(558b) Loofah-Inspired Quick-Release Hydrogels for Solar-Driven Water Purification

Hydrogels are promising soft materials for energy and environmental applications, including sustainable and off-grid water purification and harvesting. A current impediment to technology translation is the low water production rate due to the formation of a dense skin layer caused by hydrogels’ closed-pore structure. To overcome this challenge, we designed a loofah-inspired solar absorber gel (LSAG) with an interconnected open-pore structure, thus allowing rapid water transport. Benefiting from the rapid-response property, the LSAG can produce potable water from various contaminated sources at rates approaching ∼26 kg m–2 h–1. The LSAG─produced at room temperature via aqueous processing using an ethylene glycol (EG)–water mixture─uniquely integrates the attributes of poly(N-isopropylacrylamide) (PNIPAm), polydopamine (PDA), and poly(sulfobetaine methacrylate) (PSBMA) to enable off-grid water purification with an enhanced photothermal response and the capacity to prevent oil fouling and biofouling. Using the EG–water mixture was critical to forming the loofah-like structure with enhanced water transport. Remarkably, under sunlight irradiations of 1 and 0.5 sun, the LSAG required only 10 and 20 min to release ∼70% of its stored liquid water, respectively. Equally important, we demonstrate the ability of LSAG to purify water from various harmful sources, including those containing small molecules, oils, metals, and microplastics.