Lithographically Defined Micropost Arrays for Programmable Actuation and Interfacial Hydrodynamics
Lithographically Defined Micropost Arrays for Programmable Actuation and Interfacial Hydrodynamics
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DOI：
10.1021/acsapm.1c01133
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发表时间：
2021-11
影响因子：
5
通讯作者：
J. T. Brooks;J. Cribb;M. Falvo;R. Superfine
中科院分区：
文献类型：
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作者：
J. T. Brooks;J. Cribb;M. Falvo;R. Superfine
磁驱动表面附着柱（ASAP）阵列在微流体控制（包括混合和泵送）方面具有巨大潜力。被动（非致动）和主动（致动）微柱阵列也可用于控制压力驱动的流动以及流体通过微流体通道携带的微观颗粒的运动。成型技术对于生成这些微结构很流行。然而，在大表面积上制造高纵横比弹性微结构会遇到实际问题，例如脱模过程中发生的损坏。在这里，我们报告了一种制造协议，该协议使用简单的光刻工艺生成纵横比高达 23:1 且横截面积小于 1 μm2 的 ASAP。我们生成了 50 个独特的 ASAP 阵列，每个阵列在硅模具上占据 1 mm2 的面积；这些阵列具有不同的横截面形状和尺寸、纵横比以及相邻柱之间的间距。我们的方案还通过离心步骤控制 ASAP 吸头中磁性材料的水平。使用人字形 ASAP 阵列，我们已经证明了对相邻柱之间驱动相对相位的控制。此类 ASAP 可作为测试当前模型的实验平台，预测邻近的往复执行器可以在低雷诺 (Re) 数环境中成功驱动流动。
Magnetically actuating surface-attached post (ASAP) arrays have great potential in microfluidic flow control, including mixing and pumping. Both passive (nonactuating) and active (actuating) micropillar arrays can also be used to control pressure-driven flow and the motion of microscopic particles carried by the fluid through microfluidic channels. Molding techniques are popular for generating these microstructures. However, fabricating high aspect ratio elastomeric microstructures over large surface areas suffers from practical problems such as damage incurred in the demolding process. Here, we report on a fabrication protocol that generates ASAP with an aspect ratio as high as 23:1 and a cross-sectional area less than 1 μm2using straightforward photolithography processes. We generated 50 unique ASAP arrays, each occupying an area of 1 mm2on a silicon mold; these arrays have varied cross-sectional shape and size, aspect ratio, and spacings between neighboring posts. Our protocol also controls the level of magnetic material in the ASAP tips with a centrifugation step. Using a herringbone pattern ASAP array, we have demonstrated control over the relative phase of actuation between neighboring posts. Such ASAP serve as an experimental platform to test current models predicting that reciprocal actuators in close proximity can successfully drive flow in a low Reynolds (Re) number environment.