  The interaction of objects with a moving solidification front is a common
feature of many industrial and natural processes such as metal processing, the
growth of single-crystals, the cryopreservation of cells, or the formation of
sea ice. Solidification fronts interact with objects with different outcomes,
from the total rejection to their complete engulfment. We image the freezing of
emulsions in 5D (space, time, and solute concentration) with confocal
microscopy. We show the solute induces long-range interactions that determine
the solidification microstructure. The local increase of solute concentration
enhances premelting, which controls the engulfment of droplets by the front and
the evolution of grain boundaries. Freezing emulsions may be a good analogue of
many solidification systems where objects interact with a solidification
interface.
