Intelligent hybrid hydrogel with nanoarchitectonics for water harvesting from acidic fog

Abstract

With the development of society, the demand for water resources has risen has increased sharply, and water shortage is becoming a huge challenge to mankind. Therefore, it is extremely urgent to develop a convenient, low-cost, and environmentally friendly fog harvesting material. In this work, inspired by lotus stem with efficient water transport characteristics, the intelligent hybrid hydrogel (IHH) synergistically combines the characteristics of the pH-sensitive PDMAEMA polymer chain and thermo-switchable PNIPAM polymer chain, which simultaneously realizes superior efficient acidic fog uptake (∼6.5 g/g), high-density acidic fog storage, ultra-fast clean water releasing in the efficiency of ∼90% for 12 min at 60°C and high cycling stability (∼25 cycles). It is mainly attributed that the amine groups of the PDMAEMA chains are protonated under acidic state, and further the hydration is enhanced, and thus resulting the hydrogel to absorb the acid fog and swell. The PNIPAM polymer can achieve a rapidly reversible phase transition from a hydrophilic state to a hydrophobic one when the temperature beyond LCST, achieving the water releasing quickly. This IHH achieves preliminary water purification, which converts the harvested acidic fog into clean water as the freshwater generator. The IHH offers an insight into the design of novel materials that serve as the freshwater generator in complex environments of practical applications such as fog harvesting devices or systems.