Interfacial tension of immiscible polymer blends: temperature and molecular weight dependence

Anastasiadis, Spiros H.; Gancarz, Irena; Koberstein, Jeffrey T.

doi:10.1021/ma00188a015

Cited by 205 publications

(173 citation statements)

References 15 publications

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“…This is understood from the fact that mixing of long molecules is less favorable, 13 a well known phenomenon that was reported earlier. 33,34 The results also show that the effect of the low molecular weight phase ͑here this is always the drop phase except for the B3 combination͒ on the value of the interfacial tension ͑the A combinations versus the B combinations͒ is more pronounced than the ratio of the molecular weight. For example, the systems B4 and A3 have the same order of asymmetry but a large difference in the interfacial tension ␥ while the systems B3 and B4 have a big difference in asymmetry but relatively small difference in ␥.…”

Section: A Transient Interfacial Tension and Drop Size Reductionmentioning

confidence: 77%

Transient interfacial tension and dilatational rheology of diffuse polymer-polymer interfaces

Peters

Zdravkov

Meijer

2005

The Journal of Chemical Physics

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We demonstrate the influence of molecular weight and molecular weight asymmetry across an interface on the transient behavior of the interfacial tension. The interfacial tension was measured as a function of time for a range of polymer combinations with a broad range of interfacial properties using a pendant/sessile drop apparatus. The results show that neglecting mutual solubility, assumed to be a reasonable approximation in many cases, very often does not sustain. Instead, a diffuse interface layer develops in time with a corresponding transient interfacial tension. Depending on the specific combination of polymers, the transient interfacial tension is found to increase or decrease with time. The results are interpreted in terms of a recently proposed model ͓Shi et al., Macromolecules 37, 1591 ͑2004͔͒, giving relative characteristic diffusion time scales in terms of molecular weight, molecular weight distribution, and viscosities. However, the time scales obtained from this theoretical approach do not give a conclusive trend. Using oscillatory dilatational interfacial experiments the viscoelastic behavior of these diffusive interfaces is demonstrated. The time evolution of the interfacial tension and the dilatational elasticity show the same trend as predicted by the theory of diffuse interfaces, supporting the idea that the polymer combinations under consideration indeed form diffuse interfaces. The dilatational elasticity and the dilatational viscosity show a frequency dependency that is described qualitatively by a simple Fickian diffusion model and quantitatively by a Maxwell model. The characteristic diffusion times provided by the latter show that the systems with thick interfaces ͑tens of microseconds and more͒ can be considered as slower diffusive systems compared to the systems with thinner interfaces ͑a few micrometers in thickness and less͒ can be considered as fast diffusive systems.

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Section: A Transient Interfacial Tension and Drop Size Reductionmentioning

confidence: 77%

Transient interfacial tension and dilatational rheology of diffuse polymer-polymer interfaces

Peters

Zdravkov

Meijer

2005

The Journal of Chemical Physics

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“…For instance, simulations [2][3][4][5][6][7][8] have found an entropic enrichment of chain ends at the surface, whereas a reflecting boundary gives a uniform bulk concentration right up to the surface. Furthermore, experiments [9][10][11] have observed a molecular-weight dependence in the surface tension, whereas the Silberberg argument predicts none. Naturally, these effects are due to violations in the assumptions used by Silberberg, namely the presumptions of a step-like concentration profile and the absence of an energy penalty for folding polymer chains.…”

Section: Introductionmentioning

confidence: 99%

Entropic segregation of short polymers to the surface of a polydisperse melt

Mahmoudi

Matsen

2017

Eur. Phys. J. E

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Abstract.Chain ends are known to have an entropic preference for the surface of a polymer melt, which in turn is expected to cause the short chains of a polydisperse melt to segregate to the surface. Here, we examine this entropic segregation for a bidisperse melt of short and long polymers, using self-consistent field theory (SCFT). The individual polymers are modeled by discrete monomers connected by freely-jointed bonds of statistical length a, and the field is adjusted so as to produce a specified surface profile of width ξ. Semi-analytical expressions for the excess concentration of short polymers, δφ s(z), the integrated excess, θ s, and the entropic effect on the surface tension, γen, are derived and tested against the numerical SCFT. The expressions exhibit universal dependences on the molecular-weight distribution with model-dependent coefficients. In general, the coefficients have to be evaluated numerically, but they can be approximated analytically once ξ a. We illustrate how this can be used to derive a simple expression for the interfacial tension between immiscible A-and B-type polydisperse homopolymers.

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“…We find several studies reported on the interfacial properties in terms of interdiffusion at the interface, [22][23][24][25][26] interfacial tension, [27][28][29][30] and interface width, 21,[31][32][33][34] and so forth in polymer blends. The magnitude and behavior of interface width with varying molecular weight, temperature, and film thickness have also been studied using the small angle neutron scattering, neutron reflectometry, 27,28,[33][34][35] small angle X-ray scattering, differential scanning calorimetry (DSC), 26 transmission electron microscopy, 30 and so forth with varying success.…”

Section: Introductionmentioning

confidence: 93%

“…The magnitude and behavior of interface width with varying molecular weight, temperature, and film thickness have also been studied using the small angle neutron scattering, neutron reflectometry, 27,28,[33][34][35] small angle X-ray scattering, differential scanning calorimetry (DSC), 26 transmission electron microscopy, 30 and so forth with varying success. Schnell et al 5 had studied interfaces in blends of polystyrene with either poly (p-methylstyrene) or a statistical copolymer poly(styrene-co-pbromostyrene) using neutron reflection method.…”

Section: Introductionmentioning

confidence: 99%

A new insight into interface widths in binary polymer blends based on ortho‐positronium lifetime studies

Ramya

Ranganathaiah

2012

J of Applied Polymer Sci

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The interface widths in two immiscible polymer blend (Poly vinyl chloride (PVC)/Polystyrene (PS)) and PVC/Ethylene Vinyl Acetate (EVA) are determined experimentally using hydrodynamic interaction approach through free volume measurement by positron annihilation lifetime spectroscopy. For comparison, the same study is performed in a miscible blend (Styrene Acrylonitrile (SAN)/Poly Methyl Methacrylate (PMMA)). The interfacial width (Dl) is evaluated from the hydrodynamic interaction (a) based on Kirkwood-Risemann theory and friction coefficient from Stokes equation. Friction at the interface of a binary blend evidences how close the surfaces of the polymer chains come or stay apart which in turn depends on the type of force/interaction at the interface. In this work, we define interface width from a different perspective of Flory-Huggins interaction approach. Measured composition dependent interface widths in the three blends studied clearly demonstrate the sensitivity of the present method. In miscible blend, high friction at the interface results in stronger hydrodynamic interaction and hence smaller interface widths (0.36-1.97 Å ), whereas weak or no interaction in immiscible blends produce wider widths (2.81-25.0 Å ).

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Interfacial tension of immiscible polymer blends: temperature and molecular weight dependence

Cited by 205 publications

References 15 publications

Transient interfacial tension and dilatational rheology of diffuse polymer-polymer interfaces

Transient interfacial tension and dilatational rheology of diffuse polymer-polymer interfaces

Entropic segregation of short polymers to the surface of a polydisperse melt

A new insight into interface widths in binary polymer blends based on ortho‐positronium lifetime studies

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