Department of Marine Engineering, Dalian Maritime University, Dalian 116026, China.
Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON N2L3G1, Canada.
J Colloid Interface Sci. 2018 Jan 1;509:432-439. doi: 10.1016/j.jcis.2017.09.020. Epub 2017 Sep 7.
Electrokinetic movement of spherical polystyrene particles at different liquid-fluid interfaces was experimentally investigated in this paper. A novel method was developed to place the particles rightly at the interfaces formed in a large plastic container. The velocity was measured by an optical microscope. The experimental results show that the particles (3, 5 and 10μm in diameter) at the water-air interface, water-dodecane interface and NaCl solution-air interface move in the opposite direction of the applied electric field. The magnitude of the particles' velocity increases linearly with the increase in the applied electric field. Moreover, for particles of the same size, the electrokinetic velocity at the liquid-fluid interfaces is larger than particles' electrophoretic velocity in the bulk liquid phase. Under the same electric field, however, the electrokinetic velocity of smaller particles at the liquid-fluid interfaces is larger than that of larger particles. Such results are attributed to the surface charges at the liquid-fluid interface and the particle-liquid interface.
本文实验研究了不同液-液界面上球形聚苯乙烯颗粒的电动运动。本文开发了一种新方法，可将颗粒正确放置在大型塑料容器中形成的界面处。通过光学显微镜测量速度。实验结果表明，在水-空气界面、水-十二烷界面和 NaCl 溶液-空气界面处的颗粒（直径为 3、5 和 10μm）沿与外加电场相反的方向运动。颗粒的速度随着外加电场的增加呈线性增加。此外，对于相同尺寸的颗粒，在液-液界面处的电动速度大于在主体液相中的颗粒电泳速度。然而，在相同的电场下，较小颗粒在液-液界面处的电动速度大于较大颗粒的电动速度。这些结果归因于液-液界面和颗粒-液体界面处的表面电荷。
