Topology-Regulated Coarsening and Interfacial Morphologies in Amphiphilic Polymer-Fluid Blends

We employ three-dimensional dissipative particle dynamics simulations to study the coarsening behavior of binary simple fluids blended with amphiphilic polymers of distinct topologies. Linear, branched, and ring copolymers preferentially adsorb at fluid-fluid interfaces. The topological constraints associated with these polymers affect their conformation, interfacial packing, and transport properties. In the early stage, domain growth follows inertial hydrodynamic scaling, <i>R</i>(<i>t</i>) ∼ <i>t</i>^2/3, characteristic of simple fluids. Polymer adsorption subsequently reduces the effective interfacial tension and increases interfacial drag. All systems initially follow inertial hydrodynamic growth, followed by a topology-dependent crossover to saturation. The saturation length increases linearly with polymer chain length and decreases inversely with polymer concentration, consistent with our arguments regarding interfacial coverage by the polymers. We demonstrate that polymer topology systematically alters domain connectivity, interfacial curvature, and coarsening rates. This leads to deviations from Porod scattering and the formation of rough, fractal-like interfaces. The interfacial fractal dimension serves as a measure of the degree of roughness and is correlated with the complexity of the topology. These results establish macromolecular topology as an effective control parameter for tuning hydrodynamic coarsening and arrested morphologies in polymer-fluid mixtures, with direct implications for the design of polymer-stabilized emulsions and structured soft materials.