Calculation of the vapor-liquid coexistence of polymer-grafted nanoparticles

Abstract

In this work, molecular simulations are used to calculate the vapor-liquid equilibrium (VLE) of polymer-grafted nanoparticles under a wide range of conditions, with the main goal to explore the balance between nanoparticle-polymer interactions on the phase behavior. Brownian dynamics simulations are performed using coarse-grained model, generic enough to be applicable to a wide range of systems but with parameters which are directly relatable to physical systems. The VLE is calculated using the quench dynamics technique. This study demonstrates a strong connection between the VLE and the grafting architecture. It is observed that the critical temperature is reduced as the number of grafts or length of the grafts is increased, and the phase envelope is expanded as the nanoparticle diameter increases. The role of graft topology for systems with low surface coverage is also presented. Additionally, our simulation results are also compared with SAFT-VR, demonstrating good qualitative agreement between simulation and theory.