Low-dimensional water transport can be drastically enhanced under atomic-scale confinement. However, its microscopic origin is still under debate. In this work, we directly imaged the atomic structure and transport of two-dimensional water islands on graphene and hexagonal boron nitride surfaces using qPlus-based atomic force microscopy. The lattice of the water island was incommensurate with the graphene surface but commensurate with the boron nitride surface owing to different surface electrostatics. The area-normalized static friction on the graphene diminished as the island area was increased by a power of ~–0.58, suggesting superlubricity behavior. By contrast, the friction on the boron nitride appeared insensitive to the area. Molecular dynamic simulations further showed that the friction coefficient of the water islands on the graphene could reduce to <0.01.

中文翻译：

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用原子分辨率探测二维水传输的结构超润滑性


在原子尺度的限制下，低维水的传输可以得到极大的增强。然而，其微观起源仍存在争议。在这项工作中，我们使用基于 qPlus 的原子力显微镜直接对石墨烯和六方氮化硼表面上二维水岛的原子结构和传输进行成像。由于表面静电不同，水岛的晶格与石墨烯表面不相称，但与氮化硼表面相称。随着岛面积增加约 0.58 次方，石墨烯上的面积归一化静摩擦力减小，表明超润滑行为。相比之下，氮化硼上的摩擦似乎对该区域不敏感。分子动力学模拟进一步表明，石墨烯上水岛的摩擦系数可以降低至<0.01。