| Summary: | 碩士 === 國立清華大學 === 動力機械工程學系 === 102 === In the past research, lots of micropump devices were developed. However, most of them have its limit in actual applications, including large size, external tubing required, cannot achieve multi-stage manipulation, liquid preloading required, hard to achieve precise control, bad on-chip capability etc. In this thesis, the developed miniaturized vacuum module made of shape memory polymer, with our new mold, successfully achieve commercialized requirement like small size, easy demolding, low price, and be able to mass production. By easy-attaching process, and developed fully-integrated PID (proportional-integral-derivative) temperature control heating system, the vacuum modules also achieve two-stage, programmed heating system, and precise control. This research successfully improves the cons of previous micropump devices, and also has a deeper investigation in heat interference, long-term storage, and dynamic transformation of the developed vacuum module.
This research could be divided into three parts. In the first part, we have a further investigation in the past vacuum module. In the exothermic and endothermic experiment the (C.V) Coefficient of Variation value between three batches of vacuum module are 3.69% and 5.33%. And by changing the shape from square to circular, the material consumption can be reduced by 22.6% and with a better transformation tolerance. And we further miniaturized the vacuum module, reducing the cross-section area to 44.18%, compared to past vacuum module. After the grid analysis, the moving point transformation ratio is 0% in circular shape and 33.65% in square shape.
In the second part, we investigated the dynamic transformation of the developed vacuum module. With the developed PID temperature control heating system, we use laser displacement instrument to examine the thickness change in constant temperature heating. We got the conclusion that we need at least 20 second to actual trigger the transformation in thickness of vacuum module. And also in the repeating heating experiment, we need more heating interval than previous one to get further thickness change. In the long-term storage experiment, the best storage condition was in the refrigerator - only 1% change in 246 days was measured. In other hand, 6.7% change in the room with air-conditioner was still acceptable.
In the third part, we investigate the condition in chip application. Here we test three different heating temperatures, and knowing in higher heating temperature, the transformation did speed up. However, this causes great effect in the temperature inside the chip microchannel. And by the IR photography analysis, we change our heating program to 2-Step heating, setting 100°C for the first 40 second and 80°C for the continuous 40 second, which has the best balance between transformation speed and temperature in the microchannel. Also the generated back pressure was also investigated. In single vacuum module, -1.5 psi ~ -2 psi was measured, and in the actual on-chip multi-stage experiment, -0.3 psi was measured in first stage, and -0.7 psi was measured in second stage. Furthermore, six actual chips were tested and successfully achieved two-stage precise microfluidic delivery.
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