A versatile synthesis route for metal@SiO2 core–shell nanoparticles using 11-mercaptoundecanoic acid as primer
A versatile synthesis route for metal@SiO2 core–shell nanoparticles using 11-mercaptoundecanoic acid as primer
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DOI：
10.1039/c3tc31171f
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发表时间：
2013-09
影响因子：
6.4
通讯作者：
Youlin Zhang;X. Kong;B. Xue;Q. Zeng;Xiaomin Liu;Langping Tu;Kaiqiaing Liu;Hong Zhang
中科院分区：
文献类型：
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作者：
Youlin Zhang;X. Kong;B. Xue;Q. Zeng;Xiaomin Liu;Langping Tu;Kaiqiaing Liu;Hong Zhang
将Stober方法直接应用于贵金属纳米颗粒（NPs）（如金（Au）和银（Ag） NPs）上的二氧化硅外壳提出了挑战，因为贵金属NPs在酒精溶液中不稳定，并且对二氧化硅的化学亲和力较低。本文介绍了一种利用11-巯基十六烷酸（MUA）作为硅壳与贵金属NPs之间的连接分子的方法。MUA通过金属- s键取代NPs表面的标准封盖剂，与NPs表面紧密结合。在MUA稳定后，NPs可以转移到醇溶液中，并表现出对二氧化硅的化学亲和力。通过标准的Stober方法，通过改变四乙氧基硅烷（TEOS）的量，可以直接在mua修饰的NPs表面涂覆厚度可控、光滑均匀的二氧化硅壳。与文献报道的这种粒子的包覆方法相比，该方法不仅可以成功地包覆柠檬酸稳定的Au或Ag纳米棒，而且可以扩展到包覆油胺（OA）稳定的Au纳米棒和十六烷基三甲基溴化铵（CTAB）稳定的Au纳米棒（NRs），通过MUA取代NPs表面的原始配体。此外，获得的metal@SiO2核壳纳米粒子已成功应用于metal@SiO2@荧光团纳米粒子的等离子体纳米天线中，用于荧光增强。
Applying the Stober method to directly coat noble metal nanoparticles (NPs) such as gold (Au) and silver (Ag) NPs with silica shells presents challenges, since the noble metal NPs are not stable in alcoholic solution and have low chemical affinity for silica. This paper describes a method which uses 11-mercaptoundecanoic acid (MUA) as a linker molecule between the silica shell and the noble metal NPs. MUA binds strongly to the surface of the NPs via a metal–S bond by replacing the standard capping agents on the surface of the NPs. Upon MUA stabilization, the NPs can be transferred into alcohol solution and show chemical affinity for silica. The MUA-modified NPs can be directly coated with thickness controlled, smooth and homogeneous silica shells via the standard Stober method by varying the amount of tetraethoxysilane (TEOS). Compared with methods reported in the literature for the coating of such particles, this method can not only be used to successfully coat citrated-stabilized Au or Ag NPs, but can also be extended to encapsulate oleylamine (OA)-stabilized Au NPs and cetyltrimethylammonium bromide (CTAB)-stabilized Au nanorods (NRs) by using MUA to displace the original ligand on the surface of the NPs. Additionally, the obtained metal@SiO2 core–shell NPs have been successfully applied as plasmonic nanoantennas for fluorescence enhancement in metal@SiO2@fluorophore NPs.