Phase separation temperatures in the ternary system polystyrene/poly(α‐methyl styrene)/cyclopentane

Saeki, Susumu; Tsubotani, S.; Kominami, Hiraku; Tsubokawa, Masakazu; Yamaguchi, Takuji

doi:10.1002/polb.1986.090240209

Cited by 7 publications

(5 citation statements)

References 49 publications

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“…However, the Flory-Huggins theory has been shown to be incomplete because the theory introduces as a constant, independent of polymer composition, concentration, or temperature which is contrary to experiment.24•25 The polymer-polymer interaction parameter also depends on the thermodynamic properties of the solution25-indeed, Saeki et al 26 have shown that can assume large positive values for the "compatible" polymers polystyrene and poly-(a-methylstyrene) when in ternary solution with solvents of unequal quality. Extensions to the Flory-Huggins theory have been proposed but these have not been incorporated in the Benmouna theory.…”

Section: Theorymentioning

confidence: 99%

Dynamic light scattering experiments on poly(vinyl methyl ether) (PVME)-polystyrene-toluene and PVME-polystyrene-carbon tetrachloride solutions

Daivis¹,

Pinder²

1993

Macromolecules

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The results of dynamic light scattering experiments on poly(vinyl methyl ether)-polystyrenetoluene and poly(vinyl methyl ether)-polystyrene-carbon tetrachloride solutions are presented. In each of these systems, the poly(vinyl methyl ether) (PVME) is approximately isorefractive with the solvent and the polystyrene (PS) is present only as a trace. The results of our experiments on PVME-PS-toluene solutions agree with previous work, giving the self-diffusion coefficient of the PS. However, a change of solvent from toluene to carbon tetrachloride produces much lower values for the effective diffusion coefficients. It is concluded that the true self-diffusion coefficient is no longer measured by this technique due to the solvent being of good quality for one polymer but only marginal for the other. This result is discussed in the context of theoretical studies of dynamic scattering from ternary polymer solutions. The scattering vector dependence of the effective diffusion coefficient obtained from cumulant fits to the DLS data is also studied.

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Section: Theorymentioning

confidence: 99%

Dynamic light scattering experiments on poly(vinyl methyl ether) (PVME)-polystyrene-toluene and PVME-polystyrene-carbon tetrachloride solutions

Daivis¹,

Pinder²

1993

Macromolecules

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“…T g for pure polystyrene is ∼100 °C, but a 60% mixture of polystyrene in various solvents appears to have a T g below 23 °C . A 60% mixture should remain a one-phase system at 23 °C (estimated from refs and ). A compression of the adsorbed layers to this composition should thus not cause a glass transition or phase separation.…”

Section: Discussionmentioning

confidence: 99%

Effects of Time and Compression on the Interactions of Adsorbed Polystyrene Layers in a Near-ϑ Solvent

1997

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We have investigated the effects of molecular weight, adsorption time, force-measuring rate, and repeated compression-decompression cycles (previous history) on the interactions between high molecular weight polystyrenes adsorbed on mica from dilute cyclopentane solutions under near-Θ solvent conditions. On the first slow approach, a long-range bridging attraction, which needs several minutes to fully develop for each incremental movement of the surfaces, is found at separations below 6Rg. The interaction becomes a steep hard-wall repulsion at separations below 0.5Rg. With increasing molecular weight the thickness of the adsorbed layers increases, and the attractive bridging force on approach and adhesion on separation decreases. Self-consistent field theory underestimates the onset location and depth of the attractive minima but accurately predicts the location of the hard-wall repulsion. For shorter (nonequilibrium) adsorption times, the bridging attraction and adhesion are stronger and occur at smaller separations, consistent with incomplete coverage. If the first approach and compression are done slowly, the layers become "irreversibly" compressed and no long-range bridging attraction is observed on subsequent approaches, even after allowing the polymer layers to relax for several days.

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“…EPLs are thin polymer films (⩽ 5 μ m) deposited onto a surface, intended to extend the qualitative or quantitative limit of detection by attracting organic compounds via chemical and/or physical interactions. The incorporation of such films into chemical sensors has been heavily researched since the late 1980s [68, 69]. EPLs have been demonstrated as efficient and highly sensitive coatings for diverse evanescent waveguide-based optical monitoring systems [70–76].…”

Section: Sensor Functionalization For Enhanced Specificitymentioning

confidence: 99%

Mid-infrared materials and devices on a Si platform for optical sensing

Singh¹,

Lin²,

Patel³

et al. 2014

Science and Technology of Advanced Materials

160

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In this article, we review our recent work on mid-infrared (mid-IR) photonic materials and devices fabricated on silicon for on-chip sensing applications. Pedestal waveguides based on silicon are demonstrated as broadband mid-IR sensors. Our low-loss mid-IR directional couplers demonstrated in SiNx waveguides are useful in differential sensing applications. Photonic crystal cavities and microdisk resonators based on chalcogenide glasses for high sensitivity are also demonstrated as effective mid-IR sensors. Polymer-based functionalization layers, to enhance the sensitivity and selectivity of our sensor devices, are also presented. We discuss the design of mid-IR chalcogenide waveguides integrated with polycrystalline PbTe detectors on a monolithic silicon platform for optical sensing, wherein the use of a low-index spacer layer enables the evanescent coupling of mid-IR light from the waveguides to the detector. Finally, we show the successful fabrication processing of our first prototype mid-IR waveguide-integrated detectors.

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Phase separation temperatures in the ternary system polystyrene/poly(α‐methyl styrene)/cyclopentane

Cited by 7 publications

References 49 publications

Dynamic light scattering experiments on poly(vinyl methyl ether) (PVME)-polystyrene-toluene and PVME-polystyrene-carbon tetrachloride solutions

Dynamic light scattering experiments on poly(vinyl methyl ether) (PVME)-polystyrene-toluene and PVME-polystyrene-carbon tetrachloride solutions

Effects of Time and Compression on the Interactions of Adsorbed Polystyrene Layers in a Near-ϑ Solvent

Mid-infrared materials and devices on a Si platform for optical sensing

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