According to the Chinese Academy of Sciences, October 19, 2016, recently, the research team of the University of Science and Technology of China has made important progress in water transport of graphene nanochannels in cooperation with Andre Geim, a Nobel Prize winner of physics and professor of the University of Manchester in the United Kingdom. Wang Fengchao, a special associate researcher at China University of Science and Technology, is the co-author of the paper.
As we all know, graphene is a two-dimensional crystal composed of carbon atoms with only one layer of atomic thickness. Graphene is not only the thinnest material, but also the surface is very smooth. Using this characteristic of graphene, researchers have proposed a new method to construct nanochannels. The size adjustment accuracy of the channels can be controlled at 0.34 nm, which is the smallest nanochannel ever prepared in the laboratory.
Nano-scale material transport has been one of the focuses of current experimental and theoretical research, especially when the channel size is small to the molecular level, the surface properties of the channel and solid-liquid interface interaction will play a decisive role in material transport. The results show that water moves at a high speed in a nearly frictionless state in the nanochannel, but the flow details and mechanism in the channel are difficult to characterize and analyze by current experimental methods. The core contribution of the research team of China University of Science and Technology in this work is: theoretical analysis and molecular simulation are used to study the water transport mechanism in nano-channels. It is found that the solid-liquid interface interaction at molecular scale will increase the driving force of water transport, thus greatly improving the water transport efficiency and making the fluid transport at nano-scale. The size effect is quite different from the macroscopic scale. The study reveals that the solid-liquid interface interaction has a decisive influence on the nano flow behavior.
Fig. 1. Graphene nanochannel; size effect of water transport at nanoscale observed in experiments and simulations; water flow in the nanochannel in molecular simulations
Nanochannels constructed precisely by two-dimensional materials, such as graphene, provide a new platform and ideas for nanoscale material transport. This study not only has a significant impact on the understanding and cognition of the fluid transport mechanism at nanoscale, but also provides important reference for the design and development of novel nanofluidic devices. The nanodevices based on the design scheme of the nanochannel will further enhance the applications of two-dimensional materials such as graphene in filtration, screening, seawater desalination and gas separation.