Movie S3.

Silica superballs with m = 3.9 are dispersed in the presence of a mixture of PEO (molecular weight 8 M) and pNIPAM depletants. At 27 °C, the superballs assemble into square crystallites, as observed when the particles are dispersed with pNIPAM alone. As the temperature is increased we observe that the lattice shifts to a Λ1 configuration as observed when the superballs are dispersed with PEO alone. This happens because at higher temperatures the interactions induced by the pNIPAM weaken whereas those induced by the PEO are fixed. By cycling the temperature, we are able to observe a reversible solid-to-solid phase transition over several iterations.