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We herein report a novel, short asymmetric synthesis of (−)-dehydro-exo-brevicomin (DHB, 1), a sex pheromone isolated from house mice, in 44% overall yield, the highest yield reported so far, over eight steps from trans-3-hexen-1-ol (7). We successfully prepared the target molecule (−)-1 from spontaneous intramolecular acetalisation after the photoisomerisation of trans-enone 6, which generated the corresponding cis-enone 5in situ, the possible biosynthetic precursor of DHB.

Composite particles consisting of elastic silicone and glassy poly(methyl methacrylate) (PMMA) were prepared. Seeded polymerization of methyl methacrylate (MMA) was carried out in the presence of silicone elastic particles, which were prepared via a radical-mediated thiol–ene click reaction between thiol-terminated silicone oil and a trifunctional allyl compound in a suspension system. The obtained particles exhibited a sea-island structure comprising small PMMA domains and a silicone matrix, and the size of the PMMA domains could be controlled via the polymerization temperature. Moreover, core–shell composite particles consisting of a silicone core and PMMA shell were successfully prepared using highly cross-linked silicone seed particles. Interestingly, the morphology of the composite particles could be alternated between sea-island and core–shell structures by controlling the annealing temperature. Microcompression tests indicated that, the hardness of the composite particles also can be changed: the hardness of sea-island composite particles was similar to the silicone particles, that of the core–shell particles was more than seven times greater than that of the silicone particles.

Fibres composed of carbon nanotubes (CNT) can be used to make lightweight materials with high mechanical strength and electrical conductivity. However, the reported properties have been much poorer than those of the individual CNT. To address this discrepancy, it is necessary to elucidate the relationship between the fibres' structure and their properties. Here, we systematically investigated the CNT length and fibre density dependences of the electrical and the mechanical properties of CNT fibres produced by the wet-spinning method. The obtained specific conductivities of the fibres were almost proportional to the effective CNT lengths, whereas such correlations were less apparent for the fracture strengths and Young's moduli.

We herein report a novel, short asymmetric synthesis of (-)-dehydro-exo-brevicomin (DHB, 1), a sex pheromone isolated from house mice, in 44% overall yield, the highest yield reported so far, over eight steps from trans-3-hexen-1-ol (7). We successfully prepared the target molecule (-)-1 from spontaneous intramolecular acetalisation after the photoisomerisation of trans-enone 6, which generated the corresponding cis-enone 5in situ, the possible biosynthetic precursor of DHB.

A route that has resulted in the synthesis of preparaherquamide, (+)-VM-55599, and premalbrancheamide using a common intermediate is reported., A full account of our studies toward reverse-prenylated indole alkaloids that contain a bicyclo[2.2.2]core is described. A divergent route is reported which has resulted in the synthesis of preparaherquamide, (+)-VM-55599, and premalbrancheamide. An intramolecular Dieckmann cyclization between an enolate and isocyanate was used to forge the bicyclo[2.2.2]diazaoctane core that is characteristic of these molecules. The pentacyclic indole scaffold was constructed through a one-pot Hofmann rearrangement followed by Fischer indole synthesis. The utilization of our previously reported indole peripheral functionalization strategy also led to natural products including malbrancheamides B, C, stephacidin A, notoamides F, I and R, aspergamide B, and waikialoid A. Ultimately, the divergent route that we devised provided access to a wide range of prenylated indole alkaloids that are differently substituted on the cyclic amine core.

Azaspirene and related congeners, which possess various biological activities, have a unique spirocyclic core structure. However, there are few studies on the chemical properties of (-)-azaspirene, despite the fact that it may provide important insights into unveiling the biosynthetic pathway. Here, we report a nine-step chemical synthesis of an azaspirene analogue with a new finding that the natural (-)-azaspirene skeleton easily racemizes in neutral aqueous media.

We have developed stacked nanocarbon polymer actuators that are composed of several nanocarbon polymer actuator films using nonwoven fabric as insulation layers. The nonwoven fabric prepared through electrospinning methods has extremely-low-density structures, which do not significantly prevent the motions of each nanocarbon actuator layer. Therefore, stacking several thin nanocarbon polymer actuators using nonwoven fabric as insulation layers is expected to increase generated force without decreasing the displacement of a one-layer actuator. We have prepared stacked actuators with one, two, three, four, and seven layers using this method. The displacement and blocking force of these actuators are measured and compared with those of one-layer actuators of different thicknesses. Displacement is weakly dependent on the thickness of the actuator films of the stacked actuators. On the contrary, it decreases considerably as the thickness of the actuator film of the one-layer actuator increases. In both cases, blocking force is proportional to the thickness of actuator films. We have developed a stacked actuator model based on a trilayer actuator model and confirmed the experimental results using the model.

