Collaborative Research: Multiscale Mechanics of Adsorption-Deformation Coupling in Soft Nanoporous Materials

合作研究：软纳米多孔材料吸附变形耦合的多尺度力学

• 批准号: 2331017
• 负责人: Wenjie Xia
• 金额: $ 20.67万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-15 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2331017&HistoricalAwards=false
• 关键词: Collaborative; Research; Multiscale; Mechanics; Adsorption

This grant supports research to pursue a fundamental understanding of adsorption-deformation coupling in soft nanoporous materials. The research will develop corresponding mechanical theories, aiming to better predict hygroscopic movements in complex nanoporous media and control sorption-induced actuation by design where sorption refers to the binding of ions to charged surfaces. Soft nanoporous materials having characteristic pore sizes below 100 nm are ubiquitous in nature (e.g., cellulose, protein) and in engineering applications (e.g., cement, gel, nanocomposites). These materials often exhibit significant swelling/shrinkage upon adsorption/desorption of fluids/gases due to nanoconfinement effects resulting from their network topology and interfacial interactions. Nature uses such stimuli-responsive features of cellulose nanofibers to facilitate the dispersal of plant seeds upon humidity change. Bio-inspired soft nanoporous materials have been recently developed for fast and reliable actuators, sensors, and artificial muscles driven by sorption of solvent molecules. This project will establish and validate a multiscale mechanics framework informed by pore-scale thermodynamics and molecular simulations for predicting the sorption-induced straining of nanoporous materials. The project will also pursue an educational initiative involving new course development on multiscale poromechanics and pre-college outreach by harnessing the excitement surrounding nano-engineered materials and leveraging it with the exceptional infrastructure for innovation and education at the participating institutes. This research is driven by the hypothesis that the complex coupling between sorption and deformation in nanoporous media can be predicted by focusing on two key pore-scale attributions, namely the disjoining pressure and surface tension induced by solid-adsorbate interactions. To test this hypothesis, the study will first establish a continuum theory guided by the thermodynamics of mixtures, i.e., by viewing material as a superposition of the solid, fluid and surface phases, through which the smeared pore-scale forces appear as macroscale adsorption stresses acting on the porous skeleton. Expressions of pore-scale forces will be then sought via molecular dynamics (MD) simulations and surrogate pore models. Specifically, simplified pore models will be developed based on Gibbs’ excess treatment of nanoconfined fluid films to link pore-scale forces induced by sorption with experimentally measurable quantities (i.e., adsorption isotherm). The pore model will be validated by MD simulations of nanopores subjected to fluid adsorption. These microscale forces will then be upscaled via statistical homogenization to complete the poromechanics framework. Finally, the theory will be applied to model the sorption-deformation behavior of amorphous cellulose interacting with water vapor. The prediction will be validated against experimental data and MD simulation results obtained from the same material system. The research will challenge the current paradigm of poromechanics where short-range interactions and surface forces within individual pores have been routinely neglected. If successful, the research will greatly expand our fundamental understanding on mechanics of active and soft porous materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该赠款支持研究，以追求对软纳米多孔材料中增加吸附性构耦合的基本理解。这项研究将开发相应的机械理论，旨在更好地预测复杂纳米多孔介质中的吸湿运动，并通过设计通过设计来控制焊接诱导的动作，其中焊接是指离子与带电表面的结合。具有特征性孔径低于100 nm的特征性孔径的软纳米多孔材料本质上是普遍存在的（例如纤维素，蛋白质）和工程应用（例如，水泥，凝胶，纳米复合材料）。由于其网络拓扑结构和界面相互作用引起的纳米浓度效应，这些材料在增加/吸附/气体时通常会显示出明显的肿胀/收缩。大自然使用纤维素纳米纤维的这种刺激性响应特征来促进湿度变化时植物种子的分散。最近已经开发了由溶解分子吸附的快速可靠的执行器，传感器和人工肌肉的生物启发的软纳米多孔材料。该项目将建立并验证由孔隙尺度热力学和分子模拟所启示的多尺度机械框架，以预测吸附纳米多孔材料的应激性劳止。该项目还将通过利用围绕纳米工程材料的兴奋并利用其出色的基础架构来实现参与机构的创新和教育，通过利用围绕纳米工程材料的兴奋并利用它的兴奋，涉及有关多尺度门学和大学前宣传的新课程开发的教育计划。这项研究是由以下假设驱动的：可以通过关注两个关键的孔隙尺度属性，即，固态粘结压力和表面张力是由固体吸附物相互作用引起的。为了检验这一假设，该研究将首先建立一个由混合物的热力学引导的连续理论，即，通过将材料视为固体，流体和表面相的叠加，通过该材料，涂抹的孔隙尺度的力通过该材料在其上显示出宏观尺度上的吸附应力在多孔骨架上添加了作用。然后，将通过分子动力学（MD）模拟和替代孔模型寻求孔隙尺度力的表达。具体而言，将基于吉布斯对纳米夹层流体膜的过多处理，以将吸附诱导的孔隙尺度的力与实验测量量（即吸附等温线）联系起来，开发简化的孔模型。孔模型将通过受到流体吸附的纳米孔的MD模拟来验证。然后，这些显微镜将通过统计均匀化来升级，以完成Poromechanics框架。最后，该理论将应用于模拟与水蒸气相互作用的无定形纤维素的吸附性变形行为。该预测将根据实验数据和MD仿真结果进行验证。这项研究将挑战当前的门力学范式，在这些孔中通常会忽略单个孔内的短距离相互作用和表面力。如果成功的话，这项研究将大大扩展我们对活跃和软多孔材料机制的基本理解。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响审查标准通过评估来支持的。

项目成果

Dispersion characteristics and mechanical properties of epoxy nanocomposites reinforced with carboxymethyl cellulose functionalized nanodiamond, carbon nanotube, and graphene

• DOI: 10.1002/pc.27785
• 发表时间: 2023-09
• 期刊: Polymer Composites
• 影响因子: 5.2
• 作者: Dawei Zhang;Ying Huang;Wenjie Xia;Luyang Xu;Xingyu Wang

Influence of Chain Stiffness on the Segmental Dynamics and Mechanical Properties of Cross-Linked Polymers

• DOI: 10.1021/acs.macromol.3c01077
• 发表时间: 2023-09
• 期刊: Macromolecules
• 影响因子: 5.5
• 作者: Xiangrui Zheng;Wenjian Nie;Yafang Guo;Jack F. Douglas;Wenjie Xia

Particle alignment effects on mechanical properties of cellulose nanocrystal thin films

颗粒排列对纤维素纳米晶薄膜力学性能的影响

• DOI: 10.1039/d2ma00870j
• 发表时间: 2023
• 期刊: Materials Advances
• 影响因子: 5
• 作者: Son, Hyeyoung;Smith, Dawson Michael;Li, Zhaofan;Chang, Taehoo;Xia, Wenjie;Davis, Chelsea Simone
• 通讯作者: Davis, Chelsea Simone

Understanding the graphene-polymer interfacial mechanical behavior via coarse-grained modeling

• DOI: 10.1016/j.commatsci.2023.112109
• 发表时间: 2023-04
• 期刊: Computational Materials Science
• 影响因子: 3.3
• 作者: Yang Wang-;W. Nie;Liang-zhi Wang;Dawei Zhang;K. Niu;W. Xia