Prof. Dr. Axel Müller

Silica is an important mineral in biology and technology and many protocols have been developed for the synthesis of complex silica architectures. The current report shows that silsesquioxane/polymer hybrid nanoparticles are efficient templates for the fabrication of silica particles with a star or raspberry-like morphology. The shape of the resulting particles depends on the chemistry of the polymer arms. With poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) arms, spherical particles with a less electron dense core form. With poly{[2-(methacryloyloxy)ethyl] trimethylammonium iodide} (PMETAI), star or raspberry-like particles form. Electron microscopy, electron tomography, and small-angle X-ray scattering show that the particles have a complex structure, where a silsequioxane nanoparticle carrying the polymer arms is in the center. Next is a region, which is polymer-rich. The outermost region of the particle is a silica layer, where the outer parts of the polymer arms are embedded. Time-resolved ζ-potential and pH measurements, dynamic light scattering, and electron microscopy reveal that silica formation proceeds differently if PDMAEMA is exchanged for PMETAI.