KR20110122244A - Elastomer actuator having metal electrode with electrical conductivity degradation prevented - Google Patents

Abstract

PURPOSE: An elastomer actuator having a metal electrode with electrical conductivity degradation prevented are provided to increase a contact point between metal particles by adding a carbon nanotube to a metal paste electrode layer. CONSTITUTION: In an elastomer actuator having a metal electrode with electrical conductivity degradation prevented, an electrode layer(200) is formed with a metal paste. The metal paste contain metal particles(202) and a carbon nanotube(201) which are formed in both sides of a dielectric elastomer film The carbon nanotube has bimodal or trimodal distributions. The metal particles is comprised of a silver, gold, and platinum having average diameter of 1nm to 50um. The electrode layer contains a carbon nanotube of 0.001-30 parts by weight based on 100 parts by weight.

Description

Elastomer Actuator having Metal Electrode with Electrical Conductivity Degradation Prevented}

The present invention relates to an elastomeric actuator, and in particular, the electric conductivity of the metal paste electrode is prevented from being deteriorated due to the elastic deformation of the actuator, and the electrical conductivity of the electrode provided in the actuator is improved by the elastic deformation of the elastomeric actuator. It relates to an elastomeric actuator.

Recently, interest in electrode forming technology using carbon or nano metal has been increasing. The electrode forming technology is used for solar cells, display devices, and the like, and it is expected that the use of the touch pad will increase rapidly due to the influence of the i-pad.

In particular, in order to be used in a display in which elasticity is important, such as a haptic phone using a touch-screen, electrodes must be formed on the upper and lower sides of the elastic polymer, and to be used in a display device such as a touch-screen. It is urgent to develop a technology of a polymer-based actuator having excellent electrical properties while maintaining elasticity.

As is known, actuators refer to devices that convert electrical energy and mechanical work at the macro or micro level, and polymer-based electromechanical actuators have been studied for decades.

As the electrode material of the actuator, conductive oxides such as indium tin oxide (ITO), conductive particles such as metal particles, and conductive polymers are used.However, in the case of forming a metal film with a paste solution, an electrode formed by using a paste by stretching of the actuator is used. When the film is formed of a conductive polymer, the electrode deteriorates severely and the sheet resistance of the electrode itself is high. When the film is formed of a conductive oxide, the flexibility of the electrode is low and a high temperature process is essential. There is a problem that the polymer-based actuator itself is thermally deformed.

SUMMARY OF THE INVENTION An object of the present invention is to provide an elastomeric actuator which is prevented from deteriorating the electrical conductivity of the metal paste electrode during physical deformation of the actuator and has excellent reproducibility and precise deformation.

The elastomeric actuator according to the present invention comprises a dielectric elastomer film; And an electrode layer formed of a metal paste containing metal particles and carbon nanotubes on opposite sides of the dielectric elastomer film.

In detail, the elastomeric actuator according to the present invention contracts in the thickness direction of the elastomeric actuator by the voltage applied to the metal paste electrode layer, and elastic deformation occurs in the plane direction of the electrode layer, and the elastic deformation of the elastomeric actuator is performed. In this case, the carbon nanotubes increase the contact point between the carbon nanotubes and the carbon nanotubes or between the carbon nanotubes and the metal particles, thereby preventing a decrease in the surface electrical conductivity of the elastomeric actuator.

In this case, the metal paste electrode layer refers to an electrode layer formed by applying a metal paste containing metal particles and carbon nanotubes to the dielectric elastomer film.

In order to prevent reduction of the electrical conductivity in the plane direction when elastic deformation of the elastomeric actuator, the carbon nanotubes contained in the metal paste electrode layer are bimodal based on the distribution of the aspect ratio of the carbon nanotubes. ) Or trimodal distribution, and in detail, the long-to-short ratio distribution of carbon nanotubes is 10 to 10 ² first peak, 10 ³ to 10 ⁴ second peak and 10 ⁵ to 10 ⁶ It is characterized by having two or more peaks selected from the third peak of.

In the elastic deformation of the elastomeric actuator, in order to reduce the contact resistance between the carbon nanotubes and the metal particles, the metal particles are preferably precious metals which are silver (Ag), gold (Au), platinum (Pt), or a mixture thereof. Do.

In addition, in the elastic deformation of the elastomeric actuator, in order to uniformly increase the contact point in the entire region of the metal paste electrode, the diameter distribution of the metal particles preferably has a unimodal distribution, the average of the silver particles The diameter is preferably 1 nm to 50 m.

In the elastic deformation of the elastomeric actuator, in order to prevent a decrease in electrical conductivity in the plane direction, the electrode layer preferably contains 0.001 to 30 parts by weight of carbon nanotubes based on 100 parts by weight of the metal particles, and the metal paste electrode layer is made of metal It is preferable to further contain 0.001 to 30 parts by weight of graphene (graphene) based on 100 parts by weight of particles.

The dielectric elastomer film of the elastomeric actuator according to the present invention is characterized by satisfying the following relational formula (1).

