School of Physics and Astronomy, University of Manchester, Manchester, UK.
Science. 2012 Jan 27;335(6067):442-4. doi: 10.1126/science.1211694.
Permeation through nanometer pores is important in the design of materials for filtration and separation techniques and because of unusual fundamental behavior arising at the molecular scale. We found that submicrometer-thick membranes made from graphene oxide can be completely impermeable to liquids, vapors, and gases, including helium, but these membranes allow unimpeded permeation of water (H(2)O permeates through the membranes at least 10(10) times faster than He). We attribute these seemingly incompatible observations to a low-friction flow of a monolayer of water through two-dimensional capillaries formed by closely spaced graphene sheets. Diffusion of other molecules is blocked by reversible narrowing of the capillaries in low humidity and/or by their clogging with water.
纳米孔道的渗透在过滤和分离技术材料的设计中非常重要，因为在分子尺度上会出现异常的基本行为。我们发现，由氧化石墨烯制成的亚微米厚的膜可以完全阻止液体、蒸汽和气体（包括氦气）的渗透，但这些膜允许水无阻地渗透（H(2)O 通过膜的渗透速度至少比 He 快 10(10)倍）。我们将这些看似矛盾的观察结果归因于通过紧密间隔的石墨烯片形成的二维毛细管中单分子层水的低摩擦流动。在低湿度下，通过毛细管束的可逆收缩或通过毛细管被水堵塞，阻止了其他分子的扩散。
