This work presents a study on the influence of eight different ionic liquids (ILs) in the composition of dry membranes used for gaseous CO₂ optical sensing. The presence of CO₂ causes a displacement of a colorimetric pH indicator toward its acid form that increases the emission intensity of the luminophore by an inner filter process. The influence of ILs in the membrane on the stability and dynamic behavior—usually the main drawbacks of these sensors—of the membranes is studied. The characterization of the different membranes prepared was carried out and the discussion of the results is presented. In all cases, the response and recovery times improved considerably, with the best case being response times of only 10 s and recovery times of 48 s, compared to response and recovery times of 41 and 100 s, respectively, for membranes without IL. The useful life of the detection membranes is also considerably longer than that of membranes that do not include IL, at least 292 days in the best case. The sensing membrane without luminophore and only containing the pH indicator is proposed for the color-based measurement of CO₂ using a digital camera for possible use in food-packaging technology.

中文翻译：

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光学传感器上的离子液体，用于气态二氧化碳

这项工作提出了对八种不同离子液体（ILs）对用于气态CO ₂光学传感的干膜组成的影响的研究。CO ₂的存在导致比色pH指示剂向其酸形式的位移，从而通过内部过滤过程增加了发光体的发射强度。研究了膜中IL对膜的稳定性和动态行为（通常是这些传感器的主要缺点）的影响。对所制备的不同膜进行了表征，并对结果进行了讨论。在所有情况下，响应和恢复时间都得到了显着改善，最好的情况是响应时间仅为10 s，恢复时间为48 s，相比之下，没有IL的膜的响应和恢复时间分别为41和100 s。检测膜的使用寿命也比不包含IL的膜的使用寿命长得多，在最佳情况下至少为292天。₂使用数码相机在食品包装技术中可能使用。