Mapping Atomistic to Coarse-Grained Polymer Models Using Automatic Simplex Optimization To Fit Structural Properties

Reith, Dirk; Meyer, H.; Müller‐Plathe, Florian

doi:10.1021/ma001499k

Cited by 214 publications

(232 citation statements)

References 24 publications

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“…As center of the coarsegrained (CG) beads, the monomer center of mass (excluding the sodium ion) was chosen. Bonded as well as non-bonded terms were parameterized by systematically varying the interactions until the structure of the atomistic model was reproduced 42 . This also allowed us to neglect all explicit water molecules and sodium ions (necessarily present in the parent atomistic simulation) in subsequent CG simulations.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…For four samples, the molar masses M W and the radii of gyration R G were measured as well. The PAA samples were of polydispersity D P between 1.5 and 1.8 and diluted in aqueous NaCl-containing solution (0.1 − 1 mol/l) 11 .…”

Section: Numerical Resultsmentioning

confidence: 99%

“…10 it is clear that ρ should be subject to an N −(1−ν) correction for finite chain length; nevertheless, experiments have so far not reported a systematic dependence on molecular weight. Typically, values around ρ ≈ 1.5 11,12 , or ρ ≈ 1.6 / ρ ≈ 1.3 for different solvents 10 are found in the good-solvent regime. In view of the inaccuracies of the experiments (R G typically has an error of 5% 10 ) the inability to observe a systematic behavior in N is not very surprising.…”

Section: Introductionmentioning

confidence: 99%

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Corrections to scaling in the hydrodynamic properties of dilute polymer solutions

Dünweg

Reith

Steinhauser

et al. 2002

The Journal of Chemical Physics

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We discuss the hydrodynamic radius RH of polymer chains in good solvent, and show that the leading order correction to the asymptotic law RH ∝ N ν (N degree of polymerization, ν ≈ 0.59) is an "analytic" term of order N −(1−ν) , which is directly related to the discretization of the chain into a finite number of beads. This result is further corroborated by exact calculations for Gaussian chains, and extensive numerical simulations of different models of good-solvent chains, where we find a value of 1.591 ± 0.007 for the asymptotic universal ratio RG/RH , RG being the chain's gyration radius. For Θ chains the data apparently extrapolate to RG/RH ≈ 1.44, which is different from the Gaussian value 1.5045, but in accordance with previous simulations. We also show that the experimentally observed deviations of the initial decay rate in dynamic light scattering from the asymptotic Benmouna-Akcasu value can partly be understood by similar arguments.

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Section: Numerical Resultsmentioning

confidence: 99%

Section: Numerical Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Corrections to scaling in the hydrodynamic properties of dilute polymer solutions

Dünweg

Reith

Steinhauser

et al. 2002

The Journal of Chemical Physics

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“…Knowing that water at room temperature has a Bjerrum length of about = 7 Å and that the relative permittivity of water is about ⑀ r Ϸ 80, and assuming that a typical polyelectrolyte such as polyacrylate has a coarse-grained monomer size of about Ϸ 7 Å, 46 then our simulations imply that these phase transitions will occur only in solvents for which Ͼ28 Å, or equivalently ⑀ r Ͻ 20. Such solvent conditions cannot be reached with aqueous NaCl solutions near the physiological concentration.…”

Section: A Discontinuous Volume Phase Transitionsmentioning

confidence: 90%

Molecular simulation of the swelling of polyelectrolyte gels by monovalent and divalent counterions

