Investigation of Morphology and Structure of Poly(ethylene glycol)-Coated Silver Nanowires by Electron Microscopy / 分析化学

ABSTRACT

Poly(ethylene glycol)(PEG) coated silver nanowires has been hydrothermally prepared at a very slow rate, in which PEG was used as both a mild capping agent and a weak reductant. As-prepared silver nanowires(SNWs) have been characterized using scanning electron microscopy) and transmission electron microscope), which showed that the SNWs are usually longer than 100 μm and their diameters(each SNW has a uniform thickness) vary mainly in the range of 80～300 nm. Surprisingly, some of these silver nanowires connected) by their two ends to form some close-looped silver nanowires, which hitherto has not been reported elsewhere. The existence of close-looped silver nanowires supports the mechanism that nanowires can evolve from fusion of some nanoparticles and/or shorter nanorods. Careful TEM characterization and selected area electron) diffraction revealed that the silver nanowires kept a five-fold twinned structure, which is opposite to some reports) that a long-time incubation will lead to the disappearance of this twin structure. This work demonstrates the situation that deeper investigation is still needed for understanding the structure transformation of silver) nanowires.