Intrinsic Anti-Freezing and Unique Phosphorescence of Glassy Hydrogels with Ultrahigh Stiffness and Toughness at Low Temperatures

被引：93

作者：

Hou, Li Xin ^{[1
]}

Ju, Huaqiang ^{[1
]}

Hao, Xing Peng ^{[1
]}

Zhang, Haoke ^{[1
]}

Zhang, Lei ^{[2
]}

He, Zhiyuan ^{[3
]}

Wang, Jianjun ^{[4
]}

Zheng, Qiang ^{[1
]}

Wu, Zi Liang ^{[1
]}

机构：

[1] Zhejiang Univ, Dept Polymer Sci & Engn, Key Lab Macromol Synth & Functionalizat, Minist Educ, Hangzhou 310058, Peoples R China

[2] Zhejiang Univ, Coll Opt Sci & Engn, State Key Lab Modern Opt Instrumentat, Hangzhou 310027, Peoples R China

[3] Beijing Inst Technol, Sch Mat Sci & Engn, Beijing 100081, Peoples R China

[4] Chinese Acad Sci, Inst Chem, Key Lab Green Printing, Beijing Natl Lab Mol Sci, Beijing 100190, Peoples R China

来源：

ADVANCED MATERIALS | 2023年 / 35卷 / 21期

基金：

中国国家自然科学基金;

关键词：

anti-freezing properties; glassy state; hydrogels; hydrogen bonds; toughness; WATER; ICE; TISSUE; DYNAMICS; FRACTURE; DENSE;

D O I：

10.1002/adma.202300244

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Most hydrogels become frozen at subzero temperatures, leading to degraded properties and limited applications. Cryoprotectants are massively employed to improve anti-freezing property of hydrogels; however, there are accompanied disadvantages, such as varied networks, reduced mechanical properties, and the risk of cryoprotectant leakage in aqueous conditions. Reported here is the glassy hydrogel having intrinsic anti-freezing capacity and excellent optical and mechanical properties at ultra-low temperatures. Supramolecular hydrogel of poly(acrylamide-co-methacrylic acid) with moderate water content (approximate to 50 wt.%) and dense hydrogen-bond associations is in a glassy state at room temperature. Since hydrogen bonds become strengthened as the temperature decreases, this gel becomes stronger and stiffer, yet still ductile, with Young's modulus of 900 MPa, tensile strength of 30 MPa, and breaking strain of 35% at -45 degrees C. This gel retains high transparency even in liquid nitrogen. It also exhibits unique phosphorescence due to presence of carbonyl clusters, which is further enhanced at subzero temperatures. Further investigations elucidate that the intrinsic anti-freezing property is related to a fact that most water molecules are tightly bound and confined in the glassy matrix and become non-freezable. This correlation, as validated in several systems, provides a roadmap to develop intrinsic anti-freezing hydrogels for widespread applications at extreme conditions.

引用

页数：11