© 2017 Macmillan Publishers Limited, part of Springer Nature. Stephacidin A and its congeners are a collection of secondary metabolites that possess intriguing structural motifs. They stem from unusual biosynthetic sequences that lead to the incorporation of a prenyl or reverse-prenyl group into a bicyclo[2.2.2]diazaoctane framework, a chromene unit or the vestige thereof. To complement biosynthetic studies, which normally play a significant role in unveiling the biosynthetic pathways of natural products, here we demonstrate that chemical synthesis can provide important insights into biosynthesis. We identify a short total synthesis of congeners in the reverse-prenylated indole alkaloid family related to stephacidin A by taking advantage of a direct indole C6 halogenation of the related ketopremalbrancheamide. This novel strategic approach has now made possible the syntheses of several natural products, including malbrancheamides B and C, notoamides F, I and R, aspergamide B, and waikialoid A, which is a heterodimer of avrainvillamide and aspergamide B. Our approach to the preparation of these prenylated and reverse-prenylated indole alkaloids is bioinspired, and may also inform the as-yet undetermined biosynthesis of several congeners.

Neat carbon nanotube (CNT) fibers produced by wet spinning methods offers a potential for high-strength and electrically conductive lightweight materials. For improving their performances, it is necessary to understand how each manufacturing process affects the raw CNTs and implicates the effects in the fiber properties. Recently, we found that the lengths of the clean CNT channels can be estimated by far-infrared (FIR) spectroscopy based on the plasmon resonance model. In this paper, the relationship between the mechanical properties and electric conductivities of the neat CNT fibers, and the lengths of the constituent CNTs are systematically studied by using different types of single-walled CNTs (SWCNTs) with various diameters and different dispersing times. Irrespective of the type of CNTs or the tube diameters, Young moduli, fracture strengths, and electric conductivities of the CNT fibers were found to be related to the CNT lengths estimated from the FIR spectra. The results prove that the evaluation...

Electromechanically active polymers (EAP) behave as actuators, i.e., temporarily change their shape when subjected to electric stimulus. However, in applications where a steady state of an actuator is required for an extended period of time (e.g., displaying characters of Braille text), EAPs need an active driving signal. Shape memory polymers, on the other hand, can be fixed to a preferred shape using appropriate stimuli such as temperature change and mechanical stress. Combining the electromechanical properties with the shape memory functionality could increase the efficiency and utility of EAP materials. As bucky-gel actuators–-a subtype of EAPs–-have been reported to possess a quite characteristic viscoelastic response, this paper proposes to implement them as shape-fixable EAPs. We employ four different shape-fixing techniques, out of which two allow programming the bucky-gel actuator in a controlled direction without any external stress or temperature change. These shape-fixing methods utilize composite driving signal consisting of high-frequency section to generate Joule heating within the material while low-frequency rectangular component deforms the bucky-gel laminate. It is concluded that bucky-gel actuators can achieve steady deformation by using solely the electrical input. By using the proposed methods for adding the shape-fixing functionality to an existing EAP device, no constructional changes of the system are required.

Due to their soft polymeric backbone and metal-free compositions, bending electromechanically active bucky-gel laminates are attractive candidates for actuators in applications in a variety of fields such as medicine and space technology. However, the soft structure of these materials also proposes challenges to engineering new devices as the unorthodox composition requires that the developer really understands the mechanical nature of these actuators. As the composition of bucky-gel laminates includes porous polymer filled with ionic liquid but also carbon nanotubes, the viscoelastic nature and how it possibly affects actuator performance is of great interest. Several customised mechanical tests are implemented on both electrically active and inactive bending bucky-gel actuators to investigate their mechanical properties. It is reported that these materials are highly viscoelastic and their mechanical relaxation can be described by generalised Maxwell model for solids. Moreover, these viscoelastic effects are shown to depend on the level of input voltage, thus, altering the overall performance of the actuator. Temperature measurements reveal remarkable thermal dissipation during the actuation cycles, which, as the dynamic measurements demonstrate, alters the mechanical properties of bucky-gel actuators.

