JP5332027B2 - Actuator element using carbon nanotube electrode with conductive additive - Google Patents

Abstract

Disclosed is the creation of an actuator that operates stably with high generating power in a broader frequency band. Provided is an electrically conductive thin film configured from a polymer gel comprising an auxiliary conducting agent, carbon nanotubes, an ionic liquid and a polymer.

Description

  The present invention relates to a conductor having a conductive thin film and an actuator element. Here, the actuator element is an actuator element whose driving force is an electrochemical process such as electrochemical reaction or charge / discharge of an electric double layer.

  As an actuator element operable in the air or in vacuum, an actuator using a gel of carbon nanotube and ionic liquid as a conductive stretchable active layer has been proposed (Patent Document 1).

  The structure of the conventional element uses a gel of carbon nanotubes and an ionic liquid as a stretchable active layer, and has a sandwich structure of electrode layers with the ionic liquid gel as an electrolyte layer. The performance of the actuator is mainly evaluated by three parameters of expansion / contraction rate, response speed, and generated force, but it is difficult to improve or improve these three parameters simultaneously. For example, an actuator element consisting of carbon nanotubes and ionic liquid gel is considered to have a better actuator response as the film has better conductivity. However, if carbon nanotubes are added at a high concentration in order to increase conductivity, the film itself becomes hard and deforms. Response is poor. On the other hand, by increasing the concentration of the ionic liquid, the ionic conductivity can be improved. However, if the ionic liquid is added too much, the element itself becomes soft and the generated force decreases. As described above, when one of the three parameters is improved, one or two of the remaining parameters are often sacrificed.

JP-A-2005-176428 WO2007 / 078005 WO2006 / 011655

Don N. Futaba, Kenji Hata, Takeo Yamada, Tatsuki Hiraoka, Yuhei Yamamizu, Yozo Kakudate, Osamu Tanaike, Hiroaki Hatori, Motoo Yumura and Sumio Iijima, Nature Materials, Vol. 5, 987 (2006). Kenji Hata et al, Water-Assisted Highly Efficient Synthesis of Impurity-Free Single-Walled Carbon Nanotubes, SCIENCE, 2004.11.19, vol.306, p.1362-1364

  An object of the present invention is to create an actuator that operates stably in a higher frequency and a wider frequency band with the aim of further increasing the functionality of the actuator element.

  As a result of repeated investigations in view of the above problems, the present inventor produces an actuator element that is greatly improved in both expansion and contraction performance and generating force by adding an additive that assists conductivity to the actuator element that has been developed so far. Succeeded. Moreover, the response speed was also greatly improved by optimizing the amount of additive.

  The present invention provides the following conductive thin film, laminate and actuator element.

  1． A conductive thin film composed of a polymer gel containing a conductive assistant, carbon nanotube, ionic liquid and polymer.

  2． Item 2. The conductive thin film according to Item 1, wherein the conductive auxiliary agent is at least one selected from the group consisting of a conductive polymer, carbon particles, a mesoporous inorganic material, and a metal oxide.

  3． Item 1. A laminate comprising one or more conductive thin films according to item 1 or 2, and one or more electrolyte membranes composed of an ionic liquid and a polymer.

  Four. An actuator element comprising the laminate according to Item 3.

  Five. On the surface of the electrolyte membrane composed of an ionic liquid and a polymer, at least two conductive thin film layers having the conductive thin film according to Item 1 or 2 as electrodes are formed in an insulated state, and a potential difference is generated between the conductive thin film layers. Item 5. The actuator element according to Item 4, which is configured to be deformable by providing

  According to the present invention, by using the conductive auxiliary agent, the expansion / contraction rate and the generated force can be greatly improved, thereby providing an actuator element capable of a high generated force response. Furthermore, the speed of the stretching response can be improved by optimizing the amount of the conductive auxiliary agent to be added.

The evaluation method by the laser displacement meter used for the actuator element displacement evaluation method in the Example of this invention is shown. FIG. 2A is a diagram showing an outline of an example of the configuration of the actuator element (three-layer structure) of the present invention, and FIG. 2B is a configuration of an example of the actuator element (5-layer structure) of the present invention. FIG. It is a figure which shows the operating principle of the actuator element of this invention. It is a figure which shows the outline of the other example of the actuator element of this invention. Frequency dependence (rectangular wave) of the expansion / contraction ratio of the actuator of Example 1 containing polyaniline. ±2.0V@200-5mHz. V-I-D response (±2.0V@0.1Hz) of the actuator of Example 1 containing polyaniline. Stretch rate = 0.72%; charge amount = + 65mC, -69mC. Frequency dependence of the expansion / contraction rate of the actuator of Example 2 including MCM41 (rectangular wave). ±2.0V@200-5mHz. V-I-D response (±2.0V@0.1Hz) of the actuator of Example 2 including MCM-41. Stretch rate = 0.59%; charge amount = + 23mC, -22mC. Frequency dependence of the expansion / contraction rate of the actuator of Example 3 including MCM-41 (rectangular wave). ±2.0V@200-5mHz. V-ID response (±2.0V@0.1Hz) of the actuator of Example 3 including MCM-41. Stretch rate = 0.59%; charge amount = + 37mC, -36mC. The frequency dependence (rectangular wave) of the expansion-contraction rate of the actuator of the comparative example 1 which does not use a conductive support agent. ±2.0V@200-5mHz. V-ID response (±2.0V@0.1Hz) of the actuator of Comparative Example 1 that does not use a conductive auxiliary agent. Stretch rate = 0.49%; charge amount = + 28mC, -28mC. Comparison of VID when only CNT and CB are used Comparison of expansion / contraction ratio of CNT / CB mixed system (frequency change) Comparison of expansion / contraction ratio of CNT / CB mixed system (frequency: 0.005 Hz) Frequency dependence (rectangular wave) of the expansion / contraction rate of the actuators of Examples 1 and 7 to 10 containing polyaniline and Comparative Example 1 not containing polyaniline. ±2.0V@200-5mHz. Voltage dependence (rectangular wave) of the displacement of the actuator of Example 11 containing ruthenium oxide and Comparative Example 3 not containing ruthenium oxide. ±0.5~3.0V@0.1Hz.

