Reaching large lengths and long times in polymer dynamics simulations

TL;DR

This paper introduces an efficient lattice model for simulating long-term dynamics of dense polymer systems, enabling the study of phase separation and domain growth over extended timescales.

Contribution

The authors develop a high-performance lattice simulation method for polymer dynamics, capable of modeling large systems over long times with detailed interaction effects.

Findings

Observed phase separation in dense binary polymer mixtures.

Confirmed domain growth follows t^{1/3} law in late-stage dynamics.

Simulated over 46,000 polymers on a large lattice, demonstrating scalability.

Abstract

A lattice model is presented for the simulation of dynamics in polymeric systems. Each polymer is represented as a chain of monomers, residing on a sequence of nearest-neighbor sites of a face-centered-cubic lattice. The polymers are self- and mutually avoiding walks: no lattice site is visited by more than one polymer, nor revisited by the same polymer after leaving it. The dynamics occurs through single-monomer displacements over one lattice spacing. To demonstrate the high computational efficiency of the model, we simulate a dense binary polymer mixture with repelling nearest-neighbor interactions between the two types of polymers, and observe the phase separation over a long period of time. The simulations consist of a total of 46,080 polymers, 100 monomers each, on a lattice with 13,824,000 sites, and an interaction strength of 0.1 kT. In the final two decades of time, the domain-growth is found to be d(t) ~ t^1/3, as expected for a so-called "Model B" system.