In-flight plasma modification of nanoparticles produced by means of gas aggregation sources as an effective route for the synthesis of core-satellite Ag/plasma polymer nanoparticles

Core-satellite nanoparticles (NPs), i.e. nanoparticles with a core decorated by small nanoparticles, have become highly attractive in a wide range of applications that comprises for instance ultra-sensitive bio-sensing, bio-imaging, targeted drug delivery or catalysis. Although many methods had been developed to produce such nanomaterials, some challenges such as high complexity of used protocols or low purity of synthetized nanoparticles, are still faced. In this study we report on the detailed investigation of a novel, fully plasma-based strategy that allows for the fabrication of silver/plasma polymer core-satellite NPs. The studied deposition procedure utilizes in-flight sputter-deposition of silver onto plasma polymer (C:H:N:O) nanoparticles produced by means of a gas aggregation source (GAS). It is shown that the silver atoms generated by magnetron sputtering of a silver target in an auxiliary plasma chamber located in between the output orifice of the GAS and the main deposition chamber are effectively captured by C:H:N:O nanoparticles as they pass through the inoculation zone of the deposition system. This results in the formation of small Ag nano-islands on the surface of C:H:N:O nanoparticles as witnessed by transmission electron microscopy. Furthermore, it is demonstrated that the size and number of silver satellites may be varied by the magnetron current used for the silver sputtering.