Department of Chemistry and Biochemistry, The Florida State University, Tallahassee, Florida 32306, USA.
Langmuir. 2011 Jul 5;27(13):8241-7. doi: 10.1021/la2015258. Epub 2011 Jun 8.
The diffusion coefficient is a fundamental parameter for devices exploiting the ion transport properties of polyelectrolyte multilayers (PEMUs) and complexes. Here, the transport of ferricyanide through a multilayer made from poly(diallyldimethylammonium chloride) (PDADMA) and polystyrene sulfonate (PSS) was studied as a function of temperature or salt concentration. Accurate and precise measurements of ion diffusion coefficients were obtained using steady-state electrochemistry to determine the flux and Fourier transform infrared (FTIR) spectroscopy to measure the PEMU concentration. It was found that the concentration of ferricyanide inside the film decreased with temperature. Membrane transport is strongly thermally activated with activation energy 98 kJ mol(-1). A potential shift with decreasing salt concentration in cyclic voltammograms was translated into a differential flux caused by significantly higher diffusion coefficients for ferricyanide as compared to ferrocyanide.
扩散系数是利用聚电解质多层（PEMU）和复合物的离子传输特性的器件的基本参数。 在这里，研究了铁氰化物通过由聚二烯丙基二甲基氯化铵（PDADMA）和聚苯乙烯磺酸盐（PSS）制成的多层膜的传输作为温度或盐浓度的函数。 通过稳态电化学测量通量并使用傅里叶变换红外（FTIR）光谱测量 PEMU 浓度，获得了离子扩散系数的精确和精确测量。 发现膜内铁氰化物的浓度随温度降低而降低。 膜传输强烈地随温度升高而被热激活，活化能为 98 kJ mol(-1)。 循环伏安图中盐浓度降低引起的电势偏移转化为由于铁氰化物与亚铁氰化物相比扩散系数明显更高而引起的差分通量。
