Hydrogels have found a wide array of applications in engineering and science disciplines due to their interesting and versatile properties. The mechanical and physicochemical properties of hydrogels are sensitive to external stimuli including pH, ionic strength, temperature, electric field, etc. Superabsorbent hydrogels are able to store and gradually release water into their surrounding in response to external stimuli. The release of water from hydrogels into the microstructure of a porous matrix is driven by the capillary-osmotic interactions present at the interface between hydrogels and the porous matrix. 
In this study, we present the results of an experimental investigation into the swelling and deswelling of hydrogels in a porous solid containing an ionic solution. The dependence of hydrogels‚Äô swelling behavior on ions and their concentration in the solvent was examined. The deswelling of hydrogel as a function of matrix microstructure and relative humidity was investigated. Hydrogels used in this study were comprised of cross-linked poly (sodium acrylate-acrylamide) copolymer, swollen in an aqueous solvent containing varied concentrations of Na+ and Ca2+ counterions. Hydrogels with varied concentrations of monomers were also prepared to examine the effect of polymer structure on its response. The mechanical properties of hydrogels were evaluated using the uniaxial test in a microtensile stage. The deswelling of hydrogels in contact with porous matrices of varied porosities and pore morphologies and at constant relative humidity levels of 95%, 85%, and 75% was monitored and discussed. 


Chemical and mechanical processes during deswelling of hydrogels in a porous solid

The Virtual Technical Meeting of the Society of Engineering Science 2020 is the first fully virtual meeting of the SES community to envision and connect during the hiatus created by Covid-19, providing a platform for the exchange of ideas, and to showcase the latest research in the field of engineering science.

[Visit the Programme](https://drive.google.com/file/d/1BoCPBzrr1IQFANuzQI8a-paXCJoOcCkB/view?usp=sharing) | [Visit the Prerecorded Video/Poster List](https://drive.google.com/file/d/1XHLeEXJxEFjCSsNScuLDfMwy1X7oy7oJ/view?usp=sharing) | [View the Session Grid](https://drive.google.com/file/d/1VeDOC-Ev5m_ymYjXnjaXSZHR3_DARiLt/view?usp=sharing)