This review paper focuses on the recent studies of electroactive polymer actuators that have a triple-layered configuration composed of an ionic-gel electrolyte layer sandwiched by nano-carbon dispersed ionic-liquid gel electrode layers (bucky-gel actuator) for the purpose of development of practical devices. The review covers recent studies of the developments of the materials of the bucky-gel actuators and their electromechanical modeling. In the final section, the application to an ultra-thin and ultra-light Braille display based on the bucky-gel actuator is described. © 2013 Society of Chemical Industry

The development is described of an electromechanical bimorph actuator composed of ionic liquid gel sandwiched by electrochemically treated millimeter-long single-walled carbon nanotubes (SG-SWNT). Electrochemical doping of the SG-SWNT and electrochemical polymerization of polypyrrole on the surface of the SG-SWNT improved the performance of a previously reported actuator using non-treated SG-SWNTs. The conductivity of the SG-SWNT sheets treated at the anodic potential (doped) was found to be three times larger than that of the original film. The generated strain of the actuator prepared from the doped SG-SWNT sheets was increased compared to that prepared from non-doped sample. Moreover, the generated strain of the actuator from the doped SG-SWNT sheets swelled with ionic liquid (IL) was increased to twice that without ILs. The electropolymerization of pyrrole on the surface of the SG-SWNT sheet was carried out. The conductivity of the SG-SWNT was seven times larger after the electropolymerization. The ge...

Actuators were developed using activated multi-walled carbon nanotube (MWCNT)–ionic liquid (IL) gel electrodes, and were compared with non-activated MWCNT- and single-walled carbon nanotube (SWCNT)-based actuators, in terms of their electrochemical and electromechanical properties. Furthermore, the effects of variations in the IL on the electrochemical and electromechanical properties of the activated MWCNT–NH2/IL gel electrode actuators were investigated. The performance of the activated MWCNT–NH2 polymer actuator surpassed that of the SWCNT actuator, in terms of the strain and maximum generated stress. For the MWCNT–NH2 actuators, the strain and maximum generated stress were dependent on the IL species.

The electrochemical and electromechanical properties of poly(vinylidene fluoride- co -hexafluoropropylene) actuators developed using multi-walled carbon nanotube (MWCNT)-ionic liquid gel electrode containing manganese oxide (MnO 2 ) were compared with those using ionic gels with only-MWCNTs, with MWCNTs and ruthenium oxide (RuO 2 ) or with only-single-walled carbon nanotube (SWCNTs). The double-layer capacitance of the MWCNT electrode containing MnO 2 was larger than the one with the MWCNT electrode containing RuO 2 , only-MWCNTs or only-SWCNTs. Furthermore, the MWCNT electrode containing MnO 2 exceeded the performance of the other three actuators in terms of both strain and maximum generated stress. Both MWCNTs and MnO 2 were required to produce large strain and quick response actuators that surpassed the performance of the polymer actuator containing only-SWCNTs.

The electrochemical and electromechanical properties of actuators developed using a non-activated multi-walled carbon nanotube (MWCNT)–ionic liquid (IL) gel electrode containing ruthenium oxide (RuO2) were compared with only-MWCNT and only-single-walled carbon nanotube (SWCNT) based actuators. The double-layer capacitance of the non-activated MWCNT electrode containing RuO2 was larger than that of the only-MWCNT electrode. The non-activated MWCNT polymer actuator containing RuO2 surpassed the performance of the only-MWCNT and only-SWCNT actuators in terms of the strain and maximum generated stress. Both MWCNTs and RuO2 were required to produce large strain and quick response actuators that surpassed the performance of the only-SWCNT polymer actuator and exhibited characteristics sufficient for practical applications (e.g. tactile display).

The effects of ionic liquid (IL) and composition (ratio of carbon nanotube (CNT):polymer:IL) on the electrochemical and electromechanical properties of actuators containing activated and non-activated multi-walled carbon nanotube (MWCNT)-IL gel electrodes were investigated. The electrochemical and electromechanical properties of actuators containing the activated and non-activated MWCNT-IL gel electrodes were compared to those of a single-walled carbon nanotube (SWCNT)-based actuator. The double-layer capacitance of the activated MWCNT (MWCNT-COOH) electrode and the strain and maximum generated stress for the MWCNT-COOH or MWCNT actuator are dependent on both the IL and composition. For the MWCNT-COOH actuator containing 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI[BF 4 ]) (MWCNT-COOH:poly(vinylidene fluoride- co -hexafluoropropylene):EMI[BF 4 ] = 30:30:35), the strain was 0.78–0.80% for the frequency range of 0.01–0.005 Hz, which was ca. twice that measured for the SWCNT actuator, and the maximum generated stress was ca. 1.8–2.5 times larger than that observed for the SWCNT actuator. Therefore, the common CNT activated MWCNT actuator can generate a maximum stress sufficient for practical purposes without using specialized SWCNT. Furthermore, the actuator containing MWCNT-COOH performed better than those containing SWCNTs or MWCNTs, and gave a more rapid response.

