Different Stages of Polymer-Chain Collapse Following Solvent Quenching–Scaling Relations from Dissipative Particle Dynamics Simulations

Abstract

We study the collapse of a linear bead-spring chain under a sudden quench in solvent conditions using explicit-solvent dissipative particle dynamics. We investigate the collapse stages of our 50 ≤ N ≤ 1000 bead chains by studying local structures identified by an extended clustering algorithm. We find evidence for the three early stages proposed by Halperin and Goldbart [Phys. Rev. E 2000, 61, 565–573]. Their apparent scaling with the chain length is ∝N 0, N 0.82(6), and N 1.04(2). These values are similar to the predicted ones, and deviations likely stem from the approximations made. The scaling of the overall collapse time with the chain length τc ∝ N 0.94(2), the decay of the squared radius of gyration (R g 2(0) – R g 2(t)) ∝ t 1.09(1), and the growth of blobs along the chain ⟨Sn ⟩ ∝ t 1 are all found to be approximately linear.

Simulation of Elastomers by Slip-Spring Dissipative Particle Dynamics

“…Depending on the underlying mapping, a DPD bead may represent a few atoms, chain segments, or even entire domains of soft-matter systems. This flexibility along with the low computational costs gives access to mesoscopic time and length scales, making DPD a popular method for the simulation of polymer melts, ,, solutions, − and even elastomeric systems. ,,, In this work, we follow the method of Groot and Warren, where the conservative force is purely linear and defined by a repulsion parameter a ij and a cutoff radius r c . Details can be found in the Simulation Details and ref .…”

Combination of Hybrid Particle-Field Molecular Dynamics and Slip-Springs for the Efficient Simulation of Coarse-Grained Polymer Models: Static and Dynamic Properties of Polystyrene Melts

“…Inspired by the phenomenological picture of tube-like dynamical constraints, recent developments in modeling techniques to predict the dynamics of high-molecular-weight polymers have been heavily involved. Examples include the CG blob MD simulations of Padding and Briels and several versions of slip-link models at different levels of coarse-graining. − Multiple slip-spring simulations have also been developed over the recent years in the single-chain form by Likhtman and in the multichain form by Uneyama and Masubuchi, Chappa et al, Langeloth et al, and Ramírez-Hernández et al However, intensive studies are still ongoing, − attempting to map properties of interest with these generic models at high-level coarse-graining to realistic polymers. More recently, Theodorou and co-workers developed a multiscale strategy that bridges detailed MD simulations to mesoscopic slip-spring-based Brownian dynamics simulations. , The combination of the slip-spring model with systematic highly CG polymer models offers a promising way to model the entangled polymers, retaining reasonable molecular information in spatial–temporal scales close to experiments.…”

State Transitions and Crystalline Structures of a Single Polyethylene Chain: MD Simulations

“…First, the collapse temperature T collapse reflects the balance of the intramolecular interaction and thermal motion, which is similar to the Θ temperature in polymer solutions . However, the pathway of the coil–globule transition is different from those in solvents, where local blobs collapse. , In comparison, only global aggregation takes place in our simulation at this transition stage.…”

“…1 However, the pathway of the coil−globule transition is different from those in solvents, where local blobs collapse. 74,75 In comparison, only global aggregation takes place in our simulation at this transition stage.…”