载Ag纳米粒子温度刺激响应性杂化微凝胶的制备与组装及其用于SERS基底的研究

Surface enhanced Raman spectroscopy (SERS) is a kind of analytical method with superhigh sensitivity, which can provide the information of molecular structure. However, two problems are existing for SERS method due to its substrate materials. One is poor reproducibility of its analysis results, and the other is that the analytes capable of being analyzing by SERS method are limited. For example, the compounds with hydroxy group, such as phenols, are hard to be analyzed by SERS method. In order to address these problems, new types of substrate materials for SERS are designed and will be prepared in the project. Firstly, Ag nanoparticles loading hybrid microgels were prepared by in-situ reduction of the Ag+ ions incorporated within PNIPAM microgels. Secondly, some reactive groups will be introduced on their surfaces by modification. Finally, the monolayer film with stable ordered structure will be prepared by assembly of the composite microgels under suitable conditions, followed by post-crosslinking reaction. Using the monolayer film as substrate, the SERS method cabable of analyzing trace amount of 1-naphthol or 2-naphthol in aqueous solution qualitatively or quantitatively will be established. The scientific significance of the project lies in preparation of multi-functional composite materials with ordered structure. Its practical value is reflected by potential applications of the established SERS method in conveniently and rapidly monitoring the 1-naphthol or 2-naphthol concentration in environmental water samples.

表面增强拉曼光谱（SERS）是一种既有超高灵敏度，又能提供分子结构信息的分析方法。然而受基底材料所限，SERS方法目前存在两方面问题：一是分析结果的重复性差；二是适合分析的对象少，例如难以分析酚类化合物。为解决这些问题，本项目拟设计并制备新型的SERS基底材料。首先通过原位还原法将Ag纳米粒子负载在单分散性良好的聚（N-异丙基丙烯酰胺）微凝胶中，制得载Ag纳米粒子的温度刺激响应性杂化微凝胶。然后通过改性在其表面引入具有反应活性的基团，最后在适当条件下使杂化微凝胶组装并经后交联反应形成具有稳定有序结构的单层膜。以制得的单层膜为基底，建立可定量分析水溶液中痕量1-萘酚或2-萘酚的SERS方法。本项目的科学意义在于对具有有序结构的智能杂化材料实现可控制备，其实际价值在于：以研究的新型基底建立的SERS分析方法有望用于环境水样中1-萘酚和2-萘酚的方便和快速检测。

采用静电纺丝技术结合热处理工艺将单分散性良好的银纳米粒子（AgNPs）或Au@Ag双金属核壳复合纳米棒（Au@AgNRs）均匀地负载到温度响应性纳米纤维或其壳层中，制得了四种复合纳米纤维膜。这些复合纳米纤维膜可作为新型的无需支撑的柔性固态SERS基底，这解决了胶体贵金属纳米粒子基底存在的储存稳定性差和检测结果重复性差的问题。这些SERS基底都是将单分散的AgNPs或Au@AgNRs负载到温度响应性纳米纤维膜中，因此可通过升高检测温度来增强这些基底的SERS活性，从而提高了检测灵敏度。利用静电相互作用将Au@AgNRs负载在滤纸中制备了另外一种新型SERS基底。将单分散的AgNPs或Au@AgNRs负载到纳米纤维膜或滤纸中，制得的柔性且无需支撑的SERS基底具有宏观形状和机械强度，储存稳定，使用方便，并且可通过擦拭来收集固体样品表面的残留物来进行SERS检测，从而解决了过去用SERS基底和其它手段分析水果蔬菜表面农药残留需要复杂制样过程的缺点。并且，用温度响应性杂化纳米纤维膜还可通过SERS光谱来监测催化反应的中间产物，由此推测反应机理。本项目制得的5种新型SERS基底在环境监测、催化反应、食品安全分析等领域有广阔的应用前景。