Viscoelastic effects in early stage phase separation in polymeric systems

We examine how viscoelasticity affects early stage spinodal decomposition in polymer solutions and blends when fluctuations of the stress and the composition are coupled in dynamics. The coupling is increased with increasing asymmetry between the two components. We introduce a long viscoelastic length ξve within which the stress relaxation governs the composition relaxation. It can be of the order of the tube length in the reptation theory in strongly asymmetric polymer blends. For shallow quenching phase separation proceeds on time scales slower than the stress relaxation time τ and the kinetic coefficient depends on the wave number q as q−2 for qξve>1. On the other hand, for deep quenching phase separation takes place as in gels on time scales faster than τ. We describe the crossover between these two cases by assuming a single stress relaxation time.We examine how viscoelasticity affects early stage spinodal decomposition in polymer solutions and blends when fluctuations of the stress and the composition are coupled in dynamics. The coupling is increased with increasing asymmetry between the two components. We introduce a long viscoelastic length ξve within which the stress relaxation governs the composition relaxation. It can be of the order of the tube length in the reptation theory in strongly asymmetric polymer blends. For shallow quenching phase separation proceeds on time scales slower than the stress relaxation time τ and the kinetic coefficient depends on the wave number q as q−2 for qξve>1. On the other hand, for deep quenching phase separation takes place as in gels on time scales faster than τ. We describe the crossover between these two cases by assuming a single stress relaxation time.

[1]  Taniguchi,et al.  Network Domain Structure in Viscoelastic Phase Separation. , 1996, Physical review letters.

[2]  G. Fredrickson,et al.  EARLY STAGE SPINODAL DECOMPOSITION IN VISCOELASTIC FLUIDS , 1996 .

[3]  H. Eckerlebe,et al.  Effect of the Onsager coefficient and internal relaxation modes on spinodal decomposition in the high molecular isotopic blend polystyrene/deutero‐polystyrene studied with small angle neutron scattering , 1996 .

[4]  N. Nemoto,et al.  Dynamic Light Scattering and Dynamic Viscoelasticity of Poly(vinyl alcohol) in Aqueous Borax Solutions. 2. Polymer Concentration and Molecular Weight Effects , 1996 .

[5]  Tanaka,et al.  Universality of viscoelastic phase separation in dynamically asymmetric fluid mixtures. , 1996, Physical review letters.

[6]  E. Helfand,et al.  Concentration fluctuations in sheared polymer solutions , 1995 .

[7]  H. Wittmann,et al.  Projection of the Rouse model onto macroscopic equations of motion for polymers under shear , 1994 .

[8]  A. Onuki.  Dynamic scattering and phase separation in viscoelastic two-component fluids , 1994 .

[9]  K. Binder.  Phase transitions in polymer blends and block copolymer melts: Some recent developments , 1994 .

[10]  K. Kawasaki,et al.  Relaxation and growth of concentration fluctuations in binary fluids and polymer blends , 1993 .

[11]  Tanaka.  Unusual phase separation in a polymer solution caused by asymmetric molecular dynamics. , 1993, Physical review letters.

[12]  T. Hashimoto,et al.  Time‐resolved small‐angle neutron scattering study of spinodal decomposition in deuterated and protonated polybutadiene blends. I. Effect of initial thermal fluctuations , 1993 .

[13]  D. Schwahn,et al.  Early state of spinodal decomposition studied with small angle neutron scattering in the blend deuteropolystyrene and polyvinylmethylether: A comparison with the Cahn–Hilliard–Cook theory , 1992 .

[14]  M. Doi,et al.  Dynamic coupling between stress and composition in polymer solutions and blends , 1992 .

[15]  A. Onuki.  Viscoelastic effect on nucleation in semidilute polymer solutions , 1992 .

[16]  T. Hashimoto,et al.  “Butterfly” Light Scattering Pattern in Shear-Enhanced Concentration Fluctuations in Polymer Solutions and Anomaly at High Shear Rates , 1992 .

[17]  J. Egmond,et al.  Time‐dependent small‐angle light scattering of shear‐induced concentration fluctuations in polymer solutions , 1992 .

[18]  Kuwahara,et al.  Spinodal decomposition in a polymer solution. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[19]  Wu,et al.  Mode selection in the dynamics of sheared polymer solutions. , 1992, Physical review letters.

[20]  Nishimori,et al.  Anomalously slow domain growth due to a modulus inhomogeneity in phase-separating alloys. , 1991, Physical review. B, Condensed matter.

[21]  Wu,et al.  Enhanced concentration fluctuations in polymer solutions under shear flow. , 1991, Physical review letters.

[22]  G. Berry,et al.  Moderately concentrated solutions of polystyrene: 4. Elastic and quasi-elastic light scattering at the Flory theta temperature , 1990 .

[23]  K. Kawasaki,et al.  Dynamics and Patterns in Complex Fluids , 1990 .

[24]  Michael Rubinstein,et al.  Two-parameter scaling for polymers in Θ solvents , 1990 .

[25]  A. Akcasu.  Microscopic derivation and extension of the Cahn-Hilliard-Cook theory in polymer blends , 1989 .

[26]  K. Kawasaki,et al.  Concentration dynamics in polymer blends and block copolymer melts , 1989 .

[27]  Helfand,et al.  Large fluctuations in polymer solutions under shear. , 1989, Physical review letters.

[28]  K. Kawasaki,et al.  Spongelike domain structure in a two-dimensional model gel undergoing volume-phase transition. , 1989, Physical review. A, General physics.

[29]  Adam,et al.  Dynamical studies of polymeric cluster solutions obtained near the gelation threshold: Glasslike behavior. , 1988, Physical review letters.

[30]  James E. Martin,et al.  Critical dynamics of the sol-gel transition. , 1988, Physical review letters.

[31]  J. Jäckle,et al.  Theory of structural evolution in viscoelastic binary liquid mixtures after a temperature jump , 1988 .

[32]  R. Larson.  Constitutive equations for polymer melts and solutions , 1988 .

[33]  M. Brereton,et al.  Mutual diffusion in binary polymer mixtures as measured by dynamic light scattering , 1987 .

[34]  S. Edwards,et al.  The Theory of Polymer Dynamics , 1986 .

[35]  Kurt Binder,et al.  Kinetics of phase separation in the presence of slowly relaxing structural variables , 1986 .

[36]  A. Onuki.  Late stage spinodal decomposition in polymer mixtures , 1986 .

[37]  M. Delsanti,et al.  Dynamical behavior of semidilute polymer solutions in a .THETA. solvent: quasi-elastic light scattering experiments , 1985 .

[38]  C. Palmstrøm,et al.  Interdiffusion and marker movements in concentrated polymer-polymer diffusion couples , 1984 .

[39]  K. Binder.  Collective diffusion, nucleation, and spinodal decomposition in polymer mixtures , 1983 .

[40]  P. Meakin,et al.  Phase separation dynamics: Comparison of experimental results , 1983 .

[41]  M. Delsanti,et al.  Viscosity and longest relaxation time of semi-dilute polymer solutions: II. Theta solvent , 1983 .

[42]  F. Brochard.  Gel-like modes. of polymer solutions in « θ » solvents , 1983 .

[43]  P. Pincus.  Dynamics of fluctuations and spinodal decomposition in polymer blends. II , 1981 .

[44]  P. Gennes.  Dynamics of fluctuations and spinodal decomposition in polymer blends , 1980 .

[45]  P. Gennes.  Scaling Concepts in Polymer Physics , 1979 .

[46]  Toyoichi Tanaka,et al.  Spectrum of light scattered from a viscoelastic gel , 1973 .