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Hydrodynamic interactions (HIs) play a critical role in the self-organization of colloidal suspensions and biological solutions. However, their roles have remained elusive particularly for charged soft matter systems. Here we consider the role of HIs in the self-assembly of oppositely charged colloidal particles, which is a promising candidate for electrical tunable soft materials. We employ the fluid particle dynamics method to consider many-body HIs and the coupling between the colloid, ion, and fluid motions. We find that, under a constant electric field, oppositely charged colloidal particles form clusters and percolate into a gel network, unlike bundlelike aggregates aligned in the field direction observed by Brownian dynamics simulations neglecting HIs. We reveal that the cluster-forming tendency originates from the incompressibility-induced "inverse squeezing flow" effect that dramatically slows down the disaggregation of attached colloids. Our findings indicate that the HI selects a unique kinetic pathway to the nonequilibrium colloidal self-assembly.

Zwitterionic modification of colloids with weak acids and bases represents a promising strategy in creating functional materials with tunable properties and modeling the self-organization of charged proteins. However, accurate incorporation of the dynamic dissociation or association of ionization groups known as charge regulation (CR) is often intractable in theoretical and computational investigations since charge redistribution and configuration need to be evolved self-consistently. Using hybrid Monte Carlo and molecular dynamics simulations, we demonstrate that a dilute suspension of overall charge-neutral zwitterionic Janus nanoparticles shows a conformational transition from an open assembly of string or bundle to compact cluster along with the variation in pH. The behavior under CR is qualitatively different from the commonly employed constant charge condition where the transition is absent. The CR-induced clustering is due to the inhomogeneous and fluctuating charges localized near the equatorial boundary of the Janus particle. These features are enhanced particularly at low salt concentration and high electrostatic coupling strength. Our results indicate the critical role of charge regulation in the spatial self-organization of zwitterionic nanoparticles.

Unlike crystals, glasses age or devitrify over time, reflecting their non-equilibrium nature. This lack of stability is a serious issue in many industrial applications. Here, we show by numerical simulations that the devitrification of quasi-hard-sphere glasses is prevented by suppressing volume fraction inhomogeneities. A monodisperse glass known to devitrify with `avalanche'-like intermittent dynamics is subjected to small iterative adjustments to particle sizes to make the local volume fractions spatially uniform. We find that this entirely prevents structural relaxation and devitrification over aging time scales, even in the presence of crystallites. There is a dramatic homogenization in the number of load-bearing nearest neighbors each particle has, indicating that ultra-stable glasses may be formed via `mechanical homogenization'. Our finding provides a physical principle for glass stabilization and opens a novel route to the formation of mechanically stabilized glasses., 6 pages, 4 figures, 1 ancillary video file, 1 supplementary PDF

A key question in glass physics is what the origin of slow glassy dynamics is. The liquid structure is a natural candidate; however, an apparently severe counterexample has been known. Two model glass-forming liquids, with the standard Lennard-Jones interaction potential and its Weeks-Chandler-Andersen variation without the attractive tail, exhibit very similar structures at the two-body level but drastically different dynamical behaviors in the supercooled states. Here we look at the liquid structure through a (many-body) structural order parameter Θ characterizing the packing capability of local particle arrangements. We show that the structures of these two systems seen by Θ are actually very different at a many-body level, but, quite surprisingly, the macroscopic structure (Θ)-dynamics (τ_{α}) relationships commonly follow a Vogel-Fulcher-Tammann-like function. Furthermore, the mutual information analysis reveals strong local structure-dynamics correlations. Therefore, we conclude that attractive interactions affect the liquid structure in a nonperturbative manner, but a general structural origin of slow dynamics holds for these systems.

One of the biggest unresolved problems in crystallization phenomena is the significant discrepancy in the nucleation rate between experiments and simulations even for the simplest liquid, i.e., the hard-sphere system. A popular explanation for this discrepancy is the neglect of hydrodynamic interactions (HI) in simulation studies. By comparing simulations with and without HI, we show that the long-time diffusive dynamics of the colloids is slowed down more rapidly by hydrodynamic lubrication effects with increasing volume fraction. We find that the kinetics of both nucleation and growth are controlled by this long-time diffusion and that it is possible to account for most of the effects of HI by rescaling with this timescale. Therefore, we conclude that HI is not the primary cause of the accelerated nucleation rates observed in experiments.

