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ABSTRACT: The melting point and viscosity of [CF(3)OCF(2)CF(2)BF(3)](-) based ionic liquids are significantly lower than those of [CF(3)CF(2)CF(2)CF(2)BF(3)](-) based ionic liquids, indicating that the oxygen atom plays a key role in the preparation of low-melting and low-viscosity ionic liquids.
Chemical Communications 03/2010; 46(10):1730-2. · 6.17 Impact Factor
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ABSTRACT: The purpose of this paper is to study an electrochemical property and actuation mechanism of an actuator using same electrolyte and three different electrode (carbon nanotube (SWNT)/ionic liquid (IL)/polymer gel electrode, SWNT/IL gel electrode and Au paste as an electrode) in air, and to investigate the actuator which performs much better. We developed a PVdF(HFP)-IL gel actuator using only Au paste as an electrode layer in air (non-Faradaically driven type), i.e., the electrode layer was not composed of polymer, IL and SWNT, and the electrolyte layer was composed of polymer and IL. Furthermore, in the previous paper, the electrode layers that laminate the electrolyte layer expanded or contracted, giving rise to a bending motion of the actuator strip (Fig. 1(c) type), in this paper, we showed that, at our conventional actuator (Fig. 1(c) type) and actuator with non-polymer-supported bucky gel electrodes containing internal IL (Fig. 1(b) type), the electrolyte layer also expand or contract, giving rise to a bending motion of the actuator. As a result, we show that polymer-IL gel of the electrolyte is important factor in the field of the low-voltage electroactive polymer (EAP) actuator, and we are considered that these results become the important design principle of the low-voltage EAP actuator.
Sensors and Actuators B-chemical - SENSOR ACTUATOR B-CHEM. 01/2010; 145(2):775-780.
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ABSTRACT: A bucky-gel actuator based on active electrodes composed of activated carbon nanofibers (ACNFs), ionic liquids (ILs) and poly (vinylidene fluoride-co-hexafluoropropylene (PVdF(HFP)) as polymer support have been developed (ACNF-actuator). The frequency dependence of the displacement was measured for the actuators containing seven kinds of ILs. The frequency responses of the ACNF-actuators were one order of magnitude lower than those of the SWCNT-actuators. The reason for this is attributed to the lower conduc-tivity of the ACNF-electrode. In order to improve the response of the ACNF-actuator, the electrode of the actuator was optimized by mixing the ACNFs with SWCNTs (ACNF–SWCNT electrode) or vapor grown carbon fibers (VGCFs) (ACNF–VGCF electrode) for the purpose of increasing the conductivity of the electrode. We have improved the performance of the actuator by optimizing the ratio of the two carbons. We are thus able to tune nano-carbon materials for specific applications of the electromechanical actuator.
03/2009;
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Advanced Materials 02/2009; 21(16):1582 - 1585. · 13.88 Impact Factor
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ABSTRACT: The alignment behaviour of triphenylene‐based compounds possessing fluoroalkylated and alkyl side chains was investigated for the hexagonal columnar (Colh) mesophase on polyimide‐, cetyltrimethylammonium bromide (CTAB)‐, and indium tin oxide‐coated glass substrates by polarizing optical microscopy. It was found that 2,6,10‐trinonyloxy‐3,7,11‐tris(1H,1H,2H,2H,3H,3H‐perfluorononyloxy)triphenylene and 2,6,11‐trinonyloxy‐3,7,10‐tris(1H,1H,2H,2H,3H,3H‐perfluorononyloxy)triphenylene exhibit spontaneous homeotropic alignment on these substrates. On the other hand, it was found that 2,6,10‐triheptyloxy‐3,7,11‐tris(1H,1H,2H,2H,3H,3H‐perfluoroheptyloxy)triphenylene, 2,6,11‐triheptyloxy‐3,7,10‐tris(1H,1H,2H,2H,3H,3H‐perfluoroheptyloxy)triphenylene, 2,6,10‐trihexyloxy‐3,7,11‐tris(1H,1H,2H,2H,3H,3H‐perfluorohexyloxy)triphenylene, 2,6,11‐trihexyloxy‐3,7,10‐tris(1H,1H,2H,2H,3H,3H‐perfluorohexyloxy)triphenylene, 2,6,10‐tributyloxy‐3,7,11‐tris(1H,1H,2H,2H,3H,3H‐perfluorobutyloxy)triphenylene and 2,6,11‐tributyloxy‐3,7,10‐tris(1H,1H,2H,2H,3H,3H‐perfluorobutyloxy)triphenylene do not show such spontaneous homeotropic alignment on these substrates. These results indicate that the spontaneous homeotropic alignment of the Colh phase could be easily attained by the introduction of an appropriate length of the fluoromethylene chains in the peripheral parts of discogens. Therefore, it is suggested that the balance between the hydrocarbon part including the triphenylene core and the fluoroalkyl part determines the alignment control behaviour. Furthermore, it was found that alignment behaviour is independent of the rotation symmetry of the chemical structure but is dependent on the number of fluoromethylene chains in the chemical structure.
