On the basis of theoretical simulation, mixed homopolymer brushes grafted on nanoparticles will exhibit ordered polyhedral morphology as the particle size reaches nanometer scale. Direct proof of this prediction is yet to be realized. In this work, we utilized three-dimensional (3D) scanning transmission electron microscopy (STEM) tomography to study the self-assembled morphology of mixed polystyrene (PS)/poly(tert-butyl acrylate) (PtBA) brushes grafted on 67 nm silica particles. The PtBA and PS molecular weights are 22.2 and 23.4 kDa, respectively. The grafting density for PtBA and PS brushes are 0.54 and 0.31 chains/nm2, respectively. Due to the less dense packing of PS brushes, PS forms more or less isolated domains inside the PtBA matrix. From 3D STEM, PS domains protrude from the silica surface and connect between neighboring particles. This is the first time that detailed 3D morphology is clearly observed for mixed homopolymer brushes grafted on inorganic nanoparticles.

3D TEM imaging of polystyrene/poly(<i>tert</i>-butyl acrylate) mixed brushes grafted on silica nanoparticles

246th National Meeting (2013)

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3D TEM imaging of polystyrene/poly(tert-butyl acrylate) mixed brushes grafted on silica nanoparticles