posted on 2023-02-08, 16:34authored byYuxuan Lin, Ke Shao, Shuai Li, Na Li, Shuxue Wang, Xiaochun Wu, Cui Guo, Liangmin Yu, Petri Murto, Xiaofeng Xu
Environmental
humidity and thermal control are of primary importance
for fighting global warming, growing energy consumption, and greenhouse
gas emissions. Sorption-based atmospheric water harvesting is an emerging
technology with great potential in clean water production and passive
cooling applications. However, sorption-based humidity management
and their hybrid applications are limited due to the lack of energywise
designs of hygroscopic materials and devices. Herein, all polymeric
3D foams are developed and evaluated as hygroscopic and photothermal
materials. The gas-foaming method generates closed-cell structures
with interconnected hydrophilic networks and wrinkled surfaces, expanding
hygroscopic, photothermal, and evaporating areas of the 3D foams.
These unique advantages lead to efficient water vapor sorption in
a wide broad relative humidity (RH) range of 50–90% and efficient
water release in a wide solar intensity (0.4–1 sun) and temperature
range (27–80 °C). The reversible moisture sorption/release
in 50 adsorption/desorption cycles highlights the excellent durability
of the 3D foams compared to conventional inorganic desiccants. The
3D foams disclose passive and efficient apparent temperature regulation
in warm and humid environments. Moreover, the use of the 3D foams
as loose fill for fruit preservation and packaging is demonstrated
for the first time by taking the merit of the 3D foams’ moisture-absorbing,
quick-drying, cushioning, and thermal-insulating properties. This
work presents an integrated design of polymeric desiccants and scaffolds,
not merely delivering stable water adsorption/desorption but also
discovering innovative hybrid applications in humidity management
and protective packaging.