臺灣博碩士論文加值系統

本論文的目的在探討利用光碟片(CD)形式之微流體平臺做特定濃度元件的研發。主要的設計包含2個注入槽，2個接收槽，4條主要的流道，藉由設計流道的幾何圖形可以得到特定的濃度。利用CO2雷射雕刻機在厚度1 mm 的PMMA-壓克力基材上，製作出微流道等主結構的微流體平臺。雷射雕刻機可以快速的雕刻出所需要的流道尺寸及圖形；且此光碟片形式之微流體平臺是可以重複使用的。壓克力基材- PMMA ，這是一種可塑性高、輸水性的材料，富有高透明度、較便宜且加工簡單、便利的優點。另一方面，利用冷膜(PVC)來護貝雕刻的結構，達到防止在實驗進行中液體會溢出流道的目的。工作流體所使用的是紅色食用色素與水，當兩種流體交會時會得到深淺不同的紅色，而產生不同的濃度反應。利用鑽孔機改造的旋轉機制，使光碟在瞬間達到5,000RPM(忽略加速度的影響)，進而產生離心力，以便操控流體流入接收儲存槽內。
實驗結果顯示此光碟片之微流體平台可以獲得從0%到100%之間不同的濃度。藉由改變流道的寬度或是長度，得到30.6%，40.6%，50.7%，60.5%等特定的濃度。利用216灰階來處理所得到的紅色色素灰階值，分析從0%到100% 的濃度，可得到較高解析度的濃度分布曲線。雖然，實驗結果顯示準確性並不如預期的完美，但這光碟片之微流體平臺的設計，的確可以提供方便且快速的方法獲得不同的濃度。在本實驗中，雕刻時產生的結構粗糙度、旋轉或是注入時氣泡的產生和以及科氏力對流體的的影響，這些都是本實驗中需要改進的問題關鍵。

The goal of this thesis is to design a microfluidic platform on a compact disk (CD) that performs generation of concentration. Design concept consists of two supply reservoirs, two receiving reservoirs, and four main channels. The microchannel geometries are varied in order to attain a particular concentration. The CD microfluidic platform was fabricated using CO2 laser engraver on the material poly(methylmethacrylate) (PMMA). PMMA was chosen due to that it is inexpensive, transparent, and ease of fabrication without a cleanroom. Channel encapsulation was performed using gloss cold lamination film, with the material polyvinyl chloride (PVC). Fluid samples used were red food dye and clear water. The spin protocol was just one step with rotational speed at 5,000 RPM, under negligible acceleration.

Results show distinct concentration between 0% to 100% was obtained. Concentrations of 30.6%, 40.6%, 50.7%, 60.5% are obtained due to changes in channel width and length as designed. Analysis by gray level from 0% to 100% proves that it is a simple and accurate way to measure concentration gradient. The proposed design using centrifugal-based platform can provide convenient and speedy way for generation of concentration. However, accuracy is not as good as expectation; the difference between analysis and experimental concentration was within 10%. Roughness, bubble formation and Coriolis force in the structure are believed to be the key problems that need to be improved. This CD microfluidic platform might be useful to rapidly attain the desired concentration for chemical and/or biology applications.

Abstract……………………………………………………………………………5
中文摘要……………………………………………………………………..6
Chapter 1. Introduction………………………………………………………7
1.1 Microfluidic technology…………………………………………………….7
1.2 Motivation and goal……………………………………………………….10
Chapter 2. Theory……………………………………………………………..11
2.1 Flow in Centrifugal platform…………………….....................................11
2.2 Consideration of non purely radial flow……….…………………………13
2.3 Design concept and analysis …………………………………………….14
Chapter 3. Compact disk (CD) Fabrication……………………………18
3.1 Characteristic of PMMA material……………………...………………….18
3.2 CO2 laser engraving……………………………………………………….18
3.3 Ultrasonic cleaner………………………………………………………….20
3.4 Bonding……………………………………………………………….........21
Chapter 4. Experimental Aspects………………………………….....…..23
4.1 Sample preparation and power source……………..…………...………23
4.2 Experimental setup………………………………………………………...25
4.2.1 Verification of fabricated geometries……………………….…......26
4.2.2 Effect of Coriolis force……………………………………...............27
4.2.3 Effect of channel width and length on concentration……………..29
4.2.4 Measurement of concentration via gray level test…………..…....31
Chapter 5. Experimental Results………………...…………………34
5.1 Gray level test……………………………………………………………...34
5.2 Parameters of CD platform………………………………..………….…..36
5.3 Effect of Coriolis force…………………………………………………......43
5.4 Effect of channel width on concentration………...…………………......44
5.5 Effect of channel length on concentration…………………………….…50
5.6 Discussion………………………………………….………………………53
Chapter 6. Conclusions and Future Work…………………………….57
6.1 Conclusions………………………………………………………….….....57
6.2 Suggestions……………………………………………..………………....57
Reference………………………………………………………………………….59

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