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Abstract. Supramolecular β-cyclodextrin (β-CD) was used as a soft template for the fabrication of long silver nanowires. A novel design using self-assembled β-CD for the reduction of silver ions was studied. The concentrations of iron chloride, silver nitrate, and the template were controlling factors for the growth of the silver nanowires. Iron chloride was used to accelerate and facilitate the formation of the silver nanowires and inhibit oxidative etching. However, an excessive concentration of Fe+3 resulted in etching of the silver nanostructures. Furthermore, the silver concentration was another controlling factor. The length of the silver nanowires increased as the concentration of silver cations increased. Nevertheless, an excess concentration of silver cations formed various silver crystalline structures. In this study, the optimal ratio between iron chloride and silver nitrate was determined to be 1:13.3. A maximum length of 10 µm was achieved using a concentration of 0.13 M for the soft template. Moreover, the junction of two growing silver nanowires was observed, forming a long fused nanowire, and some significant boundaries were observed. The observed results were further confirmed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. X-ray diffraction (XRD) and energy dispersive spectrometer (EDS) analyses were used to indicate the presence of silver and the formation of crystalline materials.
Keywords: nanomaterials, β-cyclodextrin, heat-induced sol-gel template, silver nanowires
1.Introduction
Silver is one of the most important industrial metals in modern technologies, with the highest electrical and thermal conductivity of any metal and the lowest contact resistance, which has allowed it to be used as an interconnection, particularly in the form of wires [1, 1], in a wide variety of commercial applications, including conductive inks, electronic products, cosmetics, antibacterial medical products and coatings [3].
Currently, nanotechnology is aimed at fabricating functional and fine-tuned materials, devices and systems through the control of matter at the nanometerlength scale of less than 100 nm, where properties differ significantly from those at larger scales. For example, although both bulky silver and nanosilver possess high thermal and electrical conductivities, bulky silver has a metallic color and a high melting point (above 900 °C), which diverges from the properties of nanosilver (i.e., light-yellow color in solution and antibacterial properties). These differences lead to 'nano-generation'. Therefore, silver nanoparticles have...