Dielectrowetting on curved surfaces
Dielectrowetting on curved surfaces
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DOI：
10.1063/5.0092216
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发表时间：
2022-05
影响因子：
4
通讯作者：
É. Ruiz-Gutiérrez;P. Baker;A. Edwards;M. Newton;I. Sage;R. Ledesma‐Aguilar;G. McHale;C. V. Brown
中科院分区：
文献类型：
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作者：
É. Ruiz-Gutiérrez;P. Baker;A. Edwards;M. Newton;I. Sage;R. Ledesma‐Aguilar;G. McHale;C. V. Brown
弯曲和柔性衬底上的可编程射流系统越来越受到人们的关注。实现可编程性的一种方法是使用电压驱动来控制表面上的顺序润湿和去湿。特别是，液体介电技术最近被证明能够通过在初始固着液滴下面施加空间周期电势来在通常具有液体排斥性的但刚性的基质上形成铺展的液膜。在这项工作中，我们演示了如何利用介电泳力在弯曲而灵活的液体基板一侧形成薄的、矩形的、电绝缘液体薄膜。我们发现，薄膜形成的实验阈值电压[公式：见文本]在−0.4 mm−1<；[公式：见文本]和0.26 mm−1的范围内与衬底曲率[公式：见文本]的值呈单调关系。通过考虑作用在薄膜上的应力平衡，包括拉普拉斯压力和麦克斯韦应力，我们得到了与曲率相关的实验阈值电压测量很好地定量一致的解析理论表达式。由此产生的物理洞察以及在具有正曲率和负曲率的弯曲和柔性衬底上的可编程润湿性的演示为成像、显示和生化分析的应用提供了基础。
Programmable fluidic systems on curved and flexible substrates are of increasing interest. One approach to achieving programmability is the controlled sequential wetting and dewetting on a surface using voltage actuation. In particular, liquid dielectrophoresis techniques have recently been shown to provide the ability to form a spread liquid film on a normally liquid repellent, but rigid, substrate via applying a spatially periodic electrical potential underneath an initial sessile droplet. In this work, we demonstrate the creation of thin, rectangular shaped, films of electrically insulating liquid on the side of a curved and flexible liquid repellant substrate using dielectrophoresis forces. We find that the experimental threshold voltage [Formula: see text] for film formation has a monotonic dependence on the value of the substrate curvature [Formula: see text] in the range −0.4 mm−1 < [Formula: see text] < 0.26 mm−1. By considering the balance of stresses acting on the films, including the Laplace pressure and the Maxwell stress, we develop an analytical theoretical expression that is in excellent quantitative agreement with our curvature dependent experimental threshold voltage measurements. The resulting physical insights and the demonstration of programmable wettability on curved and flexible substrates with both positive and negative curvature provide the foundations for applications in imaging, displays, and biochemical analysis.