Colloid surfactants for emulsion stabilization

Abstract

A robust and straight-forward approach to synthesize uniform amphiphilic dimer colloid surfactants, consisting of a hydrophilic bulb and a hydrophobic bulb, was introduced. The formation of nonspherical dimer particles is found to be enhanced by the incompatibility-driven phase separation between the two polymer networks. It is found that the control over the particle geometry and the size ratio of the two bulbs can be achieved by changing the volume ratio of the monomer solution to the crosslinked polystyrene (CPS) seed. The propensity for the particles to orient with specific directionality is essential to form dense assemblies of particles at the interface, and to achieve stronger adsorption to interfaces. The formation of nonspherical drops of emulsion is found to be due to the fusion of two or more partially covered droplets until the interface is filled with the amphiphilic dimer particles.