  Particle shape is a critical parameter that plays an important role in
self-assembly, for example, in designing targeted complex structures with
desired properties. In the last decades an unprecedented range of monodisperse
nanoparticle systems with control over the shape of the particles have become
available. In contrast, the choice of micron-sized colloidal building blocks of
particles with flat facets, i.e., particles with polygonal shapes, is
significantly more limited. This can be attributed to the fact that, contrary
to nanoparticles, the larger colloids are significantly harder to synthesize as
single crystals. Herein, we demonstrate that the simplest building block, such
as the micron-sized polymeric spherical colloidal particle, is already enough
to fabricate particles with regularly placed flat facets, including completely
polygonal shapes with sharp edges. As an illustration that the yields are high
enough for further self-assembly studies we demonstrate the formation of 3D
rotator phases of fluorescently labelled, micron-sized and charged rhombic
dodecahedron particles. Our method for fabricating polyhedral particles opens a
new avenue for designing new materials.
