DMREF: A Fundamental Approach to Study the Effect of Structural and Chemical Composition in Functionalized Graphene Materials

该项目的中心目标是通过以多尺度和协同的方式结合理论，建模和实验来建立材料设计的范式转变，以最大限度地提高纳米复合材料的强度和韧性，这些材料使用氧化石墨烯模仿天然珍珠层的性能。预计具有最佳重叠几何形状的氧化石墨烯片通过可调化学作用结合在一起，将模仿珍珠母。具体而言，这项研究将导致表征的多层纳米复合材料系统的变形机制，通过研究的强度和刚度的两个单独的原子级薄片，以及它们的交联元素。该项目旨在对货车德瓦尔斯相互作用、氢键和化学交联、构象和几何组装在调节基于氧化石墨烯的纳米复合材料的机械行为中所起的作用有一个基本的理解。功能化石墨烯片和宏观氧化石墨烯材料的机械性能将通过一系列迭代合成-组装-建模循环来优化。基于MEMS技术和原子力显微镜的新型纳米力学测试方法将被应用于测量具有“砖和砂浆”般分级结构的少层氧化石墨烯材料的力学行为。新的交联化学，如硫醇胺，将被探索赋予显着改善控制剪切相互作用，通过共价键断裂和改造。不同的几何重叠层和构象的片材将被探讨。原位电子显微镜力学测试，产生原子和微观尺度上的多个长度尺度的特性，再加上计算建模使用从头算和半经验的方法，将量化的界面强度和变形的负载转移机制。开发的洞察力将用于指导宏观纳米复合材料的合成，该材料利用石墨烯的强度和受自然启发的分级组装结构。预计预测和定制氧化石墨烯机械性能的标准的开发-的纳米复合材料将被转移到广泛的纳米复合材料，并将优化材料的设计过程与层次结构，包括刚性结构单元和延展性交联元件。这些下一代合成材料对于航空航天、卫星、汽车、军事和医疗保健行业的进步至关重要。该研究还将作为研究生和博士后研究员在基于结构的材料设计的关键前沿和在合成，建模和分层测量领域的跨学科科学研究的艺术的优秀培训平台。

The central goal of this project is to establish a paradigm shift in material design by combining theory, modeling, and experimentation in a multiscale and synergistic manner to maximize the strength and toughness of nanocomposite materials that emulate the performance of natural nacre using graphene oxide. It is expected that graphene oxide sheets with optimal overlap geometry, bonded together by tunable chemistry, will mimic nacre. Specifically, this research will lead to characterization of the deformation mechanisms of multilayer nanocomposite systems through studies of the strength and stiffness of both the individual atomically thin sheets as well as their crosslinking elements. This project aims to develop a fundamental understanding of the roles that van der Waals interactions, hydrogen bonds, and chemical crosslinking, conformation, and geometrical assembly play in modulating the mechanical behavior of nanocomposite materials based on graphene oxide. The mechanical performance of functionalized graphene sheets and macroscopic oxidized-graphene materials will be optimized through a series of iterative synthesis-assembly-modeling cycles. Novel nanoscale mechanical testing methods based on MEMS technologies and AFM will be applied to measure the mechanical behavior of few-layer graphene oxide materials with "brick-and-mortar" like hierarchical structures. New crosslinking chemistries, such as thiol-amines, will be explored to impart significant improvements in controlling shear interactions through covalent bond breaking and reformation. Varying geometrical overlap between layers and conformations of the sheets will be explored. In-situ electron microscopy mechanical testing, to yield atomic and micro-scale characteristics on multiple length scales, coupled with computational modeling using ab initio and semi-empirical methods, will quantify the interface strength and deformation governing load-transfer mechanisms. The developed insight will then be used to guide the synthesis of a macroscopic nanocomposite material that takes advantage of the strength of graphene and the hierarchically assembled structures inspired by Nature.It is expected that the development of criteria for predicting and tailoring the mechanical properties of graphene oxide-based nanocomposite materials will be transferable to a wide range of nanocomposites and will optimize the design process of materials with hierarchical structure that incorporate stiff building blocks and ductile crosslinking elements. These next-generation synthetic materials are essential for advances in the aerospace, satellite, automotive, military, and healthcare industries. The research also will serve as an excellent training platform for graduate students and postdoctoral fellows in the critical frontier of structure-based material design and in the art of interdisciplinary scientific research in the areas of synthesis, modeling, and hierarchical measurements.