- 學位論文
以雙相水凝膠顆粒作為微型pH及溫度感測器之研究
Research of Bihydrogel Particles as pH and Thermal Microsensor
摘要
環境感應性水凝膠(Stimuli-responsive hydrogel)在外界環境發生改變時，水凝膠的體積能隨環境參數產生劇烈變化，近年來已有相當多的研究將此類材料應用在環境感測器上。 本實驗室先前曾參考雙金屬片(Bimetallic strip)在溫度變化下因為兩種金屬體積膨脹程度不同而使金屬片彎曲的概念，以pH感應性水凝膠─丙烯酸(acrylic acid)，製作出pH雙相水凝膠感測器[1]。本研究延續此概念並以溫度感應性水凝膠─N-異丙基丙烯醯胺(NIPAAm)，製作出溫度雙相水凝膠感測器以驗證此概念廣泛通用在各種感應性水凝膠材質上。我們以靜止流微影術(Stop-Flow Lithography)將溫度敏感性的NIPAAm與不具溫度敏感性的高分子材質聚乙二醇二丙烯酸(PEGDA)交聯聚合成溫度雙相水凝膠感測器。當環境溫度變化時，感測器兩相因對於溫度的敏感性不同而有不同的體積變化，使感測器粒子彎曲，再依其彎曲角度對應環境溫度關係以達到觀測之目的。我們也研究溫度感測器在環境溫度變化下粒子彎曲的反應時間，並應用感測器於測量施加電場下微流道因焦耳熱效應而造成的溫度變化。為了讓雙相水凝膠感測器更為方便使用，我們也對感測器的形狀做改變，將具不同環境敏感度的兩相水凝膠材質間隔開成H形，並在非環境敏感側加上刻度。相對於其他感測器，雙相水凝膠感測器製作成本低廉且易大量製造，又無需連接龐大的訊號處理器，使其非常適合用於量測難以深入的微小侷限環境的環境參數。
並列摘要
Stimuli-sensitive hydrogels change dramatically in volume in response to alterations of certain environmental parameter. In recent years, this category of materials has attracted much attention in field of sensors. We proposed a pH microsensor consisting of two parallel phases of pH-sensitive hydrogel, acrylic acid, and insensitive hydrogel, PEGDA[1]. Working similarly to bimetallic strip, this type of sensor can bend to different degree on the corresponding environmental parameter and therefore was named bihydrogel microsensers. To demonstrate this general idea is also workable for microsensors sensitive to environmental parameters other than pH value, we use temperature-sensitive hydrogel, NIPAAm, and PEGDA to form temperature bihydrogel microsensors. We measure the response time of the temperature bihydrogel microsensors, and also apply them to measure the temperature rise caused by Joule heating in microchannel. Besides we also propose H-shaped pH and temperature bihydrogel microsensors with two separate phases of stimuli-sensitive and insensitive hydrogels. With marked graduations on the phase of stimuli-insensitive hydrogel, the measurements of the environmental parameters are more direct and convenient. These freestanding bihydrogel particles are low-cost and easy to manufacture by stop-flow lithography printing technique in PDMS microchannel. They are particularly suitable for use in confined environment where most sensors are unable to fit in.