聚乙烯醇
自愈水凝胶
材料科学
热导率
化学工程
热的
复合材料
高分子化学
热力学
物理
工程类
作者
Junliang Zhang,Chenyang Tang,Qingqing Kong,Mukun He,Peng Lv,Hua Guo,Yongqiang Guo,Xuetao Shi,Junwei Gu
出处
期刊:Soft science
[OAE Publishing Inc.]
日期:2025-01-26
卷期号:5 (1)
被引量:21
摘要
Although polyvinyl alcohol (PVA) hydrogels display huge potential in tissue engineering, flexible and wearable electronic devices and soft robotics, their low intrinsic thermal conductivity and weak mechanical properties severely limit their wider applications in these areas. Herein, a Hofmeister effect-assisted “directional freezing-stretching” tactic is employed for simultaneously enhancing the intrinsic thermal conduction and mechanical properties of PVA hydrogels. The hydrogels are obtained through directional freezing followed by salting-out treatment and subsequent mechanical stretching and salting-out (DFS). The DFS PVA hydrogel with 15 wt% of PVA and a stretching ratio of 4 (DFS4) exhibits the highest thermal conductivity of 1.25 W/(m·K), which is 2.4 and 2.8 times that of PVA hydrogel prepared through frozen-thawed (FT) [0.52 W/(m·K)] and frozen-salted out (FS) [0.45 W/(m·K)] methods, respectively. The DFS4 PVA hydrogel also possesses greatly improved mechanical performances, exhibiting an elongation at break of 163.1%. In addition, the tensile strength, toughness, and elastic modulus of DFS4 PVA hydrogel significantly increase to 27.1 MPa, 25.3 MJ·m-3, and 21.5 MPa from 0.4 MPa, 0.32 MJ·m-3, and 0.07 MPa for FT PVA hydrogels, respectively. It is elucidated that the salting-out effect generates hydrophobic and crystalline regions, while directional freezing and stretching enhance the chain orientation in the DFS strategy. These effects synergistically contribute to the improvement of thermal conductivity and mechanical properties of PVA hydrogels.
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