石墨烯气凝胶力电行为多尺度研究

Graphene aerogels are one of the multi-functional lightweight materials combining load bearing, energy absorption, sensing, chemical adsorption, etc. They are believed to hold great potential applications in many fields, such as lightweight protective structures, flexible pressure sensors, smart materials and structures, environmental materials and so on. Therefore, they have attracted a lot of research interests in recent years. The graphene aerogels exhibit unique mechanical and electrical properties, such as superelasticity, viscoelasticity, piezoresistive effect. However, as the very complicated hierarchical structures of graphene aerogels, the previous research works mainly focused on the synthesizing of graphene aerogels and measuring their mechanical, electrical, chemical properties. There still lacks a comprehensive theoretical model to explore the mechanisms of the superelasticity, viscoelasticity and piezoresistance of graphene aerogels, so as to the constitutive relations of graphene aerogels. In this project we will study the mechanical and electrical behaviors of graphene aerogels in multiscale and aims to explore the relations between macroscale mechanical, electrical properties and the hierarchical structures. We will study the self-assembly of graphene sheets in a solution and figure out the key factors influencing the microstructures of graphene aerogels. Then, we will develop the micromechanical models of the wall and cell of graphene aerogel to explore the mechanisms of the superelasticity, viscoelasticity, piezoresistance, and then develop the viscoelastic constitutive relations of graphene aerogels. At last, we will develop a multilevel analyzing and optimizing model to guide the optimizing and engineering design of graphene aerogels.

石墨烯气凝胶是一种多功能轻质材料，集力学承载、能量吸收、传感、化学吸附等功能于一体，在轻质防护结构、柔性传感器、智能材料与结构、环保材料等多方面都有非常重要的应用价值，引起了广泛的研究兴趣。石墨烯气凝胶具有非常独特的力学、电学行为，如超弹性，粘弹性，压阻效应等。然而，由于石墨烯气凝胶非常复杂的多级结构，前人的研究大多集中在材料制备和性能表征，还不清楚石墨烯气凝胶超弹性、粘弹性、压阻效应的微观机理，尚缺乏相应的粘弹性本构关系。本项目拟通过多尺度的方法研究石墨烯气凝胶力学、电学行为，揭示其宏观力、电行为与各级微观结构的关系。我们将研究各级微观结构的自组装过程，找出影响各级微观结构的关键因素，发展石墨烯气凝胶胞壁、胞元的力学模型，揭示石墨烯气凝胶超弹性、粘弹性、压阻效应的微观机理，建立粘弹性本构关系。在此基础上发展石墨烯气凝胶多级分析、优化模型，为石墨烯气凝胶优化设计和工程应用提供指导。

石墨烯气凝胶具有轻质高强、可重复吸能、比表面积大、热学、电学性能优异，在轻质防护结构、柔性传感器、智能材料等领域都有重要应用。在本项目中我们致力于发展石墨烯气凝胶多尺度力学模型和优化设计方法，分别从二维材料片层、胞壁多层结构和气凝胶多孔结构出发构建石墨烯气凝胶结构-性能关联关系，为开发新型高性能石墨烯气凝胶提供理论指导。.针对石墨烯气凝胶的组成单元-石墨烯片层，我们发展了二维材料相场晶体模型，可以得到任意曲面石墨烯构型，建立了石墨烯面内孔洞、拓扑缺陷、几何构型与面内拉伸性能的关系联系。研究了石墨烯层间不同类型交链的力学性质以及石墨烯层间碳纳米管夹杂弯曲力学行为，从而为高面内力学性能和高层间载荷传递能力的石墨烯片层设计提供指导。.在石墨烯气凝胶胞壁层面，我们把石墨烯单层弯曲能引入到传统铁木辛柯梁模型中，发现层状材料和结构的弯曲行为由一个无量纲参数控制。对于多层石墨烯断裂，我们发现了逐层断裂和整体断裂两种模式，并得到了其判定条件。根据石墨烯层状材料面内导热特点，建立了层状材料热导模型，可以很好的描述层状材料热传导行为。提出了自修复交链增强增韧模型，并基于此得到了层状材料优化设计方法。.在石墨烯气凝胶多孔结构方面，建立了石墨烯气凝胶相变结构，可以很好的解释石墨烯气凝胶加卸载能量耗散，发展了石墨烯气凝胶电导模型，发现了层间接触电阻和缺陷主导的石墨烯气凝胶电导行为。此外，利用前面发展了相场晶体生长模型，得到了石墨烯气凝胶多孔模型，可以用来研究石墨烯气凝胶热、力、电耦合行为。在材料复合层面，提出了石墨烯膜/高分子双连续模型，通过石墨烯膜连续断裂增强增韧。.该项目发表SCI论文33篇，其中3篇文章发表在固体力学知名期刊JMPS上，相关结果获得国家自然科学二等奖-范德华层状介质的滑移行为和力学模型。

内容获取失败，请点击重试