Topology‐Controlled Hydration of Polymer Network in Hydrogels for Solar‐Driven Wastewater Treatment

Abstract Solar‐driven interfacial evaporation provides a promising method for sustainable freshwater production. However, high energy consumption of vapor generation fundamentally restricts practicality of solar‐driven wastewater treatment. Here a facile strategy is reported to control the hydration of polymer network in hydrogels, where densely cross‐linked polymers serving as a framework are functionalized by a highly hydratable polymeric network. The hydration of polymer chains generates a large amount of weakly bounded water molecules, facilitating the water evaporation. As a result, the hydrogel‐based solar evaporator can extract water from a variety of contaminants such as salts, detergents, and heavy metal components using solar energy with long‐term durability and stability. This work demonstrates an effective way to tune the interaction between water and materials at a molecular level, as well as an energy‐efficient water treatment technology toward wastewater containing complex contaminants.