鏡像介電濕潤效應應用於平行微液滴操控、介電泳 微粒子分離與雙凸液態微透鏡之研究

Abstract

本篇論文主要是以鏡像介電濕潤現象為一出發點，並且分別衍生出雙微液滴平行處理微流體晶片、絕緣介電泳晶片、與可變焦式雙凸液態微透鏡三個大方向。 雙微液滴平行處理微流體晶片與傳統晶片最大不同之處在於置放一介電薄膜於傳統晶片之上下兩平行ITO玻璃基板中，將原先微液滴操控空間一分為二，當施加適當電壓時，兩0.55 □L微液滴可同時被操控而不需增加電路之複雜性。並且利用此操控雙微液滴的方法再與絕緣結構介電泳技術的結合，我們將雙微液滴移至10 x 10 □m2矩陣孔洞處，並且施予適當的電壓產生不均勻電場，藉由介電泳技術分離5 □m與1 □m之微粒子，並且堆積待測微粒子於洞口處，達到分離與濃縮之功效。 在另一方面藉由鏡像介電濕潤之現象，我們將其應用至光學上，欲發展出一套可變焦式雙凸液態微透鏡，在此雙微液滴大小約為1.2 □L，經實驗測試其焦距範圍約0.8 mm至1 mm之間。在發展的初期，我們則採用開放式介電濕潤結構之晶片，藉由施加電壓於1.2 □L微液滴改變液態透鏡之焦距，並且改變電極設計移動我們的微液滴，發展出一簡易之雷射定位系統。

In this thesis, we investigate the phenomenon of mirror- electrowetting-on-dielectric (MEWOD) and demonstrate its applications of parallel droplet manipulations, dielectrophoretic microparticle separations assisted by insulator-based dielectrophoresis (iDEP), and dual convex tunable liquid lenses.

First, we design a parallel droplet manipulation device, where two droplets are manipulated on two vertically arranged planes, separated by a dielectric sheet. Two stacked droplets can be actuated concurrently by MEWOD without increasing the complexity of the control circuits. Second, we integrate MEWOD and iDEP to manipulate droplets and separate microparticles. Droplets containing 1 □m and 5 □m microparticles are transported by MEWOD to a 10 x 10 □m2 microhole array. Separation of microparticles is then obtained by iDEP.

Third, we applied MEWOD to achieve dual convex liquid lenses. The focal length of the tested convex liquid lens composed of two 1.2 □L droplets is tunable from 0.8 mm to 1 mm. A laser tracking system using a tunable liquid lens is examined by EWOD with coplanar electrodes. By altering the contact angle and the position of a droplet, the laser beam can be focused on a desired position in space.