Determining Oxygen Diffusion Coefficients in Polymer Films by Lifetimes of Luminescent Complexes Measured in the Frequency Domain
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- 作者：Walter J. Bowyer ; Wenying Xu ; and J. N. Demas
- 刊名：Analytical Chemistry
- 出版年：2004
- 出版时间：August 1, 2004
- 年：2004
- 卷：76
- 期：15
- 页码：4374 - 4378
- 全文大小：51K
- 年卷期：v.76,no.15(August 1, 2004)
- ISSN：1520-6882
文摘
Polymer films doped with luminescent ruthenium complexes are proving to be important oxygen sensors. Wedescribe a technique using lifetime measurements in thefrequency domain for determining the diffusion coefficientof oxygen through various polymer supports. These fundamental measurements will allow for more rationaldesign of improved sensors. Three types of polymers weredoped with [Ru(4,7-diphenyl-1,10-phenanthroline)3]Cl2.We monitored the luminescence versus time after applying a step increase in the oxygen pressure at the surfaceof the film. We modeled the decrease in apparent lifetimeas a function of time using the diffusion coefficient ofoxygen in the polymer as the only adjustable parameter.The model accurately predicted the lifetime versus timecurves, and diffusion coefficients agreed well with thoseobtained from intensity measurements. The advantagesand disadvantages of the lifetime technique to those usedearlier are discussed.