Collapse Dynamics of Chemically Active Flexible Polymer

We investigate the structural and dynamical properties of a chemically active flexible polymer chain immersed in a solvent bath by using hybrid molecular dynamics (MD) and multiparticle collision dynamics (MPCD) simulation techniques in a three-dimensional space. The source of activity on the polymer is the self-generating, nonequilibrium solvent gradient caused by the chemical reaction at different sites on the polymer. The chemical gradient then leads to the generation of the local tangential force along the filament. Here we present the effect of activity on the configurational dynamics of a flexible chain emphasizing globule-like transformation at the higher activity. Particular attention is paid to how the radius of gyration (R g) changes with the activity. We find that the polymer undergoes a coil-to-globule-like transition with increasing active force. Decreasing the Flory scaling exponent of R g, the correlation of the end-to-end vector C(t) and radial distribution g(r) of the monomers around the filament quantifies this transition. We also analyze the motion of a polymer and its center of mass in terms of time-averaged mean-squared displacement (MSD). The superdiffusive motion of the active flexible polymer reverts to random walk at a long time scale with an enhanced diffusion, where the scaling of the diffusion coefficient is the same as the Zimm model.