Geometrical Properties and Interface Dynamics:  Time Evolution of Spinodal Interface in a Binary Polymer Mixture at the Critical Composition

Jinnai, Hiroshi; Nishikawa, Yukihiro; Morimoto, H.; Koga, Tadanori; Hashimoto, Takeji

doi:10.1021/la991024q

Cited by 85 publications

(57 citation statements)

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“…More recent numerical simulations confirmed this scaling behavior, and provided some insights about the geometry in real space [10][11][12]. Meanwhile, access to direct space was made possible by new techniques of observation, such as scanning laser confocal microscopy: curvatures could be measured on phase-separated polymer blends [13,14]. These observations are especially relevant to discuss the local mechanisms that govern the coarsening: pinch-off was for instance observed in a colloidal glass [15].…”

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confidence: 86%

Fragmentation and Limits to Dynamical Scaling in Viscous Coarsening: An Interruptedin situX-Ray Tomographic Study

et al. 2014

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X-Ray microtomography was used to follow the coarsening of the structure of a ternary silicate glass experiencing phase separation in the liquid state. The volumes, surfaces, mean and Gaussian curvatures of the domains of minority phase were measured after reconstruction of the 3D images and segmentation. A linear growth law of the characteristic length scale ∼ t was observed. A detailed morphological study was performed. While dynamical scaling holds for most of the geometrical observables under study, a progressive departure from scaling invariance of the distributions of local curvatures was evidenced. The latter results from a gradual fragmentation of the structure in the less viscous phase that also leads to a power-law size distribution of isolated domains.Introduction -The construction of a theoretical framework describing the phase separation of binary liquids [1][2][3] has been fueled by successive experimental developments. Up to the 90's, most experimental observations were performed in the Fourier space, with light or neutron scattering. Model systems were immiscible solutions [4,5], and polymer blends [6,7], or glasses [8]. These experiments confirmed that the dynamical scaling assumption is relevant for these systems, i.e. it is possible to rescale the structure factor by a unique length scale . This length increases with a power law: (t) ∼ t α , α depending on the growth regime [9]. More recent numerical simulations confirmed this scaling behavior, and provided some insights about the geometry in real space [10][11][12]. Meanwhile, access to direct space was made possible by new techniques of observation, such as scanning laser confocal microscopy: curvatures could be measured on phase-separated polymer blends [13,14]. These observations are especially relevant to discuss the local mechanisms that govern the coarsening: pinch-off was for instance observed in a colloidal glass [15]. Recent predictions concerning statistical quantities such as size or surface distributions of domains [16,17] and numerical studies of aging in phase-separating fluids [18,19] also motivate the observation in real space.The effect of the mobility on the morphology has recently raised a growing interest. Experiments on polymers revealed the spectacular influence of visco-elasticity [20]. Recent work [21] evidenced a logarithmic (stressassisted) growth for a gas-glass phase separation. Numerical simulations with a viscosity contrast [22,23] showed a strong effect on morphology. However, the influence of a sole viscosity contrast has not yet been experimentally investigated in the hydrodynamical regime.The development of X-ray microtomography provides an suitable tool to explore phase separation in 3-D, with submicron spatial resolution reached in Synchrotron facilities [24,25]. Phase-separated polymer blends were

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confidence: 86%

Fragmentation and Limits to Dynamical Scaling in Viscous Coarsening: An Interruptedin situX-Ray Tomographic Study

et al. 2014

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“…Curvature analysis is becoming increasing useful for structure analysis and classification for phase separation structure, 23,24 since three-dimensional observation by laser scanning confocal microscopy and numerical simulation can be applied to the field of morphological research in condensed matter. We wish to introduce such perspective for the morphology of the TPE/oil system.…”

Section: Comparison With Other Conceptmentioning

confidence: 99%

“…[5][6][7][8][9] However, in the past five years, several studies have reported on direct observation of phase separation phenomena using laser scanning confocal microscopy, e.g., Ribbe, 10 Jinnai, 11,12 and Hermansson. 13 Recently, the authors proposed new non-aqueous physical gels prepared with small proportions of semicrystalline thermoplastic elastomers (nearly 10 wt% polymer concentration) and large proportions of oils of low molecular weight.…”

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Superstructure Formation in Thermoplastic Elastomer and Oil Systems. Formation of a Novel Microcellular Porous Structure

