被動式水膠時序微動閥門應用於生醫免疫反應晶片之設計與製造

Design and Fabrication of Hydro-gel based Passive Micro Valve

黃振傑

指導教授 ： 曾繁根

國立清華大學/工學院/奈米工程與微系統研究所/碩士(2009年)

摘要

本篇論文設計了一個完全無外接動力之微流體控制被動閥門，在晶片完成後從進液、流體傳輸、流體停止與再動、以及出液各個流程皆依賴流道內部之物理潛能進行。流道本體是以 PDMS 對SU-8 母模翻模，再使PDMS 流道與玻片進行氧電漿接合製成，進行測試。根據楊氏方程式，流體在微流道中前進是因為表面張力帶動，若前進過程遭遇過大的流道角度改變便可因此停止，在此可應用為閥門關閉的功能。而流體的再動是藉特殊吸水高分子材料「水膠」其吸水後會大量膨漲的特性，為其設計旁支流道使其停留在閥門口附近，在主流道進液後在閥門口停留，並與水膠接觸，因而使其膨漲，得以推動 PDMS 側壁，破壞主流道流體的壓力平衡，使流體再度流動，完成閥門作動之流程。
穩定作用之下的時序閥門，可將流體停留約 20~25 秒，然而將水膠混進不同比例之長鍊水膠之後，可進一步延至 30~35 秒，並且由於長鍊水膠的存在，可約束其膨脹量，另一方面減少水膠伸長造成流道堵塞的問題，改善閥門前後之流量差。以此被動時序閥門為基礎，未來可進階應用成多個閥門連接，以多重閥門的存在直接延長流體被停留的時間。又水膠膨脹量的巨大，可使用至不同方向的流體輸送，被動時序閥便可靈活應用在各種方向以及不同時間的流體控制。

關鍵字

水膠 ； 被動閥門

並列摘要

This paper designed a micro fluidic chip containing passive micro valve to control flows in micro channel stopping and continuing flowing after specific time. It depends only on the physical energy, which is surface tension, to activate this chip operate sample loading, flow transfer, and flow switch correctly without any input power. According to Young’s Equation, flows in micro channel will encounter a negative pressure barrier when liquid meniscus goes through an abruptly increase of side wall angle. After that, hydro-gel which was UV solidified in side channel absorbs water and swells into main channel, pushes valve and restarts flow going. The gating time from flow stopping to reflowing is about 15s for prototype.
The micro channel is fabricated by PDMS modeling with SU-8 mold, and then bonding this micro channel to a glass slide after surface plasma treatment. First, fabricate different depth of channel to find out whether gating time can varied with it or not, then prepare several portions of hydro-gel with different concentration to obtain better gating time. The swelling and UV light solidified property of hydro-gels is mainly from short chain gels, therefore the existence of long chain gels will reduce the expansion, refines whole time gating efficiency, and reduce the flow rate drop resulting from over swelling of hydro-gel furthermore.

並列關鍵字

hydrogel ； passive valve

參考文獻

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