Liquid Crystals. 04/2007; 34(4):447-455.
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ABSTRACT: Two types of homologues (symmetrical and asymmetrical in rotational symmetry) of novel triphenylene compounds possessing fluoroalkyl and alkyl side chains were synthesized via an alternative method. X‐ray diffraction and DSC measurements showed that these homologues are thermotropic liquid crystals with a hexagonal columnar (Colh) mesophase. The phase transition temperatures (Colh–Iso) for both symmetrical and asymmetrical fluoroalkyloxytriphenylenes increase to about 180°C, and are independent of fluoromethylene chain and the rotational symmetry of chemical structure. The Colh phase of symmetrical and asymmetrical fluoroalkyloxytriphenylenes possessing three fluoroalkyl side chains are more stable than fluoroalkyloxytriphenylenes possessing six fluoroalkyl side chains and alkyloxytriphenylenes. The X‐ray diffraction patterns for symmetrical and asymmetrical fluoroalkyloxytriphenylenes, fluoroalkyloxytriphenylenes and alkyloxytriphenylenes in the wide‐angle region are compared.
Liquid Crystals. 03/2007; 34(3):311-324.
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Molecular Crystals and Liquid Crystals. 08/2006; 437(2005: pp. 81/[1325]–88/[1332]):81/[1325]-88/[1332].
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ABSTRACT: We studied the mechanism of surface anchoring of rodlike molecules on substrates with the surfaces corrugated at molecular scale by molecular-dynamics simulation. We constructed a model for substrates that can have anisotoropic topographical patterns such as corrugation. The structural and thermodynamic properties of rodlike molecules on the corrugated surfaces, including the elastic and anchoring properties, were calculated and the influence of the surface structure on the anchoring was discussed. We found that the rodlike molecules are aligned along the grooves of the corrugated surfaces guided by the anisotropic molecular interaction between the molecules and the corrugated surface. The strength of anchoring was found to be increased when the period of corrugation is decreased at molecular level.
The Journal of Chemical Physics 02/2006; 124(3):034704. · 3.33 Impact Factor
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ABSTRACT: Alignment behavior of a discotic liquid crystalline triphenylene (C8OBTP) on substrates coated with self-assembled monolayers (SAMs) of alkanethiol and asymmetrical alkyl disulfide was investigated by polarized microscopy. Discotic nematic (ND) and rectangular columnar (Colr) phases of C8OBTP shows a different alignment behavior depending on the element of SAMs. C8OBTP exhibits a fan-shaped texture on an alkanethiol SAM in Colr phase, while it has a tendency to show a planar alignment on asymmetrical alkyl disulfide SAM. The different elements of the SAM could influence the alignment behavior of discotic liquid crystal distinctly even in columnar mesophase which has highly self-cohesive forces of systems.
Molecular Crystals and Liquid Crystals 01/2004; 412(1):229-236. · 0.58 Impact Factor
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Chemical Communications - CHEM COMMUN. 01/2003;
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Chemistry Letters - CHEM LETT. 01/2003; 32(3):214-215.
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ABSTRACT: Infrared photo-induced alignment change of liquid crystal domains was investigated for a hexagonal columnar mesophase of liquid crystalline triphenylene derivative. A uniform and anisotropic change of domains was observed when a polarized infrared light corresponding to the wavelength of the absorption band of triphenylene core was irradiated. IR absorption dichroism is induced as a result of the reorientation of triphenylene core part. The texture observation and polarized microscopic FT-IR spectra show that a change of the molecular alignment occurred, and the direction of columns depends on the polarizing angle of an irradiated infrared light. This technique could provide a novel technology to control the columnar alignment of supra-molecular systems.
Thin Solid Films · 1.89 Impact Factor
