TANAKA LAB. Physics of Soft Condensed Matter The University of Tokyo Graduate School of Engineering Department of Applied Physics The University of Tokyo Institute of Industrial Science Department of Fundamental Engineering
Entrance > Research > Polymer, Liquid Crystal, Colloid, Membrane, Protein > Polymer System > Critical Phenomena in Polymer Solutions
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Phase Separation in a Normal Fluid MixtureViscoelastic Phase SeparationPhase Separation of Colloidal SuspensionsNumerical Simulations of Viscoelastic Phase SeparationMicro-Phase Separation in Diblock CopolymerInterplay between Wetting and Phase SeparationPhase Separation under External FieldsDynamic Control of the Smectic MembranesCritical Phenomena in Polymer SolutionsCoil-Globule Transition of a Single PolymerColloidal ‘Atom’Colloidal Gel NetworkElectrophoretic Separation of Charged ParticlesAggregation of Charged Colloidal SystemsSurface-Assisted Monodomain Formation of a Lyotropic Liquid CrystalShear-Induced Topological Transitions in a Membrane SystemSpontaneous Onion-Structure FormationSelf-Organization in Phase Separation of a Lyotropic Liquid CrystalTransparent Nematic Phase in a Liquid-Crystal-Based MicroemulsionColloidal Aggregation in a Nematic Liquid CrystalPhase Separation of a Mixture of an Isotropic Liquid and a Liquid CrystalSpontaneous Partitioning of Particles in a Membrane System

Critical Phenomena in Polymer Solutions

Critical Phenomena in Polymer Solutions Critical anomaly of viscosity has been studied for ideal polymer solutions, focusing on its dependence on the molecular weight of polymer Mw. According to the conventional understanding that polymer solutions should belong to the same dynamic universal class as classical fluids, the critical exponent of viscosity yc should be a universal constant (∼ 0.04). Contrary to this, we find that yc significantly decreases with increasing Mw. This unusual behavior can be explained by the dynamic coupling of critical concentration fluctuations with an additional slow viscoelastic mode intrinsic to polymer solutions. Our dynamic light scattering measurements support this picture.

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