Fabrication of silver nanotubes using functionalized silica rod as templates

Silver nanotubes were prepared by the adsorption of silver nanoparticles or ions at the surface of functionalized silica rod, followed by the removal of silica rod by chemical etching process with 10 M HF solution. The surfaces of silica rod were functionalized with silanol, amine or thiol group. The 3-aminopropyltrimethoxysilane (APTMS) and 3-mercaptopropyltrimethoxysilane (MPTMS) were used as functionalizing agents. In the conventional method, the fabrication of silver nanotubes by core-shell technology was not easy due to the difficulties in retaining the shell structures during the core removal process. This limitation was overcome through the method proposed in this study. The major focus of this study is on understanding the mechanism of formation of the silver nanotubes through the self-assembly behavior by the adsorption of silver nanoparticles or ions onto the silica templates. The silver coated silica rods and silver nanotubes were characterized using the field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS).