Scaling and Interactions of Linear and Ring Polymer Brushes via DPD Simulations

Abstract

Single and double layers of polymer coated surfaces are investigated by means of Dissipative Particle Dynamics (DPD), focusing on the difference between grafted ring and linear chains. Several different surface coverages σ , as well as chain lengths N and brush separations D, are analyzed for athermal, i.e., good solvent, conditions. The size in the form of the radius of gyration R g , the shape as asphericity δ ∗ , and orientation β ∗ , as well as density profiles as functions of distance from grafting plane ρ ( z ) , are studied. The effect of an added bond repulsion potential to suppress bond crossing in DPD is analyzed. Scaling laws of R g and its components R g ⊥ and R g ∥ are investigated. We find R g ∝ N ν , ν = 0.588 for surface coverages below the overlap surface concentration σ ∗ . For σ > σ ∗ we find R g ⊥ ∝ N ν ⊥ , ν ⊥ ≅ 1 and R g ∥ ∝ N ν ∥ , ν ∥ = 1 / 2 of ring brushes with the standard DPD model and ν ∥ ≅ 2 / 5 with added bond repulsion. The σ dependence of the radius of gyration was found to be R g ∝ σ μ with μ = 1 / 3 for surface coverages grater than σ ∗ . The perpendicular component R g ⊥ scales independent of the bond repulsion potential as R g ⊥ ∝ σ μ ⊥ , μ ⊥ = 1 / 3 , whereas the scaling of the parallel component exhibits a topological repulsion dependence R g ∥ ∝ σ μ ∥ , μ ∥ = − 1 / 12 for standard DPD and μ ∥ = − 1 / 6 for bond repulsion.

Developments in Polymer Theory and Simulation

“…Theoretical studies on the statistical and dynamical properties of polymers with nontrivial structures in chemical connectivity, and those of polymers with a nontrivial topology, such as knotted ring polymers in solution, have been reviewed by Deguchi and Uehara [20]. Single and double layers of polymer coated surfaces made of ring or linear chains were investigated by means of dissipative particle dynamics (DPD) by Jehser et al [21].…”

Investigation of Magneto Hydro-Dynamics Effects on a Polymer Chain Transfer in Micro-Channel Using Dissipative Particle Dynamics Method

“…In DPD method, it is assumed that the intermolecular force exerted by bead j on bead i and → f ij , consists of three parts, namely the conservative force, the dissipative force, and the random force [52].…”

Effects of primary amine-based coatings on microglia internalization of nanogels

“…Many different techniques were developed in this field, and they all go under the common name of "coarse-grained (CG)" models. Here, we employed a CG method called Dissipative Particle Dynamics (DPD), which was already successfully used for predicting the scaling and phase behavior of polymer brushes [48] and the solvent-responsive brushes in smart nanofluidic devices [49,50]. A molecular view of NG-NH 2 and NG-PEG-NH 2 surface features obtained with CG method is visible in Fig.…”