Low Friction Droplet Transportation on a Substrate with a Selective Leidenfrost Effect.
Low Friction Droplet Transportation on a Substrate with a Selective Leidenfrost Effect.
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DOI：
10.1021/acsami.6b06738
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发表时间：
2016-08
影响因子：
9.5
通讯作者：
L. Dodd;D. Wood;Nicasio R. Geraldi;G. Wells;G. McHale;B. Xu;Simone Stuart-Cole;James Martin;M. Newton
中科院分区：
文献类型：
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作者：
L. Dodd;D. Wood;Nicasio R. Geraldi;G. Wells;G. McHale;B. Xu;Simone Stuart-Cole;James Martin;M. Newton
介绍了一种节能的莱登弗罗斯特悬浮方法，用于输送液体和固体基质之间几乎无摩擦接触的微滴。通过加热单元的微工程，整个衬底的选择性区域可以被电热激活。由于莱登弗罗斯特效应，液滴可以悬浮，当衬底略有倾斜时，液滴可以进一步传输。选择性电加热在1 S内的加热单元上产生均匀的温度分布，以响应触发电压。除了这些实验观察，还进行了有限元模拟，以了解衬底热导率对选择性加热衬底的温度分布的影响。我们还生成了相图，以验证不同衬底材料的莱登弗罗斯特制度。最后，我们通过对衬底的结构设计，论证了在衬底倾斜(∼7°)时控制低摩擦高速液滴输运(∼65 mm/S)的可能性。这项工作为一种全新的液滴微流体学方法奠定了基础。
An energy saving Leidenfrost levitation method is introduced to transport microdroplets with virtually frictionless contact between the liquid and solid substrate. Through microengineering of the heating units, selective areas of the whole substrate can be electrothermally activated. A droplet can be levitated as a result of the Leidenfrost effect and further transported when the substrate is tilted slightly. Selective electroheating produces a uniform temperature distribution on the heating units within 1 s in response to a triggering voltage. Alongside these experimental observations, finite element simulations were conducted to understand the role of substrate thermal conductivity on the temperature profile of the selectively heated substrate. We also generated phase diagrams to verify the Leidenfrost regime for different substrate materials. Finally, we demonstrated the possibility of controlling low friction high speed droplet transportation (∼65 mm/s) when the substrate is tilted (∼7°) by structurally designing the substrate. This work establishes the basis for an entirely new approach to droplet microfluidics.