Moisture sorption and hydration dynamics in intrinsically hygroscopic hydrogels
Weixin Guan1,2, Dongsheng Chen3, Meng An4
1Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA.
Science Advances
|July 15, 2026
Summary
Researchers developed intrinsically hygroscopic hydrogels (IHHs) using inosine and zinc ions. These novel materials efficiently capture water vapor across a wide humidity range without needing salts, showing promise for water harvesting.
Area of Science:
- Materials Science
- Supramolecular Chemistry
- Hydrogel Technology
Background:
- Hygroscopic materials are crucial for water harvesting and moisture control.
- Conventional hydrogels require salts to absorb moisture at low relative humidity (RH).
Purpose of the Study:
- To create intrinsically hygroscopic hydrogels (IHHs) without salt deliquescence.
- To investigate the effect of pH-controlled coordination on hydrogel hygroscopicity.
Main Methods:
- Supramolecular coordination of inosine and Zn²⁺ ions.
- pH-controlled gelation process.
- Moisture sorption measurements across a wide RH range.
- Experimental and simulation-based analysis of hydration mechanisms.
Main Results:
- IHHs exhibit moisture sorption starting near 0% RH.
- Significant water uptake achieved: 0.17 g/g at 30% RH and 1.9 g/g at 95% RH.
- Reversible moisture cycling demonstrated.
- Gelation pH influences coordination environment, network structure, and sorption properties.
Conclusions:
- Coordination chemistry offers a route to salt-free hygroscopic hydrogels.
- Zn-centered motifs act as initial hydration sites.
- pH-dependent network structure modulates water uptake.
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