JP7306046B2 - gel actuator - Google Patents

Description

The present invention relates to gel actuators.

In recent years, polymer materials have attracted attention as materials for actuators that constitute mechanical and electrical circuits that convert energy and electrical signals into physical motion. In particular, a laminated gel actuator using a highly stretchable polymer gel is known as a type of actuator that enables size reduction and weight reduction. For example, the actuator is a candidate for artificial muscle due to its excellent stretchability, and is expected to be applied to products such as welfare equipment and nursing care equipment that aim to assist human movement. there is

Laminated gel actuators typically include electrodes at both ends of a specific gel, as disclosed in US Pat. It is. The gel deformed at this time is deformed by the application of voltage, but the volume itself does not change significantly.
Therefore, in order to increase the amount of change in the entire actuator, the electrode is made into a mesh structure (Patent Document 2), or the electrode itself is provided with unevenness (Patent Document 3) to provide a place where the gel can be deformed. , techniques have been developed that allow for large mutations.
In addition, Non-Patent Document 1 describes a gel actuator in which 4 pieces of gel divided into 2 mm × 2 mm sizes are arranged on a 10 mm × 50 mm stainless steel foil and arranged in 20 pieces. The purpose is to create a gap through which the gel crawls out.

JP 2012-23843 A JP 2014-32162 A WO2013/122047

The Japan Society of Mechanical Engineers Robo-mechanical Conference 2015.2A2-A08 Mechanism of displacement attenuation due to repeated driving of shrinkable PVC gel actuator

In the structures disclosed in Patent Documents 1 and 2 above, the gel moves in the same direction as the moving direction of the electrode, and the electrode sinks into the gel itself, or the gel wraps around the back side of the electrode. . For this reason, when the applied voltage is released, it is difficult to return to the original position, and the mesh electrode moves into the gel, which causes problems such as useless resistance. Therefore, it is not possible to reduce the thickness of the actuator as a whole, and the amount of deformation relative to the size of the actuator becomes small. The power it could produce wasn't necessarily great either.
The structure described in Non-Patent Document 1 discloses a structure that avoids deformation in the thickness direction, but does not disclose specific structural requirements. The structure was not such that sufficient force could be obtained.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an actuator that has a large amount of change with respect to an applied voltage, that can reduce the thickness of the entire actuator, and that can obtain a large force.

As a result of intensive studies in view of the above-mentioned actual situation, the present inventors made the gel smaller than the electrode, and furthermore, by using a plurality of island-shaped (dot-shaped) gels and providing a space around them to escape deformation, , the problem that the gel is deformed in the plane direction rather than the thickness direction is solved, and furthermore, as the distance between the electrodes is narrowed, the contact area with each electrode increases, so that the force for deformation is increased. I found that it can be done. In addition, when observing the deformation of the gel, it was found that only a very small portion of the gel was actually deformed near the periphery. It was found that the thickness was only about 300 μm, and that the other portions were only deformed by being pulled by the portion that caused the large deformation.
That is, by dividing the gel to increase the deformable perimeter and reducing the area of each divided gel to a certain value or less, it was found that a sufficient force can be exhibited as an actuator, and the present invention was reached. bottom.
In addition, by changing the volume of the gel and the contact area with the electrode according to the installation locations of the plurality of gel islands, it is possible to obtain an actuator that can respond to the case where non-uniform force is required depending on the installation locations. I found what I can do.

That is, the gist of the present invention is as follows.
[1] A unit structure comprising a gel layer having a plurality of gel portions containing a dielectric polymer material, and an anode and a cathode sandwiching the gel layer in the thickness direction, and deforming the gel layer by applying a voltage to obtain the A gel actuator that changes the distance between an anode and the cathode,
The (perimeter/area) of the contact portion between the gel portion and the adsorption-side electrode before voltage application is greater than 2 mm ⁻¹ , and
A gel actuator, wherein the circumference of the contact portion between the gel portion and the attraction-side electrode before voltage application increases after voltage application.
[2] The gel actuator according to [1], wherein (1/area) of the contact portion between the gel portion and the adsorption-side electrode before voltage application is larger than 0.32 mm ⁻² .
[3] The gel actuator according to [1] or [2], wherein the gel portion is island-shaped.
[4] The gel actuator according to any one of [1] to [3], wherein the gel portions are spaced so as not to come into contact with adjacent gel portions even when the gel portion is designed to be deformed to its maximum.
[5] The gel actuator according to any one of [1] to [4], wherein the area of the contact portion between the gel portion and the adsorption-side electrode before voltage application varies depending on the gel portion.

