Fabrication of Langmuir–Blodgett film from Polyvinylpyrrolidone stabilized NiCo alloy nanoparticles

The fabrication of monolayer/multilayer films of Polyvinylpyrrolidone (PVP) stabilized NiCo alloy nanoparticles with an average particle size 7 nm via Langmuir–Blodgett method is presented in this paper. The NiCo alloy nanoparticles were synthesized in ethanol using hydrazine hydrate as reducing agent at 60 °C in the presence of PVP and washed with a mixture of chloroform–methanol (1:1) solution to get pure PVP capped alloy nanoparticles. The NiCo alloy suspension was spread to the interface of air/water and transferred to the glass surface. The formation of a Langmuir monolayer/multilayer of PVP stabilized NiCo particles at air/water interface were revealed with the pressure-area isotherm curve. The transfer of nanoparticles on the glass surface was found to be efficient for the first six layers as exhibited by the pressure-area isotherm and increases in absorption intensity in the UV–Vis range. The atomic force microscopy results show that this film has a cubic symmetry in a two dimensional (2D) array.