We look for inherent structural characteristics hidden behind amorphous solid formation by using zero-temperature jammed packings of frictionless particles as models. Differently from previous geometrical approaches, we introduce a microscopic mechanical or vibrational order parameter $\mathrm{\ensuremath{\Psi}}$, which characterizes the susceptibility of particle motion to infinitesimal thermal excitation. We show that (i) the distribution of $\mathrm{\ensuremath{\Psi}}$ has a power-law tail toward high $\mathrm{\ensuremath{\Psi}}$ and (ii) the spatial organization of $\mathrm{\ensuremath{\Psi}}$ is characterized by a nontrivial scale-free correlation. Both findings (i) and (ii) are regarded as a real-space manifestation of marginal stability due to critical self-organization of jammed packings toward mechanical equilibrium. Furthermore, we find that the power-law exponent of the $\mathrm{\ensuremath{\Psi}}$ distribution tail shows a critical-like scaling behavior toward the unjamming transition, which unveils an intriguing interplay between jamming criticality and marginal stability. Our microscopic order parameter provides new structural insights into the marginal stability and instability of jammed packings and may shed light on the important common structural feature of amorphous solids.

Thermophoresis, which is mass transport induced by a temperature gradient, has recently attracted considerable attention as a new way to transport materials. So far the study has been focused on the transport of discrete structures such as colloidal particles, proteins, and polymers in solutions. However, the response of soft continuous structures such as membranes and gels to a temperature gradient has been largely unexplored. Here we study the behavior of a lamellar phase made of stacked surfactant bilayer membranes under a temperature gradient. We find the migration of membranes towards a low-temperature region, causing the increase in the degree of membrane undulation fluctuations towards that direction. This is contrary to our intuition that the fluctuations are weaker at a lower temperature. We show that this can be explained by temperature-gradient-induced migration of membranes under the topological constraint coming from the connectivity of each membrane. We also reveal that the pattern of an edge dislocation array formed in a wedge-shaped cell can be controlled by a temperature gradient. These findings suggest that application of a temperature gradient provides a novel way to control the organization of soft continuous structures such as membranes, gels, and foams, in a manner essentially different from the other types of fields, and to manipulate topological defects.

Here, we study the phase transition kinetics in a supercooled liquid state of triphenyl phosphite by means of time-resolved polarized and depolarized light scattering to address a long-standing controversy on its mechanism, i.e., whether the phenomenon is primarily induced by liquid-liquid transition (LLT) or by nanocrystal formation. We find that the polarized scattering intensity exhibits a peak as a function of time, and its low wave number limit is nonzero for any annealing temperatures, both of which strongly indicate the nonconserved nature of an order parameter governing the transition. We also observe evolution of depolarized scattering. Above the spinodal temperature ${T}_{\mathrm{SD}}$, the depolarized scattering intensity monotonically increases with time since it is dominated by scattering from nanocrystallites, which are continuously formed during the process. Below ${T}_{\mathrm{SD}}$, on the other hand, it exhibits a distinct peak as a function of time as the polarized scattering intensity does. This appearance of the peak suggests that dielectric tensor fluctuations responsible for the depolarized scattering mainly come from isotropic density fluctuations and not from nanocrystallites, supporting the occurrence of LLT.

Extraordinary $(X)$ waves are perpendicularly injected for electron Bernstein $(B)$ wave heating into an Ohmically heated plasma from the inboard side in the WT-3 tokamak. Measurements show that absorption does not take place at the electron cyclotron resonance layer nor the upper hybrid resonance layer, but does happen midway between them. This is consistent with the ray tracing prediction, i.e., the poloidal field and poloidal inhomogeneity of toroidal field lead the $B$ waves to have a large parallel refractive index ${N}_{\ensuremath{\parallel}}$ $(g1)$, and the $B$ waves are damped away via the Doppler-shifted cyclotron resonance.

The layer compression modulus was measured near the smectic- $A$--smectic- ${C}_{\ensuremath{\alpha}}^{*}$ phase transition in a chiral smectic liquid crystal. The layer compression modulus $B$ shows marked pretransitional effects above the phase transition. The critical softening of $B$ can be fit to a simple power law. It is described by the theoretical description based on the renormalization-group method and seems to suggest a crossover behavior. These effects clearly show that the transition is not of the Landau mean-field type.

