吳政忠臺灣大學：應用力學研究所張益祥Chang, I-HsiangI-HsiangChang2007-11-292018-06-292007-11-292018-06-292004http://ntur.lib.ntu.edu.tw//handle/246246/62445Using Surface acoustic wave (SAW) to drive droplets is developed recently. SAW could induce an acoustic streaming inside a droplet and move it along the propagation direction. However, the SAW amplitudes radiated from uniform IDT are equivalent along the aperture, and they move the droplets within the same delay line simultaneously. This phenomenon is not suitable for a multi-channel microfluidic chip. For this reason, SFIT is used to replace uniform IDT. The SAW amplitude profile excited by SFIT is not uniform along the aperture, and the position of the maximum amplitude can be changed by adjusting the input frequency. Therefore, the droplets can be driven individually by varying the frequency. In addition, the frequency response can be used to detect the position of the droplet because the transmitted SAW intensity is radiated into the liquid. In this thesis, because hydrophobic film and acoustic streaming dominate the performance of driving droplets, we introduce these mechanisms first. And then, we use the coupling-of-modes (COM) model to simulate the amplitude profile and the frequency response of SFIT. According to the simulation, we can design optimum SFIT to detect and move the droplets. The frequency responses of the experiments for detecting droplets show a good agreement with the simulated results. Furthermore, the droplets are also driven respectively at different frequency by SFIT. Therefore, using SFITs to construct a multi-channel microfluidic chip is proven feasible.致謝 I ABSTRACT 2 NOTATIONS 3 CONTENTS VI FIGURES VIII TABLES X CHAPTER 1 INTRODUCTION 1 1-1 RESEARCH MOTIVATION 1 1-2 LITERATURE REVIEW 2 1-3 CONTENTS OF THE CHAPTERS 4 CHAPTER 2 ACTUATING DROPLETS BY SURFACE ACOUSTIC WAVE 6 2-1 SURFACE ENERGY 6 2-1.1 Contact angle 7 2-1.2 Self –Assembled Monolayers 8 2-2 THEORY OF MOVING DROPLETS BY SAW 10 2-2.1 Acoustic Streaming 11 2-2.2 Leaky Rayleigh Wave 14 CHAPTER 3 ANALYSIS OF SLANTED FINGER INTERDIGITAL TRANSDUCER 20 3-1 COUPLING-OF-MODES MODEL 20 3-1.1 The coupling-of-modes equations 21 3-1.2 [P] Matrix 24 3-1.3 [Y] Matrix 25 3-2 THE SIMULATION OF SFIT 27 3-2.1 Amplitude profile 27 3-2.2 Frequency response for detecting the position of droplets 32 3-3 EFFECTS OF PARAMETERS ON THE SFIT 34 CHAPTER 4 FABRICATION, MEASUREMENT AND TRANSPORT TEST 48 4-1 FABRICATION OF SAW DEVICES 48 4-2 FABRICATION OF THE HYDROPHOBIC FILM 49 4-3 DRIVING AND DETECTING THE DROPLETS 52 4-3.1 Mixing and moving the droplets 52 4-3.2 Comparison of the measurement and simulated results 53 4-3.3 Moving droplets by SFIT 55 CHAPTER 5 CONCLUSIONS AND FUTURE WORKS 72 5-1 CONCLUSIONS 72 5-2 FUTURE WORKS 73 REFERENCES 76en-US表面聲波多通道微流體晶片耦合模型理論相對振幅分佈斜交指叉式表面聲波元件C18疏水性薄膜聲射流接觸角COM modelOTSMulti-channel microfluidic chipAmplitude profileContact angleSAWSFITAcoustic streamingthesis