應用旅波電滲於微混合器之模擬與分析

Abstract

微混合器為生醫與微系統內常見的主要元件之一，經常被利用於混合生物試體或化學藥劑等，在生醫及微系統工程上佔有極為重要的角色。近年來，已發展出相當多種不同作動方式之微混合器，如聲波式混合器、電動式微混合器、磁動式微混合器等，其中利用電動式微混合器之應用更是層出不窮。在電動力學應用於微混合器方面，過去已有許多關於電熱微混合器及電滲微混合器之研究。在電滲微混合器上又可再細分為直流電滲微混合器、交流電滲微混合器和旅波電滲微混合器三大類。目前針對直流電滲及交流電滲應用於微混合器的實驗與模擬皆相當完備，在旅波電滲微混合器方面之研究則略顯不足。 本文即是利用有限元素分析軟體Comsol Multiphysics針對旅波電滲應用於微混合器之效能進行分析與討論，藉由電極陣列之相位排列、改良的平台設計使流場產生特殊之渦形，透過渦形局部擾動流體，使不同濃度之流體可於短距離內達到較佳的混合效率。本文最後提出兩種平台設計及電極相位模式之電極組，透過多個電極組之排列串接，使微混合器在400μm之流道長度內達到97.89%的高混合效率。

Micromixer is one of the commonly microfabricated components in the microfluidic devices, and it is frequently adopted for mixing diverse biological samples. In recent years, types of micromixers which are actuated with different extrenal energy inputs are constantly developed, such as the acoustic, electrokinetic, and magneto-hydrodynamic type, etc.. Below the multitudinous investigation with regard to micromixers, the application on the electrokinetic micromixer is one of popular topics. For micromixers actuated with electrokinetic mechanisms, electrothermal(ET) and electroosmotic(EO) micromixers are widely discussed. EO micromixers mainly include three categories: DCEO, ACEO and TWEO micromixers. So far, most of them are concentrated on the experimental and simulated application on DCEO and ACEO micromixers, whereas the relevant application on TWEO micromixers is extremely less. Consequently, in this paper, we will analyze and discuss the performance of TWEO micromixers with FEM software, COMSOL Multiphyiscs. In the limited length of microchannels, it is discovered from the simulation consequences that specific vortex pairs are generated by phase alternations of AC signals and geometrical modifications of electrodes, so that the flowing field can be stirred, two separated samples inside it mixed and mixing efficiency promoted. Finally, we propose two mixing modes in terms of assembling AC signal phases and electrode geometries, and 97.89% mixing efficiency can be achieved in the length of 400μm microchannels.