本研究利用微機電製程技術，並使用那菲翁(Nafion)溶液藉由表面圖樣沉積法取得陽離子選擇性的薄膜，製作出可應用於能量轉換裝置之微流體晶片。利用可逆電透析之原理，當連接兩管道之薄膜其兩端的鹽分濃度不同時，溶液中的正負離子受到那菲翁(Nafion)膜表面電荷的影響而有不同的傳輸速度，使得薄膜兩端正負電荷不同而產生一電位勢，即擴散電位。本研究在可逆電透析微晶片系統中使用氯化銀(Ag/AgCl)參考電極以及氯化鉀(KCl)作為電解液，並由此實驗得到最佳的擴散電位為90.7mV，而最大功率為54.1pW;為了更進一步討論薄膜之特性，我們改變電解液的pH值分別為4.0, 6.4, 10.0，討論此裝置在酸性或鹼性溶液之現象，由研究結果顯示，在沒有加入額外氫離子或氫氧根離子(pH為6.4)時，其擴散電位、擴散電流、輸出功率都是最佳的。此原因可歸咎於那菲翁(Nafion)膜特殊的質子傳輸機制，膜中水分子和其親水性結構結合產生–SO3-，其中氫離子與氫氧根離子易和水分子發生水合反應，使其表面電荷減少，造成較低的擴散電位和輸出功率，加上氫離子和氫氧根離子得離子遷移率不同，所以又以pH為4.0影響較鉅，pH為10.0之影響次之，藉由此研究可成功將吉布式自由能在微流體晶片上轉換成電能並得知那菲翁(Nafion)膜之特性。

In the present study, we demonstrated the fabrication of an energy conversion microchip using the standard microelectromechanical technique. This device was constructed using two microchannels connecting with Nafion junction, which performed cation selectivity fabricated by the process of surface patterned. According to the theory of reverse electrodialysis, when a concentrated salt solution and a diluted salt solution are separated by an ion-selective membrane, cations and anions would diffuse at different rates depending on the ion selectivity of the membrane; the difference of positive and negative charges at both ends of the membrane would produce a potential, called the diffusion potential. The experiment was conducted using Ag/AgCl electrodes and KCl solution, and the highest diffusion potential and diffusion current measured was 90.7mV and 54.1pW, respectively. To understand the properties of Nafion junction better, we used electrolytes at different pH values (4.0, 6.4, and 10.0). The results indicated that Nafion junction showed the maximum diffusion potential at pH 6.4and the lowest diffusion potential at pH 4.0. This finding implies that ion selectivity of Nafion decreased when additional H+ and OH-existed in the solution, as these ions would associate with water molecules and weaken the –SO3- groups of Nafion. Moreover, as the mobility of H+ is higher than that of OH-, H+ reduced the surface charge to a greater extent than OH-.

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