| dc.description.abstract | In situ scanning tunneling microscopy(STM) and cyclic voltammetry(CV) were used to examine the structure of adsorbed aniline and its oxidative polymerization with halide ions on Au(111). Before the aggregate potential, adding halide ions(chloride, bromide, iodide) to examine aniline adsorbed layer changing on Au(111) in the sulfuric acid solution containing aniline. A highly ordered Au(111)-(3×2√3)-aniline+HSO4- structure was observed at 0.7V in 0.5 M H¬2SO4 + 30 mM aniline, but we can found the structure disappear when adding iodide. Because there is a good interactions between iodide and Au(111). Iodide would replace the adsorption layer of aniline, and change into the adsorption layer of iodide. A highly ordered Au(111)-(7×7)-I moiré pattern structure was observed. Chloride and bromide are weaker than iodide, therefore we let aniline molecular adsorbed first, then adding chloride and bromide, it is maintained originally of aniline adsorption layer at 0.7V. The originally of aniline adsorption layer would oxidation aggregate, when we adjusted potential to 0.85V.
When it reached aggregate potential, in the system of iodide, the concentration of iodide would cause aggregate frame shaped different. The frame shaped of poly-aniline would follow the iodide adsorption layer, At high concentration of iodide, the adsorption layer moiré pattern structure cause curled frame shaped of poly-aniline chain, and lower concentration of iodide, the adsorption layer p×√3 structure caused aggregate along carrier direction and√3 direction of linear poly-aniline chain. In the system of chloride and bromide, it is forming of flakes grow poly-aniline on the surface, and this growth formation of structure of poly-aniline is not easy to grow layer by layer, on the second layer, it would grow in the three-dimension direction. | en_US |