针对目前液滴在方形电极上分离存在的成功率低, 分离后的子液滴体积误差大等问题, 本文提出了一种扇形电极结构的数字微流控芯片。在分析液滴在方形电极上分离的影响因素后, 结合半月形电极、哑铃状电极和弓形电极的优点设计了扇形电极。与传统分离方式相比, 新型芯片在分离前能够调整液滴的初始位置, 分离过程中能保证液滴平稳收缩, 从而提高分离的成功率和精度。最后使用去离子水作为实验对象, 对扇形芯片的分离效果进行了实验验证。结果表明: 使用扇形电极在不同极板间距下分离液滴的成功率均高于传统电极, 并且分离后的子液滴平均误差在±2%以内, 变异系数低至1.83%, 通过减少分离电极的尺寸还能进一步提高分离精度。实验数据证明了扇形分离电极数字微流控芯片能够提高分离的成功率和精度。

To address the low success rate of droplet separation and the inaccurate daughter droplet volume on the square electrode, a digital microfluidic chip with fan-shaped electrode was proposed and its separation effect was studied. After analyzing the factors affecting droplet separation on the square electrode, the fan-shaped electrode was designed in combination with the advantages of crescent electrodes, dumbbell electrode, and bow electrodes. Compared with traditional separation, the novel chip can adjust the initial position of the droplets before separation to ensure the smooth shrinkage of the droplet during the separation process and improve the success rate and precision of the droplet volume. Deionized water was used as the experimental object to verify the separation effect of the novel chip. The results show that the success rates of droplet separation at different channel heights on novel electrodes are higher than that on conventional electrodes. The average error of daughter droplets is controlled at ±2%, and the coefficient of variation is as low as 1.83%. The separation accuracy can be further improved by reducing the size of the separation electrodes. The experimental results indicate that the separation success rate and splitting precision on digital microfluidic chip with fan-shaped electrode was significantly improved.