  In the present invention, carbon nanotubes, polymers, ionic liquids and conductive assistants are used for the conductive thin film used for the electrode layer of the actuator element.

  The ionic liquid used in the present invention is also called a room temperature molten salt or simply a molten salt, and is a salt that exhibits a molten state in a wide temperature range including room temperature (room temperature). It is a salt that exhibits a molten state at ℃, preferably -20 ℃, more preferably -40 ℃. The ionic liquid used in the present invention preferably has a high ionic conductivity.

In the present invention, various known ionic liquids can be used, but a stable one that exhibits a liquid state at normal temperature (room temperature) or a temperature close to normal temperature is preferable. A suitable ionic liquid used in the present invention comprises a cation (preferably an imidazolium ion or a quaternary ammonium ion) represented by the following general formulas (I) to (IV) and an anion (X ⁻ ). Things.

In the above formulas (I) to (IV), R represents a linear or branched C _{1 to} C ₁₂ alkyl group having a straight chain or a branched chain, or an ether bond and a total number of carbon and oxygen of 3 to 12. In formula (I), R ¹ represents a linear or branched C ₁ -C ₄ alkyl group or a hydrogen atom. In the formula (I), R and R ¹ are preferably not the same. In formulas (III) and (IV), x is an integer of 1 to 4, respectively.

Examples of the linear or branched C _{1 to} C ₁₂ alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, and nonyl. , Decyl, undecyl, dodecyl and the like. Preferably carbon number is 1-8, More preferably, it is 1-6.

The _C 1 -C ₄ alkyl group having a straight-chain or branched, methyl, ethyl, n- propyl, isopropyl, n- butyl, isobutyl, sec- butyl, t- butyl.

Examples of the alkyl group having an ether bond and having a straight chain or a branch having a total number of carbon and oxygen of 3 to 12 include CH ₂ OCH ₃ , (CH ₂ ) _p (OCH ₂ CH ₂ ) _q OR ² (where, p is an integer of 1 to 4, q is an integer from 1 to 4, R ² represents CH ₃ or C ₂ H ₅₎ can be mentioned.

As anions (X ⁻ ), tetrafluoroborate ion (BF ₄ ⁻ ), BF ₃ CF ₃ ⁻ , BF ₃ C ₂ F ₅ ⁻ , BF ₃ C ₃ F ₇ ⁻ , BF ₃ C ₄ F ₉ ⁻ , hexa Fluorophosphate ion (PF ₆ ⁻ ), bis (trifluoromethanesulfonyl) imidate ion ((CF ₃ SO ₂ ) ₂ N ⁻ ), perchlorate ion (ClO ₄ ⁻ ), tris (trifluoromethanesulfonyl) carbonic acid ion (CF ₃ SO ₂ ) ₃ C ⁻ ), trifluoromethanesulfonate ion (CF ₃ SO ₃ ⁻ ), dicyanamide ion ((CN) ₂ N ⁻ ), trifluoroacetate ion (CF ₃ COO ⁻ ), organic carbon Examples include acid ions and halogen ions.

Among these, as the ionic liquid, for example, the cation is 1-ethyl-3-methylimidazolium ion, [N (CH ₃ ) (CH ₃ ) (C ₂ H ₅ ) (C ₂ H ₄ OC ₂ H ₄ OCH ₃ )] ^{+ and the} like, and those having anions such as halogen ions and tetrafluoroborate ions are specifically mentioned. In addition, it is possible to use two or more kinds of cations and / or anions to further lower the melting point.

However, the present invention is not limited to these combinations, and any ionic liquid that has a conductivity of 0.1 Sm ⁻¹ or more can be used.

  The carbon nanotube used in the present invention is a carbon-based material having a shape in which a graphene sheet is wound into a cylindrical shape, and is roughly classified into single-walled nanotubes (SWNT) and multi-walled nanotubes (MWNT) based on the number of peripheral walls. Also, various types are known, such as being divided into a chiral type, a zigzag type, and an armchair type due to the difference in the structure of the graphene sheet. Any type of carbon nanotube can be used in the present invention as long as it is referred to as such a so-called carbon nanotube.

  A suitable example of carbon nanotubes for practical use is HiPco (manufactured by Carbon Nanotechnology Inc.), which can be relatively mass-produced using carbon monoxide as a raw material. Of course, it is limited to this. is not.

