Mixing-Demixing Transition in Polymer-Grafted Spherical Nanoparticles

Polymer-grafted nanoparticles can provide property profiles than cannot be obtained individually by polymers or nanoparticles. Here, we have studied the order--disorder transition of symmetric copolymer melts of polymer-grafted nanoparticles with spherical nanoparticles by means of coarse-grained molecular dynamics simulation and a theoretical model. We find that larger size of nanoparticles leads to higher stability for given number of grafted chains and chain length reaching a point where demixing is impossible. Our results also suggest that there is a transition region, where the steric interactions of the core particles are shielded by a growing effective attractive core of the tethered polymer chains with a nontrivial dependence. We anticipate that our study will open new doors in the understanding of these systems with implications in materials science and medicine.