Local structure of semiflexible polymer melts

Honnell, Kevin G.; Curro, John G.; Schweizer, Kenneth S.

doi:10.1021/ma00216a018

Cited by 203 publications

(182 citation statements)

References 13 publications

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“…The polymer chain is treated as a flexible pearl necklace of hard-sphere monomers with segment length lϭ1.12 to be consistent with the simulation model. The polymer self structure factor p (k) is obtained from the semiflexible chain model of Honnell et al 42 The persistence length of the chain is chosen to be p ϭ1.4, which along with l/ ϭ1.12 accounts for chain flexibility and excluded volume through the average angle between any two connected segments, but does not account for excluded volume effects explicitly. Another approximation is that all sites on the chain are treated equally, thus neglecting effects due to chain ends.…”

Section: B Integral Equation Theorymentioning

confidence: 99%

Polymer–particle mixtures: Depletion and packing effects

Doxastakis

Chen

Guzmán

et al. 2004

The Journal of Chemical Physics

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The structure of polymers in the vicinity of spherical colloids is investigated by Monte Carlo simulations and integral equation theory. Polymers are represented by a simple bead-spring model; only repulsive Lennard-Jones interactions are taken into account. Using advanced trial moves that alter chain connectivity, depletion and packing effects are analyzed as a function of chain length and density, both at the bond and the chain level. Chain ends segregate to the colloidal surface and polymer bonds orient parallel to it. In the dilute regime, the polymer chain length governs the range of depletion and has a negligible influence on monomer packing in dense polymer melts. Polymers adopt an ellipsoidal shape, with the larger axis parallel to the surface of the particle, as they approach larger colloids. The dimensions are perturbed within the range of the depletion layer.

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Section: B Integral Equation Theorymentioning

confidence: 99%

Polymer–particle mixtures: Depletion and packing effects

Doxastakis

Chen

Guzmán

et al. 2004

The Journal of Chemical Physics

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“…With this closure, the PRISM integral equation ͑13͒ can be solved self-consistently. We applied the algorithm put forward by Honnell et al, 21 by assuming the direct correlation function to be a cubic polynomial, and solving numerically the system of nonlinear algebraic equations for the expansion coefficients. For this system of nonlinear equations we used standard modification of the Powell hybrid method from the NAG © library ͑Mark 18, C05NBF͒.…”

Section: Description Of the Meltmentioning

confidence: 99%

Density-functional theory of the crystallization of hard polymeric chains

Sushko

Schoot

Michels

2001

The Journal of Chemical Physics

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We study how connectivity influences the crystallization of fully flexible model polymers by applying a recently advanced amalgamation of the Green-function description of polymers, and the density-functional theory of simple liquids. Our calculations show that the model polymers only crystallize if the effective Kuhn length of the chains is sufficiently large compared with the range of the hard-core interaction between the segments. Also shown is the importance of bond-length fluctuations for the stability of the crystal phase.

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“…In such a case, the inverse of the structure factor matrix S(k)-1 can be simplified, and eq 13, 19, and 21 finally yield (25) where M w is the weight average molecular weight and P(k)z is the z-average intramolecular interference factor defined by (26) At 8=0, where P(k)z= 1, the above equation gives Kef R 0 identical with that for a monodisperse polymer solution with the molecular weight equal to Mw and (22) volume fraction equal to i5c'. Thus polydispersity in molecular weight does not change the form of the equation for Kef R 0 , if the solution contains only sufficiently high molecular weight stiff-polymer components.…”

Section: Solutions Ol Polydisperse Polymer Samplesmentioning

confidence: 99%

Light Scattering Study of Semiflexible Polymer Solutions III. Multicomponent Solutions

Sato

Jinbo

Teŕamoto

1999

Polym J

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ABSTRACT:The Rayleigh ratio R9 for multicomponent solutions containing stiff-polymer and small-molecular components of arbitrary concentrations is formulated using the scaled particle theory for wormlike spherocylinders combined with the generalized Ornstein-Zernike integral equation. The general expression for R0 obtained is applied to the following specific cases: ( 1) ternary solutions consisting of two homologous polymer species and a solvent, (2) solutions of polydisperse polymer samples, and (3) ternary solutions containing two solutes of different chemical species (e.g., one polymer dissolved in a mixed solvent). The result for the case of (1) is compared with experimental data for dilute through semidilute solutions containing two different molecular-weight samples of poly(n-hexyl isocyanate), a semiflexible polymer.KEY WORDS Light Scattering I Multicomponent Solution I Semiflexible Polymer I Structure Factor I Wormlike Cylinder Model I Poly(n-hexyl isocyanate) I Light scattering is a useful technique to characterize polymer molecules and their intermolecular interactions in solution. When applying this technique to multicomponent polymer solutions, one has to take into account some special effects inherent to multicomponent systems. 1 · 2 In order to consider these effects, light scattering theories for multicomponent polymer solutions were proposed by many authors. 3 -8 These theories are mainly concerned with dilute polymer solutions, and give us recipes to determine the true molecular weight, second virial coefficient, and radius of gyration of polymers.In Part II of this series of papers, 9 we formulated the Rayleigh ratio R 8 or the light-scattering structure factor for isotropic solutions of monodisperse wormlike spherocylinders of arbitrary concentrations, by the scaled particle theory combined with the generalized Ornstein-Zernike integral equation. The formulated R8 was shown to be favorably compared with experimental data for dilute through semidilute solutions of a semiflexible polymer, poly(n-hexyl isocyanate).In the present study, we have extended the previous formulation to multicomponent polymer solutions containing macromolecular and small-molecular components to obtain R 8 valid at arbitrary concentrations. While the present theory is not applicable to solutions of flexible polymers due to approximations used in the formulation, it is utilized to analyze light-scattering data for concentrated multicomponent solutions containing stiff-chain polymers, which include important information to characterize intermolecular interactions among solute components. 10 FORMULATION Rayleigh Ratio at the Zero-Scattering AngleConsider a solution consisting of r macromolecular and small-molecular species (solutes) and a primary solvent, and suppose that the solute species s ( = I, 2, · · ·, r) is composed of No,s identical isotropic scattering (monomer) units; for small-molecular species, the whole molecule is regarded as one scattering unit with N o.s =I. By fluctuation theories of light scattering, t...

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Local structure of semiflexible polymer melts

Cited by 203 publications

References 13 publications

Polymer–particle mixtures: Depletion and packing effects

Polymer–particle mixtures: Depletion and packing effects

Density-functional theory of the crystallization of hard polymeric chains

Light Scattering Study of Semiflexible Polymer Solutions III. Multicomponent Solutions

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