We have tried to measure purely mechanical sensory feelings of cosmetics with using commercial rheometers. To obtain mechanical parameters relating to the score of sensory feeling, we have to measure under the same condition during the evaluation of sensory feeling, that is, the movement of finger and the structure of cosmetics. Sensory feelings of madeup skin can also be measured using stress-controled rotaional rheometers if we fix a measuring part of human body without stress.
Understanding the rheological properties of cosmetic emulsions is helpful to design a new product with a desired sensory feeling. Emulsions with high dispersoid concentration have yield point, but high concentration linear polymer solution dose not. This was qualitatively explained with the difference in mobility at the contact point between dispersoids.

In order to develop the efficient thermal energy transportation systems, the dilute solution of drag-reducing surfactants and fine particle dispersion systems have been investigated. Based on the rheological characteristics of the surfactant solution systems, it was revealed that the mechanism of drag reduction phenomena basically occurs due to the laminarization of the flow. The technologies of preventing heat transfer reduction of surfactant solution were also developed. Both the micelle squeezer system and the system using the Barus effect of the visco-elastic surfactant solutions were studied. The further study on the thermal energy transportation has been performed on the latent heat transportation technologies with phase change material slurries. In order to increase the efficiency of the high temperature latent heat transportation, hardshell microcapsules containing phase change materials were fabricated. Related to this, the dispersion model of fine particles was also developed. With these activities, thermal grid, which is a thermal energy supply system for very wide region, can be realized in the near future.

Recently, tough polymer gels have been developed by introducing dynamics cross-links into polymer networks. Here, I review the molecular origins of mechanical and fracture properties for two types of dynamically cross-linked polymer gels, self-healing gels with reversible cross-links and slide-ring gels cross-linked by ring molecules. Self-healing gels show large mechanical hysteresis and high toughness due to the breaking/healing of reversible bonds. The fracture toughness of slide-ring gels is dominated by the sliding distance of slidable cross-links. Furthermore, I introduce a damageless reinforcement strategy to realize tough and instantly recoverable hydrogels utilizing strain-induced crystallization (SIC).

The flow properties of rod-like micellar (surfactant) solutions passing through circular orifices with an inner diameter of 100 µm to 1.0 mm were investigated in this study. Rod-like micellar solutions comprising a cationic surfactant [oleyl bis(2-hydroxyethyl)methylammonium chloride; Lipothoquad O/12] and a counterion (sodium salicylate; NaSal) were used. The molar concentration ratio was varied from 0.10 to 100 to change the rheological properties of the test fluid, which were evaluated using a strain-controlled rheometer and a capillary viscometer. All the rod-like micellar solutions exhibited non-Newtonian viscosity except those with molar concentration ratios of 0.10 and 0.15, which instead exhibited Newtonian viscosity consistent with that of water. In the dynamic viscoelasticity measurements, the relaxation times of the rod-like micellar solutions with molar concentration ratios other than 0.10, 0.15, and 100 were calculated by extrapolating slopes 1 and 2. For each orifice, the experimental results with water alone agreed with theoretical predictions within the experimental errors (thereby demonstrating the validity of the experimental setup). In dimensionless graphs arranged by generalized Reynolds number, the dimensionless pressure drops for the molar concentration ratios of 0.10, 0.15, 50, and 100 agreed well with the experimental (predicted) values for water. For the other rod-like-micellar solutions, the dimensionless pressure drop was larger than that for water. In other words, the rheological and flow properties were found to change with the molar concentration ratio. To discuss the experimental results in depth, the flow resistivity was calculated and was largest for the molar concentration ratio of 1.0. The increase in pressure drop was also largest for molar concentration ratio of 1.0. The Weissenberg number was used to summarize the experimental results in terms of elastic properties, and the characteristic increase in pressure drop was found to occur at a Weissenberg number on the order of 10⁰, at which elasticity was strongly expressed.

In this study, we synthesized low molecular weight organogelators, pyromellitamides (PMDA-R) and investigated the effect of product composition on their viscosity-increasing ability, focusing on the differences between synthetic conditions and those used when scaling up production. We regarded PMDA-2C₈/oleyl as a target material and synthesized the compound in both a 50 mL flask and a 1 L flask as laboratory-level syntheses. The effects of both temperature and stirring conditions on the composition and performance of the synthesized organogelators were evaluated by the steady flow characteristics and by the viscoelasticity of the solutions dissolved in isododecane. The experimental results showed that increasing the reaction temperature to shorten the reaction time resulted in significant differences in product composition. Although the rheological properties of the solutions showed similar trends in some cases, morphological observation by transmission electron microscopy (TEM) revealed that the self-organizing structures formed by the different compositions were completely different from each other. Synthesis was also carried out in a commercial-scale reactor. This study provided useful information for ‘process intensification’ by focusing on changes in products during scale-up.

Relaxation of the stress and the birefringence after a single-step deformation has been examined separately for dextran solutions and films. First, the stress-optical coefficient of the rubber component (C_R) has been determined from the measurement of dextran solutions in an ionic liquid using a homemade apparatus for the oblique-light method and a rheometer. Second, the stress-optical coefficient of the glass component (C_G) has been obtained by examining dextran films with an apparatus for simultaneous measurements of the birefringence based on polarization modulation method and the stress after uniaxial stretching. The value of C_R = 3.0 × 10⁻⁹ Pa⁻¹ has been used as a preset value in the estimation of C_G = 2.2 × 10⁻¹² Pa⁻¹. The values of C_R and C_G for dextran, a branched D-glucan, have been compared with those for pullulan, another D-glucan partly having common α-(1,6) linkage; C_R is roughly twice as much as that for pullulan, while C_G has the opposite sign. As far as available information, the linkage including the branching of D-glucan seems influential especially in C_G.

Although the entanglement network among polymers has been widely investigated, the spatial distribution of entanglement nodes has been rarely discussed. In this study, we obtained the radial distribution functions (RDFs) for the entanglement nodes from the snapshots of multi-chain slip-link simulations. The model employed in this study is the primitive chain network (PCN) model, which has been validated to reproduce the entangled polymer dynamics semi-quantitatively. The statistics of captured entanglement networks were compared to those reported for the primitive path network extracted by the CReTA procedure from the full-atomistic molecular model of a polyethylene melt. In the range of distance longer than the average strand length, the network structure from PCN does not show any structural correlation, and the intra-chain correlation is close to that for Gaussian chains with non-interacting slip-links. These features are consistent with the CReTA network and the conventional assumptions made for single-chain models. Meanwhile, in the short-range, the structural correlation in PCN is much weaker than that in CReTA. This discrepancy is because the short-range structure in PCN is realized as a result of imposed fluctuations, whereas it is determined by the minimization of the primitive path in CReTA.