Silina Yuliya E, Kuchmenko Tatyana A, Volmer Dietrich A
Leibniz Institute for New Materials (INM), Saarbrücken, Germany.
Analyst. 2015 Feb 7;140(3):771-8. doi: 10.1039/c4an00806e.
The sorption of selected hydrophilic pH-sensitive dyes (bromophenol blue, bromothymol blue, bromocresol purple, alizarin red, methyl orange, congo red, rhodamine 6G) on films of anodized aluminium oxide (AAO) was investigated in this study. Depth and pore structure of the AAO channels were adjusted by changing electrolysis time and current density during treatment of aluminium foil in oxalic acid, sulfosalycilic acid and sulfuric acid at concentration levels between 0.2 and 0.6 M. The dyes were immobilized on the AAO surface by direct saturation of the films in dye solutions. It was shown by scanning electron microscopy and X-ray spectral analysis that the dyes penetrated into the AAO channels by more than 1.5 μm, even at static saturation conditions. The anionic dyes linked to the porous AAO surface exhibited differential shifts of the UV absorption bands in their acidic/basic forms. By combining several dyes, the films have an application range between pH = 0.5-9 in aqueous media. The dye-modified AAO film was a simple, portable, inexpensive and reusable pH sensor with very fast response time and clear colour transitions.
本研究考察了选定的亲水性pH敏感染料（溴酚蓝、溴百里酚蓝、溴甲酚紫、茜素红、甲基橙、刚果红、罗丹明6G）在阳极氧化铝（AAO）膜上的吸附情况。通过在0.2至0.6 M浓度的草酸、磺基水杨酸和硫酸中处理铝箔时改变电解时间和电流密度，来调整AAO通道的深度和孔隙结构。通过将膜直接浸泡在染料溶液中使染料固定在AAO表面。扫描电子显微镜和X射线光谱分析表明，即使在静态饱和条件下，染料也能渗透到AAO通道中超过1.5μm。与多孔AAO表面相连的阴离子染料在其酸性/碱性形式下表现出紫外吸收带的差异位移。通过组合几种染料，该膜在水性介质中的应用pH范围为0.5 - 9。染料修饰的AAO膜是一种简单、便携、廉价且可重复使用的pH传感器，响应时间非常快，颜色转变清晰。
