10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Preparation of Core-Shell Nanoparticles by Aerosol-Polymerization Process
JALAL POOSTFOROOSHAN, Masoom Shaban, Alfred P. Weber, TU Clausthal
Abstract Number: 720 Working Group: Aerosol Chemistry
Abstract Core-shell nanoparticles, consisting of an inorganic scaffold and polymeric shell, have received considerable attention due to their promising applications. These nanoparticles have the potential to combine different properties of the core and shell into a single particle. Generally, polymer shells on the inorganic nanoparticles prevent particle-particle aggregation and offer excellent compatibility in a polymer matrix.
In this work, inorganic cores were initially generated by either spark discharge followed by the sintering furnace (spherical Ag nanoparticles) or nebulization of the respective suspension (SiO2 nanoparticles). Then, the inorganic nanoparticle-laden nitrogen flow was bubbled through the saturator containing the glycidyl methacrylate (GMA) as organic monomer kept usually at 80 °C. In the subsequent cooling behind the saturator back to room temperature a supersaturation was achieved resulting in the condensation of GMA vapor on the surface of the inorganic nanoparticle. Subsequently, the monomer coating was chemically polymerized ‘‘in flight’’ to form a polymer shell by addition of ammonia vapor as an initiator within the average aerosol residence time of 2 min in the polymerization reactor [1]. Moreover, the effect of numerous parameters, including the GMA saturator temperature and properties of inorganic nanoparticles on the structure of polymeric shell and coating thickness and efficiency 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 showed that monomer and polymer coating efficiency were 99% and 60%, respectively.
Highlights of the presented aerosol-polymerization procedure are the continuous, fast, simple and requires few unit operations. Moreover, in contrast to conventional wet methods such as emulsion polymerization, this technique can produce highly pure surfactant-free polymer shells and allows for a direct collection of composite nanoparticles.
[1] Poostforooshan, J.; Rennecke, S.; Gensch, M.; Beuermann, S.; Brunotte, G.-P.; Ziegmann, G.; Weber, A. P. Aerosol Sci. Technol. 2014, 48, 1111−1122.