Takuya Higashi

Anisotropic Properties of Aligned

Uniaxially aligned films of thiophene-based polymers were successfully fabricated by a novel film-forming method using the capillary action of polymer solutions without applying any mechanical or thermal stress to the polymers. Unique optical and electrical anisotropies were studied in the poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene) (pBTTT) and poly(2,5-bis(3-alkylthiophene-2-yl)thieno[2,3-b]thiophene) (pBTCT) films fabricated by the method. Moreover, the improvements of the optical and electrical properties of the aligned polymer films by thermal annealing were also demonstrated.

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OBJECTIVES To determine the reliability of an assessment of joint angular velocity using a gyro-sensor and to examine the relationship between ankle angular velocity and physical functions. DESIGN Cross-sectional. SETTING Kinesiology laboratory. PARTICIPANTS Twenty healthy young adults (mean age, 22.5 y) and 113 community-dwelling older adults (mean age, 75.1 y). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Maximal ankle joint velocity was measured using a gyro-sensor during heel-rising and jumping with knee extended. The intraclass correlation coefficient (ICC) was used to determine the intertester and intratester reliability. The Pearson correlation coefficient was used to examine the relationships between maximal ankle joint velocity and isometric muscle strength and isokinetic muscle power in young adults and also to examine the relationships between maximal ankle joint velocity and functional performance measurements such as walking time in older adults. RESULTS High reliability was found for intertester (ICC=.96) and intratester reliability (ICC=.96). The data from the gyro-sensor highly correlated with muscle strength (r range, .62-.68; P<.01) and muscle power (r range, .45-.79; P range, .01-.05). In older subjects, mobility functions significantly correlated with the angular velocity of ankle plantarflexion. CONCLUSIONS Measurement of ankle angular velocity using a gyro-sensor is both reliable and feasible, with the results representing a significant correlation to muscle power and performance measurements.

-Conjugated Polymer Films Fabricated by Capillary Action and Their Post-Annealing Effects

The effects of solvent vapor on spin-coated films of a polymorphic phthalocyanine derivative were investigated. Growth of single crystal films via redissolving organic films under solvent vapor was revealed by in situ microscopic observations of the films. X-ray diffraction measurement of the films after exposing to solvent vapor revealed the phase transition of polymorphs under solvent vapor. The direction of crystal growth was clarified by measuring the crystal orientation in a grown monodomain film. The mechanism of crystal growth based on redissolving organic films under solvent vapor was discussed in terms of the different solubilities of the polymorphs.

The Feasibility of Measuring Joint Angular Velocity With a Gyro-Sensor

A method of uniaxial crystal growth in wet-processed thin films of the mesogenic phthalocyanine 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2) is proposed. It consists of applying geometrically linear thermal stimulation to a supercooled state of liquid crystalline C6PcH2. The thin film showed highly ordered molecular stacking structure and uniaxial alignment over a macroscopic scale. An explanation of the crystal growth mechanism is suggested by taking into account the temperature range of crystal growth and the hysteresis property of C6PcH2 in the phase transition.

Single crystal growth in spin-coated films of polymorphic phthalocyanine derivative under solvent vapor

Thermal annealing effects of the aligned thiophene-based polymer films were studied. Aligned poly2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene (pBTTT) and poly2,5-bis(3-alkylthiophene-2-yl)thieno[2,3-b]thiophene (pBTCT) films were fabricated by utilizing capillary actions of polymer solutions. The optical anisotropies of the aligned films were enhanced by thermal annealing at temperatures below the phase transition. The differences in the optical anisotropies between pBTTT and pBTCT were discussed by taking the lamellar stacking structures in the aligned films and phase transition into consideration.

Uniaxial crystal growth in thin film by utilizing supercooled state of mesogenic phthalocyanine

Polymer blending effects on the properties of the mesogenic phthalocyanine thin films fabricated by heated spin-coating method were demonstrated. The spin-coated films of 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2) blended with poly(3-hexylthiophene) (P3HT) were prepared by controlling the temperatures of substrates and solutions with the mixed material, and the morphology and optical property of the fabricated film were studied. In the case of the low composite ratio of P3HT, the wide crack lines found in pure C6PcH2 films disappeared while maintaining the uniaxial aligned optic axis direction in the large-area with the diameters of exceeding 1 mm. The polymer blend effects were discussed by taking the anisotropic optical absorption and molecular stacking structure in the films into consideration.