Strong tough hydrogels via the synergy of freeze-casting and salting out

Journal Article · Wed Feb 24 00:00:00 EST 2021 · Nature (London)

DOI:https://doi.org/10.1038/s41586-021-03212-z· OSTI ID:1774154

Hua, Mutian ^[1]; Wu, Shuwang ^[2]; Ma, Yanfei ^[1]; Zhao, Yusen ^[1]; Chen, Zilin ^[1]; Frenkel, Imri ^[1]; Strzalka, Joseph ^[3]; Zhou, Hua ^[3]; Zhu, Xinyuan ^[4]; He, Ximin ^[1]

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1. Univ. of California, Los Angeles, CA (United States)
2. Univ. of California, Los Angeles, CA (United States); Shanghai Jiao Tong Univ. (China). State Key Lab. of Metal Matrix Composites
3. Argonne National Lab. (ANL), Lemont, IL (United States)
4. Shanghai Jiao Tong Univ. (China). State Key Lab. of Metal Matrix Composites

Natural load-bearing materials like tendons possess high water content of ~70% but14 are still strong and tough even when used for over 1 million cycles per year, which is owed to the hierarchical assembly of anisotropic structures across multi-length-scales . In imitation of natural systems, various hydrogels have been created via methods like electro-spinning, extrusion, compositing, freeze casting, self-assembly, and mechanical stretching for improved mechanical performance. However, in contrast to tendons, many hydrogels with the same high water content do not show high strength, large toughness or high fatigue resistance. In this work, we present a strategy to produce strong, tough and fatigue resistant hydrogels with multi-length-scale hierarchical architecture using a freezing-assisted salting-out treatment. The produced exemplary poly(vinyl alcohol) hydrogels are highly anisotropic, comprising micrometer-scale honeycomb-like pore walls, which in turn comprise interconnected nanofibrils meshes, entirely physically assembled from polymer chains. These hydrogels are made of 70-95% water but can exhibit ultra-high ultimate stress (23.5 ± 2.7 MPa) and strain (2900 ± 450%), giant 32226 toughness (210 ± 13 MJ/m , 175 ± 8 kJ/m) and remarkable fatigue threshold (10.5 ± 1.3 kJ/m), which are 10 times tougher than natural tendon. The presented strategy could expand the applicability of weak polymeric material, like hydrogels, in practical applications that requires long-term services with high-loads and abrupt-impacts and extend the development of structural hydrogels.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: National Natural Science Foundation of China (NNSFC); National Science Foundation (NSF); US Air Force Office of Scientific Research (AFOSR); US Office of Naval Research (ONR); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1774154
• Journal Information: Nature (London), Journal Name: Nature (London) Journal Issue: 7847 Vol. 590; ISSN 0028-0836
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Mechanical properties
polymers