Yin

Horkay

Douglas

et al. 2008

The Journal of Chemical Physics

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Permanently crosslinked polyelectrolyte gels are known to undergo discontinuous first-order volume phase transitions, the onset of which may be caused by a number of factors. In this study we examine the volumetric properties of such polyelectrolyte gels in relation to the progressive substitution of monovalent counterions by divalent counterions as the gels are equilibrated in solvents of different dielectric qualities. We compare the results of coarse-grained molecular dynamics simulations of polyelectrolyte gels with previous experimental measurements by others on polyacrylate gels. The simulations show that under equilibrium conditions there is an approximate cancellation between the electrostatic contribution and the counterion excluded-volume contribution to the osmotic pressure in the gel-solvent system; these two contributions to the osmotic pressure have, respectively, energetic and entropic origins. The finding of such a cancellation between the two contributions to the osmotic pressure of the gel-solvent system is consistent with experimental observations that the swelling behavior of polyelectrolyte gels can be described by equations of state for neutral gels. Based on these results, we show and explain that a modified form of the FloryHuggins model for nonionic polymer solutions, which accounts for neither electrostatic effects nor counterion excluded-volume effects, fits both experimental and simulated data for polyelectrolyte gels. The Flory-Huggins interaction parameters obtained from regression to the simulation data are characteristic of ideal polymer solutions, whereas the experimentally obtained interaction parameters, particularly that associated with the third virial coefficient, exhibit a significant departure from ideality, leading us to conclude that further enhancements to the simulation model, such as the inclusion of excess salt, the allowance for size asymmetric electrolytes, or the use of a distance-dependent solvent dielectricity model, may be required. Molecular simulations also reveal that the condensation of divalent counterions onto the polyelectrolyte network backbone occurs preferentially over that of monovalent counterions.

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“…It is also more convenient to represent a group of atoms as a spherical super atom with an isotropic potential, instead of an ellipsoidal super atom with anisotropic potential. In most studies, the super atom is defined to be a spherical particle [37,177,184,[189][190][191], but there are also some studies attempting to do generalizations for anisotropic potentials [192,193]. However, the potential functions and the coarse-grained MD simulations become rather complex, and only slightly higher accuracy can be achieved.…”

Section: (B) (A)mentioning

confidence: 99%

Challenges in Multiscale Modeling of Polymer Dynamics

et al. 2013

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The mechanical and physical properties of polymeric materials originate from the interplay of phenomena at different spatial and temporal scales. As such, it is necessary to adopt multiscale techniques when modeling polymeric materials in order to account for all important mechanisms. Over the past two decades, a number of different multiscale computational techniques have been developed that can be divided into three categories: (i) coarse-graining methods for generic polymers; (ii) systematic coarse-graining methods and (iii) multiple-scale-bridging methods. In this work, we discuss and compare eleven different multiscale computational techniques falling under these categories and assess them critically according to their ability to provide a rigorous link between polymer chemistry and rheological material properties. For each technique, the fundamental ideas and equations are introduced, and the most important results or predictions are shown and discussed. On the one hand, this review provides a comprehensive tutorial on multiscale computational techniques, which will be of interest to readers newly entering this field; on the other, it presents a critical discussion of the future opportunities and key challenges in the multiscale geometric mapping matrix between all-atomistic and coarse-grained models N number of monomers per chain N e entanglement length, which is the number of monomers between two entanglements n v number of polymer chains per unit volume n ij (n 0 (r ij )) entanglement number (at equilibrium) between particle pairs i and j p r , P R configurational probability distributions in all-atomistic and coarse-grained models, respectively R ee end-to-end distance of polymer chain R G radius of gyration of polymer chain s segment index/contour length variable along primitive chain S(q) single chain coherent dynamic scattering function Z number of entanglements per chain, defined as Z = N/N e α exponent in standard Mittag-Leffler function σ

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Mapping Atomistic to Coarse-Grained Polymer Models Using Automatic Simplex Optimization To Fit Structural Properties

Cited by 214 publications

References 24 publications

Corrections to scaling in the hydrodynamic properties of dilute polymer solutions

Corrections to scaling in the hydrodynamic properties of dilute polymer solutions

Molecular simulation of the swelling of polyelectrolyte gels by monovalent and divalent counterions

Challenges in Multiscale Modeling of Polymer Dynamics

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