Mechanistic Models of the Mechanical Response of Self-healing Hydrogels

自修复水凝胶机械响应的机理模型

• 批准号: 1537087
• 负责人: Chung-Yuen Hui
• 金额: $ 42万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1537087&HistoricalAwards=false
• 关键词: Mechanistic; Models; Mechanical; Response; Self

A hydrogel is a network of molecular chains into which water is absorbed and trapped, forming a material that is typically 90 percent or more water. Hydrogels have a wide range of current and potential applications such as scaffolds for laboratory grown tissue, drug delivery systems, biosensors, and consumer products. Hydrogels typically break at low levels of stretching, limiting their use in load bearing applications. Newly developed hydrogels consisting of stiff and soft interpenetrating networks can stretch like rubber. However, once they start to tear the damage is irreversible. By replacing the stiff network's covalent bonds with bonds that can reform, the material can become self-healing. This project seeks to understand the physics and mechanics of such gels and to develop mathematical models that will explain the self-healing behavior. Such models will establish connections between molecular scale features and mechanical response and enable researchers to build simulation models of engineered hydrogel systems. The model will be embedded in the context of an analysis code widely used in mechanics. We envision that such models would aid in the engineering of potential load-bearing applications of self-healing gels such as artificial cartilage and actuators for soft machines. The project will also provide opportunities for us to reach out to prospective students through hands-on discovery of the unexpected properties of self-healing hydrogels. In recent years polymer chemists have made tremendous strides in the synthesis of biocompatible, tough, low friction, self-healing hydrogels. Currently, models are lacking that link fatigue resistance, fracture, and time dependent, self-healing behavior to the underlying, rate dependent bond breaking and reformation processes. This research bridges this gap by: (a) designing and executing experiments to measure these mechanical behaviors using a model material system, (b) defining quantitative models relating these behaviors to bond breaking and reformation kinetics. Experiments will include tension testing, measurements crack growth rate tests and crack healing under monotonic and cyclic loading. The research will provide understanding of how the observed macroscale properties (strength, time dependence, fracture, fatigue and self-healing) are related to underlying deformation and separation mechanisms at the molecular level. The constitutive and failure models will also provide a quantitative link between these observable mechanical properties and relevant microscale parameters such as the different types of physical bonds, their strengths, and breaking/healing kinetics. The project will advance the field of mechanics by building a framework for constitutive and fracture models that are linked directly to the microstructure and that can be used in structural finite element simulations.

水凝胶是一个分子链网络，水被吸收和捕获，形成通常90％或更多水的材料。 水凝胶具有广泛的当前和潜在应用，例如用于实验室种植组织，药物输送系统，生物传感器和消费产品的支架。 水凝胶通常在较低的拉伸水平上破裂，从而限制了它们在负载轴承应用中的使用。 新开发的水凝胶由僵硬和柔软的互穿网络组成，可以像橡胶一样伸展。但是，一旦他们开始撕裂伤害是不可逆转的。 通过用可以改革的债券代替僵硬的网络的共价债券，材料可以变得自我修复。 该项目旨在了解这种凝胶的物理和机制，并开发将解释自我修复行为的数学模型。这样的模型将在分子尺度特征和机械响应之间建立连接，并使研究人员能够构建工程水凝胶系统的仿真模型。 该模型将嵌入在机械中广泛使用的分析代码的上下文中。我们设想这样的模型将有助于工程进行自我修复凝胶的潜在承载应用，例如人造软骨和软计算机的执行器。 该项目还将通过动手发现自我修复水凝胶的意外属性来为我们提供与潜在学生接触的机会。 近年来，聚合物化学家在合成生物相容性，坚韧，低摩擦，自我修复水凝胶的合成方面取得了长足的进步。 当前，缺乏将疲劳抗性，断裂和时间依赖的自我修复行为与基本，依赖性依赖性债券断裂和改革过程联系起来的模型。这项研究通过：（a）设计和执行实验通过模型材料系统来测量这些机械行为，（b）定义定量模型，将这些行为与键断裂和改革动力学相关联。 实验将包括张力测试，测量裂纹生长速率测试以及在单调和循环负载下进行裂纹愈合。该研究将提供对观察到的宏观特性（强度，时间依赖，断裂，疲劳和自我修复）如何与分子水平的潜在变形和分离机制有关的。 本构和故障模型还将在这些可观察到的机械性能与相关显微镜参数（例如不同类型的物理键，强度和破坏/愈合动力学）之间提供定量联系。 该项目将通过建立一个直接链接到微观结构的构型和断裂模型的框架来推动力学领域，并可以用于结构有限元模拟。

项目成果

Time-temperature equivalence in a PVA dual cross-link self-healing hydrogel

• DOI: 10.1122/1.5029466
• 发表时间: 2018-07
• 期刊: Journal of Rheology
• 影响因子: 3.3
• 作者: Mincong Liu;Jingyi Guo;C. Hui;C. Creton;T. Narita;A. Zehnder

Fracture mechanics of a self-healing hydrogel with covalent and physical crosslinks: A numerical study

• DOI: 10.1016/j.jmps.2018.03.009
• 发表时间: 2018-11-01
• 期刊: JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
• 影响因子: 5.3
• 作者: Guo, Jingyi;Liu, Mincong;Hui, Chung-Yuen
• 通讯作者: Hui, Chung-Yuen

Crack tip stress based kinetic fracture model of a PVA dual-crosslink hydrogel

• DOI: 10.1016/j.eml.2019.100457
• 发表时间: 2019-05
• 期刊: Extreme Mechanics Letters
• 影响因子: 4.7
• 作者: Mincong Liu;Jingyi Guo;C. Hui;A. Zehnder

Large deformation effect in Mode I crack opening displacement of an Agar gel: A comparison of experiment and theory

• DOI: 10.1016/j.eml.2016.05.005
• 发表时间: 2016-12
• 期刊: Extreme Mechanics Letters
• 影响因子: 4.7
• 作者: Rong Long;M. Lefranc;E. Bouchaud;C. Hui

Finite strain theory of a Mode III crack in a rate dependent gel consisting of chemical and physical cross-links

由化学和物理交联组成的速率相关凝胶中 III 型裂纹的有限应变理论

• DOI: 10.1007/s10704-018-00335-9
• 发表时间: 2019
• 期刊: International Journal of Fracture
• 影响因子: 2.5
• 作者: Hui, Chung Yuen;Guo, Jingyi;Liu, Mincong;Zehnder, Alan
• 通讯作者: Zehnder, Alan