  Examples of the polymer used in the present invention include a copolymer of a fluorinated olefin having a hydrogen atom and a perfluorinated olefin such as polyvinylidene fluoride-hexafluoropropylene copolymer [PVDF (HFP)], and polyvinylidene fluoride (PVDF). Homopolymers of fluorinated olefins having hydrogen atoms such as perfluorosulfonic acid (Nafion), poly (meth) acrylates such as poly-2-hydroxyethyl methacrylate (poly-HEMA), polymethyl methacrylate (PMMA) , Polyethylene oxide (PEO), polyacrylonitrile (PAN), and the like.

  Examples of the conductive auxiliary agent include conductive polymers, mesoporous inorganic materials, metal oxides, carbon particles, and gold fine particles.

  The addition of the conductive auxiliary agent can be expected to improve the electronic conductivity of the electrode, to fill the polymer mesh formed by the CNT and the polymer, and to improve the generated pressure.

Examples of the conductive polymer include polyacetylene, polyaniline, polythiophene, polypyrrole, polyfluorene, polyphenylene, polyphenylene sulfide, poly (1,6-heptadiyne), polybiphenylene (polyparaphenylene), polyparaphenylene sulfide, and polyphenylacetylene. , Poly (2,5-thienylene), polyindole, poly-2,5-diaminoanthraquinone, poly (o-phenylenediamine), poly (quinolinium) salt, poly (isoquinolinium) salt, polypyridine, polyquinoxaline, polyphenylquinoxaline Etc. These conductive polymers may have various substituents. Specific examples of such substituents include, for example, C ₁ -C ₁₂ alkyl group having a straight-chain or branched, hydroxyl, C ₁ -C ₁₂ alkoxy group having a linear or branched, amino group, carboxyl group, a sulfonic acid group, a halogen group, a nitro group, a cyano group, C ₁ -C ₁₂ alkyl sulfonic acid having a straight-chain or branched, the amino group or the like (C ₁ -C ₄ alkyl having a straight chain or branched) di Can be mentioned.

  The use of a conductive polymer is preferable because not only the expansion / contraction ratio is greatly improved but also the generated force is high. In particular, the effect is remarkable in the low frequency range. However, when the addition amount is adjusted, both the expansion rate and the generation force can be improved even at a frequency of about 1 Hz as compared with the case where the conductive polymer is not used.

  The mesoporous inorganic material is a mesoporous inorganic material having a structure in which one-dimensional pores are regularly arranged. The “structure in which the one-dimensional pores are regularly arranged” is not particularly limited as long as it has a uniform pore diameter and the one-dimensional pores are regularly arranged. Regularly arranged means that the pores are aligned with a uniaxial orientation. The uniform pore diameter means that the pore diameter of each pore is within a certain range. The size of the pore diameter can be appropriately set, but is usually 1 to 30 nm, preferably 1.5 to 15 nm. The size of the pores can be made differently by changing the surfactant. Specific examples of the structure in which the one-dimensional pores are regularly arranged include a hexagonal structure, an orthorhombic structure, and a monoclinic structure.

  Such a mesoporous inorganic material can be prepared using a surfactant capable of forming a regular pore structure as a template.

  As the mesoporous inorganic material, a desired material can be appropriately used. For example, silica, titania, zirconia, alumina, silica-alumina, silica-titania, tin phosphate, niobium phosphate, aluminum phosphate, titanium phosphate, and their oxides, nitrides, sulfides, selenides, tellurium A compound, complex oxide, complex salt, or the like can be used. Of these, silicon-containing oxides such as silica are particularly preferable in terms of excellent heat resistance, chemical resistance, and mechanical properties.

A preferred mesoporous inorganic material is MCM-41. MCM-41 is a regular structure (honeycomb structure) with a pore size (2.7 nm) and specific surface area (up to 1000 m ² / g) comparable to that of CNT, which can reduce the amount of CNT added and is advantageous in terms of cost. In addition, it can function as a one-dimensional channel that efficiently moves the ionic liquid. While not wishing to be bound by theory, the inventor believes that mesoporous inorganic materials can be used for efficient adsorption of cations or electrode templates.

Examples of the metal oxide include titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ), aluminum oxide (Al ₂ O ₃ ), and ruthenium oxide (RuO ₂ ).

  Examples of the carbon particles include carbon black, ketjen black, acetylene black, artificial graphite, carbon fiber, furnace black, channel black, lamp black, and thermal black.

  When carbon particles are used, as in the case where a conductive polymer is used, the stretch rate and the generated force are greatly improved. In addition, the use of an appropriate amount of carbon particles is preferable because the expansion ratio and the generation force are improved in a wider frequency range (200 Hz to 5 mHz).

  These conductive auxiliary agents can be used alone or in combination of two or more.

  The conductive thin film layer used for the electrode layer of the actuator element is composed of a carbon nanotube, an ionic liquid, a polymer, and a conductive additive.

The preferred blending ratio of these components in the conductive thin film layer is:
carbon nanotube:
3 to 90% by weight, preferably 16.6 to 70% by weight, more preferably 20 to 50% by weight;
Ionic liquid:
5 to 80% by weight, preferably 15 to 73.4% by weight, more preferably 20 to 69% by weight;
polymer:
4 to 70% by weight, preferably 10 to 68.4% by weight, more preferably 11 to 64% by weight;
It is.

  The conductive auxiliary agent is blended in an amount of 3 to 90 parts by weight, preferably 4 to 65 parts by weight, based on 100 parts by weight of the total amount of carbon nanotubes, ionic liquid and polymer.

