Tunable Synthesis of Ag Films at the Interface of Ionic Liquids and Water by Changing Cationic Structures of Ionic Liquids

The design of green and ingenious strategies for the fabrication of anisotropic nanoparticles and their assembly is particularly important in the advancement of nanoscience and nanotechnology but still remains an enormous challenge. In this work, the Ag films, with variously shaped particles as building blocks, were successfully prepared at the interface of different ionic liquids and water (ILs–H2O) under ambient conditions only by using ILs with different cationic structures. The as-prepared Ag films with different morphologies were characterized and analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray powder diffraction. The possible growth mechanisms were also suggested for the formation of differently morphological Ag films at the ILs–H2O interface. The as-obtained Ag films could be directly applied to perform surface-enhanced Raman scattering (SERS) studies. It was found that the nanobelt-contructed Ag films prepared at the interface of methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([N8881][Tf2N]) and water exhibited striking SERS sensitivities and good reproducibility.