Conducting polymer is a promising material for softactuators in human friendly robots. The large deformation is induced by electrochemical (EC) oxidation and reduction with low voltage operation. The contraction ratio (EC strain) is determined by the size and number of inserted anions. In this report, the origin of contraction force (EC stress) has been discussed from the measurements of strain and creeping under tensile loads in electrodeposited polypyrrole films. The blocking stress is more than 30 MPa. The EC stress relates to the elasticity of films and depends on electrolytes for preparation and operation of actuation. EC strain is found to be almost constant until certain level of load stress in films prepared with larger anion and operated by smaller anion, indicating muscle like behavior.
Single crystals of SrTiO3 (100) and 0.5% Nb-doped SrTiO3 (100) were irradiated with 80 MeV and 200 MeV 136Xe14+ swift heavy ions at grazing incidence. The angle between the sample surface and the beam was less than 2˚. The irradiated surfaces were examined by field-emission scanning electron microscopy (FE-SEM). On the SrTiO3 surface after osmium coating, chains of nanohillocks are observed along the ion path as reported in previous atomic force microscopy (AFM) study. In contrast, black lines accompanied by hillocks are observed on the Nb-doped SrTiO3 surface. When the Nb-doped SrTiO3 was coated with osmium, the chains of nanohillocks similar to the ones observed for SrTiO3 were observed instead of black lines. The result suggests that the black lines are depressed regions (grooves). On this basis, we proposed a new model of the hillock chain formation in the framework of Rayleigh instability. The present model assumes that the outmost surface near ion trajectory is molten, the molten column is necked at nearly equal distance interval, and finally the separated segments form individual spheres. The spheres correspond to hillocks, and the traces of molten zones would be grooves.
We examined the metal ion-responsive gelation of ionic liquid which are synthesized from (S)-nicotine. The nicotine based ionic liquid have low glass transition points, and their viscosities are comparatively low levels as ionic liquids. In case of addition of Cu(II) and Co(II) ions to the ionic liquid, the resulting metal complexes formed gels. The Cu(II)-nicotine based ionic liquid complex showed a swelling property even in the addition of three times the volume of methanol to the Cu(II)-ionic liquid gel, and the Cu(II) ion is easily recovered from the metallogel by the addition of water. Such a metal ion-responsive phase change enable application in various fields including the process of the metal extraction and the organic synthesis using metal catalysts.
The preparation of phthalocyanines are difficult because of their poor reactivity of reactants. In order to improve the reactivity, safety, and green technology in the preparation of the phthalocyanine (4-tBuPcH2), several types of ionic liquids were applied as reaction medium. In the case of using [C2-OHm2im][Br] as a reaction media, 4-tBuPcH2 was obtained in the highest yield (38%). These results suggested that the hydroxy groups, anion species, and stability of cations of ionic liquids are important to synthesis of 4-tBuPcH2. In addition, [C2-OHm2im][Br] was reused without any loss of its catalytic activity.
Conductive inorganic-organic hybrid monomers and polymers were successfully obtained by using a polymerizable imidazolium ionic-liquid with a methacryloyl group (denoted as MAImC1) and inorganic polyoxometalate cluster anion ([SiW12O40]4−, SiW12). The MAImC1-SiW12 hybrid monomer was synthesized as single crystals, the molecular and crystal structures of which were revealed by single crystal X-ray analysis. The obtained MAImC1-SiW12 hybrid monomer was found to be polymerized by a radical polymerization using AIBN as an initiator to form inorganic-organic homo- and copolymers. The hybrid copolymers of MAImC1-SiW12 polymerized with another polymerizable ionic-liquid (denoted as MAImC8) exhibited high conductivity of 10−3 S cm−1 order under humidified condition at near room temperature of 313 K.
This paper proposes a numerical method for estimating the ultimate clamp force of lag screw timber joints with steel side plates based on the pull-out strength and thread friction coefficient of the lag screw. Lag screw tightening tests and pull-out tests were performed using timber samples from three different wood species, for three different screw insertion angles with respect to the annual ring, to evaluate how well the predictions matched the observed empirical data. Ratios of observed to estimated ultimate clamp force ranged from 0.9 to 1.3, suggesting the proposed method well approximated the empirical trend. However, it was found that the proposed method was overestimated depending on the degree of female thread formation in the wood, so it was indicated that the reduction coefficient should be taken into consideration.
We present the aggregation effects of the precipitant chloride salts with different cations, namely KCl, MgCl2 and CaCl2, on hen egg-white lysozyme (HEWL) crystallization, characterized by forward static light scattering at small angles. The pre-crystalline HEWL solutions with the chloride salts exhibit non-integer power-law profiles of forward light scatterings, indicating formation of fractal aggregates. The fractal aggregates with a closely packed structure were formed in the solutions with the chloride salts under crystallization conditions. The crystallization ability ranking of the cations almost agrees with the Hofmeister series. CaCl2 presented the slowest crystal growth of HEWL, owing to the weakest effect of aggregation on HEWL among the chloride salts studied.