An enhanced entangled polymer model for dissipative particle dynamics

Sirk, Timothy W.; Slizoberg, Yelena R.; Brennan, John G.; Lı́sal, Martin; Andzelm, Jan

doi:10.1063/1.3698476

Cited by 129 publications

(162 citation statements)

References 25 publications

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“…[21] The DPD polymer model thus cannot capture the effects of entanglements for long polymer chains, unless an additional bond-bond repulsion interaction is introduced to the polymer model. [22][23][24] With the bond-bond repulsion interaction, DPD is capable to simulate topology and dynamics of entangled polymer melts. [25,26] Real polymer melts are known to follow a number of scaling laws.…”

Section: Introductionmentioning

confidence: 99%

Scaling behaviour of different polymer models in dissipative particle dynamics of unentangled melts

Posel

Rousseau

Lı́sal

2014

Molecular Simulation

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We present a dissipative particle dynamics (DPD) study of scaling behaviour for three polymer models. The scaling behaviour is explored for the conformational and dynamic properties of unentangled polymer melts. DPD employs a beadspring model together with an aggressive coarse-graining to represent polymers at the mesoscale. The first model studied utilises a simple soft repulsion potential for the bead-bead interactions together with a harmonic spring potential to connect beads into a polymer chain. The second model differs from the first model by replacing the harmonic spring with a finitely extensible nonlinear elastic spring. The third model uses realistic coarse-grain potentials for the bead-bead, spring and bending interactions based on the iterative Boltzmann inversion procedure and it corresponds to a mesoscopic model of polyethylene. We systematically vary the chain length and spring constant (in the case of the first and second models), and simulate the conformational properties such as the end-to-end distance or radius of gyration, and dynamic properties such as the centre-of-mass self-diffusion coefficient or viscosity. The scaling of the conformational and dynamic properties with chain length (scaling laws) is compared with the Rouse theory, which is considered as a standard theory for unentangled polymer melts. The comparison shows that simulated scaling laws typically agree with the Rouse scaling laws for the DPD polymer models with more than 10 DPD beads. For the shorter DPD polymers, deviations from the Rouse theory exist and become significant for the dynamic properties, especially for the viscosity of the polymer melts.

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Section: Introductionmentioning

confidence: 99%

Scaling behaviour of different polymer models in dissipative particle dynamics of unentangled melts

Posel

Rousseau

Lı́sal

2014

Molecular Simulation

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“…To circumvent this, Pan and Manke proposed a method for reducing topology violation by augmenting the segmental repulsive force into the sum of DPD forces . Most notably, Sirk et al included the fictitious bond soft repulsive potential as a penalty term for bond crossing . The modified segmental repulsive potential (mSRP) introduced by Sirk et al significantly reduced the number of fictitious chain crossing events.…”

Section: Introductionmentioning

confidence: 99%

Dissipative Particle Dynamics Study of SWCNT Reinforced Natural Rubber Composite System: An Important Role of Self‐Avoiding Model on Mechanical Properties

Ketkaew

Tantirungrotechai

2018

Macro Theory & Simulations

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Dissipative particle dynamics (DPD) is used to predict the mechanical properties of crosslinking‐polyisoprene (PI) reinforced by single‐walled carbon nanotube (SWCNT). The role of the increasing concentration of SWCNT up to 8% in morphology of PI composite is investigated. The carbon nanotube (CNT) restricts the polymer movement as indicated by the reduction of mean square displacement and the end‐to‐end distance. The analysis of CNT bundle reveals that the CNT forms bundle of many sizes depending on its concentration. The mechanical reinforcement of the PI composites is attributed to the restricted motion of crosslinked entangled polyisoprene and to the alignment of aggregated CNT along the elongation direction. However, the DPD alone fails to account for the change in Young's modulus of the composite system as a function of the SWCNT concentration. Using the modified segmental repulsive potential (mSRP), which prevents polymeric chain crossing and enhances polymer entanglement, can address this shortcoming. The mSRP is necessary for correct description of mechanical reinforcement in a polymer composite system. To obtain quantitative agreement with the experimental modulus, the polyisoprene interaction parameter is modified from the published value by 10%. This modified parameter is found to work well for the simulation of polyisoprene composites.

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“…Therefore a modified soft segmental repulsive potential [28] was added between CG beads to inhibit chain crossing. We used a segmental bead diameter of 0.5 nm.…”

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confidence: 99%

Resolving Dynamic Properties of Polymers through Coarse-Grained Computational Studies

et al. 2016

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Coupled length and time scales determine the dynamic behavior of polymers and underlie their unique viscoelastic properties. To resolve the long-time dynamics it is imperative to determine which time and length scales must be correctly modeled. Here we probe the degree of coarse graining required to simultaneously retain significant atomistic details and access large length and time scales. The degree of coarse graining in turn sets the minimum length scale instrumental in defining polymer properties and dynamics. Using linear polyethylene as a model system, we probe how coarse graining scale affects the measured dynamics. Iterative Boltzmann inversion is used to derive coarse-grained potentials with 2-6 methylene groups per coarse-grained bead from a fully atomistic melt simulation. We show that atomistic detail is critical to capturing large scale dynamics. Using these models we simulate polyethylene melts for times over 500 µs to study the viscoelastic properties of well-entangled polymer chains.Polymer properties depend on a wide range of coupled length and time scales, with unique viscoelastic properties stemming from interactions at the atomistic level. The need to probe polymers across time and length scales to capture polymer behavior makes probing dynamics, and particularly computational modeling, inherently challenging. With increasing molecular weight, polymer melts become highly entangled and the longtime diffusive regime becomes computationally inaccessible using atomistic simulations. In these systems the diffusive time scale increases with polymerization number N faster than N 3 , becoming greater than 10 10 times larger than the shortest time scales even for modest molecular weight polymers. While it is clear that the largest lengths scales of polymer dynamics are controlled by entanglements, the shortest time and length scales required to resolve dynamic properties are not obvious. This knowledge is critical for developing models that can transpose atomistic details into the long time scales needed to model long, entangled polymer chains.One path to overcoming this computational challenge is to coarse grain the polymer, reducing the number of degrees of freedom and increasing the fundamental time scale. The effectiveness of this process depends on retaining the smallest length scale essential to capturing the polymer dynamics. The process of coarse graining amounts to combining groups of atoms into pseudoatom beads and determining the bead interaction potentials [1,2]. Simple models like the bead-spring model [3], capture characteristics described by scaling theories, but disregard atomistic details and cannot quantitatively describe properties like structure, local dynamics or densities. Immense efforts have been made to systematically coarse grain polymers and bridge the gap of time and length scales while retaining atomistic characteristics [4]. One critical issue underlying the coarse graining process is the degree to which a polymer can be coarseA single C96H194 PE chain represented with in...

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An enhanced entangled polymer model for dissipative particle dynamics

Cited by 129 publications

References 25 publications

Scaling behaviour of different polymer models in dissipative particle dynamics of unentangled melts

Scaling behaviour of different polymer models in dissipative particle dynamics of unentangled melts

Dissipative Particle Dynamics Study of SWCNT Reinforced Natural Rubber Composite System: An Important Role of Self‐Avoiding Model on Mechanical Properties

Resolving Dynamic Properties of Polymers through Coarse-Grained Computational Studies

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