Compressible Colloidal Clusters from Pickering Emulsions and Their DNA Functionalization*

In this study for DNA-mediated colloidal assembly with pre-assembled clusters, DNA sequences, areal density of DNA, particle number density and size ratio are key parameters for determining equilibrium structures. We developed a simple and facile method to produce compressible colloidal clusters were prepared by assembling azide-functionalized non-crosslinked polymer particles using fluorinated oil-in-water emulsion droplets. The particles were adsorbed onto the droplet interface, which were packed to form clusters during slow evaporation of the oil. Because we use non-crosslinked polystyrene particles for colloidal clusters instead, which can be merged partially through solvent annealing, the compression ratio can be precisely controlled. Then, the clusters were coated by DNA using an strain-promoted alkyne–azide cycloaddition reaction. As the particles are not crosslinked, the shape of the DNA-coated clusters can be further modified to control the compression ratio through plasticization.