We develop a new simulation method of colloidal suspensions, which we call a "fluid particle dynamics" (FPD) method. This FPD method, which treats a colloid as a fluid particle, removes the difficulties stemming from a solid-fluid boundary condition in the treatment of hydrodynamic interactions between the particles. The importance of interparticle hydrodynamic interactions in the aggregation process of colloidal particles is demonstrated as an example. This method can be applied to a wide range of problems in colloidal science.

We demonstrate by numerical simulations that spinodal decomposition of fluid mixtures is strongly dependent upon their ``fluidity,'' which characterizes the relative importance of the two relevant transport mechanisms, hydrodynamic flow and diffusion. Thus, it may not be ``universal,'' at least in two dimensions. For a high fluidity, we find ``spontaneous double phase separation.'' We confirm that this unusual phenomenon is caused by the following mechanism: High fluidity causes rapid geometrical coarsening of domains due to a hydrodynamic process, which is too fast for diffusion to follow. This brings the system out of equilibrium and induces secondary phase separation.

Here we demonstrate that the unusual thermodynamic behavior of water can be explained by a simple two-order-parameter Landau-type theory naturally and physically, without considering the effects of a liquid-liquid critical point. To describe the hydrogen-bonding effects on the phase behavior, we introduce a bond order parameter $S$, in addition to the density order parameter $\ensuremath{\rho}$. We ascribe the unusualness of water to the competing orderings of $\ensuremath{\rho}$ and $S$, or their strong negative coupling. We argue that in usual liquids the crystallization is primarily a result of the ordering of $\ensuremath{\rho}$, while in water it is a result of the ordering of $S$ at ambient pressure.

Colloids immersed in a critical binary liquid mixture are subject to critical Casimir forces (CCFs) because they confine its concentration fluctuations and influence the latter via effective surface fields. To date, CCFs have been primarily studied in thermodynamic equilibrium. However, due to the critical slowing down, the order parameter around a particle can easily be perturbed by any motion of the colloid or by solvent flow. This leads to significant but largely unexplored changes in the CCF. Here we study the drag force on a single colloidal particle moving in a near-critical fluid mixture and the relative motion of two colloids due to the CCF acting on them. In order to account for the kinetic couplings among the order parameter field, the solvent velocity field, and the particle motion, we use a fluid particle dynamics method. These studies extend the understanding of CCFs from thermal equilibrium to nonequilibrium processes, which are relevant to current experiments, and show the emergence of significant effects near the critical point.

We demonstrate here a dynamic phase transition between a periodic state without coarsening and a nonstationary state with coarsening, for a binary polymer mixture periodically driven above and below its instability point. For a nonstationary state we have found, in both symmetric and off-symmetric mixtures, the growth of a two-level structure characterized by two length scales. There is no self-similarity in this pattern evolution. A dynamic phase diagram of the dynamic stability of the phase has been obtained for the first time: Hydrodynamic interaction is found to have a strong effect on the dynamic stability limit through its dependence on the composition symmetry.

The elementary process of droplet coarsening has been studied for phase-separating binary liquid mixtures. For a slightly asymmetric quench, we have found two new types of coarsening behavior: (i) a multiple collision caused by the coupling effect between the shape relaxation after binary collision and the geometrical configuration of neighboring droplets and (ii) a collision-induced collision likely caused by collision-diffusion coupling. For a nearly symmetric mixture the droplet density is so high that we probably need to consider new mechanisms of droplet coarsening unique to fluid systems, which originate from the coupling between concentration and velocity fields.

The critical anomaly of the complex shear modulus has been studied for ideal polymer solutions in the frequency range from 1 Hz to 400 Hz. The logarithmic critical divergence is observed for both the real and imaginary parts of the complex shear modulus. It is found that the strength of the critical anomaly decreases with an increase in the degree of polymerization N, while the noncritical background increases with N, indicating the significance of the viscoelastic effect. The critical anomaly is likely suppressed by the viscoelastic effects through the spontaneous coupling between the stress field and the order parameter fluctuation.

Water is a very poor glass former, but its link to the thermodynamic and kinetic anomalies remains elusive. We experimentally reveal that the glass-forming ability and fragility of a water-salt mixture are closely related to its equilibrium phase diagram. We propose that frustration between local and global orderings controls both the glass-forming ability and the fragility. Relying on the same role of salt and pressure, which commonly break tetrahedral order, we apply this idea to pure water under pressure. This scenario not only explains unusual behavior of water-type liquids such as water, Si, and Ge but also provides a mechanism for a link between the equilibrium phase diagram, glass-forming ability, and fragility for various materials including oxides, chalcogenides, and metallic glasses.