When submitted to square-wave potentials of ±2 V, single-walled carbon nanotube films with an ionic liquid, taking part of an actuator, show high-frequency electromechanical responses (up to 100 Hz), with anodic current evolutions showing two maxima. Similar anodic chronoamperometric responses have been obtained from films of conducting polymers exchanging balancing anions with the electrolyte during reaction, being described by two stretched exponential functions deduced on physico-chemical bases: oxidation under nucleation–relaxation structural control and oxidation/swelling completion under diffusion control. Now by adding a third stretched function, describing a greater contribution now of the charge of the electrical double layer, a good mathematical fit of the chronoamperometric response of the carbon nanotube films was carried out. By recovering the original physico-chemical meaning of the electrochemical stretched functions, capacitive and structural faradic components of the chronoamperometric charge were quantified as a function of the applied frequency (1–10 Hz). The capacitive component of the charge ranges with frequency between 8.6% and 12.2% of the involved charge. The faradic (reactive) component ranges between 91.4% and 87.8%, being the main contributor to the volume variations in the actuating films. The order of magnitude of the diffusion coefficients was 10 −6 cm 2 s −1 , in good agreement with the fast response of the reactive actuators constructed with those materials. A good separation of capacitive and faradic components will allow a better design of electrochemical applications of single-walled carbon nanotube films.

We fabricate double layer films composed of millimeter-long ‘super-growth’ carbon nanotube (SG-SWNT) and polypyrrole (PPy) by electropolymerization of pyrrole on the SG-SWNT film surface under various conditions. Electrical and mechanical properties as well as morphologies of the obtained double layer films are studied by a four-probe DC current method, stress–strain measurements and scanning electron microscope (SEM) measurements. The growth process of PPy on the SG-SWNT film during electropolymerization is also investigated in detail. SG-SWNT/PPy double layer films show higher electrical conductivities and breaking strengths compared to both SG-SWNT and PPy single layer films. The fracture surface morphologies of the double layer films revealed that very fine fibrous SG-SWNTs came out on the cleavage section of PPy particles. Such a interconnected structure between SG-SWNTs and PPy was supposed to allow a new electrical conductive pass and reinforce the strength of the composite materials. Actuation performances of the SG-SWNT/PPy double layer films were also demonstrated in an aqueous solution. One of the features of this actuator is reversion of displacement direction depending on scan rate range when a relative amount of PPy component is large. This reversion of displacement direction is supposed to be based mainly on volume changes of PPy governed by several factors including ion movement, while volume changes of both SG-SWNT and PPy layers should contribute the actuation behavior.

Actuators were developed using activated and non-activated multi-walled carbon nanotube (MWCNT)–ionic liquid (IL) gel electrodes and compared to a single-walled carbon nanotube (SWCNT)-based actuator with respect to the electrochemical and electromechanical properties. The activated MWCNT–COOH/polymer actuator surpassed the SWCNT/polymer actuator in terms of the generated strain.

The effects of polymer species (poly(vinylidene fluoride)) (PVdF) homopolymer or poly(vinylidene fluoride- co -hexafluoropropylene) (PVdF(HFP) copolymer), average molecular weight of the polymer, and the HFP content in PVdF(HFP) on the electrochemical and electromechanical properties of actuators using polymer-supported single-walled carbon nanotube (SWCNT)–ionic liquid (IL) gel electrodes were investigated. For the PVdF (Kynar 741 or 761) actuator containing 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI[BF 4 ]), the generated strain was 0.90–1.05% for the frequency range of 0.01–0.005 Hz, which was over twice as large as that for the PVdF(HFP) (Kynar Flex 2801) actuator. Furthermore, it is considered that the HFP content should be low (or zero) for large generated strain and zero for large maximum stress. The PVdF actuator performs much better than the PVdF(HFP) actuator and has a quick response, sufficient for practical application (e.g., tactile displays).

Polyaniline (PANI) or carbon black (CB) was used as a conductive additive in porous electrodes of a dry-type carbon nanotube (CNT)-polymer actuator to improve the actuation properties. We estimated the strain from the bending motion of the actuator in the frequency range of 200–0.005 Hz. The generated stress was calculated from the Young’s modulus of the electrode film and the maximum strain. Eight different types of electrode films were prepared by changing the mixed amount of PANI or CB into the CNT electrode film. When a same amount of PANI (50 mg) against CNT (50 mg) was added to the CNT electrode (in the case of CNT/PANI(50/50)), the strain of CNT/PANI(50/50) was increased to be almost three times larger than that of CNT(50) (without any additives). As a result, CNT/PANI(50/50) showed more than five times the generated stress compared to CNT(50). Using 40 mg of CB as an additive, CNT/CB(50/40) showed a more than four times larger stress compared to CNT(50). The electrochemical properties such as conductivity and capacitance were also investigated and discussed. An asymmetrical three-layered actuator element was fabricated to investigate the actuation mechanism. The results imply that the anode contracts and the cathode expands.

