Collaborative Research: Chemical and Dynamic Heterogeneities in Interfaces for Adaptive Polymer Nanocomposites

合作研究：自适应聚合物纳米复合材料界面的化学和动态异质性

基本信息

批准号：
1825250
负责人：
Pinar Akcora
金额：
$ 30.54万
依托单位：
Stevens Institute of Technology
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-15 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1825250&HistoricalAwards=false
关键词：
Collaborative Research Chemical Dynamic Heterogeneities

项目摘要

Polymer composites are widely used as lightweight functional materials for a breadth of applications, including sensors, wearable electronics, and biomedical applications. These materials, however, often suffer from low mechanical strength, particularly at elevated temperatures. Soft hybrid materials with high strength under extreme conditions have been developed at small scales, but to scale these materials up to manufacturing capacities, the fundamental mechanisms of controlling the mechanical behavior of these materials must be understood. This award supports fundamental research to uncover the underlying physics and chemistry that control the high mechanical and functional performance of adaptive polymer nanocomposites. The scientific knowledge resulting from this research has the potential to enable a new class of high-performance materials, and the combined experimental and computational approaches build on an educational paradigm that provides opportunities for students participating in the research, training the next generation workforce in advanced engineering techniques.A driving motivation of this research is to develop mechanically adaptive materials based on the unique dynamic behavior of nanocomposites. The material system of interest consists of miscible polymers with large differences in glass transition temperature (Tg), coupled with a dispersion of nanoparticles. Spherical nanoparticles adsorbed within a high-Tg polymer and dispersed in a low-Tg polymer matrix have been shown to result in a thermally-induced stiffening behavior. In this research program, the investigators examine the role of chemical and dynamic heterogeneities in particle-polymer interfaces of such polymer nanocomposites to understand the mechanical characteristics of adaptivity. Chemical heterogeneities in interfacial polymer layer are studied to explain the reinforcement phenomena in different polymer architectures and with different particle shapes (nanotubes and nanospheres). Conformation of chains, in looped, stretched, and collapsed states, will be explored via molecular dynamic computational simulations to support the experimental results. Computer simulations are designed to run in parallel with experiments to guide experimental work and to inform material design space. More importantly, the influence of various molecular physical parameters such as chain stiffness can be identified by these simulations. Deformation of polymer nanocomposites under large oscillatory shear will be utilized to reveal the fundamental mechanism of adaptive mechanics in composites. Existing network theories will be used to analyze the non-linear rheological data and the effects of different polymer architectures on particle behavior. The knowledge gained from this project will transform the current knowledge of static properties of nanocomposites to extend to dynamically adaptive polymer hybrids.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.

聚合物复合材料被广泛用作轻巧的功能材料，用于广泛应用，包括传感器，可穿戴电子和生物医学应用。但是，这些材料通常会遭受机械强度较低的影响，尤其是在温度升高时。在极端条件下具有高强度的软混合材料已经在小尺度上开发出来，但是要将这些材料扩展到制造能力，必须了解控制这些材料机械行为的基本机制。该奖项支持基础研究，以揭示控制自适应聚合物纳米复合材料的高机械和功能性能的基本物理和化学。这项研究产生的科学知识有可能启用一类新的高性能材料，实验和计算方法的组合以教育范式为基础，为参与研究的学生提供了机会，在高级工程技术中培训下一代劳动力。这项研究的动机驱动动力是开发基于唯一动态型的机械适应性材料的机械适应性材料。感兴趣的材料系统由具有玻璃过渡温度（TG）差异较大的混杂聚合物组成，并与纳米颗粒的分散相结合。已经显示出在高-TG聚合物中吸附并分散在低TG聚合物基质中的球形纳米颗粒已显示出导致热诱导的僵硬行为。在该研究计划中，研究人员研究了这种聚合物纳米复合材料的化学和动态异质性在颗粒聚合物界面中的作用，以了解适应性的机械特征。研究了界面聚合物层中的化学异质性，以解释不同聚合物体系结构和不同颗粒形状（纳米管和纳米球）中的增强现象。链的构象将通过分子动态计算模拟来探索循环，拉伸和倒塌状态的构象，以支持实验结果。计算机模拟旨在与实验并行运行，以指导实验工作并为材料设计空间提供信息。更重要的是，可以通过这些模拟来识别各种分子物理参数（例如链刚度）的影响。在大型振荡剪切物下，聚合物纳米复合材料的变形将用于揭示复合材料中自适应力学的基本机制。现有的网络理论将用于分析非线性流变学数据以及不同聚合物架构对粒子行为的影响。从该项目中获得的知识将改变纳米复合材料的静态特性的当前知识，以扩展到动态自适应聚合物混合动力。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智力优点和更广泛影响的审查标准通过评估来获得支持的。