School of Chemistry, University of Hyderabad , Hyderabad 500 046, India.
Langmuir. 2013 Oct 22;29(42):13050-7. doi: 10.1021/la402594j. Epub 2013 Oct 9.
The utility of polymer-metal nanocomposite thin films with in situ generated silver nanoparticles as substrates for surface-enhanced Raman scattering (SERS) is demonstrated. Thin films of poly(vinyl alcohol) and poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) containing Ag nanoparticles generated in situ through thermal annealing and photoirradiation, respectively (Ag-PVA and Ag-PVVV), are investigated as potential SERS substrates using 4-aminothiophenol and rhodamine 6G as probe molecules. The fabrication protocols are extremely simple and the materials inexpensive. The Ag-PVA substrate is found to produce Raman spectral enhancement factors of ~10(6), whereas Ag-PVVV, a novel nanocomposite thin film developed in the present study, provides enhancement factors of ~10(7). A unique advantage of these nanocomposite films is demonstrated by fabricating them by the in situ process as a thin coating inside glass capillaries and using these disposable SERS substrates for the sensitive detection of the probe molecules. The thin film substrates prepared on glass plates and capillaries facilitate convenient sample preparation for recording the Raman spectra and provide strongly enhanced spectra with high reproducibility, allowing picomols of the analytes to be detected. These aspects combined with the ease of fabrication and low cost of these in situ fabricated nanocomposite thin films make them highly attractive SERS substrates.
本文展示了原位生成银纳米粒子的聚合物-金属纳米复合材料薄膜作为表面增强拉曼散射（SERS）基底的实用性。通过热退火和光辐照分别原位生成银纳米粒子的聚（聚乙烯醇）和聚（醋酸乙烯酯-乙烯醇-丁醇共聚物）薄膜（Ag-PVA 和 Ag-PVVV）被用作 4-巯基苯胺和罗丹明 6G 等探针分子的潜在 SERS 基底进行了研究。制备方案非常简单，材料也很便宜。Ag-PVA 基底产生的拉曼光谱增强因子约为 10^6，而在本研究中开发的新型纳米复合薄膜 Ag-PVVV 提供的增强因子约为 10^7。通过原位过程在玻璃毛细管内制成薄膜涂层，并使用这些一次性 SERS 基底对探针分子进行灵敏检测，证明了这些纳米复合材料薄膜具有独特的优势。在玻璃片和毛细管上制备的薄膜基底便于进行样品制备，以记录拉曼光谱，并提供具有高重现性的强增强光谱，允许检测到皮摩尔级别的分析物。这些方面结合了这些原位制备的纳米复合材料薄膜易于制造和低成本的特点，使它们成为极具吸引力的 SERS 基底。
