Ostwald ripening for designing time-dependent crystal hydrogels

Qianwei Liu; Yuanlai Fang; Xinhong Xiong; Weiming Xu; Jiaxi Cui

doi:10.1002/anie.202320095

Ostwald ripening for designing time-dependent crystal hydrogels

Angew Chem Int Ed Engl. 2024 Apr 22;63(17):e202320095. doi: 10.1002/anie.202320095. Epub 2024 Mar 15.

Authors

Qianwei Liu¹, Yuanlai Fang^{1

2}, Xinhong Xiong^{1

3}, Weiming Xu¹, Jiaxi Cui^{1

3}

Affiliations

¹ Department: Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China Chengdu, Sichuan, 611731, China.
² Institute for Advanced Study, Chengdu University, Chengdu, 610106, P. R. China.
³ Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou, 313001, P. R. China.

PMID: 38419359
DOI: 10.1002/anie.202320095

Abstract

Ostwald ripening (OR), a classic solution theory describing molecular transfer from metastable crystal to stable one, is applied to design time-dependent crystal hydrogels that can automatically change their mechanical properties. Using a system made from crosslinked polyacrylamide (PAM) and sodium acetate (NaAc), we demonstrate that metastable fibrous crystal networks of NaAc preferably form in PAM hydrogels via a polymer-involving mismatch nucleation. These fibrous crystals would undergo OR and evolve into isolated bulk crystals, leading to a significant reduction in material rigidity (179 folds) and interfacial adhesion (20 folds). This transformation can be applied to program time-dependent self-recovery in shape and self-delamination. Since OR is a ubiquitous, robust feature of various crystals, the approach reported here represents a new direction for designing advanced transient soft materials.

Keywords: Ostwald ripening; crystal hydrogel; mechanical properties; mismatch nucleation; time-dependency.

Abstract

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