Application of random phase approximation to the dynamics of polymer blends and copolymers

Akcasu, A. Ziya; Benmouna, M.; Benoît, H.

doi:10.1016/0032-3861(86)90185-0

Cited by 110 publications

(108 citation statements)

References 15 publications

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“…One is due to Pusey et for the study of mixtures of hard spheres in solution having different sizes, and the general theory of multicomponent polymeric systems was formulated by Akcasu et al [77][78][79][80][81][82] [91][92][93][94][95] that in any incompressible ternary mixture consisting of two polymers and a solvent in the semi-dilute range, the total dynamic structure factor &(q, t ) is a sum of two exponentials:…”

Section: Dynamic Behavior Of Neutral Polymer Mixtures In Solutionmentioning

confidence: 99%

Scattering properties of multicomponent polymer solutions: polyelectrolytes, homopolymer mixtures and diblock copolymer

Borsali

1996

Macro Chemistry & Physics

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SUMMARYThis article reviews the understanding of static and dynamic scattering properties of multicomponent polymer systems in solution achieved during the past decade. We shall describe particularly ternary polymer systems which include polyelectrolyte solutions (polyiodcounter-iondwater), mixture of homopolymers (A and B)/solvent and the case of diblock copolymer (A-B, linear or cyclic) solutions. The purpose of this paper is not an extensive survey of theoretical and experimental results obtained on the scattering behavior of these systems but rather an updating of recent results. For polyelectrolyte systems we shall focus, by means of scattering techniques, on the conformation of the polyelectrolyte chain and on the structure of the system induced by the dominant electrostatic interactions in solution involving polyions, counter-ions and solvent. As for the mixture of homopolymers in solution and diblock copolymer/solvent systems, we shall mainly discuss their dynamic behavior and show that using linear response theory and the Random Phase Approximation (RPA), two relaxation modes describe the autocorrelation functions as revealed using dynamic light scattering (DLS) or/and Neutron Spin Echo (NSE) techniques: the first mode characterizes the concentration fluctuations and the second one the composition fluctuations. We shall discuss the scattering properties of these systems on the basis of recent developments with emphasis on possible coiling of the polyelectrolyte chain at low charge density and also how important parameters such as the mobility of the chain (diffusion process) and the interaction parameter (compatibility), which control the dynamics and the thermodynamics in homopolymer mixtures and diblock copolymer systems, could be deduced from scattering experiments.

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Section: Dynamic Behavior Of Neutral Polymer Mixtures In Solutionmentioning

confidence: 99%

Scattering properties of multicomponent polymer solutions: polyelectrolytes, homopolymer mixtures and diblock copolymer

Borsali

1996

Macro Chemistry & Physics

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“…9 From the dynamics point of view, mean field theory for incompressible monodisperse systems 10,11 predicts that these composition fluctuations relax via an internal chain mode or breathing mode with a relaxation rate that is independent of q. This mode arises from the relative translational motion of the center of mass of the blocks.…”

Section: Introductionmentioning

confidence: 99%

Relaxation processes in a lower disorder order transition diblock copolymer

Sanz

Ezquerra

Hernández

et al. 2015

The Journal of Chemical Physics

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The dynamics of lower disorder-order temperature diblock copolymer leading to phase separation has been observed by X ray photon correlation spectroscopy. Two different modes have been characterized. A non-diffusive mode appears at temperatures below the disorder to order transition, which can be associated to compositional fluctuations, that becomes slower as the interaction parameter increases, in a similar way to the one observed for diblock copolymers exhibiting phase separation upon cooling. At temperatures above the disorder to order transition TODT, the dynamics becomes diffusive, indicating that after phase separation in Lower Disorder-Order Transition (LDOT) diblock copolymers, the diffusion of chain segments across the interface is the governing dynamics. As the segregation is stronger, the diffusive process becomes slower. Both observed modes have been predicted by the theory describing upper order-disorder transition systems, assuming incompressibility. However, the present results indicate that the existence of these two modes is more universal as they are present also in compressible diblock copolymers exhibiting a lower disorder-order transition. No such a theory describing the dynamics in LDOT block copolymers is available, and these experimental results may offer some hints to understanding the dynamics in these systems. The dynamics has also been studied in the ordered state, and for the present system, the non-diffusive mode disappears and only a diffusive mode is observed. This mode is related to the transport of segment in the interphase, due to the weak segregation on this system.

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“…The expression (3.9) was extended to L L × -matrices of the density-density timecorrelation functions and the corresponding susceptibilities in refs [18][19][20][21][22]. The expression (3.7) for the…”

Section: Generalized Hydrodynamicsmentioning

confidence: 99%

“…In particular, it is within the DRPA that the "breathing" mode in block copolymers [19] and large-scale "composition" relaxation in polydisperse blends of homopolymers [20] were predicted and described as consistent with the experimental data (see Refs. [21][22][23][24][25][26][27] and references therein). (Some authors [28][29][30] claimed that the DRPA couldn't explain the "fast mode diffusion behavior", which is sometimes observed experimentally.…”

Section: Introductionmentioning

confidence: 99%

Frequency dispersion of sound propagation in Rouse polymer melts via generalized dynamic random phase approximation

Erukhimovich

Kudryavtsev

2003

Eur. Phys. J. E

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Application of random phase approximation to the dynamics of polymer blends and copolymers

Cited by 110 publications

References 15 publications

Scattering properties of multicomponent polymer solutions: polyelectrolytes, homopolymer mixtures and diblock copolymer

Scattering properties of multicomponent polymer solutions: polyelectrolytes, homopolymer mixtures and diblock copolymer

Relaxation processes in a lower disorder order transition diblock copolymer

Frequency dispersion of sound propagation in Rouse polymer melts via generalized dynamic random phase approximation

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