Wang Tao, Korposh Sergiy, James Stephen, Lee Seung-Woo
Graduate School of Environmental Engineering, The University of Kitakyushu, 1-1 Hibikino, Kitakyushu, 808-0135, Japan.
Optics and Photonics Group, Department of Electrical and Electronic Engineering, University of Nottingham, Nottingham, NG7 2RD, UK.
Mikrochim Acta. 2020 Nov 17;187(12):663. doi: 10.1007/s00604-020-04603-1.
Highly sensitive and selective long-period grating (LPG) fiber-optic sensors modified with molecularly imprinted TiO nanothin films were fabricated. The films were deposited onto the surface of the optical fiber via liquid-phase deposition (LPD), using tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) as a template. Three LPG resonance bands were monitored during film deposition, which was of duration 4.5 h. Prior to template removal, heat treatment at 60 °C under high-humidity conditions led to an increase in refractive index of the TiO film, evidenced by changes in the central wavelengths of the attenuation bands. After template removal using HCl solution (0.01 M), the TMPyP-imprinted film-modified LPG sensor showed higher sensitivity to the template molecule than to structurally related guest molecules. This was measured at the 1st and 2nd resonance bands, with wavelengths ranging from 690 to 738 nm and 815 to 905 nm, respectively. No selective binding of the template was observed with a non-imprinted TiO film prepared in the same manner. Furthermore, the heat-treated imprinted films exhibited a substantial enhancement of photocatalytic activity for template irradiation. In particular, the self-cleaning property of the imprinted film-modified LPG sensor under ultraviolet irradiation led to highly efficient and selective binding to the template. The mechanism of the interaction between the template and the TiO matrix was investigated by UV-vis and Fourier-transform infrared (FTIR) spectroscopies. Additionally, morphological studies using scanning electron microscopy (SEM) were conducted. Graphical abstract.
制备了用分子印迹TiO纳米薄膜修饰的高灵敏度和高选择性长周期光栅（LPG）光纤传感器。通过液相沉积（LPD）将薄膜沉积在光纤表面，使用四（N-甲基吡啶-4-基）卟啉（TMPyP）作为模板。在持续4.5小时的薄膜沉积过程中监测了三个LPG共振带。在去除模板之前，在高湿度条件下于60°C进行热处理导致TiO薄膜的折射率增加，这通过衰减带中心波长的变化得以证明。使用HCl溶液（0.01M）去除模板后，TMPyP印迹薄膜修饰的LPG传感器对模板分子的灵敏度高于对结构相关客体分子的灵敏度。这是在第一和第二共振带处测量的，波长范围分别为690至738nm和815至905nm。以相同方式制备的非印迹TiO薄膜未观察到模板的选择性结合。此外，经热处理的印迹薄膜对模板照射表现出显著增强的光催化活性。特别是，印迹薄膜修饰的LPG传感器在紫外线照射下的自清洁特性导致其与模板的高效且选择性结合。通过紫外可见光谱和傅里叶变换红外（FTIR）光谱研究了模板与TiO基质之间的相互作用机制。此外，还使用扫描电子显微镜（SEM）进行了形态学研究。图形摘要。
