Co-assembly of Au nanorods with Ag nanowires within polymer nanofiber matrix for enhanced SERS property by electrospinning

Abstract

Gold nanorods (AuNRs) can be successfully co-assembled with Ag nanowires (AgNWs) to form a kind of AuNR-AgNW nanocomposite by electrostatic attraction, in which the AuNRs are arranged along the long axial direction of the AgNWs with a preferential string-like alignment. The assembled AuNR-AgNW nanocomposites are then further embedded within polyvinyl alcohol (PVA) nanofibers by electrospinning, by which both AuNRs and AgNWs can be stabilized and arranged along the axis of polymer nanofibers. When the polymer nanofibers are aligned by collecting on a copper mesh with a woven structure, the AuNR-AgNW nanocomposites assembled within the electrospun nanofibers are also arranged. The influences of the AuNR-AgNW assemblies with different amounts of AuNRs attached on AgNWs on the optical properties and surface enhanced Raman scattering (SERS) enhancement have been investigated. The resulting AuNR-AgNW/PVA electrospun mats show red-shifted and broader absorption bands and higher SERS performances compared with the normal casting films with randomly dispersed AuNRs and AgNWs, or electrospun mats with monometallic components, due to the order alignment of AuNR-AgNW nanocomposites on a large scale.

Nanowire Assemblies for Flexible Electronic Devices: Recent Advances and Perspectives

“…The SERS spectra of the aligned electrospun nanofibers containing different concentrations of Ag NWs after absorbing 4,4ʹ‐bipyridine are presented in Figure c, showing an increase in signal strength at 1600 cm −1 by increasing the concentration of assembled Ag NWs as large electromagnetic fields were formed with the space among Ag NWs decreased. Besides the assembly of one type of material, our group has also focused on the coassembly of different metal components (GNRs with Ag NWs) within the long axial direction of poly(vinyl alcohol) (PVA) nanofiber through the electrospinning technique . By using the electrospinning process, the GNR–Ag NW/PVA electrospun nanofibers were prepared.…”

Functionalized Inorganic Nanoparticles for Magnetic Separation and SERS Detection of Water Pollutants

“…Recently, many works have reported the design of Ag–Au nanohybrids because the combination of the two metals can also form hotspots with enhanced SERS sensitivity. Hence, Ag–Au bimetallic NPs, with distinct sizes and shapes, have been used in the SERS detection of a variety of organic molecules, such as dyes, thiol compounds, 3,3‐diethylthiatricarbocyanine iodide, and biomolecules . Girão et al described the synthesis of Au, Ag and colloidal nanoalloys of Ag–Au which have been used in SERS studies of rhodamine 6G .…”

Electrospun Polymer Nanofibers Decorated with Noble Metal Nanoparticles for Chemical Sensing

“…Different polymers or ceramic nanofibers, such as PVA [100, 116, 117], cellulose [118], poly(methyl methacrylate) (PMMA) [119], chitosan [106], poly (acrylic acid) (PAA)/PVA [120], and silica [121] have been utilized to combine with different Ag or Au nanostructures to fabricate the flexible substrate for SERS. PVA is a nontoxic, biocompatible polymer, which has good electrospinability, and it is a popular material for electrospinning.…”

“…Zhang et al used a seed-mediated surfactant-directed approach to synthesize Au nanorods (AuNRs), and these Au NRs exhibited good alignment along the axial direction of the nanofibers, which demonstrates that electrospinning is a powerful tool to assemble anisotropic nanorods on a large scale [100]. Ag and Au nanostructures can be co-assembled into the PVA nanofibers [117, 123]. Different SERS effects can be obtained by varying the Au/Ag ratio and the excitation wavelength due to the different activities of Au and Ag nanostructures under different wavelengths [124].…”