In this study, we investigated a dependence of anionic species of ionic liquids (ILs) (IL: perfluoroalkyltrifluoroborate anions ([C n F 2 n +1 BF 3 ] − ( n = 0, 1, 2) and bis(perfluoroalkylsulfonyl)imide anions ([(C m F 2 m +1 SO 2 )(C n F 2 n +1 SO 2 )N] − ( m , n = 0, 1, 2)) on electrochemical and electromechanical properties. 1-Ethyl-3-methylimidazolium (EMI + ) was selected as a cation for ILs. 1-Ethyl-3-methylimidazolium trifluoromethyltrifluoroborate (EMI[CF 3 BF 3 ]), 1-ethyl-3-methylimidazolium pentafluoroethyltrifluoroborate (EMI[CF 3 CF 2 BF 3 ]), 1-ethyl-3-methylimidazolium fluorosulfonyl(trifluoromethylsulfonyl)imide (EMI[FTA]) and 1-ethyl-3-methylimidazolium pentafluoroethylsulfonyl(trifluoromethylsulfonyl)imide (EMI[C 1 C 2 ]) were synthesized according to the literatures. The generated strains of the bucky-gel electrodes of the actuators containing EMI[CF 3 BF 3 ] (in the high frequency range: 10–0.5 Hz) and EMI[CF 3 CF 2 BF 3 ] (in the high frequency range of 1–0.5 Hz) are larger than that containing EMI[BF 4 ] (that is to say the quick response). For low frequencies (0.1–0.005 Hz), the generated strain containing EMI[CF 3 CF 2 BF 3 ] was larger than those containing other ILs (EMI[C n F 2 n +1 BF 3 ] ( n = 0, 1) and EMI[(C m F 2 m +1 SO 2 )(C n F 2 n +1 SO 2 )N] ( m , n = 0, 1, 2)). The Young's modulus of actuators containing EMI[CF 3 BF 3 ] and EMI[CF 3 CF 2 BF 3 ] were 145 and 110 MPa, respectively. The melting points of EMI[CF 3 BF 3 ] and EMI[CF 3 CF 2 BF 3 ] are lower than that of EMI[BF 4 ]. Therefore, trifluoromethyltrifluoroborate ([CF 3 BF 3 ] − ) and pentafluoroethyltrifluoroborate ([CF 3 CF 2 BF 3 ] − ) anions performed much better as the actuator using the polymer-supported bucky-gel electrode containing the IL. These results are considered to be the actuator enough to apply actual applications (e.g. tactile display).

We investigated an effect for alkaline metal salts or an alkaline earth metal salt on electrochemical and electromechanical properties of an actuator using a single-walled carbon nanotube (SWCNT)-ionic liquid (IL) gel electrode, and much better performance of the actuator containing the metal salt/IL. The actuator containing the alkaline metal salt /IL or alkaline earth metal salt/IL performed much better than that containing only the IL. It is considered that the higher ionic conductivity of the gel electrolyte layer containing the alkaline metal salt /IL or alkaline earth metal salt/IL produces the quick response actuator, and that the large capacitance gives the large generated strain.

The effects of alkaline earth metal salts (Magnesium bis(trifluoromethanesulfonyl)imide (Mg[TFSI] 2 ) and Calcium bis(trifluoromethanesulfonyl)imide (Ca[TFSI] 2 )) on electrochemical and electromechanical properties of an actuator using a polymer-supported single-walled carbon nanotube (SWCNT)-ionic liquid (IL) gel electrode were investigated. The ionic conductivities of the gel electrolyte layers with the molar ratios of Mg[TFSI] 2 /1-ethlyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMI[TFSI]) = 0.05, 0.1 and 0.25, and Ca[TFSI] 2 /EMI[TFSI] = 0.05, 0.1 and 0.25 were higher than that containing only EMI[TFSI]. We found large capacitance value 51–89 Fg −1 at a slow sweep rate 1 mV s −1 . The generated strains of the polymer-supported SWCNT-IL gel electrodes of the actuators with the molar ratios of Mg[TFSI] 2 /EMI[TFSI] = 0.1 (in all frequency range; 100–0.005 Hz) and Ca[TFSI] 2 /EMI[TFSI] = 0.05 and 0.1 (in the frequency range; 1–0.005 Hz) were larger than that containing only EMI[TFSI]. In previous paper, the effects of Li salts (Li[BF 4 ] and Li[TFSI]) on the electrochemical and electromechanical properties of an actuator using a polymer-supported SWCNT-IL gel electrode were investigated. Consequently, the generated strain of the actuator with the molar ratios of Mg[TFSI] 2 /EMI[TFSI] = 0.1 is larger than those containing Ca[TFSI] 2 /EMI[TFSI], Li[TFSI]/EMI[TFSI] and Li[BF 4 ]/EMI[BF 4 ] for the wide frequencies (100–0.005 Hz). As the summary, the actuator containing Mg[TFSI] 2 /EMI[TFSI] or Ca[TFSI] 2 /EMI[TFSI] performed much better than that containing only IL. It is considered that the higher ionic conductivity of the gel electrolyte layers containing Mg[TFSI] 2 /EMI[TFSI] or Ca[TFSI] 2 /EMI[TFSI] produces the quick response actuators, and that the large capacitance gives large generated strain. The actuator containing Mg[TFSI] 2 /EMI[TFSI] performed much better than those containing Ca[TFSI] 2 /EMI[TFSI], Li[TFSI]/EMI[TFSI] and Li[BF 4 ]/EMI[BF 4 ] for the wide frequencies (100–0.005 Hz). These results are considered to be the actuator enough to apply actual applications (e.g. tactile display).

