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Dynamic scaling theory model

The classical theory predicts values for the dynamic exponents of s = 0 and z = 3. Since s = 0, the viscosity diverges at most logarithmically at the gel point. Using Eq. 1-14, a relaxation exponent of n = 1 can be attributed to classical theory [34], Dynamic scaling based on percolation theory [34,40] does not yield unique results for the dynamic exponents as it does for the static exponents. Several models can be found that result in different values for n, s and z. These models use either Rouse and Zimm limits of hydrodynamic interactions or Electrical Network analogies. The following values were reported [34,39] (Rouse, no hydrodynamic interactions) n = 0.66, s = 1.35, and z = 2.7, (Zimm, hydrodynamic interactions accounted for) n = 1, s = 0, and z = 2.7, and (Electrical Network) n = 0.71, s = 0.75 and z = 1.94. [Pg.184]

In what follows we will discuss systems with internal surfaces, ordered surfaces, topological transformations, and dynamical scaling. In Section II we shall show specific examples of mesoscopic systems with special attention devoted to the surfaces in the system—that is, periodic surfaces in surfactant systems, periodic surfaces in diblock copolymers, bicontinuous disordered interfaces in spinodally decomposing blends, ordered charge density wave patterns in electron liquids, and dissipative structures in reaction-diffusion systems. In Section III we will present the detailed theory of morphological measures the Euler characteristic, the Gaussian and mean curvatures, and so on. In fact, Sections II and III can be read independently because Section II shows specific models while Section III is devoted to the numerical and analytical computations of the surface characteristics. In a sense, Section III is robust that is, the methods presented in Section III apply to a variety of systems, not only the systems shown as examples in Section II. Brief conclusions are presented in Section IV. [Pg.143]

In order to achieve these goals, we have adopted a multi-scale approach that comprises molecular and mesoscopic models for the liquid crystal. The molecular description is carried out in terms of Monte Carlo simulations of repulsive ellipsoids (truncated and shifted Gay-Berne particles), while the mesoscopic description is based on a dynamic field theory[5] for the orientational tensor order parameter, Q. ... [Pg.223]

Tournassat et al. (2009) compared the BSM and TLM models with molecular dynamics simulations of a montmorillonite/water interface at the pore scale in 0.1 M NaCl. Simulation-derived values were compared with macroscopic model results obtained from the classical models. Although the Na concentration profile is well reproduced in the diffuse layer, anion exclusion is overestimated by the BSM and TLM theories under the experimental conditions employed the agreement between molecular dynamics simulated and modeled diffuse-layer composition is less accurate with TLM than with BSM. However, the potentials at the three planes of interest are accurately reproduced. It was also showed that molecular dynamics simulations can be used to constrain BSM parameters or, in combination with zeta potential measurements, TLM parameters, by providing suitable values for the capacitance parameters. [Pg.436]

The scaling theory captures the essential features of star polymer in both good and 0 solvent conditions and predicts power-law dependences for the overall star size Rsai on number of branches/and the degree of polymerization N. These scaling predictions were tested by molecular dynamics and Monte Carlo simulations " and experimentally. " Although certain discrepancies were detected (see, e.g., the discussion in Reference 68), a simple bloh model remains an important theoretical tool to interpret experimental data on nonionic star macromolecules. [Pg.61]

In case of semidilute systems without entanglement (c > c ), in regions above the correlation length, the Rouse motion is faster than the Zimm motion because the Zimm motion is hindered by a coupling between the chains and Rouse dynamics apply [30]. For a detailed derivation of the Rouse and Zimm models, the scaling theory and some older viscosity reviews see references [24, 30, 90]. [Pg.48]


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