School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.
National Graphene Institute, University of Manchester, Manchester M13 9PL, UK.
Science. 2017 Oct 27;358(6362):511-513. doi: 10.1126/science.aan5275.
In the field of nanofluidics, it has been an ultimate but seemingly distant goal to controllably fabricate capillaries with dimensions approaching the size of small ions and water molecules. We report ion transport through ultimately narrow slits that are fabricated by effectively removing a single atomic plane from a bulk crystal. The atomically flat angstrom-scale slits exhibit little surface charge, allowing elucidation of the role of steric effects. We find that ions with hydrated diameters larger than the slit size can still permeate through, albeit with reduced mobility. The confinement also leads to a notable asymmetry between anions and cations of the same diameter. Our results provide a platform for studying the effects of angstrom-scale confinement, which is important for the development of nanofluidics, molecular separation, and other nanoscale technologies.
在纳流控领域，可控地制造尺寸接近小分子离子和水分子的毛细管一直是一个终极但看似遥远的目标。我们报告了通过有效去除体单晶中单个原子层而制造的最终极窄狭缝中的离子传输。原子级平坦的埃级狭缝具有较小的表面电荷，这允许阐明空间位阻效应的作用。我们发现，水合直径大于狭缝尺寸的离子仍然可以渗透，尽管迁移率降低。这种限制也导致相同直径的阴离子和阳离子之间出现明显的不对称性。我们的结果为研究埃级限制的影响提供了一个平台，这对于纳流控、分子分离和其他纳米技术的发展非常重要。
