Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany.
Sensors (Basel). 2012 Dec 12;12(12):16954-63. doi: 10.3390/s121216954.
Monodisperse polystyrene nanoparticles with a diameter of 173 nm were incorporated into a polydimethylsiloxane matrix where they display an iridescent color that can be attributed to the photonic crystal effect. The film is of violet color if placed in plain water, but turns to red in the presence of the non-polar solvent n-hexane. Several solvents were studied in some detail. We show that such films are capable of monitoring the water content of ethanol/water mixtures, where only 1% (v/v) of water leads to a shift of the peak wavelength of reflected light by 5 nm. The method also can be applied to determine, both visually and instrumentally, the fraction of methanol in ethanol/methanol mixtures. Here, a fraction of 1% of methanol (v/v) results in a wavelength shift of 2 nm. The reflected wavelength is not influenced by temperature changes nor impeded by photobleaching. The signal changes are fully reversible and response times are <1 s.
直径为 173nm 的单分散聚苯乙烯纳米颗粒被掺入聚二甲基硅氧烷基质中，在该基质中它们呈现出彩虹色，这归因于光子晶体效应。如果将薄膜放在普通水中，它呈紫色，但在非极性溶剂正己烷存在下则变为红色。我们详细研究了几种溶剂。我们表明，这种薄膜能够监测乙醇/水混合物的含水量，其中仅 1%（体积/体积）的水就会导致反射光的峰值波长偏移 5nm。该方法还可用于通过视觉和仪器来确定乙醇/甲醇混合物中甲醇的分数。在这里，甲醇的分数为 1%（体积/体积）会导致波长偏移 2nm。反射波长不受温度变化的影响，也不受光漂白的阻碍。信号变化是完全可逆的，响应时间<1s。
