Controllable Nanotribological Properties of Graphene Nanosheets.
Controllable Nanotribological Properties of Graphene Nanosheets.
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石墨烯纳米片的可控纳米摩擦学特性
DOI：
10.1038/srep41891
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发表时间：
2017-01-31
影响因子：
4.6
通讯作者：
Liu L
中科院分区：
文献类型：
--
作者：
Zeng X;Peng Y;Lang H;Liu L
石墨烯作为一种众所周知的固体润滑剂，由于制备方法或后处理的不同，其表面和结构特征也不同，因此具有不同的纳米摩擦学性能。通过等离子体处理和热还原，制备了具有可控表面润湿性和结构缺陷的石墨烯纳米片。利用标定原子力显微镜研究了石墨烯纳米片的纳米摩擦学性能。摩擦力随等离子体处理时间的延长而增大，这是由于表面润湿性的增加和结构缺陷的引入。短时间等离子体处理摩擦力的增加是由于表面亲水性的增强。长时间的等离子体处理增加了摩擦力，这可以归因于表面亲水性增强和产生的结构缺陷的综合作用。当表面性能通过热还原统一时，结构缺陷作为单一因素也增加了摩擦力。经过等离子体处理的石墨烯纳米片的表面润湿性和纳米摩擦学性能可以随着时间的推移恢复到初始水平。提出了一种改进的弹簧模型来阐述表面润湿性和结构缺陷对纳米摩擦学性能的影响。
Graphene as one type of well-known solid lubricants possesses different nanotribological properties, due to the varied surface and structural characteristics caused by different preparation methods or post-processes. Graphene nanosheets with controllable surface wettability and structural defects were achieved by plasma treatment and thermal reduction. The nanotribological properties of graphene nanosheets were investigated using the calibrated atomic force microscopy. The friction force increases faster and faster with plasma treatment time, which results from the increase of surface wettability and the introduction of structural defects. Short-time plasma treatment increasing friction force is due to the enhancement of surface hydrophilicity. Longer-time plasma treatment increasing friction force can attribute to the combined effects of the enhanced surface hydrophilicity and the generated structural defects. The structural defects as a single factor also increase the friction force when the surface properties are unified by thermal reduction. The surface wettability and the nanotribological properties of plasma-treated graphene nanosheets can recover to its initial level over time. An improved spring model was proposed to elaborate the effects of surface wettability and structural defects on nanotribological properties at the atomic-scale.