介電泳致動之虛擬微流道與連續液體幫浦

Abstract

在本論文中將介電泳(Dielectrophoresis)作為驅動液體的機制，此機制可使微流體在電極圖案上形成無固體邊界之虛擬微流道(Virtual Microchannel)，而將其應用在微流體晶片中的液體微幫浦(Micropump)、微粒子收集(Microparticle Trapping)以及液體微混合器(Micromixer)。先以兩個不同強度的外加電壓製造出液體邊界的壓力差來驅動液體，並驗證液體微幫浦的功能；再以不同的電壓強度控制液體兩端的壓力差值，來討論微液體流速、元件結構設計與外加電壓的關係。藉由調變電壓及流道幾何尺寸，目前可獲得從13.31 到217.1 nl/s的流速，若將流道設計為特殊形狀，便可利用介電泳力將微粒子從液體中收集出來。除此之外，利用電壓控制液體壓力差的方式提出了一個電致式微混合器，針對微流體系統中的層流特性，此混合器可均勻且高效率的在虛擬微流道中產生擾流。本論文提出了一種可整合於實驗室晶片之微流體驅動方式，並且針對此方式提出粒子收集以及微流體混合的整合性功能。

In this thesis we use dielectrophoresis (DEP) technology to form a virtual microchannel to drive liquid based on a special arranged pattern of electrodes. This research can be applied to implement on-chip micropump, to do particle trapping and to generate efficient micromixer. We use two different voltages to create a pressure difference at the liquid boundaries to drive the liquid and to perform the function of liquid micropump. Also, we did an analysis among the voltages we applied, the pressures, the structures of device and the velocities of liquid. By changing the voltages and dimensions of liquid channels, we can manipulate the flow rate in the range from 13.31 to 211.9 nl/s. In addition, we can sort particles by designing special patterns in the microchannel to create non-uniform electric field to induce negative dielectrophoresis phenomenon of particles such that these particles would be trapped by the non-uniform electric field. This micropump can also be used to create a very efficient microfluidic mixer. Because of the laminar flow, normally the microfluidic mixing mainly achieved by diffusion so it’s slow. We designed a Y-shape microchannel and controlled the micropump pressure on the two inlet reservoirs to create unsteady laminar flow to achieve the high speed mixing. This thesis presents a novel dielectrophoresis micropump which is not only easy to fabricate and has a steady and tunable flow rate. With simple arrangement and designs, it also can be used to do particle tapping and to create a microfluidic mixer.