Manipulation of nano/microdroplets has recently received a great deal of attention because of its promising applications. In this study, electrowetting-on-dielectric (EWOD)-induced nanodroplet splitting between two parallel plates is investigated via molecular dynamics (MD) simulations. The results show that the splitting and non-splitting dynamics closely depend on the charge density applied to electrodes. There exists a critical charge density, above which successful splitting is observed. The plate gap and electrode size are found to significantly influence the critical charge density. Furthermore, MD simulations also demonstrate that the criterion of splitting for millimeter-sized droplets fails to predict nanodroplet splitting. On the basis of two simple geometric relations between the droplet and electrode sizes, a new criterion, 1/2 ≤ R₀/l ≤ (3/π − 1/4)^1/2, is proposed to estimate whether nanodroplets can be split, where R₀ is the initial wetting radius of nanodroplets on the plates when no charge is applied to electrodes, and l is the electrode size. The proposed criterion is in good agreement with MD simulations.

由于其前景广阔的应用，纳米/微滴的操作最近受到了广泛的关注。在这项研究中，通过分子动力学（MD）模拟研究了电介质上电润湿（EWOD）诱导的两个平行板之间的纳米液滴分裂。结果表明，分裂和非分裂动力学紧密取决于施加到电极上的电荷密度。存在临界电荷密度，在该临界电荷密度之上可观察到成功分裂。发现板间隙和电极尺寸显着影响临界电荷密度。此外，MD模拟还表明，毫米级液滴的分裂标准无法预测纳米液滴的分裂。基于液滴和电极尺寸之间的两个简单几何关系，新的标准1/2≤ 建议使用R ₀ /  l≤（3 / π  -1 / 4）^1/2来估计纳米液滴是否可以分裂，其中R ₀是当不向电极施加电荷时纳米液滴在板上的初始润湿半径，以及l是电极尺寸。所提出的标准与MD模拟非常吻合。