Conformation and Diffusivity of Ring and Linear Polyethylene Oxide in Aqueous Solution: Molecular Topology Dependent Concentration Effects and Comparison with Experimental Data

Abstract

AbstractAtomistic molecular dynamics simulations are performed on aqueous solutions of ring and linear polyethylene oxide (PEO) under good solvent conditions for the investigation of their conformation and diffusion dynamics. The systems simulated span a wide range of molecular weights (from 2 to 10 k) and polymer concentrations. In the limit of infinite dilution, both conformational and dynamic properties appear to be practically molecular topology independent as far as their dependence on chain length and concentration is concerned, and a very favorable agreement is observed with respect to relevant well‐established theoretical predictions, experimental data, and earlier simulation studies. Crossing over to the semidilute regime, molecular topology starts to bear a distinct effect on the observed conformations of the two different molecular geometries. On the other hand, the diffusion dynamics of PEO in the semidilute regime appears to be practically molecular topology independent judging from the dependence of the chain center‐of‐mass diffusivity on chain length and concentration. Indeed, and despite the fact that ring molecules exhibit consistently a faster dynamics than their linear homologs over the entire concentration range simulated, the estimated concentration scalings for both types of architecture are strikingly similar. The findings of this work are compared with scaling arguments and available experimental data.