The Structure of Grafted Polystyrene Layers in a Range of Matrix Polymers

Clarke, C. J. S.; Jones, Richard; Edwards, J. L.; Shull, Kenneth R.; Penfold, J.

doi:10.1021/ma00110a043

Cited by 63 publications

(61 citation statements)

References 7 publications

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“…The entanglement of the PS brushes and the PS matrix may cause the subdiffusive NP behavior. Moreover, it has been reported that the polymer matrix chains, which are shorter than those of the brushes, can intrude into the brushes and wet brushes because of entropic interactions [32][33][34][35][36][37]. This observed crossover between subdiffusion and hyperdiffusion may be explained as follows: The NPs are trapped in the PS matrix due to the entanglement effect between the PS brushes and the PS matrix, and they migrate with a jump to other sites via release process.…”

Section: B Fitting Analysis Based On the Dc-ctrw Modelmentioning

confidence: 99%

Dynamical crossover between hyperdiffusion and subdiffusion of polymer-grafted nanoparticles in a polymer matrix

et al. 2013

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The dynamical behavior of polystyrene-grafted silica nanoparticles dispersed in an atactic polystyrene matrix was studied using x-ray photon correlation spectroscopy. The time-autocorrelation functions were subjected to fitting analyses based on continuous-time random walk models. The nanoparticles exhibited non-Brownian behavior, and as the temperature increased, the crossover from hyperdiffusion to subdiffusion occurred at 1.25T_{g}, where T_{g} is the glass transition temperature of the matrix polystyrene. Hyperdiffusive behavior is caused by the dynamical heterogeneity of the polymer matrix associated with the glass transition. When the temperature was higher than 1.25T_{g}, the interaction of the grafted polymers with the polymer matrix became relatively significant, and caused a dramatic change in the dynamical behavior of the nanoparticles.

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Section: B Fitting Analysis Based On the Dc-ctrw Modelmentioning

confidence: 99%

Dynamical crossover between hyperdiffusion and subdiffusion of polymer-grafted nanoparticles in a polymer matrix

et al. 2013

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“…Of great importance is the practice of improving the fracture strength of interfaces through the use of a few grafted chains, attached by one end to the substrate or interface through chemical sorption. 1 At high enough values of the surface density of the grafted chains, the melt assumes the form of a brush, characterized by a highly ordered structure similar to that observed in stretched networks. 2 Establishing quantitative relations between chemical constitution and macroscopically manifested properties of such systems and predicting their structure and mechanical properties is highly desirable, because this can tremendously facilitate the rational design of multiphase systems containing macromolecular chains.…”

Section: Introductionmentioning

confidence: 95%

Detailed atomistic Monte Carlo simulation of grafted polymer melts. I. Thermodynamic and conformational properties

Daoulas

Terzis

Mavrantzas

2002

The Journal of Chemical Physics

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The thermodynamic and conformational properties of polymer melts grafted on a solid substrate as obtained from detailed, atomistic Monte Carlo simulations with the end-bridging algorithm are presented. The interface between a basal graphite plane (as well as a non-interacting hard surface) and a bulk polyethylene (PE) melt, a few or all chains of which are grafted on the plane, has been studied. Three different PE melts, of mean molecular length C78, C156, and C250, have been investigated, at grafting densities ranging from 0.54 to 2.62 nm−2. For melts composed of grafted and free chains, it is observed that, at moderate to high surface densities (σ⩾1 nm−2), the region close to the substrate is fully occupied by segments belonging to grafted chains, which are forced by their chemical grafting to have their first segment on the interface. As the grafting density increases, free chains are progressively expelled from the surface region, in agreement with scaling arguments and the predictions of lattice-based self-consistent mean-field (SCF) theory. For melts grafted on a graphite plane, it is also seen that the local melt density in the region closest to the interface is systematically higher than in the bulk, exhibiting distinct local maxima due to polymer adsorption. Results for the chain conformation tensor demonstrate that chains are significantly stretched in the direction perpendicular to the surface, even for moderate surface densities. For the C250 (PE) melt at a grafting density σ=1.31 nm−2, for example, the average chain dimension perpendicular to the interface is 1.9 times larger than its equilibrium value in the bulk. The profile of the chain end density is seen to exhibit universal behavior in agreement with the predictions of the SCF theory. Additional results concerning the mean chain conformational path and the structure of the interfacial area for both systems studied (fully grafted and mixtures of grafted and free chain systems) are also presented.

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“…There has been a variety of end groups in polymers used to generate such self-assembled layers [6][7][8][9][10][11][12] and by virtue of their grafting, chemical or physical, to an interface these polymers can be described as telechelic. The objectives of the majority of these investigations has chiefly been the examination of polymer brush layers, comparison with the predictions of theory and evaluation of the kinetics of formation of the brush like layer.…”

Section: Introductionmentioning

confidence: 99%

Partitioning of a heterotelechelic polystyrene to separate interfaces of thin films

Richards

Thompson

Bucknall

et al. 2001

The European Physical Journal E

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Heterotelechelic deuteropolystyrenes have been synthesised with a tertiary amine functionality at one end and a fluorocarbon group at the other end of the polymer chain. A layer of this polymer, circa 120Å thick, has been attached to the surface of a silicon substrate and subsequently covered with a much thicker layer of hydrogenous polystyrene. The combination has then been annealed at 413 K under vacuum for defined times and the subsequent distribution of the deutero heterotelechelic polymer determined using nuclear reaction analysis and neutron reflectometry. The influences of annealing time, molecular weight and thickness of the hydrogenous polymer have been examined. Nuclear reaction analysis showed that an excess of the heterotelechelic polymer formed at both interfaces with a larger excess remaining at the substrate-polymer interface. When the molecular weight of the hydrogenous polymer is lower than that of the deuteropolymer, the deutero layer is initially swollen by the hydrogenous polymer but the thickness then decreases as deutero polymer becomes detached from the silicon substrate and an additional excess layer is eventually formed at the vacuum-polymer surface. When the molecular weight of the hydrogenous polymer is higher, there is an initial shrinkage of the deuteropolymer layer, but the original thickness (∼ radius of gyration of the deuteropolymer) is regained on prolonged annealing. There is no evidence for bridging between the two interfaces by the heterotelechelic polymer. After five days annealing the volume fraction distribution of the deuteropolymer at the silicon substrate was well described by a self-consistent field model where the only adjustable parameter was the sticking energy of the tertiary amine group to the silicon substrate for which a value of 8 kBT was obtained. Comparison of the dependence of the equilibrium layer thickness of the deuteropolymer on the equilibrium grafting density at the silicon surface with the predictions of scaling theory for brush-like polymer layers suggested that the grafted molecules were in the ideal, unperturbed brush region.

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The Structure of Grafted Polystyrene Layers in a Range of Matrix Polymers

Cited by 63 publications

References 7 publications

Dynamical crossover between hyperdiffusion and subdiffusion of polymer-grafted nanoparticles in a polymer matrix

Dynamical crossover between hyperdiffusion and subdiffusion of polymer-grafted nanoparticles in a polymer matrix

Detailed atomistic Monte Carlo simulation of grafted polymer melts. I. Thermodynamic and conformational properties

Partitioning of a heterotelechelic polystyrene to separate interfaces of thin films

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