SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2022, Vol. 42 ›› Issue (2): 210-218.DOI: 10.1016/j.cjche.2021.07.028

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Determination of interfacial tension and viscosity under dripping flow in a step T-junction microdevice

Li Ma, Yongjin Cui, Lin Sheng, Chencan Du, Jian Deng, Guangsheng Luo   

  1. State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
  • 收稿日期:2021-05-18 修回日期:2021-07-07 出版日期:2022-02-28 发布日期:2022-03-30
  • 通讯作者: Guangsheng Luo,E-mail:gsluo@tsinghua.edu.cn
  • 基金资助:
    This work was financially supported by the National Natural Science Foundation of China (21991104).

Determination of interfacial tension and viscosity under dripping flow in a step T-junction microdevice

Li Ma, Yongjin Cui, Lin Sheng, Chencan Du, Jian Deng, Guangsheng Luo   

  1. State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
  • Received:2021-05-18 Revised:2021-07-07 Online:2022-02-28 Published:2022-03-30
  • Contact: Guangsheng Luo,E-mail:gsluo@tsinghua.edu.cn
  • Supported by:
    This work was financially supported by the National Natural Science Foundation of China (21991104).

摘要: Microfluidic approaches for the determination of interfacial tension and viscosity of liquid-liquid systems still face some challenges. One of them is liquid-liquid systems with low interfacial and high viscosity, because dripping flow in normal microdevices can't be easily realized for the systems. In this work, we designed a capillary embedded step T-junction microdevice to develop a modified microfluidic approach to determine the interfacial tension of several systems, specially, for the systems with low interfacial tension and high viscosity. This method combines a classical T-junction geometry with a step to strengthen the shear force further to form monodispersed water/oil (w/o) or aqueous two-phase (ATP) droplet under dripping flow. For systems with low interfacial tension and high viscosity, the operating range for dripping flow is relative narrow whereas a wider dripping flow operating range can be realized in this step T-junction microdevice when the capillary number of the continuous phase is in the range of 0.01 to 0.7. Additionally, the viscosity of the continuous phase was also measured in the same microdevice. Several different systems with an interfacial tension from 1.0 to 8.0 mN·m-1 and a viscosity from 0.9 to 10 mPa·s were measured accurately. The experimental results are in good agreement with the data obtained from a commercial interfacial tensiometer and a spinning digital viscometer. This work could extend the application of microfluidic flows.

关键词: Step T-junction, Interfacial tension, Viscosity, Force balance

Abstract: Microfluidic approaches for the determination of interfacial tension and viscosity of liquid-liquid systems still face some challenges. One of them is liquid-liquid systems with low interfacial and high viscosity, because dripping flow in normal microdevices can't be easily realized for the systems. In this work, we designed a capillary embedded step T-junction microdevice to develop a modified microfluidic approach to determine the interfacial tension of several systems, specially, for the systems with low interfacial tension and high viscosity. This method combines a classical T-junction geometry with a step to strengthen the shear force further to form monodispersed water/oil (w/o) or aqueous two-phase (ATP) droplet under dripping flow. For systems with low interfacial tension and high viscosity, the operating range for dripping flow is relative narrow whereas a wider dripping flow operating range can be realized in this step T-junction microdevice when the capillary number of the continuous phase is in the range of 0.01 to 0.7. Additionally, the viscosity of the continuous phase was also measured in the same microdevice. Several different systems with an interfacial tension from 1.0 to 8.0 mN·m-1 and a viscosity from 0.9 to 10 mPa·s were measured accurately. The experimental results are in good agreement with the data obtained from a commercial interfacial tensiometer and a spinning digital viscometer. This work could extend the application of microfluidic flows.

Key words: Step T-junction, Interfacial tension, Viscosity, Force balance