Negative hydration expansion hydrogel metamaterials through microstructural design for minimally expanding absorbent applications

Negative hydration expansion hydrogel metamaterials through microstructural design for minimally expanding absorbent applications

Chemical Engineering Journal

10.1016/j.cej.2025.163376

https://doi.org/10.1016/j.cej.2025.163376

Sirawit Pruksawan, Rigel Lu Jun Teo, Yi Ting Chong, David W. Rosen, Fuke Wang

15 June 2025

Pruksawan, S., Teo, R. L. J., Chong, Y. T., Rosen, D. W., & Wang, F. (2025). Negative hydration expansion hydrogel metamaterials through microstructural design for minimally expanding absorbent applications. Chemical Engineering Journal, 514, 163376. https://doi.org/10.1016/j.cej.2025.163376

Hydrogels are highly hydrophilic materials with substantial water absorption, which renders them well-suited for various applications. However, this property often leads to significant expansion, which can be excessive and restrict their use in applications requiring dimensional stability. Although negative hydration expansion (NHE) hydrogel metamaterials have been developed to induce contraction rather than expansion upon water absorption, all existing achievements rely on composites with other materials, altering the hydrogel’s intrinsic properties. This study introduces an approach to developing NHE hydrogel metamaterials using a conventional hydrogel and microstructural design, without incorporating additional materials. By incorporating a diffusion-controlled architecture within the hydrogel to induce anisotropic swelling kinetics, the metamaterials undergo a controllable shape transformation, enabling contraction rather than expansion upon water absorption and vice versa upon water desorption. These metamaterials are particularly suitable for applications requiring high dimensional stability, such as hydrogel absorbents or dressings, where high absorbency is needed without undesirable expansion.

Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

This research / project is supported by the A*STAR - A*STAR Career Development Fund
Grant Reference no. : C233312015

This research / project is supported by the A*STAR - Singapore RIE2025 Manufacturing, Trade and Connectivity (MTC) Programmatic Fund
Grant Reference no. : M24N3b0028

This research / project is supported by the A*STAR - Manufacturing, Trade and Connectivity (MTC) Individual Research Grant
Grant Reference no. : M23M6c0110

https://oar.a-star.edu.sg/communities-collections/articles/23103

1385-8947

Institute of Materials Research and Engineering