Researchers in the US have designed a sustainable polymer gel that can harvest large quantities of water from the surrounding air, even in low-humidity conditions. Created by Youhong Guo and colleagues at the University of Texas at Austin, the low-cost material combines water-absorbing plant fibres with cellulose, which expels water when heated.

Guo and colleagues have shown that in 14–24 cycles of water uptake and release in arid conditions, 1 kg of the gel can produce more than 6 l of water per day in 15% relative humidity. At 30% relative humidity, up to 13 l per day can be produced.