Asymmetric Composite Nanoparticles with Anisotropic Surface Functionalities

Asymmetric inorganic/organic composite nanoparticles with anisotropic surface functionalities represent a new approach for creating smart materials, requiring the selective introduction of chemical groups to dual components of composite, respectively. Here, wereport the synthesis of snowman-like asymmetric silica/polystyrene heterostructure withanisotropic functionalities via a chemical method, creating nanostructure possibly offeringtwo-sided biologic accessibility through the chemical groups. Carboxyl group was introducedto polystyrene component of the snowman-like composites by miniemulsion polymerizationof monomer on local surface of silica particles. Moreover, amino group was then grafted toremained silica surface through facile surface modification of the composite nanoparticles.The asymmetric shape of these composites was confirmed by TEM characterization.Moreover, characteristics of anisotropic surface functionalities were indicated by Zetapotential measurement and confocal laser microscopy after being labeled with fluorescentdyes. This structure could find potential use as carriers for biological applications