According to the present invention, it is possible to provide an actuator that has a large amount of change with respect to an applied voltage, can reduce the thickness of the entire actuator, and can obtain a large force.

FIG. 2 is a diagram schematically showing the configuration and action of an actuator having a unit structure consisting of a gel layer and two electrodes, which is an embodiment of the present invention; In the actuator according to one embodiment of the present invention, the configuration and action of the actuator in which the gel portions are arranged so as to leave a gap so as not to contact the adjacent gel portions even when the gel portions are designed to be deformed to the maximum. It is a figure represented typically. In the drawing, the electrodes on the upper surface of the actuator, the external power supply, and the switches are omitted. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing the configuration and action of a laminated actuator provided with an insulating layer between adjacent actuators, which is an embodiment of the present invention; FIG. 4 is a diagram schematically showing the configuration and action of a laminated actuator having a gel layer between adjacent actuators, which is one embodiment of the present invention.

Embodiments of the present invention will be described in detail below, but these descriptions are examples (representative examples) of embodiments of the present invention, and the present invention is not limited to these contents as long as they do not exceed the gist of the present invention.
Moreover, in the present invention, unless otherwise specified, "two electrodes" means a combination of an anode and a cathode. Also, when a combination of "one electrode" and "another electrode" is used, it indicates that one of them is the anode and the other is the cathode.
Also, the actuators in FIGS. 1 to 4 are shown schematically, and the present invention is not limited to the size of each member or the size ratio between each member shown in these figures.

In the present invention, the term "gel-like" refers to a state in which a fluid sol-like decomposition product solidifies and spontaneously loses its fluidity while maintaining its elasticity. is referred to as a "gel-like substance" (or simply "gel").
In addition, unless otherwise specified, the description of "gel part" in the present invention indicates one independent gel-like substance provided in the gel layer, and further, the description of "gel layer" is not specified. As long as it is a concept including all the gel parts provided in one gel layer.
In addition, unless otherwise specified, the description of the “contact surface” or “contact area” between the gel layer (or gel portion) and the electrode in the present invention refers to the gel layer (or gel portion) and the anode or cathode. Indicates the contact surface or contact area with either one of

In the present invention, unless otherwise specified, the characteristic value relating to the "gel part" is calculated as the average value of the characteristic values of each of the plurality of gel parts provided in the gel layer. For example, the “thickness of the gel portion” means a value calculated by dividing the total thickness of each of the plurality of gel portions provided in the gel layer by the number of the gel portions. The "peripheral length of the contact portion between the gel portion and the adsorption-side electrode" is obtained by dividing the total peripheral length of the contact portion between the plurality of gel portions provided in the gel layer and the adsorption-side electrode before voltage application by the number of gel portions. The definition of these gel portions is the same as that of other characteristic values.
Moreover, unless otherwise specified, the “contact portion” means a portion where the gel portion and the adsorption-side electrode are in contact with each other.

A gel actuator (also referred to simply as an "actuator"), which is one embodiment of the present invention, comprises a gel layer including a plurality of gel portions containing a dielectric polymer material, and an anode and a cathode sandwiching the gel layer in the thickness direction. A gel actuator that deforms the gel layer by applying a voltage and changes the distance between the anode and the cathode, wherein the contact portion (circumference) between the gel portion and the adsorption side electrode before voltage application is (Length/Area) is greater than 2 mm ⁻¹ , and the peripheral length of the contact portion between the gel portion and the adsorption-side electrode before voltage application increases after voltage application.
Moreover, in the present invention, "plurality" means "two or more".

