate approximately 5.6 kg of freshwater daily. This solar evaporator, designed simply and resistant to salt, possesses substantial potential for alleviating freshwater scarcity.