Hiroya Kodama

Reconsideration of the renormalization-group theory on intermittent chaos

Abstract The renormalization-group theory has made us believe that the average laminar length for type III intermittency is inversely proportional to the control parameter. However this does not agree with the result of numerical computations. This contradiction is removed through studying the scaling relation for the length of each laminar.

Real-space mean-field approach to polymeric ternary systems

Phase separated structure of ternary blends of A and B homopolymers and symmetric AB diblock copolymer is investigated using a lattice (real-space) self-consistent field theory. This paper includes the detailed description of our published results [Kodama, Komura, and Tamura, Europhys. Lett. 53, 46 (2001)] as well as more extended calculations. We consider the symmetric case, namely, (i) both A and B homopolymers have the same degree of polymerization NA=NB; (ii) AB diblock copolymer of length NAB is symmetric; (iii) average volume fractions of A and B homopolymers are equal. We looked into the influence of relative chain lengths α=NA/NAB on the phase separated structure. Our numerical simulations are performed in the real space without assuming the symmetry of the structure a priori. For the fixed copolymer length and α<1, the typical length scale of the microphase separated structure become smaller for relatively shorter homopolymer chains (small α). In other words, the homopolymers becomes more efficie...

Statistical mechanics and crossover scaling for Pomeau-Manneville type intermittent chaos

Abstract On the basis of the statistical mechanics formalism, we study analytically intermittent chaos, concerning ourselves with the q -phase transition near the bifurcation point. The crossover exponents for the Renyi entropies, the singularity spectrum and the q -weighted rate of bursts are rigorously obtained.

Mean-field studies of block copolymer/homopolymers blends

Equilibrium structure of ternary blends of A and B homopolymers and symmetric AB block copolymer is investigated using self-consistent field theory by means of computer simulations. We demonstrate that bicontinuous polymeric microemulsions (PME) can appear as a result of microphase separation without any long-range order.