Dynamic Transformation of Bio-Inspired Single-Chain Nanoparticles at Interfaces

Interfacial behavior of macromolecules dictates their intermolecular interactions, which can impact processing and application of polymers for pharmaceutical and synthetic use. Using molecular dynamics simulations, we observe the evolution of a random heteropolymer in the presence of liquid-liquid interfaces. The system of interest forms single-chain nanoparticles through hydrophobic collapse in water, lacking permanent crosslinks and making their morphology mutable in new environments. The complex amphiphilic polymers are shown capable of stabilizing high energy water-hexane interfaces, often unfolding to maximize surface coverage. Despite drastic changes to polymer conformation, monomer presence in the water phase is generally maintained and most changes are due to increased hydrophobic solvent exposure towards the oil phase. These results are then compared to behavior at the water-graphene, where the macromolecules adsorb but do not remodel. The polymer behavior is shown to depend significantly upon both its own amphiphilic character and the deformability of the interface.