Molecular transport through capillaries made with atomic-scale precision

By B. Radha, A. Esfandiar, F. C. Wang, A. Rooney, K. Gopinadhan, A. Keerthi, A. Mishchenko, A. Janardanan, P. Blake, L. Fumagalli and 6 more. Nature, 2016

646 citations recorded by the source corpus.

Nanometre-scale pores and capillaries have long been studied because of their importance in many natural phenomena and their use in numerous applications. A more recent development is the ability to fabricate artificial capillaries with nanometre dimensions, which has enabled new research on molecular transport and led to the emergence of nanofluidics. But surface roughness in particular makes it challenging to produce capillaries with precisely controlled dimensions at this spatial scale. Here we report the fabrication of narrow and smooth capillaries through van der Waals assembly, with atomically flat sheets at the top and bottom separated by spacers made of two-dimensional crystals with a precisely controlled number of layers. We use graphene and its multilayers as archetypal two-dimensional materials to demonstrate this technology, which produces structures that can be viewed as if individual atomic planes had been removed from a bulk crystal to leave behind flat voids of a height chosen with atomic-scale precision. Water transport through the channels, ranging in height from one to several dozen atomic planes, is characterized by unexpectedly fast flow (up to 1 metre per second) that we attribute to high capillary pressures (about 1,000 bar) and large slip lengths. For channels that accommodate only a few layers of water, the flow exhibits a marked enhancement that we associate with an increased structural order in nanoconfined water. Our work opens up an avenue to making capillaries and cavities with sizes tunable to ångström precision, and with permeation properties further controlled through a wide choice of atomically flat materials available for channel walls.

Subfields: Biomedical Engineering, Materials Chemistry, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/18af94169e08740290e25b34f5260073a3de13f9

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Biomedical Engineering

1. K. Novoselov
2. W. Jin
3. Gongpin Liu
4. A.K. Geim
5. Takashi Taniguchi
6. Kenji Watanabe
7. Olga Kazakova
8. C. Melios

In Materials Chemistry

1. K. Novoselov
2. Takashi Taniguchi
3. Kenji Watanabe
4. A.K. Geim
5. W. Jin
6. Pablo Ares
7. Gongpin Liu
8. A. Esfandiar

In Water Science and Technology

1. W. Jin
2. Gongpin Liu
3. Olga Kazakova
4. C. Melios
5. V. Panchal
6. C. Giusca

Citations in the corpus

• Anomalously low dielectric constant of confined water (2018, positive): “Note that both topographical and dielectric measurements were always carried out at low (few %) humidity because the water reservoir attached to the back side of the Si/SiN was completely isolated from the AFM chamber whereas a water flux through the channels themselves was so small (22) that it cou”
• Water on graphene: review of recent progress (2018, methodology): “Extremely fast water flow was demonstrated through artificial capillaries ingeniously fabricated using graphite crystals separated by an array of spacers made from few-layer graphene, enabling atomic precision over the channel height [54].”
• Pervaporation membrane materials: Recent trends and perspectives (2021, background): “The complex fabrication with very small area and low pore density limits this kind of graphene membranes to theoretical study [142,143].”