Fabrication of an organic-inorganic hybrid LB film of a magnetic polyoxometalate

A paramagnetic organic-inorganic hybrid Langmuir-Blodgett (LB) film was produced through orientation-controlled stabilization of a Ni-containing magnetic polyoxometalate (((NBu4)3 [PW9NiO43(HOOCC2H4PO)2]): Ni-POM) monolayer by attaching electrostatically hydrophobic N,N-dimethyldodecyl amine (DMDA). Although the Ni-POM itself did not show any development of surface pressure upon monolayer spreading, the surface pressure-area isotherm showed the formation of very stable monolayer on the water subphase when the polyoxometalate was spread together with DMDA. The hybrid LB films transferred on solid substrates were characterized by XPS and XRD spectra. The XPS spectra indicated the presence of Ni-POM in the LB film. The AFM image of the LB film showed that the Ni-POM particles were totally spread to monolayer. The X-ray diffraction spectra showed POMs are positioned to two-dimensionally spread multiplayer film. The peaks due to (100) and (200) planes are interpreted as the hybrid multiplayer film is composed of multilayer monolayers. The Ni-POM showed characteristic paramagnetic susceptibility, which was monitored by a SQUID magnetometer.