In this paper, bucky-gel electrodes containing various ionic liquid species were prepared by casting, using “bucky gel”, a gelatinous room-temperature ionic liquid (IL) containing single-walled carbon nanotubes (SWCNT). Their electrochemical impedance responses were measured and analyzed. Also, the electromechanical responses of the actuators composed of two bucky-gel electrodes sandwiching an ionic liquid gel layer were studied by measuring the displacement due to an applied sinusoidal voltage at various frequencies. All impedance data were successfully simulated by the equivalent circuit model of a porous electrode based on the transmission line circuit model. By using the same parameter values of the porous electrode model, the frequency dependence of the strain generated in the bucky-gel actuators can be simulated. On the basis of the experimental and simulation results, the electromechanical responses of the bucky-gel actuator were analyzed by taking into account the electrochemical properties of the...

The effects of Li salts (Lithium tetrafluoroborate (Li[BF 4 ]) and Lithium bis(trifluoromethanesulfonyl)imide (Li[TFSI])) on the electrochemical and electromechanical properties of an actuator using a polymer-supported single-walled carbon nanotube (SWCNT)-ionic liquid (IL) gel electrode were investigated. The ionic conductivities of the gel electrolyte layers with molar ratios of Li[BF 4 ]/1-ethlyl-3-methylimidazolium tetrafluoroborate (EMI[BF 4 ]) = 0.1 and 0.5, and Li[TFSI]/1-ethlyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMI[TFSI]) = 0.1 and 0.3 were higher than those containing only EMI[BF 4 ] and only EMI[TFSI], respectively. We found a large capacitance value 65–96 F/g at a slow sweep rate 1 mV s −1 . The actuator containing Li salt/IL performed much better than that containing only IL. It is considered that the higher ionic conductivity of the gel electrolyte layer containing Li salt/IL produces the quick response actuator, and that the large capacitance gives a large generated strain.

Two different types of additives were mixed into the electrode of carbon nanotube (CNT) actuators low-voltage-driven in air to investigate the influence of additives on the actuator performance. The electrode was composed by single-walled carbon nanotubes (SWNTs), an ionic liquid (IL), a base polymer, and an additive. The generated strain was estimated by measuring displacement changes of the actuator element in the frequency range between 5 mHz and 200 Hz. In case of a non-conductive additive, that is, mesoporous silica (MCM-41), the maximum strain of the actuator increased about 1.6 times as large as that of the non-additive actuator. On the contrary, a conductive additive, polyaniline (poly-An), caused a remarkable improvement of the strain (ca. 3 times) for the actuator. It is found that this improvement was achieved by the effective charge storage in the actuator element. The generated stress was also determined by Hooke's law with the parameter of the maximum strain and the Young's modulus of actuator composite.

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 conductivity 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.

In the previous papers, we have reported the first dry actuator that can be fabricated simply by layer-by-layer casting, using ‘bucky gel’, a gelatinous room-temperature ionic liquid (IL) containing single-walled carbon nanotubes (SWNTs). In this paper, the electromechanical and electrochemical properties of the bucky-gel actuators composed of the bucky-gel electrode and the gel electrolyte layers containing seven kinds of internal ILs were studied for exploring the details of the actuation mechanism. We measured the frequency dependence of the displacement response of the bucky-gel actuator and it can be successfully simulated by the electrochemical kinetic model. From the simulated result for the frequency dependence of the electromechanical response of the bucky-gel actuators, we determined two parameters for the simulation, the generated strain at a limit of low frequency and the time constant. The time constant was represented by the equivalent circuit composed of series combination of the ionic resistance R, the double-layer capacitance C and the electrode resistance Rel. The IL-dependence of the time constant was determined by that of the ionic resistance R of the gel electrolyte layer. The generated strain at a limit of low frequency is considered to be related to the electromechanical mechanism of the bucky-gel actuator. From their dependence on the IL species and the theoretical modeling reported in the previous papers, we conclude that both the steric repulsion effect due to the transfer of ions to the electrode and ‘the charge injection’ give the bending motion of the bucky-gel actuator. The volume-changes of the cathode and anode change according to the sizes of the cation and anion, respectively. The ion size gives the dependence of the bending motion of the bucky-gel actuator on the internal ionic species.