A morphological and kinetic change is found in the late stage of surface pattern formation on a gel plate. It results from a dynamic ordering process originating from a strong constraint from the bottom surface. The scattering function changes its form from a single-peaked, broad function to a multipeaked one, reflecting the morphological change from a treelike pattern to a honeycomblike one. The characteristic size of the pattern initially grows as ${\mathit{t}}^{1/2}$, and then relaxes to its equilibrium value. This kinetic change coincides well with the morphological one.

Colloidal gelation is caused by the formation of a percolated network of colloidal particles suspended in a liquid. Thus far the major transport process leading to gelation has been believed to be the Brownian diffusion of particles. Contrary to this common belief, we reveal by numerical simulations that many-body hydrodynamic interactions between colloidal particles also play an essential role in gelation: They significantly promote gelation, or lower the colloid volume fraction threshold for percolation, as compared to their absence. We find that the incompressible nature of a liquid component and the resulting self-organization of hydrodynamic flow with a transverse (rotational) character are responsible for this enhancement of network-forming ability.

Using molecular dynamics simulations, we show clear evidence for the nonlocal mesoscopic nature of the anomalous viscous transport in a supercooled liquid and its direct link to dynamic heterogeneity: (i) a distinct crossover from the microscopic to macroscopic viscosity at a mesoscopic length scale, which is comparable to the correlation length of dynamic heterogeneity and grows with an increase in the degree of supercooling; (ii) a strong anisotropic decay of the shear-stress autocorrelation at a finite wave number, which indicates intrinsic decoupling between the longitudinal and transverse dynamics. Our findings suggest the fundamental importance of the growing dynamic correlation in anomalous transport and shed new light on the nature of slow dynamics.

Here we study the relation between the mobility and the translational diffusion in supercooled two-dimensional polydisperse colloidal liquids, using numerical simulations. We find an apparent violation of the Einstein-Smoluchowski (ES) relation D=kB T micro (D: diffusion constant; mu: mobility; kB; Boltzmann's constant; T: temperature). The violation is a direct consequence of the fact that it is difficult for a driven particle to enter a jammed region with high order due to its yield stress. The degree of this apparent ES violation is controlled solely by the characteristic size of slow jammed regions, xi. Our finding implies that the characteristic time of this problem is not the structural relaxation time tau alpha but the lifetime of dynamic heterogeneity, tau xi. A supercooled liquid can be regarded to be ergodic only over tau xi, which may be the slowest intrinsic time scale of the system.

Recently, the role of hydrodynamic interactions in the selection of a kinetic pathway for phase transitions has attracted considerable attention. Here we study this problem numerically by taking as an example a coil-globule transition of a single polymer, which is a prototype model of protein folding. When a swollen polymer collapses into a globule state, hydrodynamic interactions accelerate the transition. We find, on the other hand, that when a rather compact polymer collapses into the same final state, hydrodynamic interactions decelerate the transition due to a slow squeezing process of the solvent. We reveal that the degree of the initial enhancement of anisotropy of the polymer configuration determines whether hydrodynamic interactions accelerate or decelerate the collapsing dynamics. We also discuss the possible relevance of squeezing flow effects in protein folding.

A supercooled liquid generally exhibits marked shear-thinning behavior, but its detailed mechanism remains elusive. Here we study the dynamics of structural rearrangements in supercooled liquids under shear, using two-dimensional (2D) molecular dynamics simulation. To elucidate the relationship between heterogeneous dynamics and the rheological behavior, we extend the four-point correlation function, which has been used for analyzing ``dynamic heterogenity'' in a quiescent condition, to a system under steady shear. In the Newtonian regime, the rearrangement dynamics is strongly heterogeneous in space, but remains isotropic. Contrary to this, in the non-Newtonian regime, where marked shear-thinning behavior appears, we find a novel dynamic effect: The mobile region tends to form anisotropic ``fluidized bands.'' This finding suggests a link between nonlinear rheology and inhomogeneization of flow.

