低温下具有超高刚度和韧性的玻璃态水凝胶的本征抗冻和独特磷光,Advanced Materials

当前位置： X-MOL 学术 › Adv. Mater. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

低温下具有超高刚度和韧性的玻璃态水凝胶的本征抗冻和独特磷光
Advanced Materials ( IF 27.4 ) Pub Date : 2023-02-23 , DOI: 10.1002/adma.202300244
Li Xin Hou ₁ , Huaqiang Ju ₁ , Xing Peng Hao ₁ , Haoke Zhang ₁ , Lei Zhang ₂ , Zhiyuan He ₃ , Jianjun Wang ₄ , Qiang Zheng ₁ , Zi Liang Wu ₁

Affiliation

大多数水凝胶在零下温度下会冻结，导致性能下降和应用受限。大量使用冷冻保护剂来提高水凝胶的抗冻性能；然而，也存在伴随的缺点，例如不同的网络、降低的机械性能以及在水性条件下冷冻保护剂泄漏的风险。这里报道的是玻璃水凝胶，它在超低温下具有固有的抗冻能力和优异的光学和机械性能。聚（丙烯酰胺-co）的超分子水凝胶-甲基丙烯酸）具有适度的水含量（≈50 wt.%）和密集的氢键缔合，在室温下处于玻璃态。由于氢键随着温度的降低而增强，这种凝胶变得更坚固、更硬，但仍具有延展性，杨氏模量为 900 MPa，拉伸强度为 30 MPa，-45 °C 时的断裂应变为 35%。这种凝胶即使在液氮中也能保持高透明度。由于羰基簇的存在，它还表现出独特的磷光，这种磷光在零下温度下进一步增强。进一步的研究表明，内在的抗冻特性与大多数水分子紧密结合并限制在玻璃状基质中并变得不可冻结的事实有关。这种相关性在多个系统中得到验证，

"点击查看英文标题和摘要"

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

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 (≈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 °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.

更新日期：2023-02-23

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南