Tohru Okuzono

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Drying processes of polymer solutions on a solid substrate enclosed by bank are studied in the slow limit of the solvent evaporation. A simple model is proposed to examine the final shape of the film after drying. Analytical expressions of the final shape in terms of the initial parameters are obtained. It is shown that the craterlike and basinlike shapes(More)
A simple model is proposed for the skin formation in the evaporation process of a polymer solution at a free surface. In this model the skin is regarded as a gel phase formed near the free surface, and the dynamics is described by a diffusion equation for the polymer concentration with moving boundaries. The equation is solved both analytically and(More)
Drying processes of polymer solutions on a solid substrate are studied, based on the two-fluid model for polymer solutions or gels. A simplified model which can describe a skin formation process is proposed to examine the diffusion process of polymers and the evaporation process of solvent. The authors show that when a skin (gel phase) is formed, the(More)
We studied how the addition of surfactants alters the drying and film formation processes of polymer solution droplets with contact lines strongly fixed by bank structures. We found that even if the amount of surfactant is quite small, it drastically changes the final profile of the polymer film from a ringlike profile to a flat profile. This property is(More)
Uniformly shaped, charged colloidal particles dispersed in water form ordered "crystal" structures when the interaction between the particles is sufficiently strong. Herein, we report the behavior of "impurity" particles, whose sizes and/or charge numbers are different from those of the bulk, on addition to the charged colloidal crystals. These impurities(More)
We report on the controlled clustering of oppositely charged colloidal particles by the adsorption of ionic surfactants, which tunes charge numbers Z of particles. In particular, we studied the heteroclustering of submicron-sized polystyrene (PS) and silica particles, both of which are negatively charged, in the presence of cetylpyridinium chloride (CPC), a(More)
We investigate the effect of temporal modulation on the spatiotemporal patterns produced by phase separation in chemically reactive ternary mixtures. The temporal modulation is introduced by making one of the reaction rates periodic in time. Our main concern is the stability of traveling waves, which appear above a Hopf-type bifurcation at a finite wave(More)
An alternative model of phase-separating reactive mixtures is proposed. In this model both phase separation and chemical reactions simultaneously take place and a traveling coherent structure can be formed through a Hopf bifurcation at a finite wave number. Numerical simulations show that, depending on the parameters, either lamellar or hexagonal structures(More)
Photoinduced orientational waves in illuminated liquid-crystalline monolayers is one of the most remarkable far-from-equilibrium phenomena that systems of soft condensed matter exhibit. We model this behavior from a phenomenological point of view, taking the anisotropic photoexcitation of molecules into account. Numerical simulations as well as theoretical(More)
A model of phase separation of chemically reactive ternary mixtures is constructed. In this model, spatially periodic structures that coherently propagate at a constant speed emerge through a Hopf bifurcation at a finite wave number. It is shown by computer simulations that both lamellar and hexagonal structures undergo a coherent propagating motion in two(More)