<1. Configuration of Actuator>
FIG. 1 is a diagram schematically showing the configuration and action of an actuator 1 having a unit structure consisting of a gel layer and two electrodes, which is one embodiment of the present invention. The actuator 1 includes a unit structure including a gel layer 11 having a gel portion 10 and electrodes 12 and 13 sandwiching the gel layer 11 in the thickness direction. In the actuator 1, as shown in FIG. 1, when no voltage is applied, the gel layer 11 between the two electrodes has a uniform thickness, and when a voltage is applied in the thickness direction, the gel is displaced. , the overall thickness of the actuator 1 is reduced.
Thus, the actuator 1 can switch between the displacement state and the state of returning to the original thickness by turning on and off the operation of applying voltage between the two electrodes 12 and 13 . That is, the actuator 1 acts as an actuator that is displaced in the thickness direction by a voltage application operation.

When the electrode 12 is the cathode and the electrode 13 is the anode, when a voltage is applied between these electrodes, charge accumulates in the gel layer from the cathode 12 . As a result, an electrostatic adsorption action occurs on the surface of the anode 13, causing creep deformation of the gel in the vicinity of the anode. As shown in FIG. 1, when a voltage is applied between two electrodes, creep deformation causes the gel layer 11 to take a hem-like shape (like crawling on the electrode) on the side in contact with the anode 13 . When the applied voltage is removed, the electrostatic force disappears and the elasticity of the gel restores the gel layer to its original state.
In the present invention, the electrode (electrode 13 in FIG. 1) on the side that spreads like a skirt due to the adsorption action of the gel portion is referred to as an "adsorption side electrode".

In the gel actuator of the present invention, by making the gel part smaller than the electrode in the planar direction, the gel can be easily deformed in the planar direction, and the unevenness of the electrode, which was conventionally required to increase the displacement, can be omitted. . This not only makes it possible to reduce the thickness of the entire actuator and simplify the manufacturing process, but also makes it possible to easily manufacture an actuator having an arbitrary planar shape or curved surface structure.
In addition, by reducing the planar size of each gel portion provided in the gel layer, the amount of deformation when voltage is applied can be increased. By increasing , the restoring force can be increased.

In addition, by reducing the size of the gel portion in the planar direction, it is possible to easily manufacture a gel actuator having a large area, which has been difficult to mold by drying a solvent or forming a film under pressure.
From this point of view, the criterion for the size of the gel portion is that the (perimeter/area) of the contact portion between the gel portion and the adsorption electrode before voltage application is greater than 2 mm ⁻¹ . The simplest structure that satisfies this condition is one in which the gel portion is a circle with a diameter greater than 2 mm. More specifically, "(perimeter/area)" is defined as (the perimeter of the contact portion between the gel portion and the attraction-side electrode before voltage application/the contact portion between the gel portion and the attraction-side electrode before voltage application. area).
Here, (peripheral length/area) means an index of the ratio of contribution to deformation of the gel portion, and the larger the value, the larger the portion contributing to deformation.
(perimeter/area) is required to be greater than 2 mm ⁻¹ , preferably greater than 2.5 mm ⁻¹ , more preferably greater than 3 mm ⁻¹ , and preferably greater than 4 mm ⁻¹ Especially preferred. Considering that the deformed portion has a circumference of about 500 μm, this corresponds to a columnar gel portion with a diameter of 1 mm, which is deformed over almost the entire area. In addition, although there is no particular upper limit to (perimeter/area), it is usually 400 mm ⁻¹ or less.
The perimeter and area can be measured by measuring the dimensions of the cross section of the gel portion, CT scanning, or the like. If there are many objects with different shapes and sizes, the average area and average perimeter can be obtained by image processing.
Further, if the (peripheral length/area) satisfies the above range, a part of the entire actuator is provided with a gel portion in which the (peripheral length/area) is smaller than the above range, as long as the effects of the present invention are not hindered. , a small number (for example, about 20% or less of the total number).
Furthermore, in the gel actuator whose output is deformation in the height direction of the plane, if you want to make the output in the plane uneven (or if the load is not uniform in the plane direction), the position of the gel part, the distribution density, By adjusting the radial distribution, the desired displacement output can be easily generated.

