The charging behavior of metal nanoparticles bouncing from conductive surfaces was investigated in a single-stage-lowpressure-impactor. Ag and P t particles of a fixed particle size between 20 nm and 100 nm were impacted on targets of bulk Au and P t, respectively, and the resulting contact charge was measured as a function of impact velocity. The influence of target hardness was revealed by the comparison to measurements with soft nanostructured layers obtained by direct current sputtering of Au and P t on mica discs. From the dataset, regions of elastic, elastoplastic, and fully plastic particle deformation were identified, and the size-dependent effective yield stress for the respective particle materials was calculated. The influence of electron back-tunneling in the separation phase of the collision on the effective contact charge is discussed.

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This article presents a novel method to encapsulate gas-borne nanoparticles with a polymeric shell. This method implies heterogeneous condensation of monomer vapor around the surface of nanoparticles as nuclei and polymerization is then subsequently started by addition of NH 3 as aerosol initiator. Ag and SiO 2 nanoparticles were generated as inorganic core by spark discharge and nebulization, respectively, and glycidyl methacrylate (GMA) was used as organic monomer. The effect of several parameters, including vapor pressure of monomer and properties of inorganic core such as morphology, material, particle size, and production method on the thickness of polymeric shell and morphology of resulting nanocomposites has been investigated. The particle size distribution and morphology of the resulting core-shell nanoparticles have been studied via scanning mobility particle sizer (SMPS) and transmission electron microscope (TEM). Finally, the coating efficiency was determined by aerosol photoemission (APE) and the results show that monomer and polymer coating efficiency are 99% and 60%, respectively.

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