(Relationship 1)

(z is the dielectric elastomer film thickness when no voltage is applied to the metal paste electrode layer, and z ^v is the dielectric elastomer film thickness when voltage is applied to the metal paste electrode layer.)

The elastomeric actuator according to the present invention has the effect of having a constant electric conductivity by compensating for the decrease in the electrical conductivity caused by the deformation of the metal paste electrode layer and preventing the decrease in the electrical conductivity of the electrode due to the physical deformation of the electrode, while maintaining the elasticity of the electrode It has the effect of having constant and reproducible electrical conductivity, and it is effective to prevent the decrease in electrical conductivity regardless of the degree of deformation of the electrode according to the magnitude of the voltage applied to the electrode. There is an effect of maintaining a constant electrical conductivity.

1 is a view showing an example of an elastomeric actuator according to the present invention,
2 is a view showing an example of a metal paste electrode layer in the elastomeric actuator according to the present invention,
3 is a view showing another example of the metal paste electrode layer in the elastomeric actuator according to the present invention,
3 is an example showing the distribution of the long and short ratios of the carbon nanotubes contained in the metal paste electrode layer in the elastomeric actuator according to the present invention.
4 is a view showing another example of the metal paste electrode layer in the elastomeric actuator according to the present invention.
Description of the Related Art [0002]
100: dielectric elastomeric film 100 ': modified dielectric elastomeric film
210, 220, 200: metal paste electrode layer
210 ', 220', and 200 ': modified metal paste electrode layer
201: carbon nanotube 203: graphene
202: Metal Particles

Hereinafter, the elastomeric actuator of the present invention will be described in detail with reference to the accompanying drawings. The drawings introduced below are provided by way of example so that the spirit of the invention to those skilled in the art can fully convey. Therefore, the present invention is not limited to the following drawings, but may be embodied in other forms, and the following drawings may be exaggerated in order to clarify the spirit of the present invention. Also, throughout the specification, like reference numerals designate like elements.

Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

1 is an example of an elastomeric actuator according to the present invention, as shown in Figure 1 (a), the elastomeric actuator according to the present invention is a dielectric elastomer film (elastomer film, 100) and the dielectric elastomer And a metal paste electrode layer 200 formed on the two opposing surfaces of the film by using metal paste, respectively.

In this case, the elastomeric actuator is formed so that the upper metal paste electrode layer 210 and the lower metal paste electrode layer 220 face each other with the dielectric elastomer film 100 interposed therebetween, as shown in FIG. 1 (b). Likewise, when a voltage V is applied between the upper electrode layer 210 and the lower electrode layer 220, an electrostatic force is generated by charges caused by the two electrode layers 210 and 220.

Due to the electrostatic force, the dielectric elastomer film 100 is subjected to mechanical pressure in the thickness direction t of the dielectric elastomer film 100, as shown by the arrow of FIG. The elastomeric film 100 is contracted in the thickness direction t while being stretched in the plane direction p, which is a direction belonging to the surface in which the electrode layer 200 of the dielectric elastomeric film 100 is laminated.

In this case, as shown in FIG. 1B, the thickness direction t is a stacking direction in which the dielectric elastomer film 100 and the electrode layer 200 are stacked, and the dielectric elastomer film 100 and the electrode layer 200 are stacked. Or the thickness direction of the elastomeric actuator, the plane direction is a plane perpendicular to the thickness direction, in the direction (p1, p2, p) belonging to the interface in which the electrode layer 200 is laminated in the dielectric elastomer film 100 It means any direction perpendicular to the thickness direction.

1 (c) and 1 (d) are cross-sectional views in the aa direction of FIGS. 1 (a) and 1 (b) showing the elastic deformation of the elastomeric actuators before and after voltage is applied. As shown, the dielectric elastomer film 100 is deformed by the electrostatic force applied by the voltage applied to the two electrode layers 200, and the upper electrode layer 210 and the lower electrode layer 220 formed on the dielectric elastomer film 100 are shown. ) Is also contracted along with the dielectric elastomer film 100 in the thickness direction t, and is stretched in the plane direction p.

In the elastomeric actuator according to the present invention, the metal paste electrode layer 200 contains metal particles and carbon nanotubes, and the dielectric elastomer film 100 and the electrode layer 200 are applied by a voltage applied to the electrode layer 200. ) Is contracted in the thickness direction (t) and stretched in the plane direction (p), the contact point between the carbon nanotubes and the carbon nanotubes or between the carbon nanotubes and the metal particles is increased by the carbon nanotubes. The reduction in the in-plane electrical conductivity of the elastomeric actuator is prevented.

Figure 2 is an example showing in detail the carbon nanotubes 201 contained in the metal paste electrode layer 200 in the elastomeric actuator according to the present invention, Figure 3 is an electrode layer 200 in the elastomeric actuator according to the present invention The carbon nanotube 201 and the metal particles 202 are shown in detail. In this case, although the metal particles are shown to be uniformly arranged in FIG. 3, this is to more clearly illustrate the increase in contact points due to shrinkage in the thickness direction (t) and tension in the plane direction (p). It is apparent that the same idea is maintained even when the particles 202 are randomly distributed or similarly distributed in the dense structure.