By reducing the size of the gel portion in the planar direction, it is possible to easily manufacture a gel actuator having a large area, which has been difficult to mold by solvent drying or pressurized film formation. In addition to (peripheral length/area), (1/area) of the contact portion between the gel portion and the adsorption-side electrode before voltage application can be used as a standard index for the size of the portion. In this case, (1/area) is preferably greater than 0.32 mm ⁻² . The simplest structure that satisfies this condition is one in which the gel portion is a circle with a diameter greater than 2 mm. More specifically, "(1/area)" is (1/area of the contact portion between the gel portion and the attraction-side electrode before voltage application).
Here, (1/area) means the reciprocal of the contact area per gel portion, and the greater the value, the greater the amount of deformation and the restoring force.
Then, (1/area) is preferably larger than 0.32 mm ⁻² , more preferably larger than 0.5 mm ⁻² , still more preferably larger than 0.8 mm ⁻² , more preferably larger than 1.27 mm ⁻² Larger ones are particularly preferred. Considering that the deformed portion has a circumference of about 500 μm, this corresponds to a columnar gel portion with a diameter of 1 mm, which is deformed over almost the entire area. Further, (1/area) does not need to have a particular upper limit, but is usually 10000 mm ^-2 or less, preferably 100 mm ^-2 or less.
The area can be measured by measuring the dimensions of the cross section of the gel portion or using a CT scan or the like. If there are many objects with different shapes and sizes, the average area and average perimeter can be obtained by image processing.
Further, if (1/area) satisfies the above range, a small number of gel portions having (1/area) smaller than the above range are added to a portion of the entire actuator as long as the effects of the present invention are not impaired. (For example, about 20% or less of the total number) may be included.
Furthermore, in the gel actuator whose output is deformation in the height direction of the plane, if you want to make the output in the plane uneven (or if the load is not uniform in the plane direction), the position of the gel part, the distribution density, By adjusting the radial distribution, the desired displacement output can be easily generated.

Hereinafter, the form of the gel portion provided in the gel layer will be specifically described. With respect to properties such as shape and size, which will be described below, the aspects of the plurality of gel portions provided in the gel layer may be the same or different. Further, as described above, unless otherwise specified, the characteristic value relating to the "gel part" is calculated as the average value of the characteristic values of the plurality of gel parts provided in the gel layer.

The shape of the gel part provided in the gel layer is not particularly limited as long as there is a gap for releasing deformation around it, and can be arbitrarily designed according to the application, for example, island shape (dot shape), line shape, donut shape. be able to. Among these, an island shape such as a prismatic shape or a cylindrical shape is preferable from the viewpoint of enabling efficient production of gel layer formation by a printing technique that can be transferred to a substrate, and in particular, deformation due to applied voltage. From the viewpoint of being able to increase the amount of displacement due to the uniformity of the diameter, the cylindrical shape is preferable. In the case of a cylindrical shape, it deforms uniformly in the circumferential direction, so there is also the effect of good durability. However, in the case of shapes with concave polygons and concave curved surfaces (e.g., stars), the perimeter is longer than that of convex polygons and shapes with convex curved surfaces (e.g., circles, ellipses, convex polygons, etc.). This is advantageous from the viewpoint of the amount of deformation and generated force because the length is long and the electric field is easily concentrated.

The thickness of the gel portion before voltage application is not particularly limited, and can be arbitrarily designed according to the application and the area of the electrode. It is preferably 2 µm or more, more preferably 3 µm or more, particularly preferably 5 µm or more, and most preferably 10 µm or more, while it is usually 10 mm or less, preferably 5 mm or less, and more preferably. It is 1 mm or less, particularly preferably 0.6 mm or less, and most preferably 0.2 mm or less.

The circumference of the contact portion between the gel portion and the adsorption-side electrode before voltage application is not particularly limited, and can be arbitrarily designed according to the application and the area of the electrode, but the circumference of the gel contributes to deformation. From the viewpoint of securing the area of the contact portion between the electrode and the gel portion, the thickness is usually 0.01 mm or more, preferably 0.05 mm or more, more preferably 0.1 mm or more, and particularly preferably 0.01 mm or more. 5 mm or more, and most preferably 1 mm or more. On the other hand, although there is no particular need to set the upper limit, it is usually 10 mm or less.

