Optoelectrowetting for actuation of nanoliter droplets, revisited

重新审视用于纳升液滴驱动的光电润湿

• 批准号: 500403890
• 负责人: Professor Dr. Henning Fouckhardt
• 金额: --
• 依托单位: Arbeitsgruppe Integrierte Optoelektronik und Mikrooptik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2022
• 资助国家: 德国
• 起止时间: 2021-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/500403890?language=en
• 关键词: Optoelectrowetting; actuation; nanoliter; droplets; revisited

In the preliminary numerical investigations of the applicant's group, it was proven that the previously widespread assumption that droplet pushing with OEW (optoelectrowetting) is weaker and occurs at higher frequencies than droplet pulling is not generally valid. A closer look at the equations commonly used to describe EWOD (electrowetting) and OEW and appropriate modifications show different solutions for the contact angle change versus frequency when the OEW control light is turned on. The fact that droplet shifting can also be relatively strong and occur at low frequencies (e.g., around 50 Hz) was also evidenced by experiments. This diversity also makes it difficult to optimize the chips and their operation. Nevertheless, it would be helpful for potential applications of droplet actuation using OEW if both pulling and pushing were available as actuation options: pulling, e.g., to fuse droplets, pushing possibly to split droplets.Thus, in order to open up OEW for practical and feasible use, more detailed experimental and numerical investigations must be undertaken. This is what this project is intended to revolve around, without any specific application in the background.Both the applied voltage and its modulation frequency have a strong and not easily predictable influence on the contact angle and the net OEW force. Moreover, the electrical conductivity and the size of the droplets play a role, so that an optimization for droplets of certain properties does not automatically mean an optimization also for droplets of other parameters.Optimization of devices and operation also means finding and using the maximum of the normalized OEW force on the droplets. The light line OEW (LL-OEW) concept proposed by this group has principal advantages in this regard (not only in terms of setup geometry), because the light line allows for a larger part of the droplet's contact line to be illuminated and utilized than with perpendicular incidence of light in the usual OEW concept. The results of the project would expand the toolbox of OEW use for droplet manipulation.

在申请人的小组的初步数值研究中，证明了先前普遍的假设，即利用OEW（光电润湿）的液滴推动比液滴拉动更弱并且以更高的频率发生，通常是无效的。仔细观察通常用于描述EWOD（电润湿）和OEW的方程以及适当的修改，显示了当OEW控制灯打开时接触角变化与频率的不同解决方案。液滴移动也可以相对较强并且发生在低频（例如，50 Hz左右）也得到了实验的证实。这种多样性也使得难以优化芯片及其操作。然而，如果拉动和推动都可用作致动选项，则对于使用OEW的液滴致动的潜在应用将是有帮助的：拉动，例如，因此，为了使OEW得到实际可行的应用，必须进行更详细的实验和数值研究。这就是本项目的目的所在，而不涉及任何特定的背景应用。施加的电压及其调制频率对接触角和净OEW力有很大的影响，且不易预测。此外，液滴的电导率和尺寸也起着重要作用，因此对某些特性的液滴进行优化并不意味着对其他参数的液滴也进行优化。设备和操作的优化还意味着找到并使用液滴上的归一化OEW力的最大值。该小组提出的光线OEW（LL-OEW）概念在这方面具有主要优点（不仅在设置几何形状方面），因为光线允许比通常OEW概念中的光的垂直入射更大部分的液滴接触线被照射和利用。该项目的结果将扩大OEW用于液滴操纵的工具箱。