Two-Regime Conformation of Grafted Polymer on Nanoparticle Determines Symmetry of Nanoparticle Self-Assembly

One of the key design factors that regulate the properties of grafted nanoparticles (GNPs) and their self-assembly is the conformation of the grafted polymer. On the curved surface of the GNP core, the conformation of the polymer chain is not uniform in the radial direction. The segment is a non-Gaussian chain in the concentrated polymer brush (CPB) regime near the interface between GNP core and grafted polymer, while it is less constrained in the semidilute polymer brush (SDPB) regime near the surface of GNP. Here, the property of polymer conformation showing crossover behavior at the CPB/SDPB threshold through the coarse-grain molecular dynamics simulation of nanoparticles with explicit grafted chains is explored. Moreover, the self-assembly structure depends on the effective softness, which is defined as a function of the threshold of two regimes estimated from the conformation of the polymer. The study examines the transition between concentrated polymer brush and semidilute polymer brush regimes through polymer conformation analysis. It precisely determines effective softness as an order parameter predicting self-assembly symmetry. The research utilizes self-assembly simulations to demonstrate that the symmetry predicted by effective softness aligns with simulation results. The study provides insights into nanoparticle arrangements based on polymer grafting properties. image