Solvent co-assisted ultrasound technique for the preparation of silver nanowire/polyaniline composite

Silver wire/polyaniline (Ag-0/PAni) composite was prepared by the sonochemical solvent assisted method. This composite was obtained after sonicating a silver nitrate (AgNO3) and anilinium nitrate aqueous solution in the presence of isopropyl alcohol. The presence of the alcohol decreases the polymerization kinetics of the conducting polymer and allows a more stable dispersion of the polymer composite to be obtained. As a matter of fact, precipitation of the polymer occurs when the reaction takes place in the absence of isopropyl alcohol. Scanning electron microscopy revealed that isopropyl alcohol has a remarkable effect on the growth and the morphological structure of reduced silver. Also, the reaction time is an important parameter which allows us to obtain silver wires with a mean diameter of 120 nm and a medium length of 4 mu m instead of the spherical particles ordinarily obtained by synthesis without the alcohol. Additionally, we observed that bigger silver wires with a mean diameter of 1.5 mu m and a length of 85 mu m were obtained if the reaction medium was left to rest in a dark place after the sonication process ended. X-ray diffraction (XRD) and UV-vis absorption spectroscopy indicate that the reduced silver is highly crystalline and the polymer obtained is PAni in the emeraldine salt form. (C) 2010 Elsevier B.V. All rights reserved.