Hydrodynamic and thermodynamic behavior of short-chain polystyrene in toluene and cyclohexane at 34.5.degree.C

Huber, Klaus; Bantle, Siegfried; Lutz, P.; Burchard, Walther

doi:10.1021/ma00149a017

Cited by 151 publications

(152 citation statements)

References 17 publications

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“…19 Therefore, the accuracy level of our method appears to be quantitative close to that of more rigorous methods. In general, our simulation results are in good agreement with observations [45][46][47][48][49] and the reported values from other more rigorous theoretical methods. 19,33,50 Moreover, we also computed the diffusion coefficient of the solvents by using…”

Section: Test Of the Computational Accuracy And Efficiency Of Cgh-mdsupporting

confidence: 91%

Simulation of DNA electrophoresis in systems of large number of solvent particles by coarse‐grained hybrid molecular dynamics approach

Wang

Liu

et al. 2008

J Comput Chem

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Simulation of DNA electrophoresis facilitates the design of DNA separation devices. Various methods have been explored for simulating DNA electrophoresis and other processes using implicit and explicit solvent models. Explicit solvent models are highly desired but their applications may be limited by high computing cost in simulating large number of solvent particles. In this work, a coarse-grained hybrid molecular dynamics (CGH-MD) approach was introduced for simulating DNA electrophoresis in explicit solvent of large number of solvent particles. CGH-MD was tested in the simulation of a polymer solution and computation of nonuniform charge distribution in a cylindrical nanotube, which shows good agreement with observations and those of more rigorous computational methods at a significantly lower computing cost than other explicit-solvent methods. CGH-MD was further applied to the simulation of DNA electrophoresis in a polymer solution and in a well-studied nanofluidic device. Simulation results are consistent with observations and reported simulation results, suggesting that CGH-MD is potentially useful for studying electrophoresis of macromolecules and assemblies in nanofluidic, microfluidic, and microstructure array systems that involve extremely large number of solvent particles, nonuniformly distributed electrostatic interactions, bound and sequestered water molecules.

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Section: Test Of the Computational Accuracy And Efficiency Of Cgh-mdsupporting

confidence: 91%

Simulation of DNA electrophoresis in systems of large number of solvent particles by coarse‐grained hybrid molecular dynamics approach

Wang

Liu

et al. 2008

J Comput Chem

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“…An extensive survey of literature values for D 0 and k D of polystyrene in toluene solutions was performed, and ten different references were examined. 24,[32][33][34][35][36][37][38][39][40] Most authors have studied the molecular-weight dependence of these parameters and propose relationships which usually have the form of power laws. The results of our survey are presented in Table IV.…”

Section: A Mass-diffusion Coefficient Dmentioning

confidence: 99%

Light scattering from nonequilibrium concentration fluctuations in a polymer solution

Zhang

Sengers

et al. 2000

The Journal of Chemical Physics

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Effects of viscoelasticity of bulk polymer solution on the surface modes as probed by laser light scattering J. Chem. Phys. 109, 6103 (1998) We have performed light-scattering measurements in dilute and semidilute polymer solutions of polystyrene in toluene when subjected to stationary temperature gradients. Five solutions with concentrations below and one solution with a concentration above the overlap concentration were investigated. The experiments confirm the presence of long-range nonequilibrium concentration fluctuations which are proportional to (ٌT) 2 /k 4 , where ٌT is the applied temperature gradient and k is the wave number of the fluctuations. In addition, we demonstrate that the strength of the nonequilibrium concentration fluctuations, observed in the dilute and semidilute solution regime, agrees with theoretical values calculated from fluctuating hydrodynamics. Further theoretical and experimental work will be needed to understand nonequilibrium fluctuations in polymer solutions at higher concentrations.