  The actuator element of the present invention has, for example, a three-layer structure in which the electrolyte membrane 1 is sandwiched by conductive thin film layers (electrode layers) 2 and 2 containing carbon nanotubes, an ionic liquid, a polymer, and a conductive auxiliary agent from both sides. (Figure 2A). Further, in order to increase the surface conductivity of the electrode, it may be a five-layer actuator element in which conductive layers 3 and 3 are further formed outside the electrode layers 2 and 2 (FIG. 2B).

  In order to obtain an actuator element by forming a conductive thin film layer on the surface of an electrolyte membrane, an electrode gel solution in which carbon nanotubes, ionic liquid, polymer, and conductive additive are dispersed in a solvent, and an electrolyte gel comprising the ionic liquid and polymer The solution was obtained by alternately applying, drying, and laminating the solution by a casting method, or by separately casting and drying the surface of the electrolyte membrane obtained by casting and drying as described above. It can be obtained by thermocompression bonding of a conductive thin film.

  Moreover, a conductive thin film layer can also be obtained as follows, for example. An ionic liquid is impregnated into the carbon nanotube containing the conductive auxiliary agent. Alternatively, a carbon nanotube mixed with a conductive auxiliary agent is impregnated with an ionic liquid gel solution in which an ionic liquid and a polymer are dispersed in a solvent, or the carbon nanotube mixed with a conductive auxiliary agent is immersed in the solution, and then the solvent is added. It can be obtained by drying. The electrolyte membrane can be obtained by forming an ion gel solution by a casting method and evaporating and drying the solvent.

  In the present invention, in preparing a conductive thin film layer containing a conductive auxiliary agent, carbon nanotubes and an ionic liquid, and if necessary, a polymer, it is important to mix each component homogeneously. In order to prepare a dispersion in which each component is homogeneously mixed, it is preferable to use a solvent, for example, it is particularly preferable to use a mixed solvent of a hydrophobic solvent and a hydrophilic solvent.

  Examples of the hydrophilic solvent include carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, propylene carbonate, and butylene carbonate, ethers such as tetrahydrofuran, carbon numbers of 1 to 3 such as acetone, methanol, and ethanol. And lower alcohols, acetonitrile and the like. Examples of the hydrophobic solvent include ketones having 5 to 10 carbon atoms such as 4-methylpentan-2-one, halogenated hydrocarbons such as chloroform and methylene chloride, aromatic hydrocarbons such as toluene, benzene and xylene, Examples thereof include aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane, N, N-dimethylacetamide, and the like.

  The dispersion for producing the conductive thin film of the present invention is prepared by kneading a conductive additive, an ionic liquid and carbon nanotubes into a gel, and then polymer and a solvent (for example, when the ionic liquid is hydrophilic, If the ionic liquid is hydrophobic, it may be prepared by adding a hydrophobic solvent), a conductive auxiliary agent, carbon nanotubes, ionic liquid, polymer, and if necessary. Accordingly, a solvent (for example, a mixed solvent of a hydrophilic solvent and a hydrophobic solvent when the ionic liquid is hydrophilic, or a hydrophobic solvent when the ionic liquid is hydrophobic) is added without the gelation process. A dispersion may be prepared. In that case, dispersion by ultrasonic waves is also effective for mixing the components.

  When preparing the dispersion after gelation, the ratio of the mixed solvent is preferably hydrophilic solvent: hydrophobic solvent (weight ratio) = 20: 1 to 1:10, preferably 2: 1 to 1. : 5 is more preferable.

  Moreover, when preparing a dispersion liquid without the process of gelatinization, hydrophilic solvent (PC) / hydrophobic solvent (MP) is preferably 1/100 to 20/100, more preferably 3/100 to 15/100. is there. A single solvent can also be used, in which case N, N-dimethylacetamide is preferred.

  The conductive thin film layer is composed of a polymer gel containing a conductive additive, carbon nanotube, ionic liquid and polymer.

  The blending ratio (weight ratio) of (conductive auxiliary agent + carbon nanotube + ionic liquid) and (polymer) in the conductive thin film layer is (conductive auxiliary agent + carbon nanotube + ionic liquid) :( polymer) = 1: 2. The ratio is preferably 4: 1, and more preferably (conductive auxiliary agent + carbon nanotube + ionic liquid) :( polymer) = 1: 1 to 3: 1. In this blending, a mixed solvent of a hydrophilic solvent and a hydrophobic solvent is used. A conductive auxiliary agent, carbon nanotubes, and an ionic liquid are mixed to form a gel in advance, and a polymer and a solvent (preferably a hydrophobic solvent) are mixed with the gel to obtain a dispersion for preparing a conductive thin film. In this case, (conductive aid + carbon nanotube + ionic liquid) :( polymer) is more preferably 1: 1 to 3: 1.

  The conductive thin film layer may contain some solvents (hydrophobic solvent and hydrophilic solvent), but it is preferable to remove as much solvent as possible under normal drying conditions.

  The gel composition constituting the ion conductive layer is composed of a polymer and an ionic liquid. In a preferred ion conductive layer, the blending ratio (weight ratio) of the hydrophilic ionic liquid and the polymer in obtaining the gel composition is preferably hydrophilic ionic liquid: polymer = 1: 4 to 4: 1. More preferably, the hydrophilic ionic liquid: polymer = 1: 2 to 2: 1. Also in this blending, it is preferable to use a solvent in which a hydrophilic solvent and a hydrophobic solvent are mixed at an arbitrary ratio, as described above.

