Chemical Research in Chinese Universities ›› 2025, Vol. 41 ›› Issue (5): 1056-1066.doi: 10.1007/s40242-025-5144-3

• Articles • Previous Articles     Next Articles

Effect of Tube Diameter and Tube Length on Confined Water in Nanotubes: A Molecular Dynamics Simulation Study

YAN Zidi1,2, ZHU Zhi3, KONG Xiang-Yu1,2, XIAO Hongyan1, JIANG Lei1,2   

  1. 1. Laboratory of Bio-inspired Smart Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China;
    2. University of Chinese Academy of Sciences, Beijing 100049, P. R. China;
    3. School of Optical-Electrical Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, P. R. China
  • Received:2025-07-11 Accepted:2025-08-25 Online:2025-10-01 Published:2025-09-26
  • Contact: XIAO Hongyan, E-mail: hyxiao@mail.ipc.ac.cn;JIANG Lei, E-mail: jianglei@iccas.ac.cn E-mail:hyxiao@mail.ipc.ac.cn;jianglei@iccas.ac.cn
  • Supported by:
    This work was supported by the National Key Research and Development Program of China (No. 2021YFA1200404) and the National Natural Science Foundation of China (No. 12374214).

Abstract: The confined water in carbon nanotubes (CNTs) has an extremely fast transport rate, which has aroused great research interest. Previous studies have explored how various factors affect the structures and transport properties of confined water in CNTs. However, the fundamental understanding is still incomplete. Therefore, we studied confined water systems of different diameters and lengths in detail, and considered the effects of thermal fields and terahertz fields through molecular dynamics simulations. The simulation results revealed that the tube diameter mainly affected confined water structure; the tube length regulated the overall transport performance by adjusting the dipole flipping process and molecular translocation distance of confined water. Increasing the tube length led to a decrease in water flow, but enhanced the stability of transient unidirectional transport events. When the temperature rose, water molecules accelerated their movement, resulting in an increase in the system flow. Meanwhile, the increase in temperature caused the dipole flipping of confined water more frequently, thereby making the unidirectional transport unstable and affecting the system flux. Unlike the non-selectivity of the thermal effect, terahertz light could selectively enhance the transport of confined water. The research results are expected to promote a deeper understanding of confined water in CNTs.

Key words: Confined water, Carbon nanotube, Molecular dynamics, Tube diameter, Tube length