Layer-by-layer self-assembly for controlled magnetic multilayer thin film fabrication

The copolymer poly[4'-(4-methacryloyphenyl)-2,2': 6', 2 ''-terpyridine -co-N-(vinylbenzylimino)-diacetic acid] [P(mPhtpy-co-vbda)] was synthesized by the RAFT (reversible addition fragmentation chain transfer) polymerization method and confirmed by Fourier transform infrared spectroscopy and H-1 nuclear magnetic resonance spectroscopy. The bimetallic complexes of the copolymer were prepared by chelating with Nd3+ and Co2+. The magnetic multilayer film was fabricated via layer-by-layer (LbL) self-assembly with the copolymer and metal ions (Nd3+ and Co2+). Attenuated total reflectance-infrared spectroscopy and UV-Vis spectroscopy were used to characterize the film, indicating that the driving force for fabricating the multilayer film was the coordination interaction. The magnetic behavior of the complexes and the film was measured as a function of the magnetic field strength (050 kOe) at 5 K and also of the temperature (5-300 K) at the magnetic field strength (30 kOe). The magnetic hysteresis loops of the complexes and the film showed the typical "S" shape at 5 K, exhibiting the properties of soft ferromagnetic materials.