中国物理B ›› 2019, Vol. 28 ›› Issue (7): 74701-074701.doi: 10.1088/1674-1056/28/7/074701

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Dramatic change of the self-diffusions of colloidal ellipsoids by hydrodynamic interactions in narrow channels

Han-Hai Li(李瀚海), Zhong-Yu Zheng(郑中玉), Tian Xie(谢天), Yu-Ren Wang(王育人)   

  1. 1 National Microgravity Laboratory, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2019-03-11 修回日期:2019-04-02 出版日期:2019-07-05 发布日期:2019-07-05
  • 通讯作者: Zhong-Yu Zheng, Yu-Ren Wang E-mail:zzy@imech.ac.cn;yurenwang@imech.ac.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grants Nos. U1738118 and 11372314), the Strategic Priority Research Program on Space Science, the Chinese Academy of Sciences (A) (Grant Nos. XDA04020202 and XDA04020406), and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB22040301).

Dramatic change of the self-diffusions of colloidal ellipsoids by hydrodynamic interactions in narrow channels

Han-Hai Li(李瀚海)1,2, Zhong-Yu Zheng(郑中玉)1,2, Tian Xie(谢天)1,2, Yu-Ren Wang(王育人)1,2   

  1. 1 National Microgravity Laboratory, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2019-03-11 Revised:2019-04-02 Online:2019-07-05 Published:2019-07-05
  • Contact: Zhong-Yu Zheng, Yu-Ren Wang E-mail:zzy@imech.ac.cn;yurenwang@imech.ac.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grants Nos. U1738118 and 11372314), the Strategic Priority Research Program on Space Science, the Chinese Academy of Sciences (A) (Grant Nos. XDA04020202 and XDA04020406), and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB22040301).

摘要:

The self-diffusion problem of Brownian particles under the constraint of quasi-one-dimensional (q1D) channel has raised wide concern. The hydrodynamic interaction (HI) plays an important role in many practical problems and two-body interactions remain dominant under q1D constraint. We measure the diffusion coefficient of individual ellipsoid when two ellipsoidal particles are close to each other by video-microscopy measurement. Meanwhile, we obtain the numerical simulation results of diffusion coefficient using finite element software. We find that the self-diffusion coefficient of the ellipsoid decreases exponentially with the decrease of their mutual distance X when X < X0, where X0 is the maximum distance of the ellipsoids to maintain their mutual influence, X0 and the variation rate are related to the aspect ratio p=a/b. The mean squared displacement (MSD) of the ellipsoids indicates that the self-diffusion appears as a crossover region, in which the diffusion coefficient increases as the time increases in the intermediate time regime, which is proven to be caused by the spatial variations affected by the hydrodynamic interactions. These findings indicate that hydrodynamic interaction can significantly affect the self-diffusion behavior of adjacent particles and has important implications to the research of microfluidic problems in blood vessels and bones, drug delivery, and lab-on-chip.

关键词: hydrodynamic interaction, self-diffusion, ellipsoids, channel

Abstract:

The self-diffusion problem of Brownian particles under the constraint of quasi-one-dimensional (q1D) channel has raised wide concern. The hydrodynamic interaction (HI) plays an important role in many practical problems and two-body interactions remain dominant under q1D constraint. We measure the diffusion coefficient of individual ellipsoid when two ellipsoidal particles are close to each other by video-microscopy measurement. Meanwhile, we obtain the numerical simulation results of diffusion coefficient using finite element software. We find that the self-diffusion coefficient of the ellipsoid decreases exponentially with the decrease of their mutual distance X when X < X0, where X0 is the maximum distance of the ellipsoids to maintain their mutual influence, X0 and the variation rate are related to the aspect ratio p=a/b. The mean squared displacement (MSD) of the ellipsoids indicates that the self-diffusion appears as a crossover region, in which the diffusion coefficient increases as the time increases in the intermediate time regime, which is proven to be caused by the spatial variations affected by the hydrodynamic interactions. These findings indicate that hydrodynamic interaction can significantly affect the self-diffusion behavior of adjacent particles and has important implications to the research of microfluidic problems in blood vessels and bones, drug delivery, and lab-on-chip.

Key words: hydrodynamic interaction, self-diffusion, ellipsoids, channel

中图分类号:  (Flow phenomena in quasi-one-dimensional systems)

  • 47.60.-i
47.85.Dh (Hydrodynamics, hydraulics, hydrostatics) 47.57.J- (Colloidal systems)