Here we report novel phase-separation behavior accompanying mechanical fracture ("fracture phase separation"), which is observed in polymer solutions. Surprisingly, mechanical fracture becomes a dominant coarsening process of the phase separation. The transition from viscoelastic to fracture phase separation corresponds to the "ductile-to-brittle transition" in fracture of materials under shear deformation. The only difference between fracture phase separation and material fracture is whether the deformation is induced internally by phase separation itself or externally by loading. This suggests a general physical scenario of mechanical selection of the kinetic pathway of inhomogeneization of materials under stress.

Collective behavior of driven granular matter is often strikingly analogous to that of thermal systems. Here we use a vibrated quasi-two-dimensional granular matter as a model system and investigate the mechanism of the liquid-glass transition. We demonstrate by direct observation the existence of long-lived medium-range crystalline order, which is found to be closely related to both dynamic heterogeneity and slow dynamics. Our findings are remarkably similar to recent numerical results on model thermal liquids and thus open an intriguing possibility of understanding the dynamic arrest in both thermal and athermal systems in a unified manner.

A Reply to the Comment by Fran\ifmmode \mbox{\c{c}}\else \c{c}\fi{}ois Sausset and Gilles Tarjus.

In a binary mixture of oligomers of styrene and \ensuremath{\epsilon}-caprolactone, we have studied a transition from metastability to instability by changing a quench depth systematically under an off-critical quench condition. The concentration distribution function turns out to be a good fingerprint for determining whether phase separation is nucleation-growth type or spinodal-decomposition type. We also demonstrate clear morphological and kinetice evidence of a diffuse metastable-unstable transition or crossover phenomena theoretically predicted for the system with a finite-range interaction.

Generally, phase transitions are seriously affected by spatial confinement. This effect is important for its own sake, but also for applications to nanotechnology. Here we report the first systematic experimental study on confinement effects on a liquid-liquid transition of a molecular liquid. We found that one liquid can be transformed into another purely by spatial confinement. This indicates that the liquid state cannot be specified by the temperature and pressure alone, but it is also affected by its size in a discontinuous manner: the phase of a liquid in a narrow space can, in principle, be different from that in the bulk. This finding would deepen our basic understanding of the liquid state.

A glassy state of matter results if crystallization is avoided upon cooling or increasing density. However, the physical factors controlling the ease of vitrification and nature of the glass transition remain elusive. Using numerical simulations of polydisperse hard disks, we find a direct relation between medium-range crystalline ordering and the slow dynamics which characterizes the glass transition. This suggests an intriguing scenario that the strength of frustration controls both the ease of vitrification and nature of the glass transition. Vitrification may be a process of hidden crystalline ordering under frustration, at least in our system.

Nucleation and growth are a basic elementary process of ordering. The nucleation process is controlled by a competition between interfacial and bulk energy. Thus an ordered structure of a nucleus at its birth is not necessarily the most stable thermodynamically: Ostwald step rule. In addition to this, we found the topological transformation of nuclei from the most stable bulk structure (planar lamella) to a metastable one (onion) in a lyotropic liquid crystal. This indicates that the fate of nuclei of low-dimensional internal order can also be seriously affected by an additional competition between interfacial and elastic deformation energy.

We numerically study many-body interactions among colloidal particles suspended in a nematic liquid crystal, using a fluid particle dynamics method, which properly incorporates dynamical coupling among particles, nematic orientation, and flow field. Based on simulation results, we propose a new type of interparticle interaction in addition to well-known quadrupolar interaction for particles accompanying Saturn-ring defects. This interaction is mediated by the defect of the nematic phase: upon nematic ordering, a closed disclination loop binds more than two particles to form a sheetlike dynamically arrested structure. The interaction depends upon the topology of a disclination loop binding particles, which is determined by aggregation history.

In addition to the known behavior of normal phase separation and gelation, we report novel phase-separation behavior of protein solutions as their intermediate case. A network structure of the protein-rich phase may be formed even if it is the minority phase, contrary to the conventional wisdom. This behavior is characteristic of viscoelastic phase separation found in polymer solutions. This kinetic pathway may play crucial roles in the complex phase ordering of protein solutions, in particular, protein network formation in biological systems and foods.