In a previous paper, we reported the first dry actuator that can be fabricated simply by layer-by-layer casting, using ‘bucky gel’, a gelatinous room-temperature ionic-liquid containing single-walled carbon nanotubes (SWNTs). Our actuator has a bimorph configuration with a polymer-supported internal ionic-liquid electrolyte layer sandwiched by two polymer-supported bucky-gel electrode layers, which allows quick and long-lived operation in air at low applied voltages. In this paper, we propose a new two-step process using a ball-mill method for preparing the casting solution for the bucky-gel electrode in order to improve the performance of the actuator by developing the bucky-gel electrode layer with a high content of SWNTs which are well dispersed in the electrode layer. We measured the displacement and the blocking force of the new bucky-gel actuator fabricated by hot-pressing the prepared electrode and electrolyte layers and analyzed its experimental results by the tri-layer polymer actuator model which was developed by Alici et al. for conducting polymer actuators. We developed the low-voltage driven solid-state actuator that shows the maximum stress and the strain of 4.7 MPa and 1.9%, respectively, which are comparable with any other low-voltage driven solid-state electroactive polymer actuator technology to our knowledge. The advantage of our bucky-gel actuator is not only in its good performance but also in its easy process in fabrication. The present development provides an important step for electromechanical polymer actuator technologies.

A convergent total synthesis of ouabagenin, an aglycon of cardenolide glycoside ouabain, was achieved by assembly of the AB-ring, D-ring and butenolide moieties. The multiply oxygenated cis-decalin structure of the AB-ring was constructed from (R)-perillaldehyde through the Diels–Alder reaction and sequential oxidations. The intermolecular acetal formation of the AB-ring and D-ring fragments, and combination of the intramolecular radical and aldol reactions, assembled the requisite steroidal skeleton in a stereoselective fashion. Finally, stereoselective installation of the C17-butenolide via the Stille coupling and hydrogenation led to ouabagenin.

In this study, the platelet-shaped graphene was used as a conductive additive in porous electrodes of a dry-type polymer actuator consisting of carbon nanotube (CNT), ionic liquid, and a base polymer to improve actuation properties. The generated strain was estimated from the bending motion of the actuator in the frequency range from 0.005 to 10 Hz. Ten different types of electrode film were prepared by changing the mixing amounts and surface areas of the platelet-shaped graphene. When a small amount of graphene (30 mg) relative to CNT (50 mg) was added to the CNT electrode, the strain was increased to be almost twice larger than that of CNT (50 mg) without any additives. The strain coefficient of the three-layered actuator with CNT electrodes with graphene additives is positively correlated with the capacitance per volume of such electrodes.

A convergent total synthesis of ouabagenin, an aglycon of cardenolide glycoside ouabain, was achieved by assembly of the AB-ring, D-ring and butenolide moieties., A convergent total synthesis of ouabagenin, an aglycon of cardenolide glycoside ouabain, was achieved by assembly of the AB-ring, D-ring and butenolide moieties. The multiply oxygenated cis-decalin structure of the AB-ring was constructed from (R)-perillaldehyde through the Diels–Alder reaction and sequential oxidations. The intermolecular acetal formation of the AB-ring and D-ring fragments, and combination of the intramolecular radical and aldol reactions, assembled the requisite steroidal skeleton in a stereoselective fashion. Finally, stereoselective installation of the C17-butenolide via the Stille coupling and hydrogenation led to ouabagenin.

Single-walled carbon nanotube (SWCNT) fibers are promising lightweight materials with high mechanical strength and high electrical conductivity. In a previous report, we showed a clear correlation between the fiber properties and the effective tube length of the constituent SWCNTs. According to the results, the dispersion conditions of SWCNTs in aqueous solutions were improved by changing the surfactants and dispersion methods used to prevent the reduction of their length during fiber processing. Systematic studies revealed that the mechanical properties and electrical conductivity of the SWCNT fibers were improved by decreasing their cross-sectional area and increasing the effective length of the SWCNTs.

