Conductive silver films with tunable surface properties: thickness, roughness and porosity

The organasol of nanoparticles (3 M, the particle size 6 ± 1 nm) was synthesized by the silver nitrate reduction with hydrazine in the reverse emulsions stabilized by the sodium bis(2-ethylhexyl)sulfosuccinate. The obtained silver nanoparticle emulsion was concentrated using electrophoretic concentration. The silver nanoparticle films with tunable thickness (from 3.9 ± 0.2 to 1.7 ± 0.2 µm), porosity (from 26 ± 10 to 46 ± 12%), density (from 5.7 ± 1.5 to 7.8 ± 3.0 g/cm3), roughness (from 4 ± 2 to 131 ± 19 nm) and surface electrical resistivity (from 0.03 ± 0.01 to 0.10 ± 0.01 Ohm/□) were obtained. The sintering process of the silver nanoparticle films was studied by in situ XRD experiment using synchrotron radiation. The separation procedure for the metallic films from the solid substrates was proposed. The separated sintered silver nanoparticle film was considered as a Janus membrane. The wetting asymmetry of the obtained Janus membrane was of 39°. The obtained films were considered as promising functional material with the bactericidal and the electrical conductive properties. The obtained Janus membrane could be placed on the flexible polymer substrates.