In this study, a billow-mimetically peristaltic micropump based on acousticstreaming generated by quartz actuator is reported and demonstrated. A quartz chip with the cutting angle of +5° x-cut for the extensional vibrating mode is employed as actuator as well as substrate of the micropump. The actuated zone is defined merely by patterning the top and bottom electrodes thanks to its piezoelectricity and wonderful Q-factor. Due to the high sensitivity to mass loading, the resonant frequency of quartz chip will shift downward if even a tiny mass is placed on its surface. By taking advantage of this special characteristic, there is a span of resonant frequencies in the actuated zone as a result of deviations of channel height and mass loading of working fluid with an inclined glass cover. The correspondingly local region with the specific resonant frequency which matches the frequency of signal we apply on the electrodes will vibrate and generate a jet of acoustic streaming right upon it. When the signal sweeps form a certain frequency to another, the streaming jet will also shift simultaneously and produce a net flow. Therefore, our micropump with low driving voltage and low power consumption does not need the complex control circuits which used to be adopted before and a billow-mimetically peristaltic pumping can be performed just with the sweep function of only a single function generator. An optimal sweep time, which is around 6 seconds per cycle and results in a flow speed of 102.8 μm/s with the peak-to-peak voltage of 10 volts, is measured in order to attain the most efficient pumping performance and the flow speed also can be easily modulated by tuning the voltage of actuation signal according to a characterized curve of 2nd order polynomial function. With the gentle mechanism of acoustics, we realize an unprecedented and efficient micropump which is very suitable for biomedical and biochemical applications without considerable heat, ontamination of working fluid, and strong electric field. Moreover, the problem of cross contaminations can be solved by the disposability with mass production because the quartz fabrication is referred to the standard of MEMS process.

在此研究中，我們成功地利用石英產生的聲波擾流 (acoustic streaming) 實現了一種仿浪濤之蠕動式微型幫浦；其中，擁有厚度振動模態的X 切向 (X-cut)石英晶片同時擔任了基材和制動器的角色，並且憑藉著石英本身的壓電特性和極高的品質係數 (Q-factor) ，我們即可簡單地利用沈積一對上下電極的方式，在石英晶片上定義出制動區的範圍，又因其對質量負荷的高靈敏度，即使只在石英晶片表面放置一微質量，也會造成其諧振頻率的向下偏移。因此，我們以上述的特性為基礎，利用一傾斜的玻璃上蓋形成兩側相異的流道高度，造成晶片上的流體負荷不同，進而於制動區內產生一個帶狀且連續的諧振頻率分佈，而當其上的電極被施予某一頻率的交流訊號時，唯有諧振頻率符合此一訊號頻率的局部區域將產生振動，並以一聲波噴流 (jet) 之形式將其正上方的流體驅離，因此，當訊號
於某固定頻率區間進行掃描 (sweep) 時，此噴流亦會同步的進行平移，進而產生一淨流向；有鑑於此，我們所提出的低耗能幫浦並不需藉由過去複雜的電路所控制，僅需以一台波形產生器 (function generator) 之掃描功能即可進行操作，並使幫浦內的工作流體實現一種狀似浪濤之蠕動式運動；而藉由實驗得知，在本設計中，頻率掃描的最佳速度 (sweep time) 大約為6 秒一個週期，並於操作電壓
為10 伏特的情況下，可產生102.8 μm/s 的流速，我們亦可藉由調整操作電壓的方式，輕易的對流速進行調控，其流速和電壓呈現一個近似二次多項式曲線之關係。藉由聲波的溫和機制，我們開發了一個新穎和高效率的微型幫浦，其於工作時不產生高溫及強電場，亦不對工作流體造成污染，十分適合生醫或生化檢測方面的應用，此外，由於石英符合微機電 (Micro Electro Mechanical Systems) 的標準製程，因此生醫和生化領域常在意的交叉污染之問題，可以藉由大量製造之可拋棄式幫浦的方式所解決。

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