Extreme Water Uptake of Hygroscopic Hydrogels through Maximized Swelling‐Induced Salt Loading
Name
Advanced Materials - 2023 - Graeber - Extreme Water Uptake of Hygroscopic Hydrogels through Maximized Swelling%E2%80%90Induced Salt.pdf
Description
Published version
Size
2.07 MB
Format
Adobe PDF
Checksum (MD5)
086c135db74487413a278d459f19d0c4
Author(s)
Graeber, Gustav
Díaz‐Marín, Carlos D
Gaugler, Leon C
Zhong, Yang
El Fil, Bachir
Liu, Xinyue
Wang, Evelyn N
Date Issued
March 2024
Journal
Advanced Materials
Publisher
Wiley
Citation
Graeber, Gustav, Díaz‐Marín, Carlos D, Gaugler, Leon C, Zhong, Yang, El Fil, Bachir et al. 2024. "Extreme Water Uptake of Hygroscopic Hydrogels through Maximized Swelling‐Induced Salt Loading." Advanced Materials, 36 (12).
Version
Final published version
Abstract
Hygroscopic hydrogels are emerging as scalable and low‐cost sorbents for atmospheric water harvesting, dehumidification, passive cooling, and thermal energy storage. However, devices using these materials still exhibit insufficient performance, partly due to the limited water vapor uptake of the hydrogels. Here, the swelling dynamics of hydrogels in aqueous lithiumchloride solutions, the implications on hydrogel salt loading, and the resulting vapor uptake of the synthesized hydrogel–salt composites are characterized. By tuning the salt concentration of the swelling solutions and the cross‐linking properties of the gels, hygroscopic hydrogels with extremely high salt loadings are synthesized, which enable unprecedented water uptakes of 1.79 and 3.86 gg−1 at relative humidity (RH) of 30% and 70%, respectively. At 30% RH, this exceeds previously reported water uptakes of metal–organic frameworks by over 100% and of hydrogels by 15%, bringing the uptake within 93% of the fundamental limit of hygroscopic salts while avoiding leakage problems common in salt solutions. By modeling the salt‐vapor equilibria, the maximum leakage‐free RH is elucidated as a function of hydrogel uptake and swelling ratio. These insights guide the design of hydrogels with exceptional hygroscopicity that enable sorption‐based devices to tackle water scarcity and the global energy crisis.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution-Noncommercial
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1002/adma.202211783
