Critical anomaly of multicomponent surfactant solutions, cationic surfactant (BTDAB), nonionic surfactant (C₁₄E₇), and anionic surfactant (SDS) with the addition of salts, were examined in terms of the renormalized Ising model and double critical behaviors by means of light scattering, turbidity, viscosity, and coexistence curve measurements. Fisher's renormalized Ising model behavior was observed clearly. In case of SDS with butanol and NaCl, a closed loop type phase diagram appeared. Approaching the double critical point, crossover to doubling of the critical exponents was obtained, and the critical universality was ascertained including the double critical nature. Dynamic critical behaviors were well reproduced by the modified dynamical droplet model in a unified manner taking the finite micellar size effect.

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The blue phases (BPs) are kinds of liquid crystal (LC) phases that appear in a temperature range between a chiral nematic phase and an isotropic liquid phase. Since BPs have a three-dimensional cubic structure with lattice periods of several 100 nm, they exhibit the selective Bragg reflections in the range of visible light corresponding to the cubic lattice. From the viewpoint of the application, although BPs are of interest for fast light modulators or tunable photonic crystals, it has been a problem that the temperature range of BPs is very narrow, usually less than a few K. The stabilization of BPs was shown over a larger temperature range than 60 K (260 K-326 K) across the room temperature. Furthermore, an electro-optical switching with a response time on the order of 10^-4 s was demonstrated for the stabilized BPs at room temperature. Here, fundamental properties and recent topics on BPs are reviewed.

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