The average contact area between the gel layer and the adsorption side electrode before voltage application is not particularly limited as long as it is smaller than the area of the electrode, and can be arbitrarily designed according to the application and the area of the electrode. By reducing the size of , it is less than 3.14 mm ² from the viewpoint that a gel actuator having a large area, which was difficult to mold in solvent drying or pressure film formation, can be easily manufactured. It is preferably 2 mm ² or less, more preferably 1.25 mm ² or less, and particularly preferably 0.79 mm ² or less. On the other hand, although there is no particular lower limit, it is usually 0.0001 mm ² or more, preferably 0.01 mm ² or more.
Further, the contact area between the gel portion and the adsorption-side electrode before voltage application may be the same for all the gel portions provided in the gel layer, or may be different. By changing the volume of the gel and the contact area with the electrode according to the condition, it becomes easier to deal with the case where a non-uniform force is required depending on the installation location.

The ratio of the contact area between the gel portion and the adsorption side electrode to the area of the adsorption side electrode is not particularly limited, and can be arbitrarily designed according to the application and the area of the electrode, but from the viewpoint of power supply efficiency. Therefore, it is usually 1% or more, preferably 3% or more, more preferably 5% or more, still more preferably 10% or more, particularly preferably 15% or more, while usually 100% or less, preferably 90% or less, more preferably 80% or less, still more preferably 70% or less, and particularly preferably 60% or less.

The ratio of the contact area between the gel portion and the adsorption-side electrode after voltage application (designed maximum voltage) to the contact area between the gel portion and the adsorption-side electrode before voltage application is not particularly limited. It can be arbitrarily designed according to the area, but from the viewpoint of power supply efficiency, it is usually 100% or more, preferably 102% or more, more preferably 105% or more, and still more preferably 110% or more. , Particularly preferably 120% or more, while usually 300% or less, preferably 250% or less, more preferably 200% or less, further preferably 180% or less, particularly preferably 160% % or less.

The number of gel portions provided in the gel layer is not particularly limited as long as it is plural, and can be arbitrarily designed according to the application and the area of the electrode. , preferably 25 or more, more preferably 100 or more, particularly preferably 200 or more, and most preferably 10,000 or more, while usually 100,000 or less, preferably 10,000 or less, more preferably is 5000 or less, particularly preferably 1000 or less, most preferably 500 or less.
Note that the plurality of islands may be arranged regularly or irregularly. Also, the plurality of islands may be of the same size or may be of different sizes.

The arrangement of the gel portion is not particularly limited, and can be arbitrarily designed according to the application and the area of the electrode. It is preferable to leave a gap that does not contact the adjacent gel portion even when the portion is designed to be deformed to the maximum. In FIG. 2, the electrodes on the upper surface of the actuator, the external power supply, and the switches are omitted.
The design maximum deformation is a state in which the deformation is maximum, which is set when the actuator is designed, and is usually the amount of deformation when the design maximum voltage is applied.

The actuator, which is a unit structure, can be used alone, or can be used as a laminated type in which a plurality of actuators are laminated in the thickness direction. When used in a laminated type, as shown in FIG. 3, an insulating layer is provided between adjacent actuators for lamination, and as shown in FIG. 4, a gel layer is provided between adjacent actuators for lamination. Aspects can be made.
The mode of connection between the actuator and the power supply or switch is not particularly limited. In the case of the laminated type, for example, as shown in FIG. In addition, as shown in FIG. 4, a conductive wire connected to each electrode of the actuator, which is a laminated unit structure, is connected to one power supply or switch, and the displacement of a plurality of gels is caused by ON-OFF of one switch. It can be set as the aspect which controls.
The type of the insulating layer is not particularly limited, and for example, a silicon thermal oxide film (SiO ₂ ), Si ₃ N ₄ , ZrO ₂ , Y ₂ O ₃ , ZnO, Al ₂ O ₃ or the like can be used. . In addition, the thickness of the insulating layer can be appropriately selected depending on the application, but from the viewpoint of enabling miniaturization while maintaining good insulation, it is usually 10 nm to 10 mm, preferably 1 μm to 5 mm. is.
In the laminated actuator, the characteristics of each member constituting the actuator may be evaluated for the entire laminated actuator. can be evaluated for each

