Evaluation of sub-micrometer parylene C films as an insulation layer using electrochemical impedance spectroscopy
Evaluation of sub-micrometer parylene C films as an insulation layer using electrochemical impedance spectroscopy
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DOI：
10.1016/j.porgcoat.2013.11.020
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发表时间：
2014-02-01
影响因子：
6.6
通讯作者：
Kim, Sohee
中科院分区：
文献类型：
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作者：
Chun, Wonju;Chou, Namsun;Kim, Sohee
我们使用电化学阻抗谱 (EIS) 研究了亚微米聚对二甲苯 C 薄膜随时间的绝缘性能。为此，制造了叉指电极，并用厚度为 50、100、200 和 500 nm 的聚对二甲苯 C 完全封装。 EIS 在磷酸盐缓冲盐水 (PBS) 溶液中在 90°C 加速老化条件下测量 45 天。为了分析EIS数据，使用涂层在不同退化阶段的等效电路模型，并通过曲线拟合提取最佳拟合等效电路模型的集总电路参数。使用等效电路模型和 FTIR 测量进行的阻抗分析表明，亚微米聚对二甲苯 C 涂层一旦浸入 PBS 溶液中，就会出现由于水从顶面扩散而导致的分层，尽管分层程度因膜厚度而异。水渗透亚微米厚的聚对二甲苯 C 薄膜的速度与薄膜与溶液接触的速度一样快，这与几微米厚的涂层不同，在几微米厚的涂层中，水扩散在水到达涂层底表面之前就会饱和。 (C) 2013 Elsevier B.V. 保留所有权利。
We investigated the insulation performance of sub-micrometer parylene C films over time using electrochemical impedance spectroscopy (EIS). For this, interdigitated electrodes were fabricated and completely encapsulated with parylene C in thicknesses of 50, 100, 200, and 500 nm. The EIS was measured in phosphate buffered saline (PBS) solution under an accelerated aging condition at 90 C over 45 days. To analyze the EIS data, the equivalent circuit models of coating at different stages of coating degradation were used and the lumped circuit parameters of the best fitted equivalent circuit model were extracted by curve fitting. The analysis of impedance using the equivalent circuit model and the FTIR measurements suggest that sub-micrometer parylene C coatings exhibited delamination resulting from water diffusion from the top surface as soon as being immersed in PBS solution, although the degree of delamination varied depending on the film thickness. The penetration of water through sub-micrometers thick parylene C films can occur as quickly as the film is in contact with solution, unlike for thicker coatings in several micrometers where water diffusion would be saturated before water reaches the bottom surface of the coating. (C) 2013 Elsevier B.V. All rights reserved.