  The ion conductive layer serving as a separator that separates two or more conductive thin film layers can be formed by dissolving a polymer in a solvent and following conventional methods such as coating, printing, extrusion, casting, and injection. The ion conductive layer may be formed substantially only from a polymer, or may be formed by adding an ionic liquid to a polymer.

  The polymer used for the conductive thin film layer and the ion conductive layer may be the same or different. However, the conductive thin film layer and the ion conductive layer are the same or similar in properties. It is preferable to improve the adhesion of the resin.

  The thickness of the electrolyte membrane is preferably 5 to 200 μm, and more preferably 10 to 100 μm. The thickness of the conductive thin film layer is preferably 10 to 500 μm, and more preferably 50 to 300 μm. Moreover, spin coating, printing, spraying, etc. can also be used for film formation of each layer. Furthermore, an extrusion method, an injection method, or the like can also be used.

  The actuator element thus obtained has an element length of 0.05 to 1 within a few seconds when a DC voltage of 0.5 to 4 V is applied between the electrodes (the electrodes are connected to the conductive thin film layer). Double displacement can be obtained. The actuator element can be flexibly operated in air or in vacuum.

  As shown in FIG. 3, the operating principle of such an actuator element is that when a potential difference is applied to the conductive thin film layers 2 and 2 formed on the surface of the electrolyte membrane 1 in a mutually insulated state, the conductive thin film layer 2 An electric double layer is formed at the interface between the carbon nanotube phase and the ionic liquid phase in 2, and the conductive thin film layers 2 and 2 expand and contract due to the interfacial stress. As shown in FIG. 3, the bending to the positive pole side is due to the effect of the carbon nanotubes extending more on the negative pole side due to the quantum chemical effect, and the ionic radius of the cation 4 in the ionic liquids that are often used at present. This is considered to be because the minus pole side extends more greatly due to the three-dimensional effect. In FIG. 3, 4 indicates a cation of the ionic liquid, and 5 indicates an anion of the ionic liquid.

  According to the actuator element that can be obtained by the above method, since the effective area of the interface between the gel of the carbon nanotube and the ionic liquid is extremely large, the impedance in the interfacial electric double layer is reduced, and the electrical stretching effect of the carbon nanotube is reduced. Contributes to effective use. Also, mechanically, the adhesion at the interface is good, and the durability of the device is increased. As a result, it is possible to obtain a durable element having a high responsiveness and a large amount of displacement in air or vacuum. Moreover, the structure is simple, the size can be easily reduced, and the apparatus can be operated with low power. Furthermore, by adding a conductive additive to the carbon nanotube, the conductivity and filling rate of the electrode film are improved, and a force is generated more efficiently than a conventional similar element.

  The actuator element of the present invention has dramatically improved expansion and contraction performance and generation force as compared with a conventional actuator element composed of carbon nanotubes, ionic liquid and supporting polymer (Patent Document 1). In addition, since the actuator element of the present invention operates with high durability in air and in vacuum, and operates flexibly with low voltage, the actuator of a robot that contacts a person who needs safety (for example, a home robot, a pet) Robots, amusement robots, and other personal robot actuators), robots that work in special environments such as space environments, in vacuum chambers, and rescue, and medical and welfare for surgical devices, muscle suits, bedsore prevention, etc. It is optimal as an actuator for industrial robots, brakes, and micromachines.

  In particular, in order to obtain high-purity products, in the production of materials in a vacuum environment and in an ultra-clean environment, there is an increasing demand for actuators for sample transportation and positioning in order to obtain high-purity products. In addition, the actuator element of the present invention using an ionic liquid that does not evaporate at all can be effectively used as an actuator for a process in a vacuum environment as an actuator that does not cause contamination.

  At least two conductive thin film layers are required to be formed on the surface of the electrolyte membrane. As shown in FIG. 4, by arranging a large number of conductive thin film layers 2 on the surface of the planar electrolyte membrane 1. It is also possible to make complicated movements. By such an element, conveyance by a peristaltic motion, a micromanipulator, and the like can be realized. In addition, the shape of the actuator element of the present invention is not limited to a planar shape, and an element having an arbitrary shape can be easily manufactured. For example, what is shown in FIG. 4 is one in which four conductive thin film layers 2 are formed around the rod of the electrolyte membrane 1 having a diameter of about 1 mm. With this element, an actuator that can be inserted into a narrow tube can be realized.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, it cannot be overemphasized that this invention is not limited to these Examples.

  In this example, the actuator element displacement evaluation was performed as follows.

  Actuator element displacement evaluation method: Using a laser displacement meter as shown in FIG. 1, the element was cut into a 1 mm × 10 mm strip and the displacement at a position of 5 mm when a voltage was applied was measured.

The ionic liquid (IL) used in the examples and comparative examples is ethylmethylimidazolium tetrafluoroborate (EMIBF ₄ ).

  The carbon nanotubes used in Examples and Comparative Examples are high-purity single-walled carbon nanotubes (“HiPco” manufactured by Carbon Nanotechnology Inc.) (hereinafter also referred to as SWNT).

  The polymer used in the examples and comparative examples is a polyvinylidene fluoride-hexafluoropropylene copolymer [PVDF (HFP); trade name kynar2801] (III).

  The solvent used in the examples and comparative examples is N, N-dimethylacetamide (DMAC).

  The polyaniline used in the examples is 20 wt% polyaniline on carbon black (manufactured by Aldrich, conductivity: 40 S / cm).

