Hydrogel microspheres (microgels) are composed of cross-linked hydrophilic polymer chains, and due to their fascinating properties, they found variety of applications including sensors, catalysts, and coatings.1 To realize and develop such applications, we developped a series of hydrogel/hydrophobic nanocomposite microgels synthesized by seeded emulsion polymerization in the presence of microgels (SEPM).2-6 We believe that the study of nanocomposite microgels will lead to understand the rold of local micro-hydrogel environment, such as polarity and hydrophobicity. In this presentation, we will present the impact of charge distribution in seed microgels on the structure of resultant nanocomposite microgels. Different from microgels whose charged groups are localized at their center, polystyrene nanoparticles were formed inside the core microgels when microgels whose charged groups were localized on their surface were used as cores for SEPM (Figure(a)). The nanostructures are also dependent on monomer concentration during SEPM; water-swollen microgel was occupied by hydrophobic polystyrene (Figure(b)). Additionally, the size and morphology of the composites were tuned by surfactants (Figure (c)).3 From these results, we concluded that styrene monomer can penetrate into polyelectrolyte hydrogel layer, however, resultant polystyrene nanoparticles do not favor combination with polyelectrolyte hydrogels,4 which allows us to design the morphology of composite microgels.4-6

Soft nanocomposite hydrogel microspheres with defined nanostructures

2019 Fall National Meeting

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