Convenient synthesis and properties of polypropyleneimine dendrimer-functionalized polymer nanoparticles.
A simple synthesis of polymer core-dendrimer shell nanoparticles (NPs) in the 15-20-nm-diameter range is presented. Amine-terminated polypropyleneimine (PPI) dendrimers DAB-dendri-(NH(2))(4) and DAB-dendri-(NH(2))(16) (DAB4 and DAB16) are covalently attached to the surface of primary polystyrene-based NPs bearing reactive chlorobenzyl groups produced by microemulsion polymerization in the presence of a cationic surfactant. The grafting readily proceeds under mild conditions and leads to translucent aqueous suspensions of core-shell-type NPs with a high density of peripheral amine groups that have been characterized relative to their size and chemical composition. The dendritic shell acts as a protective ionizable outer layer and provides an improvement of the colloidal stability in neutral and acidic media. The metal-binding capacity of the PPI dendrimers is retained, and spectrophotometric titrations show that the dendrimer-grafted NPs can trap a large number of Cu(2+) ions (more than 900 Cu per NP-DAB16). These properties make them potentially valuable templates for the elaboration of hybrid nanomaterials. The reactivity of the external amine groups is used to link covalently azobenzene chromophores (disperse Red 1 residues) through aza-Michael addition in aqueous suspension. This simple method gives access to colored NPs with high dye contents in the outer layer (up to 1000-1500 dye molecules per NP), which indicates that dendrimer-functionalized NPs are valuable building blocks for the construction of multifunctional nanomaterials.
Institut Lavoisier UMR-CNRS 8180, Université de Versailles-Saint-Quentin-en-Yvelines, 45 Avenue des Etats-Unis, 78035 Versailles Cedex, France. larpent@chimie.uvsq.fr
Chantal
C
Larpent
Caroline
C
Cannizzo
Anne
A
Delgado
Fabrice
F
Gouanvé
Paresh
P
Sanghvi
Cédric
C
Gaillard
Gérard
G
Bacquet
D050091:Dendrimers / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D011126:Polypropylenes / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D019265:Spectroscopy, Near-Infrared
D050091:Dendrimers; D011126:Polypropylenes; C443641:poly(propyleneimine)