Ion diffusion in a polymer network: Monte Carlo studies and the dynamic percolation approach

Schulz, Beatrix M.; Karatchentsev, A.; Schulz, Michael; Dieterich, W.

doi:10.1016/j.jnoncrysol.2006.01.112

Cited by 5 publications

(2 citation statements)

References 12 publications

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“…In contrast, the dynamical bond percolation (DBP) model − provides a general, phenomenological approach that treats ion transport in terms of hopping transitions on a fluctuating lattice. Although this framework is quite general, the DBP model has been practically implemented with a number of simplifying assumptions, including that the array of sites is uniform and that the hopping rate is identical among all neighboring sites; as such, the DBP model has been limited to the description of generic aspects of ion diffusion in polymers, − ,, rather than addressing detailed aspects of specific polymer systems. Another possible approach is the trajectory-extending kinetic Monte Carlo (TEKMC) method, which extrapolates transport properties based on the construction of a transition matrix with statistics generated from MD trajectories. ,, Although TEKMC can be used to obtain long-timescale diffusion coefficients from shorter trajectories, it is not directly connected to an underlying model for ion transport in polymer electrolytes, which would be useful for future polymer design.…”

Section: Introductionmentioning

confidence: 99%

Chemically Specific Dynamic Bond Percolation Model for Ion Transport in Polymer Electrolytes

et al. 2015

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We introduce a coarse-grained approach for characterizing the long-timescale dynamics of ion diffusion in general polymer electrolytes using input from short molecular dynamics trajectories. The approach includes aspects of the dynamic bond percolation model [J. Chem. Phys. 1983, 79, 3133−3142] by treating ion diffusion in terms of hopping transitions on a fluctuating lattice. We extend this well-known approach by using short (i.e., 10 ns) molecular dynamics (MD) trajectories to predict the distribution of ion solvation sites that comprise the lattice and to predict the rate of hopping among the lattice sites. This yields a chemically specific dynamic bond percolation (CS-DBP) model that enables the description of long-timescale ion diffusion in polymer electrolytes at a computational cost that makes feasible the screening of candidate materials. We employ the new model to characterize lithium-ion diffusion properties in six polyethers that differ by oxygen content and backbone stiffness: poly(trimethylene oxide), poly(ethylene oxide-alt-trimethylene oxide), poly(ethylene oxide), poly(propylene oxide), poly(ethylene oxide-alt-methylene oxide), and poly(methylene oxide). Good agreement is observed between the predictions of the CS-DBP model and long-timescale atomistic MD simulations, thus providing validation of the model. Among the most striking results from this analysis is the unexpectedly good lithium-ion diffusivity of poly(trimethylene oxide-alt-ethylene oxide) by comparison to poly(ethylene oxide), which is widely used. Additionally, the model straightforwardly reveals a range of polymer features that lead to low lithium-ion diffusivity, including the competing effects of the density of solvation sites and polymer stiffness. These results illustrate the potential of the CS-DBP model to screen polymer electrolytes on the basis of ion diffusivity and to identify important design criteria.

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Section: Introductionmentioning

confidence: 99%

Chemically Specific Dynamic Bond Percolation Model for Ion Transport in Polymer Electrolytes

et al. 2015

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“…Edgecombe and Linse (2008) employed the MC method for simulating swelling and mechanical properties of various interpenetrating polymer networks, and found the different properties for charged and uncharged polymers. Schulz et al (2006) studied ionic diffusion in a polymer network with the MC method, and compared the results with the dynamic percolation approach. Klos and Pakula (2004) carried out MC simulations of neutral solutions of strongly charged polymeric chains and counterions at various temperatures and monomer concentrations, and showed that chain behavior is dominated by the entropy itself if the polymer in the environment with high temperature.…”

Section: Monte Carlo Simulationmentioning

confidence: 99%

Model development of ionic-strength-sensitive hydrogel and finite element analysis of gel and dielectrics

Lai¹

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V quantitatively. Further, the steady-state MECis model is also compared with the modified Flory-Rehner theory-I and-II, as well as the gel-swelling model. It is demonstrated that the present MECis model can work more accurately by considering more physical and chemical environmental conditions. In addition, the four parameter studies are carried out, in order to understand how the physical and chemical parameters affect the equilibrium characteristics of the ionic-strength-sensitive hydrogel, including the influences of the initial fixed charge density, the equilibrium constant, the Young's modulus, and the initial fixed charge distance on the equilibrium characteristics. The influence of these parameters is presented in terms of the swelling ratio, the chemical, electric and mechanical fields, where the distributions of several important field variables are analyzed in details, such as the fixed charge density, the ionic concentration, the electric potential, and the displacement. Apart from that, the kinetics of the ionic-strength-sensitive hydrogel is also analyzed by the transient MECis simulation, where the present model is employed first to investigate the kinetics of the swelling/shrinking and/or reversible properties of various ionic-strength-sensitive hydrogels, and then compared with the corresponding experiments. The comparisons show that the MECis model is capable of modeling and simulating of the kinetic characteristics of the ionic-strength-sensitive hydrogels accurately. The influence of the chemical and physical parameters is then studied systematically on the kinetic swelling/shrinking of the ionic-strength-sensitive hydrogel, where the reversible kinetics and the influences of the initial fixed charge density and Young's modulus on the kinetics of the hydrogel are discussed in details. The kinetics of the swelling ratio with different parameters, and the kinetic distributions of the significant field variables are analyzed as well, including the fixed charge density, the ionic concentration, the electric potential, and the displacement. Finally, the finite element methods are implemented for the investigation of the kinetic deformation of the gels in water and the equilibrium of dielectrics, respectively. Firstly, the kinetic deformation patterns of the gels with various shapes and constraints in water are analyzed by the finite element model, including the constrained, the block, the thin film, and the bonded gels, where different deformation patterns are achieved, such as the buckling, twisting, wrinkling, folding, and waving. The experiments are also carried out to observe the swelling and wrinkling of the cubic and thin film gels. The simulation is compared with the experiments and a good agreement is observed.

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Constant dielectric loss in disordered ionic conductors: Theoretical aspects

Dieterich¹,

Maass²

2009

Solid State Ionics

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Ion diffusion in a polymer network: Monte Carlo studies and the dynamic percolation approach

Cited by 5 publications

References 12 publications

Chemically Specific Dynamic Bond Percolation Model for Ion Transport in Polymer Electrolytes

Chemically Specific Dynamic Bond Percolation Model for Ion Transport in Polymer Electrolytes

Model development of ionic-strength-sensitive hydrogel and finite element analysis of gel and dielectrics

Constant dielectric loss in disordered ionic conductors: Theoretical aspects

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