  The possibility to align and organize faceted particles in the bulk offers
intriguing possibilities for the design and discovery of materials and
architectures exhibiting novel functional properties. The growth of ice
crystals can be used to trigger the self-assembly of large, anisotropic
particles and consequently to obtain three-dimensional porous materials of
large dimensions in a limited amount of time. These mechanisms have not been
explored so far due to the difficulty to experimentally investigate these
systems. Here we elucidate the self-assembly mechanisms of faceted particles
driven by ice growth by a combination of X-ray holotomography and discrete
element modeling, providing insights into both the dynamics of self-assembly
and their final packing. The encapsulation of particles is the result of a
delicate balance between the force exerted by the percolating network of
concentrated particles and the force exerted by the moving interface. We
illustrate the benefits of such self-assembly for thermal management composite
materials.