Mashita

Fukahori

2002

Polym J

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ABSTRACT:A novel microcellular porous structure, the product of a small proportion of a semi-crystalline thermoplastic elastomer (TPE) and a large proportion of low molecular weight oil, is examined. The structure is formed by the phase separation of a homogeneous mixture of TPE and oil. The system exhibits a unique three-dimensional continuous polymer network consisting of interconnected spherical cells of a few tens of micrometers in diameter. The detailed phase separation process is investigated utilizing optical microscopy, SEM, and DSC. A modulated structure, apparently attributable to spinodal decomposition, is observed in the initial stage of phase separation. However, during its evolution, this structure evolves into a clear network structure of a polymer-rich phase and clusters of a spherical oil-rich phase. Time evolution of D of a typical structure during the phase separation process at constant temperature is estimated to be D ∼ t 1 in the initial stage and D ∼ t 1/3 in the late stage. The character and role of differences in M w of components in the phase separation of the TPE/oil system are discussed in relation to the results of other studies.KEY WORDS Phase Separation / Percolation-to-Cluster Transition / Network Structure / Polymer Solution / Thermoplastic Elastomer / The phase separation process and morphology of polymer blend systems and alloys are both attractive and important from scientific and industrial perspectives, in part because the physical and mechanical properties of such polymer systems are highly dependent on their higher-order structures. Many types of phasecontrolled polymers have been developed and put to practical use over past decades.Despite numerous theoretical approaches, 1-4 most efforts to verify experimentally the kinetics of phase separation and its progress have generally been performed by indirect methods, such as time-resolved light scattering. [5][6][7][8][9] However, in the past five years, several studies have reported on direct observation of phase separation phenomena using laser scanning confocal microscopy, e.g., Ribbe, 10 Jinnai, 11, 12 and Hermansson. 13 Recently, the authors proposed new non-aqueous physical gels prepared with small proportions of semicrystalline thermoplastic elastomers (nearly 10 wt% polymer concentration) and large proportions of oils of low molecular weight. 14, 15 Observed directly with an optical microscope, the systems consist of threedimensional continuous polymer networks, constituted spherical cells of a few tens of micrometers in diameter. Each cell is connected to several other cells. Small openings occur at the connections between the cells: tunnels formed in the walls of the cells. This observation suggests that the oil-rich phases enclosed within the polymer cells are interconnected through the holes, and that the oil-rich phase is also continuous. We call this a "microcellular porous structure." The systems are quite stable thermally and dynamically and are currently used in industrial products as very soft nonaqueous and ...

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“…5 Although the kinetics of earlyto late-stage phase separation have been studied in considerable detail, [8][9][10] the kinetics of the initial stage (formation of concentration fluctuations from the uniform state) are not as well understood. In addition, the solvent-casting process, which is commonly used in making films, often accompanies the phase separation.…”

Section: Introductionmentioning

confidence: 99%

Nanometer-scale Real-space Observation and Material Processing for Polymer Materials under Atmospheric Pressure: Application of Atmospheric Scanning Electron Microscopy

et al. 2014

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Direct observation of phenomena occurring under atmospheric conditions, especially at the nanometer scale, would offer a unique opportunity to understand the dynamics of various processes. A novel electron microscope, the atmospheric scanning electron microscope (ASEM), has recently been developed and allows for the observation of nanoscale objects under atmospheric conditions. In this paper, we present some examples of dynamic phenomena in polymer materials observed using ASEM. The first example is phase separation of a binary polymer blend upon solvent evaporation, a representative example of a non-linear non-equilibrium phenomenon in physics. Phaseseparated structures were found to appear at the final stage of solvent evaporation. Also, we found that irradiation of organic liquids (e.g., dibenzyl ether) with the ASEM electron beam induced polymerization, and the resulting material showed interesting cathodoluminescence behavior. Thus, ASEM may be useful as a tool for simultaneous polymerization and fabrication, in addition to offering a means for direct nanoscale observation of materials under atmospheric conditions.

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Geometrical Properties and Interface Dynamics: Time Evolution of Spinodal Interface in a Binary Polymer Mixture at the Critical Composition

Cited by 85 publications

References 62 publications

Fragmentation and Limits to Dynamical Scaling in Viscous Coarsening: An Interruptedin situX-Ray Tomographic Study

Fragmentation and Limits to Dynamical Scaling in Viscous Coarsening: An Interruptedin situX-Ray Tomographic Study

Superstructure Formation in Thermoplastic Elastomer and Oil Systems. Formation of a Novel Microcellular Porous Structure

Nanometer-scale Real-space Observation and Material Processing for Polymer Materials under Atmospheric Pressure: Application of Atmospheric Scanning Electron Microscopy

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