Synthesis and Characterization of Surfactant-based Hydrophobic-Core Hydrophilic-Shell Nanoparticles and their Use as Encapsulation Agents

Keywords:
microemulsion, core-shell, dye-encapsulation, polarity sensors, fluorescence

Abstract:
A ternary surfactant system was used for the synthesis of hydrophobic-core hydrophilic-shell nanoparticles. A chemically active surfactant functioned as anchoring points for the growth of the shell on the surface of the particles. Dynamic light scattering, transmission electron microscopy and atomic force microscopy were used to characterize their size and the physical properties of the core and the shell. It was observed that when deposited on a substrate, the particles expand to a different degree, depending on the polarity of the substrate. Two hydrophobic fluorescent dyes-dansyl chloride and coumarin 153- were used to prove the ability of the particles to encapsulate hydrophobic compounds. The dyes emission was compared before and after the shell synthesis, showing that after the siloxane network is formed, the dye molecules reside in a more non polar microenvironment, isolated from the polar solvent. The uptake of the small hydrophobic dyes from aqueous suspensions was investigated by fluorescence. The emission of these fluorophores after they have been internalized by the nanoparticles showed that they can successfully remove hydrophobic molecules from aqueous suspension. Based on these results, we believe these particles can be used for the removal of contaminants from biological systems

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Nanotech 2006 Conference Program Abstract