Construction of PDA@PAM-CMCNa-CaCl 2 Vertical Porous Hydrogels for Solar-Powered Spontaneous Atmospheric Water Harvesting

Collecting water from the air could alleviate freshwater shortages in arid regions such as remote and inland areas. However, it is challenging to prepare adsorption materials that have high adsorption and desorption performance using straightforward synthesis routes for water harvesting applications. In this paper, a polydopamine (PDA)@Sodium polyacrylamide carboxymethyl cellulose (PAM-CMCNa)-calcium chloride (CaCl2) composite aerogel (PDCA) with a vertical channel was prepared by salt template method and photopolymerization for atmospheric water collection (AWH). The designed vertical channel promotes the rapid transport of water molecules from the atmosphere to the interior of the hydrogel through capillary action. During this process, the hydrogel further expands to prevent the leakage of the internal salt solution, which effectively improves the water vapor adsorption and desorption by hydrogel. Experimental results showed that the hydrogel can absorb 2.78 g/g of water at 90