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“…É importante ressaltar que a relação de Mark-Houwink-Sakurada (MHS) apresenta algumas limitações no seu uso em polímeros de baixa massa molar (M ≤ 20.000 g.mol -1 ). A relação não pode ser aplicada visto que as moléculas com baixa massa molar não possuem comportamento como cadeias gaussianas, mas sim como worn-like [43,44] . Outro fator que cabe comentar é que variações de concentração da solução alteram o coeficiente de fricção do solvente resultando em mudanças nos valores de [η], fato que causa um grande impacto nas medidas de cadeias de baixa massa molar [45,46] .…”

Section: Determinação Do Grau De Conversão Da Reação Do Ps-possunclassified

Caracterização viscosimétrica de nanocompósitos híbridos PS/POSS

et al. 2012

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Resumo: Nanocompósitos híbridos de poliestireno (PS) e poliedros oligoméricos silsesquioxanos (POSS) com diferentes composições e graus de hibridização foram obtidos por processamento reativo no estado fundido utilizando-se peróxido de dicumila (DCP) como iniciador, na presença ou não de estireno como agente de transferência de radical. Os materiais foram caracterizados viscosimetricamente por cromatografia de permeação em gel (GPC) usando detecção tripla por espalhamento de luz, viscosimetria e índice de refração. As amostras PS/POSS processadas com estireno apresentaram maiores valores de massa molar ponderal média (M w ) e menores valores de polidispersão (M w /M n ), devido ao maior grau de conversão da reação de hibridização do PS-POSS (28-40%) e do menor grau de degradação (cisão) das cadeias do PS, quando comparadas com amostras PS/POSS processadas sem estireno nas quais o grau de conversão ficou em torno de 24-28%. Para os sistemas PS e PS/POSS em solução com THF, os parâmetros da equação de Mark-Houwink-Sakurada (MHS), α ≅ 0,7 e log K ≅ -3,5 a -3,9 e os valores dos parâmetros de interação polímero-solvente, χ ij ≅ 0,49, não apresentaram diferenças significativas com relação aos tamanhos moleculares. Por outro lado, essas diferenças de tamanhos moleculares foram caracterizadas por uma função cumulativa da fração mássica de cadeias em função da distância média quadrática entre pontas de cadeia ( ) Palavras-chave: PS, POSS, nanocompósitos híbridos, viscosimetria. Viscometric Characterization of PS/POSS Hybrid NanocompositesAbstract: Polystyrene (PS) and polyhedral oligomeric silsesquioxanes (POSS) hybrid nanocomposites with different compositions were obtained by reactive melt processing using dicumyl peroxide (DCP) as initiator in the presence or absence of styrene as radical transfer agent. The materials were characterized by viscosimetry by means of gel permeation chromatography (GPC) using triple-detector: light scattering, viscometer and refractive index. PS/POSS samples processed with styrene showed higher weight average molecular weights (M w ) and lower polydispersity indexes (M w /M n ), as a result of higher PS-POSS conversion (28-40%) and lower PS degradation, as compared to the PS/POSS samples processed without styrene in which the degree of conversion was lower (24-28%). For the PS/POSS solutions in THF, the parameters of the Mark-Houwink-Sakurada equation, α ≅ 0.7 and log K ≅ -3.5 to -3.9, and the values of polymer-solvent interaction parameter, χ ij ≅ 0.49, were not changed with respect to changes in molecular size. On the other hand, these changes were characterized by a cumulative function of the mass fraction of chains as a function of the root mean square end to end distance ( ) 2 1/2 0 r < > .

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Hydrodynamic and thermodynamic behavior of short-chain polystyrene in toluene and cyclohexane at 34.5.degree.C

Cited by 151 publications

References 17 publications

Simulation of DNA electrophoresis in systems of large number of solvent particles by coarse‐grained hybrid molecular dynamics approach

Simulation of DNA electrophoresis in systems of large number of solvent particles by coarse‐grained hybrid molecular dynamics approach

Light scattering from nonequilibrium concentration fluctuations in a polymer solution

Caracterização viscosimétrica de nanocompósitos híbridos PS/POSS

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