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Well‐Defined SiO 2 @P(EtOx‐ stat ‐EI) Core–Shell Hybrid Nanoparticles via Sol‐Gel Processes
Author(s) -
Eckardt Oliver,
Pietsch Christian,
Zumann Oliver,
von der Lühe Moritz,
Brauer Delia S.,
Schacher Felix H.
Publication year - 2016
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201500467
Subject(s) - materials science , dynamic light scattering , nanoparticle , cationic polymerization , polymer chemistry , polymer , chemical engineering , polymerization , transmission electron microscopy , particle size , scanning electron microscope , particle (ecology) , nanotechnology , oceanography , geology , engineering , composite material
Positively charged nanoparticles (NPs) are very interesting for biomedical and pharmaceutical applications, such as nonviral gene delivery. Here, the synthesis of SiO 2 nanoparticles with a covalently grafted poly(2‐ethyl‐2‐oxazoline) (PEtOx) shell (SiO 2 @PEtOx) is presented. PEtOx with a degree of polymerization of 20 and 38 is synthesized via microwave supported cationic ring‐opening polymerization and subsequently end‐functionalized with a triethoxysilyl linker for subsequent grafting to silica particles with hydrodynamic radii of 7, 31, and 152 nm. The resulting SiO 2 @PEtOx particles are characterized by using dynamic light scattering (DLS), transmission electron microscopy (TEM, cryoTEM), and scanning electron microscopy (SEM) to determine changes in particle size. Thermal gravimetrical analysis is used to quantify the amount of polymer on the silica surface. Subsequent in situ transformation of SiO 2 @PEtOx particles into SiO 2 @P(EtOx‐ stat ‐EI) (poly(2‐ethyl‐2‐oxazoline‐ stat ‐ethylene imine) grafted silica particles) under acidic conditions inverts the surface charge from negative to positive according to ζ ‐potential measurements. The P(EtOx‐ stat ‐EI) shell could be used for the deposition of Au NP afterward.