A Robust Agar-PAM Hydrogel for Efficient Solar Steam Generation

Freshwater generation by solar distillation is a promising technology to relieve global water scarcity. However, the evaporation of water requires a lot of energy, and the fragile purifier is easily damaged, resulting in low water production in practical applications. Therefore, a material simultaneously possessing low water evaporation enthalpy and strong toughness is desired. Herein, the authors introduced agar into polyacrylamide (AP) to uniquely design hydroxyl group ramparts on the skeleton of hydrogel to uniquely design hydroxyl groups rampart on the skeleton of hydrogel to strengthen robustness of hydrogel and regulate water state, which not only reduces energy demand for evaporation but resists external disturbance. The tensile stress of CNT100-AP(1/9) hydrogel reaches the maximum value of 102 kPa while the tensile strain is 467%. Finally, a high evaporation rate of approximate to 3 kg m(-2) h(-1) with 86.2% photothermal conversion efficiency is obtained under 1 kW m(-2) illumination. The ingenious structure to wear hydroxyl groups coat on the skeleton of PAM hydrogel opens a new avenue for building a new robust and efficient solar thermal desalination system.

Automated summary

This study introduces agar and polyacrylamide to prepare a material with low evaporation enthalpy and strong toughness. The introduction of hydroxyl group ramparts on the skeleton of hydrogel not only reduces energy demand for evaporation but also enhances the resistance to external disturbance, opening a new avenue for building a new robust and efficient solar thermal desalination system.