Universitat de Barcelona, MIND-IN(2)UB Department of Electronics, Barcelona, Spain.
Lab Chip. 2010 May 21;10(10):1254-61. doi: 10.1039/b926737a. Epub 2010 Mar 12.
This paper presents an entirely polymeric microfluidic system, made of cyclo olefin polymer (COP), with integrated gold microband electrodes for electrochemical applications in organic media. In the present work, we take advantage of the COP's high chemical stability to polar organic solvents in two different ways: (i) to fabricate gold microelectrodes using COP as a substrate by standard lithographic and lift-off techniques; and (ii) to perform electrochemical experiments in organic media. In particular, fourteen parallel gold microelectrodes with a width of 14 microm and separated from their closest neighbour by 16 microm were fabricated by lithographic and lift-off techniques on a 188 microm thick COP sheet. A closed channel configuration was obtained by pressure-assisted thermal bonding between the COP sheet containing the microelectrodes and a microstructured COP sheet, where a 3 cm long, 50 microm wide and 24 microm deep channel was fabricated via hot embossing. Cyclic voltammetric measurements were carried out in aqueous and organic media, using a solution consisting of 5 mM ferrocyanide/ferricyanide in 0.5 M KNO(3) and 5 mM ferrocene in 0.1 M TBAP/acetonitrile, respectively. Experimental currents obtained for different flow rates ranging from 1 to 10 microL min(-1) were compared to the theoretical steady state currents calculated by the Levich equation for a band electrode (R. G. Compton, A. C. Fisher, R. G. Wellington, P. J. Dobson and P. A. Leigh, J. Phys. Chem., 1993, 97, 10410-10415). In both cases, the difference between the experimental and the predicted data is less than 5%, thus validating the behaviour of the fabricated device. This result opens the possibility to use a microfluidic system made entirely from COP with integrated microband electrodes in organic electroanalysis and in electrosynthesis.
本文提出了一种完全由环烯烃聚合物 (COP) 制成的微流控系统，该系统具有集成的金微带电极，可用于有机介质中的电化学应用。在本工作中，我们利用 COP 对极性有机溶剂的高化学稳定性，以两种不同的方式进行实验：（i）使用 COP 作为基底，通过标准的光刻和剥离技术制造金微电极；（ii）在有机介质中进行电化学实验。特别地，通过光刻和剥离技术在 188 µm 厚的 COP 薄片上制造了 14 个宽度为 14 µm、彼此最近的电极之间间隔为 16 µm 的平行金微电极。通过将含有微电极的 COP 薄片与微结构 COP 薄片进行压力辅助热键合，获得了封闭的通道结构，其中通过热压印在微结构 COP 薄片上制造了一个长 3 cm、宽 50 µm、深 24 µm 的通道。在水溶液和有机溶剂中进行了循环伏安测量，使用含有 5 mM 亚铁氰化钾/铁氰化钾的 0.5 M KNO3 溶液和含有 5 mM 二茂铁的 0.1 M TBAP/乙腈溶液，分别作为两种溶液。比较了不同流速（1 至 10 µL min-1）下的实验电流与根据 Levich 方程（R. G. Compton、A. C. Fisher、R. G. Wellington、P. J. Dobson 和 P. A. Leigh，J. Phys. Chem.，1993，97，10410-10415）计算得到的稳态理论电流。在这两种情况下，实验数据与预测数据之间的差异均小于 5%，从而验证了所制造器件的性能。这一结果为在有机电分析和电合成中使用完全由 COP 制成并集成有微带电极的微流控系统提供了可能性。