The total weight of the plurality of gel portions provided in the gel layer in the actuator can be arbitrarily selected according to the application of the actuator, but in particular from the viewpoint of ensuring the displacement length of the actuator having a plurality of gel layers, it is usually 10% by weight or more. , preferably 15% by weight or more, more preferably 18% by weight or more, still more preferably 20% by weight or more, particularly preferably 22% by weight or more, and preferably 50% by weight or less , more preferably 45% by weight or less, still more preferably 43% by weight or less, and particularly preferably 40% by weight or less.
The ratio of the thickness of the gel layer to the thickness of the entire actuator can be arbitrarily selected according to the application of the actuator, but is usually 0.1 to 99.98%, preferably 1 to 95%. It is more preferably ~90%, even more preferably 10-85%. By making it equal to or higher than the above lower limit, it is preferable because it is possible to reduce the effect of a decrease in displacement length due to the gel layer entering gaps such as meshes in a non-charged state. , the contact probability with the mesh can be sufficiently maintained, and the voltage required for displacement can be lowered.

<2. Gel layer>
<2-1. Raw material of the gel part>
The gel part provided in the gel layer is not particularly limited as long as it contains a dielectric polymer material. The raw materials for the gel disclosed in can be used. Further, the materials of the plurality of gel portions included in the gel layer may be the same or different, but are preferably the same from the viewpoint of making the amount of change due to applied voltage uniform.
The gel portion material is a material that undergoes flexural deformation or creep deformation due to electrical stimulation, and that contracts when a potential difference is applied. Examples of dielectric polymer materials contained in the gel portion include polyvinyl chloride, polyvinyl butyral, polymethyl methacrylate, polyurethane, polystyrene, polyvinyl acetate, nylon 6, polyvinyl alcohol, polycarbonate, polyethylene terephthalate, and polyacrylonitrile, Silicone rubber or the like can be used. Among these, polyvinyl chloride and polyvinyl butyral are preferable from the viewpoint of a substance that outputs a larger amount of displacement and generated force due to applied voltage. The method for producing these dielectric polymer materials is not particularly limited, and generally commercially available materials can be used.

The content of the dielectric polymer material in the gel portion is not particularly limited, but is usually 5% by weight or more, preferably 8% by weight or more, more preferably 8% by weight or more, from the viewpoint of obtaining a sufficient displacement length of the gel. 10% by weight or more, more preferably 12% by weight or more, particularly preferably 15% by weight or more, preferably 60% by weight or less, more preferably 50% by weight or less, and still more preferably is 45% by weight or less, particularly preferably 40% by weight or less.

When polyvinyl chloride is used as the dielectric polymer material, its number average molecular weight (Mn) is not particularly limited, but is measured by gel permeation chromatography (GPC) from the viewpoint of improving the amount of displacement when voltage is applied. In terms of polystyrene, it is 70,000 or more and 200,000 or less, preferably 75,000 or more, more preferably 80,000 or more, still more preferably 85,000 or more, and particularly preferably 90,000 or more. is preferably 180,000 or less, more preferably 160,000 or less, still more preferably 140,000 or less, and particularly preferably 120,000 or less. By setting the number-average molecular weight (Mn) of polyvinyl chloride to 70,000 or more, the resulting gel changes with time, and the electrical properties tend to be stable. On the other hand, by setting it to 200,000 or less, the obtained gel does not become too hard, and a sufficient displacement length can be obtained when a voltage is applied.

