碳纳米管/石墨烯功能复合材料的界面力学行为及多场耦合下力/热/电学性能的多尺度表征

The interfacial microscopic mechanical behaviors and debonding mechanism of carbon nanotube/graphene reinforced functional composites will be studied, and multi-field coupling analyses and multi-scale characterization of their mechanical, thermal, electrical properties will also be carried out in this project. The expressions will be derived to quantitatively describe the interactions between the carbon nanotube/graphene and the matrix in the atomic scale. The multi-scale models, which exhibit the trans-scale correlation among atomic interactions, nanoscale and macroscopic mechanical properties, will be presented to characterize the stress transfer and the debonding between the carbon nanotube/graphene and the composite matrix. Furthermore, the influence of the geometrical shapes, characteristic dimensions, alignments, surface defects and surface chemical modifications of carbon nanotube/graphene on the interfacial adhesion behaviors and stress transfer will be analyzed. In addition, the collaborative nano-mechanical experimental technology will be developed based on the atomic force microscopy probe and micro-Raman spectroscopy. The information of force-deformation will be in situ measured when the carbon nanotube/graphene is debonded, slidden and pulled out from the surface/interface of matrix. The influence of surface defects, surface chemical modifications of carbon nanotube/graphene and residual stress on the interfacial stress transfer and the debonding will be investigated. Finally, the physical relationships among electrical conductivity, thermal conductivity and macroscopic mechanical behaviors of carbon nanotube/graphene reinforced functional composites with multi-field coupling will be quantitatively characterized, and multi-scale models of their mechanical, thermal, electrical properties will be presented. Via optimal design method, the optimal mechanical, thermal, electrical properties of carbon nanotube/graphene reinforced functional composites are achieved.

本项目拟研究碳纳米管/石墨烯功能复合材料的界面微观力学行为及脱粘机理，同时对其力/热/电学性能开展多场耦合分析和多尺度表征。从原子尺度上用函数关系定量描述碳纳米管/石墨烯与基体之间的相互作用，建立从原子尺度—纳观—宏观能够精细表征碳纳米管/石墨烯与基体之间应力传递特性及脱粘演化的多尺度模型。分析碳纳米管/石墨烯的几何形态、特征尺度、取向、表面缺陷以及表面化学修饰等因素对界面粘着性能及应力传递的影响。发展基于原子力显微探针和微拉曼光谱技术的纳米力学协同测试技术，原位测量碳纳米管/石墨烯从复合材料基体表/界面脱粘、滑移及剥离时的力与变形信息，揭示表面缺陷、表面化学修饰以及残余应力等因素对界面应力传递和脱粘演化的影响。定量表征多场耦合下复合材料的电导率、导热系数与宏观力学行为之间的物理关系，建立碳纳米管/石墨烯功能复合材料的力/热/电学性能的多尺度模型，通过优化设计，实现力/热/电学性能的最优。

碳纳米管/石墨烯具有极其优异的力、热、电学性能，在聚合物基体中加入碳纳米管/石墨烯作为填充相，在理论上不仅能极大地提高复合材料的强度，而且可以实现导电和导热功能。碳纳米管/石墨烯增强复合材料的界面脱粘失效是影响复合材料整体性能的关键因素，对碳纳米管/石墨烯表面以及石墨烯/基底系统界面粘附和脱粘失效行为的研究是人们关注的热点。本项目主要开展了单层理想/含缺陷石墨烯的原子尺度建模及力学性能的理论研究、石墨烯表面/界面的粘附和摩擦性能的理论研究、石墨烯/基底系统界面粘附及失效行为的理论研究与实验表征。建立了单层理想/含缺陷石墨烯的原子尺度模型，研究了理想、含晶界、含预裂纹单层石墨烯的临界屈曲应力、强度极限、失效应变以及断裂韧性。建立了表征原子/离子与石墨烯相互作用的原子尺度模型以及原子力扫描电镜探针针尖与石墨烯相互作用的多尺度模型，研究了石墨烯表面的粘附和摩擦力学行为。建立了探针与正弦基底表面接触的接触模型，得到考虑粘附能的探针滑动摩擦力表达式，研究了基底粗糙度对于探针粘附和摩擦性能的影响。基于内聚力模型和剪滞模型，建立了石墨烯与聚合物基底材料之间相互作用的多尺度模型，研究了石墨烯/基底系统界面上的粘附性能和失效机理。分析了原子间相互作用、粘着能、石墨烯的缺陷和几何尺寸等因素对石墨烯各项力学性能的影响。基于原子力显微镜探针技术和微拉曼光谱技术，实验研究了石墨烯和石墨烯/基底系统的表面/界面粘附和摩擦性能。相关研究成果不仅可用于碳纳米管/石墨烯增强复合材料的设计，而且对药物传输系统、可再充锂离子电池以及基于石墨烯的柔性电子器件等的设计和应用有指导意义。