嵌入石墨烯对有机薄膜承载及摩擦性能影响机制

Design and development self-assembled lubrication films with low adhesion, low friction force, excellent load-carrying capacity and reliable working life is both scientifically significant and technologically important. Recently, graphene has attracted tremendous attention because of its unique properties, such as outstanding mechanic performance and super-lubrication. Accordingly, we proposed here for preparation of a series of “underlayer molecule-graphene-outlayer molecule” films with sandwich structure by self-assembly method. The reactive spots on the surface of graphene will be created by oxidizing crystalline flake graphite, followed by the reduction of graphene oxide, and the amount of reactive spots could be tuned by controlling the reduction extent. The effect of reactive spots on the surface of graphene, molecule backbones and terminal groups of self-assembled molecules on the film structure and surface chemical component will be investigated. The influence of reactive spots of graphene on the ordering and density of composite films will be evaluated. The effect of film structure and chemical component on the micro/nanotribological properties and load-carrying capacity of composite films will be discussed. It is leading to the conclusion that graphene inserted in organic films will exhibit strengthening effect on the micro/nano tribological properties and load-carrying capacity.

设计和开发具有低粘着、低摩擦、高承载、长寿命的组装润滑薄膜具有重要的科学意义和实用价值。本项目旨在利用石墨烯优异的力学性能和超润滑性，构筑“过渡层分子—石墨烯—外层分子”三明治结构组装薄膜。通过氧化石墨烯还原条件的控制，实现石墨烯表面活性位点的有效调控，考察石墨烯表面活性位点的多寡对组装薄膜稳定性及内在结构（致密度、有序性等）的影响，着重考察石墨烯基组装薄膜的内在结构、表面化学组分与复合薄膜承载能力及微/纳摩擦学性能的相关性规律，探讨石墨烯对组装薄膜微/纳摩擦学特性及承载能力的增强效应；在此基础上发展低表面能、低摩擦系数、高承载能力、优异耐磨性能的石墨烯基组装润滑薄膜。

随着微电子机械系统、微纳器件、精密制造等高技术产业的快速发展，机械部件和电子器件不断微型化、高度集成化和智能化，并且对可靠性要求越来越高。然而，这类微器件运动界面的粘着、摩擦和磨损已成为影响其可靠性与耐久性的关键因素。因此，发展纳米润滑薄膜技术是降低微器件摩擦功耗、延长服役寿命、提高可靠性的关键技术。本课题鉴于有机分子组装薄膜固有的低承载力，基于石墨烯优异的力学性能及超滑特性，重点开展了“过渡层分子—石墨烯—外层分子”三明治结构组装薄膜的制备及其承载能力和微/纳摩擦学性能研究。通过石墨烯氧化还原条件的调控，实现了高性能石墨烯的可控制备，发展了有机分子/石墨烯纳米复合薄膜、石墨烯基三明治结构复合薄膜等具有协同增强微/纳摩擦学特性的纳米复合薄膜，系统开展了石墨烯的表面物理性能、有机分子薄膜的微/纳摩擦学性能，以及石墨烯基三明治结构复合薄膜的协同增强效应等研究。研究发现石墨烯基三明治结构复合薄膜中的石墨烯承载相和有机分子减摩相间的协同效应使复合薄膜呈现出更高的承载能力和更好的润滑性能。本课题研究过程中重点突破了高性能石墨烯的可控制备、石墨烯的自组装、石墨烯的功能化和稳定分散、石墨烯基复合薄膜的多重组装、有机/无机协同润滑体系等关键技术，揭示了石墨烯基三明治结构纳米复合薄膜微结构与其承载能力和微/纳摩擦学行为之间的构性关系，探讨了石墨烯对复合薄膜微/纳摩擦学特性及承载能力的增强效应，本项目研究为设计和发展高承载长寿命的石墨烯基润滑薄膜提供了实验基础。