RT Journal Article A1 Jiaojiao Ma,Kaiwen Guan,Yu Jiang,Yang Cao,Sheng Hu; AD 固体表面物理化学国家重点实验室, 中国 ; 能源材料化学协同创新中心, 中国 ; 固体表面物理化学国家重点实验室, 中国 ; 能源材料化学协同创新中心, 中国 ; 固体表面物理化学国家重点实验室, 中国 ; 能源材料化学协同创新中心, 中国 ; 福建省能源材料科学技术创新实验室(IKKEM), 中国 ; 萨本栋微米纳米科学技术研究院, 中国 ; 固体表面物理化学国家重点实验室, 中国 ; 能源材料化学协同创新中心, 中国 ; 福建省能源材料科学技术创新实验室(IKKEM), 中国 ; 萨本栋微米纳米科学技术研究院, 中国 ; 固体表面物理化学国家重点实验室, 中国 ; 能源材料化学协同创新中心, 中国 T1 Two-dimensional capillaries assembled by van der Waals heterostructures YR 2023 IS 3 vo 16 OP 4119-OP 4129 K1 two-dimensional materials;van der Waals heterostructures;mass transport;atomic-scale capillaries;smallest confinement AB Research on two-dimensional materials in the past decades has brought many insights of low-dimensional science on a wide range of related topics. As a novel two-dimensional structure, the atomic-scale capillaries which can conceptually be seen as the empty space left by removing few layers of two-dimensional materials from their bulk van der Waals crystals offer a unique platform of investigating physical and chemical processes of ions, molecules, and atoms under two-dimensional confinements. Investigation of many important problems, such as capillary condensation and water network structure that are difficult to be explored experimentally in other confinement structures, has now been accessible; two-dimensional migration of ions, water, and gases shows abnormal transport properties beyond conventional theory prediction; influence of quantum effect to molecule permeation is observable even at room temperature. All these discoveries greatly extend our fundamental understandings of nano-science, and stimulate the development of potential applications. We review the fabrication of these two-dimensional capillaries which are created by the assembly of van der Waals heterostructures, and discuss the ultimate steric effects in the smallest possible confinements. Exotic interactions between capillary interior and confined particles are also summarized. When coupled with external stimuli, these channels exhibit tunable mass transport behaviors, which not only gives feedback to the mechanism understanding but in turn guides the channel structure optimization. SN 1998-0124 LA EN