Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, China.
University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, China.
Langmuir. 2017 Dec 5;33(48):13867-13873. doi: 10.1021/acs.langmuir.7b03538. Epub 2017 Nov 22.
Two-dimensional or three-dimensional highly ordered arrays of anisotropic nanoparticles provide attracting properties that are highly desired by the industry. Traditional assembly methods such as evaporation usually produces the nanostructure arrays only up to the millimeter scale with poor control of nanoparticle orientation, making them hardly applicable for industrial needs. Here, we report a facile method to assemble centimeter-scale gold nanorod (Au NR) arrays with highly controlled nanoparticle orientation and high reproducibility. We selectively functionalized the transverse or longitudinal facets of Au NRs with polyethylene glycol (PEG) molecules and utilized the interfacial polymeric affinity between the PEG domains on Au NRs and the PEGylated substrate to achieve the anisotropic self-assembly. The side-PEGylated Au NRs formed closely packed horizontal arrays, whereas the end-PEGylated Au NRs formed vertically standing arrays on the substrate, respectively. The obtained Au NR arrays with different orientations showed anisotropic surface-enhanced Raman scattering (SERS) performance. We showed that the vertically ordered Au NR arrays exhibited 3 times higher SERS signals than the horizontally ordered arrays.
二维或三维各向异性纳米粒子的有序排列提供了行业所期望的吸引人的特性。传统的组装方法，如蒸发，通常只能生产出达到毫米尺度的纳米结构阵列，并且对纳米粒子的取向控制较差，使得它们几乎无法满足工业需求。在这里，我们报告了一种简便的方法，可以组装厘米级的金纳米棒（Au NR）阵列，具有高度可控的纳米粒子取向和高重复性。我们选择性地用聚乙二醇（PEG）分子功能化 Au NR 的横向或纵向面，并利用 Au NR 上的 PEG 域与 PEG 化基底之间的界面聚合亲和力来实现各向异性自组装。侧-PEG 化的 Au NR 形成紧密堆积的水平阵列，而端-PEG 化的 Au NR 分别在基底上形成垂直排列的阵列。不同取向的获得的 Au NR 阵列表现出各向异性的表面增强拉曼散射（SERS）性能。我们表明，垂直有序的 Au NR 阵列表现出比水平有序阵列高 3 倍的 SERS 信号。
