Novel Devices Laboratory, School of Electronics and Computing Systems, University of Cincinnati, Cincinnati, Ohio 45221, USA.
Lab Chip. 2011 Dec 21;11(24):4221-7. doi: 10.1039/c1lc20749k. Epub 2011 Oct 28.
Laplace barriers composed of full-posts or ridges have been previously reported as a mechanism for virtual fluid confinement, but with unstable displacement (capillary fingering or fluid trapping, respectively). A new platform of 'partial-posts' eliminates the disadvantages of full-posts or ridges, while providing ~60-80% open channel area for rapid electrowetting fluid transport (>5 cm s(-1)). The fluid mechanics of partial-post Laplace barriers are far more complex than previous Laplace barriers as it involves two mechanisms: fluid can first begin to propagate either between, or under, the partial-posts. Careful design of channel and partial-post geometries is required, else one mechanism will dominate over the other. The physics and performance of partial-post Laplace barriers are verified using theoretical equations, experimental results, and dynamic numerical modeling.
先前已有报道称，全柱或脊构成的 Laplace 障壁可作为虚拟流体约束的一种机制，但存在不稳定的位移（分别为毛细指进或流体捕获）。“部分柱”的新平台消除了全柱或脊的缺点，同时为快速电润湿流体传输（>5cm/s）提供了~60-80%的开放通道面积。与先前的 Laplace 障壁相比，部分柱 Laplace 障壁的流体力学要复杂得多，因为它涉及两种机制：流体首先可以开始在部分柱之间或下方传播。需要仔细设计通道和部分柱的几何形状，否则一种机制将占主导地位。使用理论方程、实验结果和动态数值模型验证了部分柱 Laplace 障壁的物理性能和性能。
