Relaxation of amorphous multichain polymer systems using inverse kinematics

Atomic scale simulations of polymer materials is a topic of interest since it permits to reduce costly experiments to determine their physicochemical properties. In this context, modeling heterogeneously ordered multichain systems such as amorphous polymers, remains a challenging problem. A recently proposed two-step method consists of iteratively generating the structures using a simplified energy model, and subsequently relaxing the system, considering a more accurate model, in order to reduce its potential energy. This work proposes an improvement of this method by integrating a novel relaxation technique, which applies analytical rebridging moves inspired by robotics. A comparative analysis using models of amorphous polyethylene with different sizes and densities shows that the rebridging scheme described here is very effective for the simulation of long alkanes.