When polyvinyl butyral is used as the dielectric polymer material, the number average molecular weight (Mn) is 60,000 or more and 150,000 or less, preferably 70,000 or more, from the viewpoint of improving the amount of displacement when voltage is applied. more preferably 80,000 or more, preferably 140,000 or less, and more preferably 130,000 or less. By setting the number average molecular weight of the polyvinyl butyral to be equal to or higher than each of the number average molecular weights described above, continuous sheeting can be facilitated and handling is facilitated. On the other hand, if the number average molecular weight is equal to or less than the respective number average molecular weights described above, the hardness is moderate, and a sufficient displacement length against voltage can be secured.
In addition, the number average molecular weight used here uses the value of polystyrene conversion by GPC (gel permeation chromatography). When using a commercially available product, the calculated molecular weight may be listed instead of the number average molecular weight depending on the product used. Calculated molecular weights can also be used in similar ranges.

The gel portion may contain materials other than the above-mentioned dielectric polymer materials within the range in which the effects of the present invention are exhibited, and examples thereof include plasticizers and charge scavengers.

The type of plasticizer is not particularly limited, but examples thereof include diol diesters, dicarboxylic acid diesters, dimethylacetamide (DMA), diethanolamine (DEA) and the like. Examples of dicarboxylic acid esters include dibutyl adipate (DBA), dioctyl sebacate (DOS), dioctyl adipate (DOA), dimethyl phthalate (DMP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), and phthalate. Bis(2-ethylhexyl) acid (DEHP), diethyl succinate (DESuc), dimethyl adipate (DMA), diethyl sebacate (DESeb), dibutyl sebacate (DBSeb), dioctyl sebacate (DOS
eb) and the like. Among these, diol diesters and dicarboxylic acid diesters are preferred from the viewpoint of obtaining a relatively easy-to-handle and stable gel substance, and diol diesters and dicarboxylic acid diesters are particularly preferred when polyvinyl chloride is used as the dielectric polymer. is preferably used, and when polyvinyl butyral is used as the dielectric polymer, it is preferable to use dicarboxylic acid diester. The method for producing these dielectric polymer materials is not particularly limited, and generally commercially available materials can be used.

The content of the plasticizer in the gel portion is not particularly limited, but is usually 55% by weight or more, preferably 60% by weight or more, and more preferably 60% by weight or more, from the viewpoint of exhibiting a good displacement length and suppressing the stickiness of the gel surface. preferably 65% by weight or more, more preferably 70% by weight or more, particularly preferably 75% by weight or more, and preferably 95% by weight or less, more preferably 93% by weight or less; It is more preferably 90% by weight or less, and particularly preferably 85% by weight or less.

The type of charge-capturing agent is not particularly limited, but examples thereof include tetracyanoquinodimethane and 2,4,7-trinitrofluoren-9-one.

The content of the charge-capturing agent in the gel portion is not particularly limited, but is usually 0.01% by weight or more, preferably 0.02% by weight or more, and more preferably 0.02% by weight or more, from the viewpoint of exhibiting a good displacement length. is 0.03% by weight or more, more preferably 0.05% by weight or more, particularly preferably 0.1% by weight or more, and preferably 10% by weight or less, more preferably 5% by weight %, more preferably 3% by weight or less, and particularly preferably 2% by weight or less.

The density of the gel portion is usually 0.7-1.5 g/cm ³ , preferably 0.8-1.4 g/cm ³ , and more preferably 0.85-1.35 g/cm ³ . more preferred.
When the density of the gel portion is within the above range, there is an advantage that a load can be supported even if the thickness is reduced, and an increase in the weight of the actuator can be suppressed even if the thickness is increased. As for the measuring method, a general density measuring method can be applied.

<2-2. Method for manufacturing the gel portion>
The method for producing the gel part is not particularly limited, and it can be produced by a general gel production method disclosed in Japanese Patent Application Laid-Open Nos. 2012-23843 and 2014-32152. A mixed solution is prepared by adding a solvent to various raw materials, and the mixed solution is transferred to a container with good releasability such as a Teflon (registered trademark) petri dish, left to stand for a certain period of time to gel, and then peeled from the container. By doing so, a gel portion can be obtained.

