Rolling performance of liquid marbles enhanced by optimizing particles as digital microfluidics actuators
Rolling performance of liquid marbles enhanced by optimizing particles as digital microfluidics actuators
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DOI：
10.1016/j.sna.2018.02.028
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发表时间：
2018-05
影响因子：
4.6
通讯作者：
S. Imai
中科院分区：
文献类型：
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作者：
S. Imai
这项研究调查了使用液体弹珠传输少量的水作为数字微流体致动器滚动的弹珠下降倾斜的基板。选择疏水性磁性颗粒作为封装材料，因为它们很容易使用磁铁与内部液体分离。滚动角度的倾斜表面上的大理石开始移动，以及大理石滚动特性，进行了评估，为各种颗粒大小和材料。直径为0.6（0.1 μl）~ 4.5mm的磁性液体小球在Si和玻璃表面上以1.5 ~ 15°的小倾角开始滚动。结果表明，颗粒尺寸对滚动角和滚动加速度有很大影响，直径约为10 μm的细磁性颗粒具有良好的滚动性能。还根据颗粒研究了滚动角上的摩擦、滚动阻力和液体大理石的滑动滚动条件，并提出了优化颗粒尺寸和倾角（使用细颗粒和小倾角）的设计准则。磁性微粒的优异性能与其高的流动性有关，从而降低了滚动阻力。根据对颗粒结构的观察，高流动性可能来自颗粒的高凝聚力。
This study investigated the use of liquid marbles to transport small volumes of water as digital microfluidics actuators by rolling the marbles down an inclined substrate. Hydrophobic magnetic particles were chosen as the encapsulating material because they are readily separated from the inner liquid using a magnet. The rolling angles at which the marbles on an inclined surface began to move, as well as the marble rolling characteristics, were assessed for various particle sizes and materials. Magnetic liquid marbles from 0.6 (0.1 μl) to 4.5 mm in diameter started rolling at small incline angles from 1.5 to 15° on Si and glass surfaces. It was revealed that the rolling angles and the rolling accelerations were highly influenced by the size of particles and the fine magnetic particles, approximately 10 μm in diameter, exhibited excellent rolling performances. Friction on rolling angle, rolling resistance, and rolling condition with slip of liquid marbles were also investigated in terms of particles and a design guideline on optimizing a particle size and an inclination angle (using fine particles and a small inclination angle) was presented. The excellent performance of the fine magnetic particles was related to high mobility of the particles which lowered the rolling resistance. The high mobility was probably derived from high cohesiveness of the particles based on observations of the structure of particles.