When a liquid approaches its glass-transition temperatures ${T}_{g}$, the structural relaxation time $\ensuremath{\tau}$ dramatically increases. This basic feature is ubiquitous, but this increase of $\ensuremath{\tau}$ can be classified between strong and fragile extremes using ${T}_{g}$ as a scaling parameter. Liquids, whose $\ensuremath{\tau}$ obeys the Arrhenius law, are called ``strong,'' while ``fragile'' liquids have the super-Arrhenius behavior. Here we report the first continuous control of the fragility of liquid of the same material over a wide range of fragility, using a continuous liquid-liquid transition. Our study clearly demonstrates that the fragility is not a material-specific quantity, but is controlled by the order parameter governing the liquid-liquid transition, which may be the fraction of locally favored structures in the liquid.

We produced a monodomain ordered structure with the help of a surface-mediated first-order transition, using a sponge-to-lamella transition in a membrane suspension as a model system. The long characteristic length and time scales of the system allow us to observe the process of the phase ordering in a confined geometry with optical microscopy in real time. We demonstrate that a homogeneously ordered domain can be attained if we prevent nucleation in bulk by using its kinetic coupling to nucleation on the surface.

We have developed a new method of "mode-selective" dynamic light scattering spectroscopy. This method allows us to study dynamic modes usually hidden behind large fluctuations of a critical mode. Here we apply this method to measurements of three dynamic modes of the isotropic phase of liquid crystals near the isotropic-nematic transition. In conventional methods detecting thermally excited modes, the thermal diffusion and sound modes are usually overwhelmed by the orientational relaxation mode since the intensity of the last mode diverges toward the isotropic-nematic critical point. Thanks to the phase-coherent detection ability of our method, we have successfully observed the thermal diffusion and sound modes without the interference of incoherent critical orientational fluctuations.

015702-1 We numerically study phase-separation dynamics of symmetric mixtures of an isotropic liquid and a liquid crystal, incorporating nematohydrodynamics, for the first time. We find that the hydrodynamics not only accelerates the domain growth, but also leads to the breakdown of the morphological symmetry of the two phases, which occupy the same volume: The liquid-crystal-rich phase tends to form isolated domains. This symmetry breaking is revealed to be induced by the flow-alignment coupling due to the anisotropic shape of liquid crystal molecules (kinetic effects), and not by the elastic asymmetry (energetic effects).

Sawtooth crashes in an Ohmically heated plasma in the WT-3 tokamak have been observed by using soft x-ray computer tomography at three different poloidal cross sections around the torus. Initially, collapsing proceeds slowly with keeping the helical structure of an m = 1/n = 1 hot core around the torus. It accelerates as the helical hot structure is strongly deformed and fades away in the manner that the hot core at the high field side becomes obscure and disappears, while that at the low field side is deformed into a thin crescent aligned along the inversion circle, which survives even at the completion of the crash.

We found both nucleation-growth-type and spinodal-decomposition-type transformation from one liquid state to another in a "molecular liquid," triphenyl phosphite (TPP). Binodal and spinodal temperatures of this transition at ambient pressure were determined by the characteristics of morphological evolution, domain-growth kinetics, and rheological evolution. Furthermore, a distinct thermal signature of the glass transition of a second liquid was also detected in addition to that of an ordinary liquid. These findings strongly suggest the existence of a liquid-liquid transition; more precisely, a transformation of one supercooled liquid to a glassy state of another liquid, in TPP.

A new operational scenario of advanced tokamak formation was demonstrated in the JT-60U tokamak. This was accomplished by electron cyclotron and lower hybrid waves, neutral beam injection, and the loop voltage supplied by the vertical field and shaping coils. The Ohmic heating (OH) solenoid was not used but a small inboard coil (part of the shaping coil), providing less than $20%$ of total poloidal flux, was used. The plasma thus obtained had both internal and edge transport barriers, with an energy confinement time of 1.6 times H-mode scaling, a poloidal beta of 3.6, and a normalized beta of 1.6, and a large bootstrap current fraction ($g90%$). This result opens up a possibility to reduce, and eventually eliminate, the OH solenoid from a tokamak reactor, which will greatly improve its economic competitiveness.

Vitrification of a supercooled liquid is often characterized by the hypothetical kinetic instability point, the Vogel-Fulcher temperature T0, and the thermodynamic one, the Kauzmann temperature T(K). The widely believed relation T0 congruent with T(K) is regarded as the supporting evidence of a direct connection between the thermodynamics and kinetics of glass-forming liquids. Here we demonstrate that T(K)/T(0) systematically increases from unity with a decrease in the fragility, contrary to the common belief. This systematic deviation may be explained by a synergistic effect between the weaker cooperativity and the stronger tendency of short-range ordering in stronger glass formers.

