Designed Magnetic Multilayer Thin Films Fabricated via the Layer-by-Layer Assembly of Polycyanofullerenes

The layer-by-layer self-assembly technique was used to fabricate a series of multilayer thin films with poly[4'-(4-methacryloyphenyl)-2,2':6',2 ''-terpyridine] (PmPhtpy), polycyanofullerenes, and transition metals (Ni2+ and Co2+). The polymer PmPhtpy was prepared by free-radical polymerization, and this was confirmed by Fourier transform infrared (FTIR) and H-1-NMR spectroscopy. The polycyanofullerenes, which were characterized by FTIR, ultraviolet-visible (UV-vis), and C-13-NMR spectroscopy, was synthesized via the bromination of fullerene and then substitution with a nucleophilic reagent [potassium cyanide (KCN)]. The optical properties of the films were measured by attenuated total reflection infrared and UV-vis spectroscopy, and the results indicate that the driving force of the fabrication of the multilayer film was the coordination interaction. The magnetic behavior was examined as a function of the magnetic field strength at 5 K and the temperature (5-300 K). The magnetic hysteresis loops of the films showed a typical S shape at 5 K; this suggested soft ferromagnetic properties. (C) 2014 Wiley Periodicals, Inc.