Geng Lin, Han Xingzi, You Jinqing, Tian Yang, Yang Jian, Xu Huimin, Yang Wenzhong, Xu Hui
Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816 China.
Technology Center, China Tobacco Zhejiang Industrial Co., Ltd., Ningbo 315040 China.
Spectrochim Acta A Mol Biomol Spectrosc. 2025 May 15;333:125871. doi: 10.1016/j.saa.2025.125871. Epub 2025 Feb 7.
In this work, we successfully achieved controllable assembly of gold nanorods (AuNRs) into end-to-end orientation using polyacrylic acid (PAA) grafted carbon nanotube (CNT) (i.e., CNT-g-PAA) as a template. The resulting CNT-g-PAA/AuNRs hybrid assemblies were prepared via electrostatic interactions between negnative PAA-grafted CNT and positive hexadecyltrimethylammonium bromide (CTAB)-capped AuNRs. Due to the anisotropic nature of AuNRs and one-dimensional structure of CNT, the end-to-end arrangement of AuNRs immobilized on the CNT-g-PAA results in enhanced uniaxial plasmon coupling and thus stronger SERS response, as compared to the 3D SiO-g-PAA/AuNRs assemblies. In addition, PAA-functionalized CNTs ensure the predominantly end-to-end assembly of AuNRs on the CNT surface, which greatly enhances the structural stability of the assemblies. Moreover, the PAA brushes on the CNT surface contribute to the selective and efficient adsorption of cationic dyes on the SERS substrate surface. This enhancement has improved the sensitivity of the substrate, achieving detection limits for malachite green (MG) and crystal violet (CV) as low as 10 M. Our present strategy opens up an avenue for the fabrication of novel optically enhanced nanodevices.
在这项工作中，我们成功地以接枝聚丙烯酸（PAA）的碳纳米管（CNT）（即CNT-g-PAA）为模板，实现了金纳米棒（AuNRs）的可控端对端取向组装。通过接枝PAA的带负电CNT与带正电的十六烷基三甲基溴化铵（CTAB）包覆的AuNRs之间的静电相互作用，制备了所得的CNT-g-PAA/AuNRs混合组装体。由于AuNRs的各向异性性质和CNT的一维结构，与3D SiO-g-PAA/AuNRs组装体相比，固定在CNT-g-PAA上的AuNRs的端对端排列导致单轴等离子体耦合增强，从而产生更强的表面增强拉曼散射（SERS）响应。此外，PAA功能化的CNT确保了AuNRs在CNT表面主要进行端对端组装，这大大提高了组装体的结构稳定性。而且，CNT表面的PAA刷有助于阳离子染料在SERS基底表面的选择性高效吸附。这种增强提高了基底的灵敏度，实现了孔雀石绿（MG）和结晶紫（CV）低至10⁻⁹ M的检测限。我们目前的策略为新型光学增强纳米器件的制造开辟了一条途径。
