Magneto-polymer composite particles fabricated utilizing patterned perfluoropolyether elastomer molds

In this work we show the fabrication of magneto-polymer composite particles using a novel technique known as Particle Replication In Non-wetting Templates (PRINT). The shape and size of the composite particle was dictated by a patterned perfluoropolyether (PFPE) mold. The highly fluorinated nature of the PFPE elastomer make it an ideal material for use in soft lithography. Before curing, the colorless liquid is highly wetting a factor that leads to high fidelity between the master and the mold. After curing, its highly fluorinated surface reduces lipophilic solvent uptake and minimizes scum formation. Magnetite nanoparticles, sterically stabilized by covalently bound polyethyleneglycolsilane (PEG-silane) were dispersed in a mixture of PEG-monomethacrylate and PEG-triacrylate. The composite particles were photochemically cured in a UV chamber using the radical photoinitiator diethoxyacetophenone (DEAP). Particles were harvested from the elastomeric mold using either a scraping method or a sacrificial adhesive layer. Particles were purified through repeated rinsing and filtration. Particles were characterized using a variety of techniques including: Scanning Electron Microscopy, Transmission Electron Microscopy, Selected Area Electron Diffraction, and X-ray Diffraction.