The polymesoporous silica used in the examples is MCM-41: pore size = 2.7 nm, pore volume = 0.98 cm ³ / g, BET surface area = ˜1000 m ² / g.

  The carbon black used in the examples is Denka Black (granular product) manufactured by Denki Kagaku Kogyo Co., Ltd.

Preparation Example 1
[Preparation of dispersion for forming conductive thin film layer]
In a DMAC solvent, carbon nanotubes (SWNT), ionic liquid (IL), polymer [powdered PVDF (HFP)], conductive auxiliary agent (polyaniline, MCM-41, carbon particles or RuO ₂ ) are dispersed, and magnetic. A dispersion for forming a conductive thin film layer is prepared by stirring with a stirrer and then dispersing by ultrasonic waves.

[Preparation of electrolyte membrane forming solution]
An electrolyte film forming solution is prepared by dissolving an ionic liquid (IL) and a polymer [powdered PVDF (HFP)] in a solvent in the same manner as in the preparation of the conductive thin film layer forming dispersion. Here, a mixed solvent of 4-methylpentan-2-one and propylene carbonate was used as the solvent.

[Manufacture of actuator elements]
The conductive thin film and the electrolyte membrane are obtained by separately casting the dispersion and solution prepared as described above, drying the solvent overnight at room temperature, and then vacuum drying. An actuator element having a three-layer structure is obtained by sandwiching one electrolyte membrane between two obtained conductive thin films and thermocompression bonding.

[Actuator Element Evaluation Method 1]
The displacement responsiveness of the manufactured actuator element was evaluated using the apparatus shown in FIG. The actuator element was cut into a strip having a width of 1 mm and a length of 10 mm, and a 3 mm end portion was held by a holder with an electrode, and a voltage was applied in air. The displacement at a position of 5 mm from the fixed end was measured using a laser displacement meter. The displacement was examined by changing the voltage frequency from 200Hz to 5mHz.

The expansion / contraction rate (ε (%)) was calculated by the following formula from the element length (L (mm)), element thickness (W (mm)), and displacement (D (mm)) of the actuator (see FIG. 1):
ε (%) = 2DW / (L ² + D ² ) × 100
[Actuator element evaluation method 2]
The displacement responsiveness of the manufactured actuator element was evaluated using the apparatus shown in FIG. The actuator element was cut into a strip shape having a width of 1 mm and a length of 15 mm, a 3 mm end portion was held by a holder with an electrode, and a voltage was applied in air at a frequency of 0.1 Hz. Using a laser displacement meter, the displacement at a position 10 mm from the fixed end was measured. The displacement was examined by changing the voltage from ± 0.5 to 3.0V.

  The solvent used in the examples and comparative examples is N, N-dimethylacetamide (DMAC).

Example 1
Conductive thin film layer (electrode) -electrolyte membrane-conductivity using carbon nanotube (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive auxiliary agent (poly-aniline) at the following ratios: A film-like actuator element having a three-layer structure made of a conductive thin film layer (electrode) was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ /poly-An=50.3mg/80.5mg/120.2mg/50.4mg
Electrolyte: kynar2801 / EMIBF ₄ = 101.8mg / 114.3mg.

Example 2
Conductive thin film layer (electrode) -electrolyte film-conductive thin film using carbon nanotube (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive auxiliary agent (MCM-41) at the following ratios: A film-like actuator element having a three-layer structure composed of layers (electrodes) was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ /MCM-41=25.4mg/80.0mg/119.8mg/25.4mg
Electrolyte: kynar2801 / EMIBF ₄ = 101.8mg / 114.3mg.

Example 3
Conductive thin film layer (electrode) -electrolyte film-conductive thin film using carbon nanotube (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive auxiliary agent (MCM-41) at the following ratios: A film-like actuator element having a three-layer structure composed of layers (electrodes) was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ /MCM-41=50.1mg/80.0mg/140.8mg/50.1mg
Electrolyte: kynar2801 / EMIBF ₄ = 101.8mg / 114.3mg.

Example 4
Conductive thin film layer (electrode) -electrolyte membrane-conductivity using carbon nanotubes (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive additive (carbon black: CB) at the following ratios: A film-like actuator element having a three-layer structure composed of a thin film layer (electrode) was manufactured.
Electrode: CNT / CB / kynar2801 / EMIBF ₄ = 50.3mg / 8.2mg / 80.3mg / 120.7mg
Electrolyte: kynar2801 / EMIBF ₄ = 200.0mg / 202.8mg.

Example 5
Conductive thin film layer (electrode) -electrolyte membrane-conductivity using carbon nanotubes (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive additive (carbon black: CB) at the following ratios: A film-like actuator element having a three-layer structure composed of a thin film layer (electrode) was manufactured.
Electrode: CNT / CB / kynar2801 / EMIBF ₄ = 50.3mg / 24.1mg / 80.3mg / 120.6mg
Electrolyte: kynar2801 / EMIBF ₄ = 200.0mg / 202.8mg.

Example 6
Conductive thin film layer (electrode) -electrolyte membrane-conductivity using carbon nanotubes (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive additive (carbon black: CB) at the following ratios: A film-like actuator element having a three-layer structure composed of a thin film layer (electrode) was manufactured.
Electrode: CNT / CB / kynar2801 / EMIBF ₄ = 50.3mg / 40.3mg / 80.3mg / 120.6mg
Electrolyte: kynar2801 / EMIBF ₄ = 200.0mg / 202.8mg.

