Modeling the effect of compatibilizers in the coarsening of ternary polymer blends with core-shell morphology

Russo, A. Peter; Nauman, E. Bruce

doi:10.1002/(sici)1099-0488(20000515)38:10<1301::aid-polb50>3.0.co;2-m

Cited by 9 publications

(6 citation statements)

References 20 publications

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“…Finally, the maltodextrin inclusion takes on a spherical shape, and its volume is equal to the sum of the volumes of the two original inclusions. All these steps are in agreement with existing theories about the coalescence process in polymer/polymer systems. , The coalescence time, from the beginning to the end of the coalescence process shown in sequence a in Figure , was approximately 4 s.…”

Section: Resultssupporting

confidence: 90%

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Structure Evolution during Gelation at Later Stages of Spinodal Decomposition in Gelatin/Maltodextrin Mixtures

2001

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The kinetics of phase separation and gelation in kinetically trapped gelatin/maltodextrin/water gels was studied using confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). The time evolution of the morphology was followed by CLSM during temperature quenches from 60 °C to between 1 and 40 °C. The maltodextrin concentration was varied between 2.25% and 7.5% (w/w), and the gelatin concentration was held constant at 4% (w/w). Spinodal decomposition, self-similar growth, percolation-to-cluster transition, coalescence, and diffusion of maltodextrin inclusions were observed during the progress of gelation. The start and completion of these processes, the onset of phase separation, and the relative rates of phase separation and gelation were found to determine the morphology. The characteristic wavelength showed a crossover in its growth rate power law from one-third to one in a slowly gelling, near-symmetric system. Droplet and bicontinuous morphologies were observed in off-symmetric and near-symmetric quenches, respectively. Secondary phase separation occurred at low temperatures and near-symmetric composition. Partial coalescence and contracted flocculation were observed during the progress of gelation. Stereological measurements showed that the size of maltodextrin inclusions increases and that the volume fraction decreases with increasing quench temperature. In addition, the number of the maltodextrin inclusions decreases with increasing quench temperature.

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Section: Resultssupporting

confidence: 90%

“…All these steps are in agreement with existing theories about the coalescence process in polymer/polymer systems. 53,54 The coalescence time, from the beginning to the end of the coalescence process shown in sequence a in Figure 6, was approximately 4 s.…”

Section: Resultsmentioning

confidence: 99%

Structure Evolution during Gelation at Later Stages of Spinodal Decomposition in Gelatin/Maltodextrin Mixtures

2001

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“…Crist and Nesarikar's derivation was obtained for pure Ostwald ripening. The modified Cahn–Hilliard model predicts growth by Ostwald ripening and nonlinear diffusion‐induced coalescence 28. Nonlinear diffusion‐induced coalescence facilitated ripening and increased the kinetic constant, even though α was still 1/3.…”

Section: Simulation Resultsmentioning

confidence: 99%

“…Our experimental results show that the kinetic constant has a stronger relation to the volume fraction than that predicted by pure Ostwald ripening. Coalescence induced by either nonlinear diffusion28 or droplet Brownian motion7 might contribute to this increase.…”

Section: Resultsmentioning

confidence: 99%

Phase ripening in particulate binary polymer blends

Cheng

Nauman

2004

J Polym Sci B Polym Phys

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Particulate polymer-in-polymer mezodispersions show a pronounced increase in the size of the dispersed particles during melt-phase annealing. Three ripening mechanisms have been proposed: Brownian coalescence, Ostwald ripening, and hydrodynamic coarsening. The modified Cahn-Hilliard equation predicts growth by Ostwald ripening and diffusion-induced coalescence. Simulations of this mechanism show a self-similar particle size distribution, but the distribution broadens with the increasing volume fraction of the minor phase. Hydrodynamic coarsening caused by concentration gradients and random Brownian forces has been simulated according to the hydrodynamic model. The simulations show that concentration-driven hydrodynamics have little effect on the particle size distribution. Experiments have been performed to investigate the relative importance of these ripening mechanisms for polybutadiene in a polystyrene system.

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“…The mesoscale or microscale phase morphology of immiscible homopolymer blends plays a critical role in the performance of polymer-based photovoltaic and light-emitting devices as well as being of generally interest for surface patterning applications. , Both types of applications can be severely limited by the thermodynamic tendency of blend films to undergo uncontrolled phase coarsening upon heating, driven by a combination of interfacial tension between polymer components and preferential interactions at the surface and substrate. Various studies demonstrate that phase morphologies can be regulated and stabilized by additives such as random copolymers, – block copolymers, , and inorganic nanoparticles, – generally known as compatibilizers, which tend to mitigate unfavorable interactions between immiscible blend components, usually by segregating at the polymer/polymer interface. To date, the role of added compatibilizers has been limited to lowering the interfacial tension or enhancing interfacial adhesion.…”

Section: Introductionmentioning

confidence: 99%

“Smart” Self-Assembled Quantum Dots Regulate and Stabilize Structure in Phase-Separated Polymer Blends

Guo

Moffitt

2007

Chem. Mater.

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Cadmium sulfide (CdS) quantum dots (QDs) coated with mixed polystyrene (PS)/poly(methyl methacrylate) (PMMA) brush layers (PS/PMMA-CdS) self-assemble at the polymer/polymer interface of a phase-separating blend of the corresponding homopolymers, forming an encapsulating shell surrounding PMMA islands in a PS matrix. The segregated QDs regulate phase separation during spin-coating and dramatically stabilize the spin-coated blend morphologies during subsequent annealing, compared to neat PS:PMMA blends which undergo rapid phase inversion and coarsening. PS/PMMA-CdS QDs are shown to retain their photoluminescence following interfacial self-assembly and subsequent annealing. Free-standing arrays of polymer/QD rings formed via directed self-assembly can be developed by selective solvent washing and removal of homopolymers from the spin-coated films. This work demonstrates the principle that colloidal inorganic elements such as QDs, along with possessing interesting optical properties, can also play a key role in the self-organization and stability of polymer blend-based devices.

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Modeling the effect of compatibilizers in the coarsening of ternary polymer blends with core-shell morphology

Cited by 9 publications

References 20 publications

Structure Evolution during Gelation at Later Stages of Spinodal Decomposition in Gelatin/Maltodextrin Mixtures

Structure Evolution during Gelation at Later Stages of Spinodal Decomposition in Gelatin/Maltodextrin Mixtures

Phase ripening in particulate binary polymer blends

“Smart” Self-Assembled Quantum Dots Regulate and Stabilize Structure in Phase-Separated Polymer Blends

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