低功率电信号激发的不连续声表面波破裂压电基片上液滴(英文)

Splitting Drops Using Discontinuous Surface Acoustic Wave Generated by Low Electric Signal Power

提出了一种新的微流器件上液滴破裂的方法。采用微电子工艺在128°yx-LiNbO3基片上制作一对中心频率为27.5MHz叉指换能器和反射栅。瞬间下降电信号激发不连续声表面波辐射入待破裂液滴,在其内产生不连续声流。当电信号突然消失,部分微流体由于惯性力从液滴中飞逸。采用红色染料溶液进行液滴破裂实验,结果表明:当电信号功率从12.3 dBm突然降低到-3.98 dBm,压电基片上液滴能产生破裂,并且其均匀性受液滴体积影响。所提出的液滴破裂方法为微流系统进行微流分析提供了一种新的样品前处理技术,具有一定的学术价值。

A new method of splitting drops on a microfluidic device is presented. A pair of interdigital transducers with 27. 5MHz center frequency is fabricated on a 128~ yx-LiNbO3 piezoelectric substrate using microelectric technology. An ＂on-to-off＂ radio frequency signal is applied to one of interdigital transducers to excite discontinuous surface acoustic wave, which radiates into a drop to be spilt, leading to the discontinuous acoustic streaming. When acoustic streaming force is suddenly disappeared, part of liquid is run away from the drop due to the inertia. Red dye solution drops are demonstrated as the experimental sample, and the size of a drop after breakup is measured. Results show that a drop can be split when a RF signal is suddenly decreased from 12.3 dBm to -3.98 dBm. The experimental results also show that initial volume of the drop affects the uniformity of drop breakup. The presented method provides a new sample preparation technique, which will be helpful for microfluidic biochemical analysis.