Membranes are often used for material partitioning in biological systems and industry. Here we report a novel physical mechanism of particle partitioning using topological transformation of bilayer membranes. Upon phase separation of a homogeneous sponge phase of a membrane system into a dense sponge and a water phase, we found quite unusual partitioning behavior of particles into the cellar structure of a water phase. The compartments next to one having particles always have no particles, and those next to a compartment having no particles always have particles. We confirm that this partitioning is purely geometrically induced, and thus it may be universal.

Here we study the line defect in a hyperswollen lamellar phase of lyotropic liquid crystal by applying a laser trapping method. We have succeeded in directly measuring the tension of a single isolated line defect and the adhesion energy between two defects. We demonstrate a new possibility of intentional patterning of various defects by direct optical manipulation. Furthermore, local rheological measurements provide information on the membrane organization around a particle and also evidence suggesting that flow in a lamellar phase has a two-dimensional nature.

We study the nonlinear rheological behavior and the microscopic particle dynamics for a colloidal glass, to see whether recently developed models for driven glassy systems can be applied to predict the rheology. Qualitatively, all the findings predicted by the models can be retrieved in our system. Notably, the viscosity decreases strongly with the shear rate. Since it is difficult to predict non-Newtonian viscosities of colloidal systems due to long-ranged hydrodynamic interactions, this shows the promise of this approach for predicting flow behavior. In addition, the measurements allow us to relate the microscopic diffusion dynamics to the macroscopic viscosity of the system.

We demonstrate here experimental evidence of the shear-induced sponge-to-lamellar transition in a hyperswollen lyotropic system. We also show that shear flow suppresses the first-order nature of the transition, especially above a critical shear rate. The phenomena are probably caused by two effects: (i) Symmetry-breaking shear field reduces large fluctuation effects associated with the degeneracy of the possible orientations of the ordered state. (ii) Shear flow favors the lamellar phase more than the sponge phase because the interconnected membrane structure obstructs flow. The sponge structure is destabilized for shear flow strong enough to tear off the passage of the membrane.

We demonstrate here the possibility that strong dynamic asymmetry between two components of a fluid mixture generally leads to unusual phase separation (``viscoelastic phase separation''), which does not belong to the conventional classification of phase separation. In addition to polymer solutions, a mixture, one of whose components is close to its glass transition, transiently exhibits a morphology peculiar to viscoelastic phase separation, namely, a spongelike continuous pattern of the minority phase. This pattern is likely the morphology universal to elastic and viscoelastic phase separation in a dynamically asymmetric mixture containing a fluid as at least one of its components.

We have developed a new method of phonon spectroscopy using forced Brillouin scattering: A scanning interference pattern produced by intersecting two cw lasers generates the density variation (acoustic phonons) through the thermal expansion for a light-absorbing liquid. When the dispersion relation of phonons is satisfied, phonons are generated resonantly in the liquid. Continuous tuning of the frequency difference between the two lasers enables us to measure a resonance spectrum of light-excited phonons using light scattering phenomena. We demonstrate that this resonance spectrum is equivalent to the Brillouin spectrum of thermal phonons both experimentally and theoretically.

Shear effects on a nonionic lyotropic smectic liquid crystal has been studied by the simultaneous measurements of the structure factor and the viscosity, in a hyperswollen regime. We have found that (i) the flow behavior of the smectic phase is intrinsically non-Newtonian and (ii) the shear flow decreases the average interlayer spacing and increases the layer displacement fluctuations. The behavior could be explained by the following physical picture: The shear flow causes the elastic deformation of the fluctuating membranes. The resulting suppression of the fluctuations leads to the increase in the number density of layers and the weakening of the steric repulsion.

It is found that for a geometrically confined, symmetric binary mixture the secondary phase separation is spontaneously induced by the extremely quick reduction of the interface area caused by the hydrodynamics unique to bicontinuous phase separation. This hydrodynamic coarsening is likely too quick for the concentration diffusion to establish the local equilibrium. This phenomenon is generally observed for nearly symmetric binary mixtures confined both in one-dimensional and in two-dimensional capillaries, under deep quench conditions. This interface quench effect and the resulting double phase separation could exist even for bicontinuous phase separation in bulk.