イオン液体｜水界面における酸化還元反応を利用する金の樹枝状ナノファイバーの合成: 粘度とナノ構造の相関の検討

Abstract

We recently found that dendritic gold nanofibers are formed by a redox reaction at the interface between water (W) and trioctylmethylammonium bis(nonafluorobutanesulfonyl) amide, a hydrophobic ionic liquid (IL) [N. Nishi, T. Kakinami, T. Sakka: Chem. Commun., 51, 13638 (2015)]. The formation of such a highly anisotropic structure at the IL|W interface is likely to be achieved due to the viscosity difference of the two liquids, considering a proposed mechanism [F. Scholz, U. Hasse: Electrochem. Commun., 7, 541 (2005)] in which metal nanostructures grow towards the more viscous liquid phase from the liquid| liquid interface. In this paper, we considered the effect of the viscosity difference of the two liquids on the structure of the gold nanostructures formed at the liquid| liquid interface. We used two kinds of dichloromethane (DCM) solutions for the oil phase: the one thickened with polyvinyl chloride and the other containing the IL with a low viscosity compared with the IL itself. It has been revealed that not only the viscosity difference of the two liquids, but also the existence of the IL-ions in the DCM solution promote an anisotropic growth of Au at the liquid| liquid interface.