School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore, Singapore.
Institute of Advanced Studies, Nanyang Technological University, 60 Nanyang View, 639673, Singapore, Singapore.
Sci Rep. 2018 Jan 16;8(1):836. doi: 10.1038/s41598-018-19167-7.
Droplet spreading on substrates by electrowetting exhibits either of the two transient behaviours: one characterised by contact line oscillation, and the other one by slow spreading dynamics. The transition between these behaviours remains elusive due to the current limited understanding of the spreading dynamics on the hydrodynamical and electrical properties of electrowetting systems. To understand this transition we propose a model capturing the transition's occurrence based on both the hydrodynamical and electrical parameters. We derive the critical viscosity at which the transition occurs and reveal its subtle and often hidden dependence on the electrowetting dynamics. We find and experimentally verify that the condition for minimization of droplets' actuation time is only achieved at the transition. Particularly, the transition time as a function of damping ratio exhibits the general feature of Kramers' reaction-rate theory.
一种以接触线振动为特征，另一种以缓慢扩展动力学为特征。由于对电润湿系统的流体动力学和电学性质的扩展动力学的理解有限，这种行为之间的转变仍然难以捉摸。为了理解这种转变，我们提出了一个基于流体动力学和电学参数的模型来捕捉这种转变的发生。我们推导出发生转变的临界粘度，并揭示了它对电润湿动力学的微妙而常常隐藏的依赖关系。我们发现并通过实验验证，使液滴致动时间最小化的条件仅在转变时才得以实现。特别地，过渡时间作为阻尼比的函数表现出 Kramers 反应速率理论的一般特征。
