声表面波为能量源的微通道关闭研究

为控制微通道内微流体流向，提出了一种声表面波关闭微通道方法。在128°旋转Y切割X传播方向的LiNbO3压电基片上制作中心频率为27.5 MHz的叉指换能器，其激发的声表面波熔融聚二甲基硅氧烷微槽内固体石蜡，熔融后的石蜡由于毛细作用力沿微通道输运。当移去激发声表面波的电信号后，熔融石蜡固化并阻塞微通道，实现微通道关闭。以红色染料溶液为实验对象，对微通道进行关闭操作。结果表明，声表面波可以成功地实现微通道关闭操作，当电信号功率为31.7 dBm时，微通道关断时间约为5 min。本文工作对声表面波为驱动源的微阀研究具有一定的借鉴意义。

Switching off Microchannels Using Surface Acoustic Wave

For controlling the flow direction of microfluid in microchannels,a new method for switching off micro?channels by surface acoustic wave is presented. An interdigital transducer with 27.5 MHz center frequency is fabri?cated on a 128° yx-LiNbO3 piezoelectric substrate for exciting surface acoustic wave. Solid paraffin in poly(dimeth?ylsiloxane)groove is melted by surface acoustic wave and transported along a microchannel due to capillary force. As soon as the electric signal for exciting surface acoustic wave is moved off,the paraffin is solidified and blocked the microchannel. The microchannel is then switched off. Red dye solution is used to demonstrate the operation of switching off the microchannel. Results show that the microchannel can successfully be switched off by surface acoustic wave. Near five minutes switching time is obtained when the electric signal power is 31.7 dBm. The work is help for researchers to study on microvalves controlled by surface acoustic wave.