Example 7
Conductive thin film layer (electrode) -electrolyte membrane-conductivity using carbon nanotube (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive auxiliary agent (poly-aniline) at the following ratios: A film-like actuator element having a three-layer structure made of a conductive thin film layer (electrode) was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ /poly-An=50.7mg/80.0mg/121.0mg/10.4mg
Electrolyte: kynar2801 / EMIBF ₄ = 200.6mg / 201.3mg.

Example 8
Conductive thin film layer (electrode) -electrolyte membrane-conductivity using carbon nanotube (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive auxiliary agent (poly-aniline) at the following ratios: A film-like actuator element having a three-layer structure made of a conductive thin film layer (electrode) was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ /poly-An=50.3mg/80.0mg/120.8mg/20.3mg
Electrolyte: kynar2801 / EMIBF ₄ = 200.6mg / 201.3mg.

Example 9
Conductive thin film layer (electrode) -electrolyte membrane-conductivity using carbon nanotube (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive auxiliary agent (poly-aniline) at the following ratios: A film-like actuator element having a three-layer structure made of a conductive thin film layer (electrode) was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ /poly-An=50.2mg/80.8mg/121.4mg/30.4mg
Electrolyte: kynar2801 / EMIBF ₄ = 200.6mg / 201.3mg.

Example 10
Conductive thin film layer (electrode) -electrolyte membrane-conductivity using carbon nanotube (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive auxiliary agent (poly-aniline) at the following ratios: A film-like actuator element having a three-layer structure made of a conductive thin film layer (electrode) was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ /poly-An=50.7mg/80.6mg/120.1mg/40.0mg
Electrolyte: kynar2801 / EMIBF ₄ = 200.6mg / 201.3mg.

Example 11
Conductive thin film layer (electrode) -electrolyte film-conductive thin film layer using carbon nanotube (CNT), ionic liquid (EMIBF ₄ ), polymer (kynar2801) and conductive auxiliary agent (RuO ₂ ) at the following ratios: A three-layer film-like actuator element composed of (electrode) was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ / RuO ₂ = 27.8mg / 44.0mg / 70.9mg / 20.0mg
Electrolyte: kynar2801 / EMIBF ₄ = 101.8mg / 114.3mg.

Comparative Example 1
Three layers consisting of conductive thin film layer (electrode) -electrolyte film-conductive thin film layer (electrode) using carbon nanotubes (CNT), ionic liquid (EMIBF ₄ ) and polymer (kynar2801) at the following ratios: A film-like actuator element having a structure was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ = 50.2mg / 80.6mg / 121.7mg
Electrolyte: kynar2801 / EMIBF ₄ = 206.2mg / 208.3mg.

Comparative Example 2
Three layers composed of conductive thin film layer (electrode) -electrolyte film-conductive thin film layer (electrode) using carbon black (CB), ionic liquid (EMIBF ₄ ), and polymer (kynar2801) at the following ratios: A film-like actuator element having a structure was manufactured.
Electrode: CB / kynar2801 / EMIBF ₄ = 50.4mg / 80.3mg / 121.2mg
Electrolyte: kynar2801 / EMIBF ₄ = 206.2mg / 208.3mg.

Comparative Example 3
Three layers consisting of conductive thin film layer (electrode) -electrolyte film-conductive thin film layer (electrode) using carbon nanotubes (CNT), ionic liquid (EMIBF ₄ ) and polymer (kynar2801) at the following ratios: A film-like actuator element having a structure was manufactured.
Electrode: CNT / kynar2801 / EMIBF ₄ = 22.2mg / 36.0mg / 56.7mg
Electrolyte: kynar2801 / EMIBF ₄ = 101.8mg / 114.3mg.

Test example 1
Evaluation of the responsiveness to the voltage of the actuator elements obtained in Examples 1 to 6 and Comparative Examples 1 to 2 was performed by the above-described actuator element evaluation method 1. The obtained results are shown in FIGS.

From the results of FIGS. 5 to 15, the addition of polyaniline and MCM-41 as a conductive auxiliary agent dramatically improved the deformation response at low frequencies (particularly in the case of polyaniline, FIG. 5), and the maximum displacement increased. As a result, it became clear that the response at high frequency was improved by 2 to 3 times, the amount of charge was reduced (particularly in the case of MCM-41), and power saving could be realized (FIGS. 7 and 9).

  In addition, it has been clarified that by adding carbon black to the electrode, the expansion / contraction rate is improved up to about 3 times.

  The characteristic of comparing the system added with carbon black and the system added with polyaniline is that, in any case, the addition of polyaniline improves the stretch ratio by almost three times. As the frequency of the applied voltage increases, the expansion / contraction rate decreases dramatically, and at a frequency higher than 0.1 Hz, the expansion / contraction rate decreases compared to the case of no addition (Comparative Example 1). On the other hand, when carbon black was added, it became clear that, for example, even at 10 Hz, the expansion / contraction ratio was about three times larger than when no carbon black was added (FIG. 14). This means that the expansion / contraction rate of the actuator is greatly improved in a wider frequency band as an effect of adding carbon black.

