Effect of roughness-regulated migration and distribution of particles on the structural evolution of flowing polymer blends

ABSTRACT We report that the surface roughness of solid particles plays a crucial role in determining their migration and distribution within flowing polymer blends as well as their regulation ability toward the blend morphology. During slow shearing, smooth particles exhibit remarkable accumulation at the droplet/matrix interface while the rough ones prefer to locate within the droplets uniformly. As a result, droplets tend to adopt a vorticity alignment due to the strong interfacial jamming effect upon the addition of a small amount of smooth particles. In contrast, more rough particles are needed to induce a similar phenomenon via a rheological enhancement effect. The prominent discrepancy in the behavior of two kinds of particles in the blend could be understood by the diffusion and contact line pinning behavior of particles controlled by their surface roughness. Exploring the underlying mechanism may have an important implication for a rational design of universal particle emulsifiers for multiphase materials such as polymer blends and functional emulsions.