调控金纳米花表面凸起的策略及其表面增强拉曼散射活性  

Strategy for Regulating Surface Protrusion of Gold Nanoflowers and Their Surface-Enhanced Raman Scattering

作　　者：冯瑞沁 樊晔 方云 夏咏梅 Ruiqin Feng;Ye Fan;Yun Fang;Yongmei Xia(The Key Laboratory of Synthetic and Biological Colloids(Ministry of Education),School of Chemical and Material Engineering,Jiangnan University,Wuxi 214122,Jiangsu Province,China;State Key Laboratory of Food Science and Technology,Jiangnan University,Wuxi 214122,Jiangsu Province,China)

机构地区：[1]江南大学化学与材料工程学院,合成与生物胶体教育部重点实验室,江苏无锡214122 [2]江南大学,食品科学与技术国家重点实验室,江苏无锡214122

出　　处：《物理化学学报》2024年第4期184-192,共9页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(21606107)资助项目。

摘　　要：以聚乙烯吡咯烷酮(PVP)与十二烷基硫酸钠(SDS)通过阳离子架桥形成的拟聚阴离子为软模板,通过改变PVP、SDS和纳米材料前驱体氯金酸(HAu Cl_(4))浓度以及反应时间等因素,调控还原产物金纳米花形貌及粒径。表面张力、电导率、毛细管电泳及Zeta电位等实验结果表明PVP-SDS-HAu Cl_(4)形成新的拟聚阴离子,透射电子显微镜和X射线衍射结果表明SDS、PVP和HAu Cl_(4)的较低浓度组合更易获得表面凸起丰富的金纳米花。PVP-SDS拟聚阴离子发挥了二级软模板作用,在PVP(50 g·L^(-1))-SDS(2 mmol·L^(-1))-HAu Cl_(4)(0.25 mmol·L^(-1))溶液中调控合成的金纳米花为{111}晶面为主的面心立方结构,其平均等效粒径为108 nm,且表面上密集分布约16.5 nm的凸起。该金纳米花有较强的表面增强拉曼散射(SERS)活性,探针分子罗丹明6G的SERS信号强度依赖于金纳米花的表面凸起形貌。该研究中金纳米花的SERS增强因子最高达6.71×10^(7),优于同类金纳米花的文献报道水平(106);尽管低于石墨负载的金纳米粒子(1×108)或阳离子软模板合成的金纳米棒(5×109),但成功避免了基质干扰或阳离子强吸附使应用受限。Mixed solutions of polyvinylpyrrolidone(PVP)and sodium dodecyl sulfate(SDS)were investigated by capillary electrophoresis,together with other technologies,to confirm the formation of PVP-bound SDS micelles through cation-bridging association,which shows the nature of polyanions and the ability to exchange Na+of SDS with environmental cations.Because additional water-soluble precursors of nanomaterials are capable of entering the cation-bridging layer of the PVP-SDS pseudo-polyanions,we speculate that the PVP chain and PVPbound SDS micelles located on both sides of the precursor may act as a two-stage soft template to synthesize nanomaterials with unique morphologies.In this study,PVP-SDS pseudo-polyanions were used as soft templates to promote the growth of gold particles into gold nanoflowers(AuNFs).Tensiometry,conductometry,capillary electrophoresis,and zeta potential measurements confirmed the formation of the new PVP-SDS-HAuCl_(4)pseudo-polyanions.Transmission electron microscopy,X-ray diffraction,and UV-Vis spectroscopy analyses showed that the AuNFs synthesized in the mixed solution of PVP(50 gꞏL^(-1))-SDS(2 mmolꞏL^(-1))-HAuCl_(4)(0.25 mmolꞏL^(-1))possessed a face-centered cubic structure with abundant{111}crystal plane,demonstrating an average equivalent diameter of 108 nm with rich nano-protrusion of approximately 16.5 nm on the surface of AuNFs.The mechanistic study shows that PVP mainly acts as an in situ reductant for HAuCl_(4)in PVP-bound SDS micelles that simultaneously act as the primary template to govern the size of the primary gold crystals.In addition to continuously reducing HAuCl_(4),PVP functions as a secondary template,leading to primary gold crystals in a finite space linked by the PVP chain through preferential adsorption,stacked,and grown into mature AuNFs.Finally,a lower HAuCl_(4)concentration and an adequate reduction period are favorable in the aforementioned process dominated by the soft template rather than by the crystal growth rule of gold particles;thus,the reduction rate of

关 键 词：金纳米花 表面增强拉曼散射 纳米凸起 拟聚阴离子 软模板 

分 类 号：O647.11[理学—物理化学] O614.123[理学—化学]