The type of solvent used in producing the gel portion is not particularly limited as long as it dissolves the polyvinyl butyral and dicarboxylic acid diester compound. Examples include methanol, ethanol, n-butanol, n-propanol, and isopropanol. alcohol solvents such as tetrahydrofuran, ether solvents such as 1,4-dioxane, cellosolve solvents such as methyl cellosolve and ethyl cellosolve, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and the like. Examples include organic solvents such as amide solvents and nitrile solvents such as acetonitrile. These may be used individually by 1 type, or may use 2 or more types together. Among these, tetrahydrofuran, isopropanol, and methanol are preferred, and tetrahydrofuran is particularly preferred from the viewpoint of volatility and odor.

The content of the solvent in the composition before volatilizing the solvent is usually 40% by weight or more, preferably 45% by weight or more, more preferably 50% by weight or more, from the viewpoint of dissolution rate and volatilization rate. more preferably 55% by weight or more, particularly preferably 60% by weight or more, and preferably 98% by weight or less, more preferably 95% by weight or less, and still more preferably 90% by weight or less and particularly preferably 85% by weight or less.

<3. Electrode>
The shape of the anode and cathode (collectively referred to as “two electrodes”) sandwiching the gel layer in the thickness direction is not particularly limited, and the shape is such that there is a space in which the gel displaced by the application of voltage can move. Alternatively, a shape without the space may be used. The shape having a space in which the gel displaced by voltage application can move includes, for example, a shape having a notch in a part of the electrode, a shape having unevenness, a mesh shape, and the like.
In the case of the shape with the above-mentioned space, the thickness of the entire actuator cannot be reduced, and the amount of deformation with respect to the size of the actuator becomes small.
Moreover, the thickness and the type of material of the electrodes shown below may be the same or different between the anode and the cathode.

The thickness of the electrode can be arbitrarily selected according to the application of the actuator, and is usually 0.01 to 1 mm, preferably 0.012 to 0.9 mm, and more preferably 0.015 to 0.8 mm. more preferred.

The type of electrode material is not particularly limited. brass); metal oxides such as indium oxide and tin oxide, or alloys thereof (ITO, etc.); conductive polymers such as polyaniline, polypyrrole, polythiophene, and polyacetylene; acid, Lewis acid such as _FeCl3 , halogen atoms such as iodine, dopants such as metal atoms such as sodium and potassium; conductive composite materials dispersed in a matrix such as These may be used individually by 1 type, or may use 2 or more types together. Among these, stainless steel and brass are particularly preferable from the viewpoint of electrical properties, workability, and productivity.

<3. Applications of Gel Actuator>
Gel actuators are mechanical parts used in various fields such as automobile parts, electronic parts, food, pharmaceuticals, medical equipment, paper manufacturing, and inspection equipment. They convert input energy or electrical signals output by computers into physical motion. It can be used as a mechanical element that constitutes a mechanical/electrical circuit. In particular, due to the excellent stretchability peculiar to gel-based actuators, it can be applied as an artificial muscle, and can be used in welfare equipment, nursing care equipment, etc. aimed at assisting human movement.

1 Actuator 10 Gel Part 11 Gel Layer 12 Electrode 13 Electrode 14 Insulating Layer

Claims (6)

A unit structure comprising a gel layer having a plurality of gel portions containing a dielectric polymer material, and an anode and a cathode sandwiching the gel layer in the thickness direction. A gel actuator that changes the distance from the cathode,
The (perimeter/area) of the contact portion between the gel portion and the adsorption-side electrode before voltage application is greater than 2 mm ⁻¹ , and
A gel actuator, wherein a contact portion between the gel portion and the adsorption-side electrode has a circumference of 1 mm or more before voltage application, and the circumference increases after voltage application. 2. The gel actuator according to claim 1, wherein the gel portion has a thickness of 0.6 mm or less before voltage application. 3. The gel actuator according to claim 1 , wherein (1/area) of the contact portion between the gel portion and the adsorption side electrode before voltage application is larger than 0.32 mm ⁻² . The gel actuator according to any one of claims 1 to 3 , wherein the gel portion is island-shaped. The gel actuator according to any one of claims 1 to 4 , wherein said gel portions are spaced apart from adjacent gel portions so as not to come into contact with each other even at the maximum design deformation. 6. The gel actuator according to any one of claims 1 to 5 , wherein the area of the contact portion between the gel portion and the adsorption-side electrode before voltage application differs depending on the gel portion.

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