Phase Separation Dynamics

A homogeneous mixture quenched from a stable phase into a thermodynamically unstable state within a phase diagram develops into an inhomogeneous system. Spinodal decomposition (SD) is induced by the instability of an order parameter, which is usually concentration [101]. In the early stages, the SD is interpreted within the framework of the Cahn theory for an isotropic SD [102,103]. In contrast, in the late stages, the SD is governed by diffusion or hydrodynamic processes and exhibits slow coarsening [104]. There are two types of order parameters that describe a system. One is a conserved order parameter such as concentration of binary mixtures. The other is a non-conserved order parameter such as the polarization of a ferroelectric 

For practical use of PDLC, dispersions are mainly prepared by mixing a small amount of misdble monomers with liquid crystals and photo-polymerizing [1], since polymer and liquid crystals tend to be immiscible. As the polymerization evolves, the system undergoes phase separations into a liquid crystalline phase rich in liquid crystals and an isotropic phase rich in polymers. Before the system reaches equilibrium states, however, the polymerization freezes the system into a crosslinked network of polymer-rich domains. Then, the morphologies of the PDLC involve interplay among three kinetic processes polymerization, phase separation, and phase ordering. These phase separation dynamics have been simulated by some aulhors [105-108]. 

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In the case of phase-separation dynamics, the non-linear terms become increasingly important in the course of time. In contrast, for phase-dissolution kinetics, the non-linear terms are most important in the beginning and their importance declines with progressing dissolution. 

Phase-Separation Dynamics of Aqueous Hydrosypropyl Cellulose Solutions... 

KYUETAL. Phase-Separation Dynamics of Cellulose Si utions... 

The effects of chain length of added (attractive or repulsive) block copolymer on the phase separation dynamics of immiscible polymer blends are summarized... 

Theory on Phase Separation Dynamics and Morphology Evolution... 

On the basis of eq 2.16 Langer et al. developed a sophisticated theory of phase separation in binary alloys. It gave a starting point for recent statistical theories of phase separation dynamics [10], and called the LBM (Langer-Bar-on-Miller) theory. Here we touch upon it. 

Polystyrene (PS) and poly(vinylmethylether)(PVME) are mutually compatible over the entire range of composition, and their blends have thus often been chosen for experimental studies on the phase separation dynamics of binary polymer mixtures. The subsequent discussion depends heavily on the data re-... 

Kawakatsu, T, Doi, M., and Hasegawa, A. Dynamic density functional approach to phase separation dynamics of polymer systems, bit J Mod Phys C, 10, 1531-40 (1999). 

Morphological development continues until the thermoset reaches the gel point or vitrifies. The final structure will depend upon crosslinking and phase separation during crosslinking. Understanding of reaction kinetics of phase separation dynamics can provide useful information for production of optimal phase structure. 

Oono, Y. and Puri, S. 1988. Study of phase-separation dynamics by use of cell dynamics systems. I. Modeling. Physical Reviews A 38 434-453. 

Phase separation was computer simulated using finite-difference in time and space Runge-Kutta and Monte Carlo with a Hamiltonian methods (Petschek and Metiu 1983 Meakin and Reich 1982 Meakin et al. 1983). Both methods were found equivalent, reproducing the observed pattern of phase separation in both NG and SD regions. The unity of the phase separation dynamics on both sides of the spinodal has been emphasized (Leibler 1980 Yemkhimovich 1982). 

Gumming, A., Wiltzius, P., Bates, F.S., and Rosedale, J.H. (1992) Light scattering experiments on phase separation dynamics in binary fluid mixtures, Phys.Rev. A 45, 885. 

While most work on annealed PS/PMMA blends support the formation of phase-separated domains right to the surface, a recent study (134) reports that an encapsulating layer of PS-skin forms over the PMMA domains. The stxm and peem might be a good complementary tool to afm, xps, and nexafs spectroscopy to further elucidate PS/PMMA thin-film blends, their phase separation dynamics, and their surface composition (96). 

Multiscale Modeling, Fig- 8 Example of phase-separation dynamics calculation for a two-phase system [21]... 

We are developing a general purpose method for mesoscale soft-condensed matter computer simulations, based on a functional Langevin approach for mesoscopic phase separation dynamics of complex polymer liquids. This project aims to consider topics of utmost importance in chemical engineering, such as chemical reactions, convection and flow effects, surfaces and boundaries, etc. 

Polystyrene (PS) and poly(methyl methacrylate) (PMMA) are frequently used as binary model systems to study phase separation dynamics in polymer thin films and in polymer-polymer and polymer-substrate interactions (Zhu et al. 1999 Winesett et al. 2000). Using scanning force microscopy (SIM), Zhu et al. showed that, after the PS/PMM A bilayer samples were annealed for seven days at 180°C and washed in cyclohexane to selectively dissolve the PS homopolymer, the phase of PS was differently organized on the PMMA layer surface due to the content of a 30% dPS-PMMA diblock copolymer, namely in undissolved nticelles (for a thickness of 100 nm for PS layer), coexisting micelles and microanulsion structures (for 80 nm), and in microemulsion (for 50 nm). 

Key words Viscoelastic phase separation - dynamical asymmetry - two-fluid model - smoothed-particle hydrodynamics... 

Abstract We numerically investigate a shape deformation and an intramembrane phase separation dynamics of a two-component closed membrane using a purely dissipative dynamical model. It is found that deformed shapes at the late stage after off critical quenches closely resemble the echinocytsis of erythrocytes. Two effects (i) the local coupling of the... 

Malik, R Hall, C.K., and Genzer, J. (2011) Phase separation dynamics for a polymer blend compatibilized by protein-like copolymers A Monte Carlo simulation. Macromolecules, 44, 8284—8293. 

Tong, C., Zhang, H., and Yang, Y. (2002) Phase separation dynamics and reaction kinetics of ternary mixture coupled with interfadal chemical reaction. J. Phys. Chem. B, 106, 7869-7877. 

K. Jorgensen, O. G. Mouritsen, Phase separation dynamics and lateral organization of two-component lipid membranes, Biophys. J. 95 (1995) 942. 

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