Active Surface Modification for Iron Nanopowders Produced by Wire Electrical Explosion

The surface modification of metal iron nanopowders produced by wire electrical explosion (WEE) followed by immediate treatment with hexane, toluene, chloroform, and polymer solutions in hexane and toluene is investigated. It has been shown the nanopowders produced in the inert gas environment are shown to interact due to their active surface both with liquid media and with modifiers dissolved in them. X-ray diffraction and thermal analysis, including mass spectrometry, show that hexane is an inert liquid medium in respect to iron nanopowders, toluene treatment causes carbon deposition into the nanoparticle surface layers, and chloroform chemically interacts with iron nanoparticles with a high yield of FeCl2. Thermal analysis and transmission electron microscopy show that treating nanopowders with an oleic acid (OA) solution in hexane and isoprene rubber and polystyrene solutions in toluene results in the formation of a polymeric coating with a thickness of 3-6 nm at the nanoparticle surface. The polymer amount adsorbed at the surface reaches 0.4 mg/m(2) depending on the polymer concentration in the solution. The deposited polymer layer has a loose structure formed by macromolecules adsorbed within the ball conformation.