Synthesis of Ultra Small Biocompatible Magnetic Nanocomposites by Seeded Emulsion Polymerization

H. Kloust, E. Pöselt, S. Kappen, C. Schmidtke, A. Kornowski, W. Pauer, H.-U. Moritz, H. Weller
University of Hamburg, DE

Keywords: seeded emulsion polymerization, nanocrystal, polysorbate-80, phase transfer, PEG


We present the production of PEGylated particles in the lower nanometer range by a new seeded emulsion polymerization technique under micro-emulsion conditions, avoiding any treatment with high shear forces or ultrasonication. Hereby, the hydrophobic shells of the inorganic nanocrystals are used as seeds for the emulsion polymerization. This technique allows a much better control of the encapsulation process compared to conventional techniques and leads to highly reproducible and narrowly size-distributed emulsion particles over a broad size regime and a controlled number of encapsulated nanocrystals. It opens up a controllable and economic large-scale opportunity to obtain bio-applicable nanocrystals even in the size regime of 15 to 50 nm. Our approach consists of two controllable steps: first, the formation of seeds and second, shell synthesis. The approach allows to tune the number on nanocrystals per seed and to tune the thickness of the polymer shell individually. Thus the approach allows the tailored fabrication of the composites. Furthermore this approach allows the use of different kind on nanocrystals or mixtures of them and the use of functional monomers and surfactants to undergo coupling reactions.