Electromechanically active polymers (EAP) are considered a good actuator candidate for a variety of reasons, e.g. they are soft, easy to miniaturize and operate without audible noise. The main structural component in EAPs is, as the name states, a type of deformable polymer. As polymers are known to exhibit a distinct mechanical response, the nature of polymer materials should never be neglected when characterizing and modeling the performance of EAP actuators. Bucky-gel actuators are a subtype of EAPs where ion-containing polymer membrane acts as an electronically insulating separator between two electrodes of carbon nanotubes and ionic liquid. In many occasions, the electrodes also contain polymer for the purpose of binding it together. Therefore, mechanically speaking, bucky-gel actuators are composite structures with layers of different mechanical nature. The viscoelastic response and the shape change property are perhaps the most characteristic effects in polymers. These effects are known to have high dependence on factors such as the type of polymer, the concentration of additives and the structural ratio of different layers. At the same time, most reports about optimization of EAP actuators describe the alteration of electromechanical performance dependent on the same factors. In this paper, the performance of bucky-gel actuators is measured as a function between the output force and bending deflection. It is observed that effective stiffness of these actuators depends on the input voltage. This finding is also supported by dynamic mechanical analysis which demonstrates that the viscoelastic response of bucky-gel laminate depends on both frequency and temperature. Moreover, the dynamic mechanical analysis reveals that in the range of standard operation temperatures, tested samples were in their glass transition region, which made it possible to alter their shape by using mechanical fixing. The mechanical fixity above 90% was obtained when high-frequency input signal was used to heat the bucky-gel sample.

In this paper, we have developed electrochemical and electromechanical kinetic model of a bucky-gel actuator which is composed of an ionic liquid (IL) gel electrolyte layer sandwiched by electrode layers based on single-walled carbon nanotubes (SWNTs) and ILs. The electrochemical model can be applied to the electromechanical effect only due to the electric double-layer (DL) charging, or due to both the DL charging and redox reaction of SWNTs. The model was compared with the experimental results of the bucky-gel actuators.

We report on the fabrication of polymer-free carbon nanotube (CNT) fibers by a novel wet spinning method combined with a very easy and straightforward fabrication process. These fibers exhibited high electrical conductivity (14,284 ± 169 S·cm−1) and tensile strength (887 ± 37 MPa). Such high performance was made possible by the preparation of free-standing CNT fibers from a surfactant solution containing uniformly dispersed CNTs, despite the use of an organic coagulating solvent and subsequent stretching to align the CNTs in the fiber.

Actuators with a high-speed response under a high-frequency (more than 100 Hz) applied square-wave voltage of ±2 V have been developed with an electrode composed of millimeter-long single-walled carbon nanotubes synthesized by the "supergrowth method" (SG-SWNTs) and ionic liquids (ILs). Detailed studies concerning induced electric current and transferred charge in the electrode as well as cyclic voltammetric studies of the electrode revealed that the high-speed response originates from the electric current generated by an oxidation/reduction (redox) reaction in addition to electric double-layer charging. The contribution of the redox reactions of SG-SWNTs to the actuation is sensitive to the presence of supporting polymers, the thickness of the electrolyte, and the amplitude of the applied voltage.

Gilostazol not only suppresses platelet aggregation but also increses blood flow in the brain. To determine whether it is useful in patients with vertigo due to circulatory disorders in both the peripheral and the central vestibular system, we investigated its clinical effect in 19 patients with vertigo, who were over 40 years of age and whose vertigo was considerd to be caused by circulatory disturbances. A dose of 200mg/day was administrated for 4 or 8 weeks.1. The overall rate of improvement was 78% after 4 weeks and 85% after 8 weeks of treatment.2. Fifteen of the 19 patients (79%) complained of a slight headache during the first week of treatment. Seven of them recovered soon without treatment. The other eight recovered when the drug's dose was reduced by 50% or when an analgesic was administered.

In previous papers, we reported the first dry actuator that can be fabricated simply by layer-by-layer casting, using 'bucky gel', a gelatinous room-temperature ionic liquid containing single-walled carbon nanotubes (SWNTs). The actuator has a bimorph configuration with a polymer-supported internal ionic liquid electrolyte layer sandwiched by polymer-supported bucky-gel electrode layers, which allow quick and long-lived operation in air at low applied voltages. In this paper, some of the recent developments of the actuator performance are reported.

Bucky-gel actuators are ionic electromechanically active materials that bend in response to a low-voltage excitation. While bending actuators may offer new approaches in engineering solutions, the characterization of bending poses many challenges in comparison to conventional rotary motion. It is often desired to reduce the bending behaviour to a single parameter, which may lead to the loss of accuracy in modelling. A high-speed laser profilometer is utilized to characterize the bending response of different bucky-gel actuators at their full length and to critically compare the applicability of existing representation tools for bending. The best analytical representation of the bending of a bucky-gel actuator is found to be in the form of a power function. It is also observed that, along the length of the actuator, sections closer to the electrical input clamp exhibit back-relaxation (a common drawback for bending ionic actuators) already when the far end of the bending strip is still in forward motion.