Assembly of microspheres with polymers by evaporating emulsion droplets.

We study the packing of colloidal microspheres mixed with polymers in oil-in-water emulsion droplets by evaporation. The addition of polymers produces non-unique configurations of final clusters when the number of particles N inside the droplet is larger than 4. The cluster configurations are classified into three categories based on symmetry. Stablized colloidal clusters of spherical packings are observed. Our observations on packing process suggest the mechanisms which cause different and nonunique structures. The osmotic pressure and the interparticle interaction due to polymers changes the force balance between microspheres and result in different structures.