Colloidal buckets formed via internal phase separation

We report the fabrication of novel hollow particles, with a hole engineered in the shell, via a coacervation technique. These particles are termed colloidal buckets. Two sets of conditions were explored: (i) lowering the operating temperature to reduce the solvent evaporation rate, and (ii) incorporation of a third component to alter the interfacial tensions between different phases. The particles were characterised by dynamic light scattering, gas adsorption and differential scanning calorimetry. The buckets had a higher surface area than spheres of the same size and the core was easily removed by washing in a suitable solvent.