强非共价键界面石墨烯基仿贝壳材料的力学行为与防腐涂层应用

Natural nacreous materials are built from limited components, but their mechanical performances are far beyond their artificial counterparts due to the hierarchically ordered brick-and-mortar microstructure. This brick-and-mortar microstructure can be used in designing high-performance bio-inspired materials, for example, graphene-based artificial nacre materials. Due to the excellent properties of graphene, a series of resultant high-performance graphene-based artificial nacres have been fabricated. In previous studies, some high-mechanical-performance graphene-based artificial nacres have been prepared through the construction of combined covalent and hydrogen bonding interfacial interactions. However, the interfacial mechanics and optimization designs of graphene-based artificial nacre materials are yet to be comprehensively studied. Although non-covalent interaction is usually weaker than covalent bonding, some studies indicated that graphene oxide can also exhibit strong non-covalent bonding (via π-π stacking, cation-π or van der Waals interactions) with some adhesion agents. Using density functional calculations and large-scale molecular dynamics simulations, we find that graphene oxide can form strong non-covalent interaction with melamine molecules. The strength of this non-covalent interaction is close to that of covalent interaction. Therefore, it is promising that graphene-based artificial nacre can obtain higher strength and toughness simultaneously through strong non-covalent interfaces, which can also be applied in the anti-corrosion coating. In this project, we will carry out investigations on the mechanical performance and anti-corrosion coating applications of graphene-based artificial nacre materials with strong non-covalent interfacial interactions. This project closely grasps the foundational scientific research and the practical applications in engineering, and is combined with our research accumulation over the graphene-based material mechanics and design. Three core problems are selected to be studied using a combined method of both experiments and theoretical simulations: interfacial mechanical mechanisms of graphene-based nacre-like materials with the strong non-covalent interaction, multiscale mechanical methods and optimal design theory of graphene-based artificial nacre materials, and the intrinsic association between the mechanical performance and applied functionality of graphene-based artificial nacre materials. We will try to achieve a number of important innovative research results with international impacts, in the topics of graphene-based artificial nacre materials and associated anti-corrosion coating applications. Moreover, we will establish the incorporate component-structure-property correlation and optimization design theory of graphene-based artificial nacre materials at nano-micro-macro scales. The outputs of this project are supposed to promote the leapfrog development of mechanics and especially micro/nano mechanics.

天然珍珠质材料因其多层级有序的砖块-灰泥微结构而具有优异的强韧性，这种微结构模式可以被用来设计高性能仿生材料，比如石墨烯基仿贝壳材料。近期研究发现氧化石墨烯能够与三聚氰胺形成接近于共价键强度的非共价键作用，因此有望获得具有优异强韧性的仿贝壳材料并应用于防腐涂层领域。本项目拟开展石墨烯基仿贝壳材料的强非共价键界面力学行为及防腐涂层应用的相关研究，立足于基础科学研究和工程实际应用，结合申请人及团队多年来在石墨烯材料力学行为和设计领域的研究积累，拟重点研究“石墨烯基仿贝壳材料的强非共价键界面力学机理”、“石墨烯基仿贝壳材料的多尺度力学分析方法与优化设计理论”及“石墨烯基仿贝壳材料力学行为与应用功能性的内在关联”等关键科学问题。还将围绕微纳结构材料设计和组装的共性科学问题，发展多尺度力学分析方法，建立石墨烯基仿贝壳材料纳-微-宏观一体化的组分-结构-性能关联关系，为材料设计和应用提供新的理论支撑。

非共价键是一类能够动态断裂和恢复的相互作用的统称。由纳米功能单元构建而成的多层次宏观尺度材料，如珍珠母、蜘蛛丝、木材等，能够通过多样的“微构造+非共价界面”设计发挥纳米功能单元卓越的物理、化学和力学性质以实现宏观材料的多功能和优异综合力学性能，从而启发了高性能仿生纳米复合材料的设计。本项目针对非共价界面调控仿贝壳材料强韧化设计及其防腐涂层应用等开展了系统深入的研究，代表性研究成果总结如下：分子模拟发现三聚氰胺分子和氧化石墨烯之间存在非常强的非共价键相互作用并得到单分子实验验证，发展了耦合界面滑移的剪滞模型，建立了以小分子强非共价键作用调控界面的石墨烯层状材料力学设计框架，提出了一种兼顾强度和韧性的材料力学设计理论。基于非共价界面的共性特征，建立了非共价界面从分子机制到宏观力学的多尺度力学分析框架，明确了变形模式-关键特征尺寸-材料力学性能之间的内在关联，提出了非共价界面层状纳米复合材料强韧化设计的普适性理论，解决了不同尺度兼顾强度和韧性的材料设计难题。提出了一种能够有效提升仿贝壳材料中片层利用率的临界损伤控制方法，给出了借助结构优化和界面改性手段实现人工合成仿贝壳材料最大化协同增韧的优化设计方案。理论模拟结合实验表征，设计构筑了具有双层类珍珠层结构的聚酰亚胺-云母纳米复合膜，云母纳米片梯度分布设计在实现材料力学性能有效提升的同时，大幅提升了对原子氧腐蚀、紫外辐射和空间碎片等抵抗能力，有望应用于极端环境耐侵蚀涂层薄膜材料领域。项目执行期间，在Journal of the Mechanics and Physics of Solids和Nature Communications等重要学术期刊发表学术论文30余篇。项目负责人在资助期内获批承担国家自然科学基金重点项目1项，承担中国科学院战略性先导科技专项（C类）课题1项；荣获2020年度中国科学院青年科学家国际合作伙伴奖和宝钢优秀教师特等奖等。