The nonlinear electrokinetic motion of electrically induced Janus droplets (EIJDs) in a microchannel is studied in this paper. The EIJDs were fabricated by operating the positively charged aluminum oxide nanoparticles to partially cover the oil droplets with electric field. The nanoparticle coverage of the EIJDs changes with the electric field strength, which leads to the variation of the electrophoretic mobility of the EIJDs. Therefore, the electrokinetic velocity of the EIJDs in a microchannel changes nonlinearly with the electric field strength. In this research, the variations of the nanoparticle coverage under both constant and time-varying electric fields were studied first. The results indicate that the nanoparticle coverage of the EIJDs decreases with the increase of the electric field strength, and an empirical equation for calculating nanoparticle coverage as a function of the electric field was derived. Under time-varying electric field, the variation of nanoparticle coverage lags behind the change of electric field, and the nanoparticle coverage changes differently under different time-varying electric fields. The experimental results of the electrokinetic motion of the EIJDs in a microchannel confirm that the electrokinetic velocity increases nonlinearly with the electric field. Due to the lag of the nanoparticle coverage change, the variation of the electrokinetic velocity in a microchannel is different between the increasing and decreasing periods of the time-varying electric field.

本文研究了微通道内电感应Janus液滴（EIJDs）的非线性电动运动。EIJD是通过操作带正电的氧化铝纳米粒子以部分覆盖电场产生的油滴而制成的。EIJD的纳米颗粒覆盖度随电场强度而变化，这导致EIJD的电泳迁移率发生变化。因此，微通道中EIJD的电动速度随电场强度非线性变化。在这项研究中，首先研究了恒定电场和时变电场下纳米颗粒覆盖率的变化。结果表明，随着电场强度的增加，EIJDs的纳米颗粒覆盖率降低，推导了计算纳米颗粒覆盖率随电场变化的经验方程。在时变电场下，纳米粒子覆盖率的变化滞后于电场的变化，并且纳米粒子的覆盖率在不同时变电场下的变化也不同。EIJD在微通道中的电动运动的实验结果证实，电动速度随电场非线性增加。由于纳米粒子覆盖率变化的滞后，在微通道中的电动速度的变化在随时间变化的电场的增加和减少时段之间是不同的。纳米粒子的覆盖率变化滞后于电场的变化，并且纳米粒子的覆盖率在不同的时变电场下具有不同的变化。EIJD在微通道中的电动运动的实验结果证实，电动速度随电场非线性增加。由于纳米粒子覆盖率变化的滞后，在微通道中的电动速度的变化在随时间变化的电场的增加和减少时段之间是不同的。纳米粒子覆盖率的变化滞后于电场的变化，而纳米粒子覆盖率在不同时变电场下的变化也不同。EIJD在微通道中的电动运动的实验结果证实，电动速度随电场非线性增加。由于纳米粒子覆盖率变化的滞后，在微通道中的电动速度的变化在随时间变化的电场的增加和减少时段之间是不同的。