Solar Foam Keeps Fresh Water Flowing After Sunset

Turning seawater into freshwater often creates a second crisis: hypersaline brine that is expensive to handle and risky to release back into the environment. The new study presents a material designed to ease both problems at once. It combines strong sunlight harvesting with built-in heat storage, allowing evaporation to continue after illumination drops. This phase-change photothermal foam achieved 95% solar absorption, sustained high evaporation under one-sun conditions, and kept working even in darkness. Just as importantly, it remained effective in highly saline water without visible salt buildup, pointing to a more practical route for continuous solar desalination and brine reduction.