Physics-Based Prediction and Design of Absorption Properties of Moisture-Capturing Hydrogels

Moisture-capturing hydrogels have emerged as promising low-cost sorbent materials for applications including thermal management, thermal energy storage, and atmospheric water harvesting. Despite extensive efforts in the synthesis of novel hydrogels, there is a major knowledge gap between the synthesis variables and the material properties, which hinders the design of properties and system-level optimization. In this work, we develop physics-based models to predict the properties of moisture-capturing hydrogels from their composition. We develop and experimentally validate thermodynamic models that accurately predict the water uptake and absorption enthalpy as a function of humidity as relevant hydrogel synthesis variables are changed. We also develop mass transport models, using a convection-limited transport description, that accurately predict experimental absorption and desorption speeds. This work represents a major step in the design of moisture-capturing hydrogels, enabling application optimization for high performance thermal management of electronics, buildings, and people, heat storage, and atmospheric water production.