Test example 2
The generated force at the time of deformation was calculated from the maximum expansion / contraction ratio obtained in Test Example 1 and the Young's modulus of the conductive thin film layer separately measured. The Young's modulus of the conductive thin film layer was measured with TMA / SS6000 manufactured by Seiko Instruments Inc. Table 1 shows the generated force. Table 1 shows the generated force comparison at the maximum expansion / contraction rate (at 0.005 Hz). When polyaniline is added as a conductive additive, not only the conductive additive is not added (CNT (50)), but also the stretch rate is improved by nearly 3 times, and the generated force is also improved by 4 times or more. It was. On the other hand, when MCM-41 is added, the expansion / contraction rate is improved by about 1.6 times by adding the same amount of MCM-41 as CNT, but the generated force is the same as when no additive is added. When the amount of CNT in the conductive thin film layer was reduced by half and MCM-41 was added by the reduced amount (Example 2), the expansion / contraction rate was not significantly different even when the amount of CNT was reduced by half. Although it is the same level, it was found that the generation force was halved.

  In addition, when carbon black (CB) is added as a conductive auxiliary agent, carbon black alone (Comparative Example 2) greatly reduces both the expansion and contraction rate and the generated force compared to the case of CNT alone. However, when carbon black was added to CNT, it was found that adding 20 mg or more of CB to CNT (50 mg) not only improved the stretch ratio, but also increased the generation force by more than twice. Furthermore, when the amount of CB added is 40 mg (Example 6), both the stretch rate and the generated force are dramatically improved, and the deformation (stretch rate) and force (generated force) are the same as when polyaniline is added. It became clear. Further, in FIG. 14, when the frequency change of the expansion / contraction rate is compared with the case of no carbon black addition (Comparative Example 1), the expansion / contraction rate comparable to the expansion rate at 0.1 Hz without addition is, for example, 40 mg of CB. When added (Example 6), it is achieved at 10 Hz. That is, it can be said that by adding 40 mg of CB, it was possible to deform at a response speed 10 times faster to achieve the same degree of expansion / contraction. The carbon black used here is about 1000 yen / kg, which is very cheap compared to carbon nanotubes and other conductive additives. By using carbon black, actuators with high expansion and contraction force can be produced at a lower cost. It can be said that it shows the possibility of providing.

Test example 3
Evaluation of the responsiveness to the voltage of the actuator elements obtained in Examples 1, 7 to 10 and Comparative Example 1 was performed by the actuator element evaluation method 1 described above. The obtained results are shown in FIG.

From the results shown in FIG. 16, it has been clarified that by adding 10 to 50 mg of polyaniline as a conductive auxiliary agent , the expansion / contraction rate at a low frequency is greatly improved. In particular, the maximum expansion ratio (at 0.005 Hz) was maximized when 40 mg of polyaniline was added.

  Moreover, in comparatively high frequency, such as 0.1-1 Hz, Example 8 which added 20 mg of polyaniline among Examples 1 and 7-10 showed the best response.

Test example 4
For the actuator elements obtained in Examples 1 and 7 to 10, the generated force at the time of deformation was calculated from the maximum expansion ratio obtained in Test Example 3 and the Young's modulus of the conductive thin film layer separately measured. The Young's modulus of the conductive thin film layer was measured with TMA / SS6000 manufactured by Seiko Instruments Inc. Table 2 shows the generated force. Table 2 shows the generated force comparison at the maximum expansion / contraction rate (at 0.005 Hz). It has been clarified that when 10-50 mg of polyaniline is added as a conductive auxiliary agent, both the maximum expansion ratio and the generated force are greatly improved as compared with the case where no conductive auxiliary agent is added (Table 1, CNT (50)).

Test Example 5
Evaluation of the responsiveness with respect to the voltage of the actuator element obtained in Example 11 and Comparative Example 3 was performed by the actuator element evaluation method 2 described above. The obtained result is shown in FIG.

From FIG. 17, it can be seen that by adding ruthenium oxide as a conductive additive, the deformation response is dramatically improved by applying a voltage greater than ± 1.5V.

DESCRIPTION OF SYMBOLS 1 Electrolyte membrane 2 Conductive thin film layer 3 Conductive layer 4 Cation of ionic liquid 5 Anion of ionic liquid

Claims (3)

Laminating conductive thin film composed of polymer gel containing conductive auxiliary agent, carbon nanotube, ionic liquid and polymer (excluding conductive polymer) and one or more electrolyte membranes composed of ionic liquid and polymer A laminated body comprising :
The conductive auxiliary agent is at least one selected from the group consisting of the following (1) to (4):
(1) polyacetylene, polyaniline, polythiophene, polypyrrole, polyfluorene, polyphenylene, polyphenylene sulfide, poly (1,6-heptadiyne), polyparaphenylene, polyparaphenylene sulfide, polyphenylacetylene, poly (2,5-thienylene), At least one conductive polymer selected from the group consisting of polyindole, poly-2,5-diaminoanthraquinone, poly (o-phenylenediamine), and polypyridine,
(2) Carbon black,
(3) mesoporous silica and
(4) metal oxide,
And the compounding ratio of a conductive support agent is 4-65 weight part with respect to 100 weight part of total amounts of a carbon nanotube, an ionic liquid, and a polymer . An actuator element comprising the laminate according to claim 1 . On the surface of the electrolyte membrane composed of an ionic liquid and a polymer, said conductive conductive thin layer thin film and the electrodes are at least two forms from each other insulated, deformable by applying a potential difference between the conductive thin film layer The actuator element according to claim 2 , which is configured as follows.

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