As shown in FIG. 3A, the metal paste electrode layer 200 contains carbon nanobuttes 201 having a large aspect ratio together with the metal particles 202.

As the metal paste electrode layer 200 is deformed, the density of the metal particles 202 in the thickness direction t increases and the density of the metal particles 202 in the plane direction p decreases, resulting in the surface of the elastomeric actuator. Direction is reduced, the electrode layer 200 contains the carbon nanotubes 201 having a large aspect ratio, the carbon nanotubes 201 in the thickness direction (t) compressive stress and surface direction ( twisted by the tensile stress in p), carbon nanotubes 201 having arbitrary directions are rearranged in parallel with the plane direction p of the dielectric elastomer film 100.

As shown in FIG. 2 (b), the carbon nanotubes 201 are rearranged in parallel to the plane direction p by applying a voltage to the electrode layer 200, and thus the carbon nanotubes in the plane direction. The contact point between the carbon nanotube and the carbon nanotube (cp) of FIG. 2 (b) is increased, so that even if the elastomeric actuator is deformed, reproducible and very high electric conductivity (electric conductivity in the surface direction) is obtained. As shown in (b), the carbon nanotubes 201 are rearranged in parallel to the plane direction p and at the same time, the carbon nanotubes 201 and the metal are changed by the density change of the metal particles 202. The contact point (cp) in FIG. 3 (b) also increases between the particles 202.

In detail, the metal particles 202 have a high density in the thickness direction t and a decrease in the surface direction p, and the electrical conductivity lowered by the density reduction in the surface direction p is reduced. The rearrangement of the carbon nanotubes 201 and the metal particles 202 is compensated by an increase in the contact point, thereby preventing a decrease in electrical conductivity in the plane direction p.

As described above, in the elastomeric actuator according to the present invention, since the metal paste electrode layer 200 formed using the metal paste contains the metal particles 202 and the carbon nanotubes 201, the electrical conductivity is reduced. It is characterized by improving the electrical conductivity of the electrode layer 200 provided in the elastomeric actuator by using the physical deformation of the elastomeric actuator, thereby reducing the electrical conductivity due to the deformation of the electro-mechanical energy conversion of the elastomeric actuator At the same time as the efficiency is increased, the electrical conductivity of the metal paste electrode layer 200 provided in the elastomeric actuator is improved as the electro-mechanical energy conversion efficiency is increased.

In this case, in order to increase the contact point due to rearrangement of the carbon nanotubes, the long-to-short ratio of the carbon nanotubes 201 contained in the metal paste electrode layer 200 is preferably 10 to 10 ⁶ .

More specifically, in order to more effectively increase the contact point in the plane direction by the rearrangement of the carbon nanotubes, as shown in FIG. 3, the carbon nanotubes 201 of the metal paste electrode layer 200 are carbon nanotubes. It is characterized by having a bimodal (trimodal) or trimodal (trimodal) distribution based on the distribution of the aspect ratio of.

As shown in FIG. 3, as the distribution of the long-to-short ratio of the carbon nanotubes 201 has a multiple distribution having two or more peaks, a constant voltage V is applied to the metal paste electrode layer 200. When applied, rearrangement of carbon nanotubes effectively creates a very large number of new contact points, and prevents a decrease in electrical conductivity in the plane direction p regardless of the magnitude of the voltage V applied to the elastomeric actuator. The electrical conductivity in the plane direction p is kept constant even in a transient state in which a voltage V is being applied to the elastomeric actuator. Accordingly, when the elastomeric actuator is utilized, the deformation of the actuator occurs stably and reproducibly even when a voltage of a certain waveform is applied, and the deformation of the actuator due to the changed voltage is precisely controlled.

Characteristically, the distribution of long and short ratios of the carbon nanotubes 201 may include a first peak (peak1 of FIG. 3) having an average long and short ratio (ar1 of FIG. 3) of 10 to 10 ² , and an average long and short ratio (of FIG. 3). ar2) two or more peaks selected from a second peak of 10 ³ to 10 ⁴ (peak 2 of FIG. 3) and an average long-term ratio (ar3 of FIG. 3) of a third peak of 10 ⁵ to 10 ⁶ (peak 3 of FIG. 3) It is preferable that it is a distribution having

The long-to-short ratio of the first to third peaks of the carbon nanotubes 201 reduces the electric conductivity in the plane direction p when the dielectric elastomer film 100 and the metal paste electrode layer 200 of the elastomeric actuator are deformed. It is a long-term ratio ratio distribution that does not occur.

When the carbon nanotubes 201 have the above-described distribution, the carbon nanotubes 201 and the metal particles 202 at the density change in the thickness direction t and the plane direction p of the metal particles 202. In order to evenly increase the contact point between the electrodes in a large area of the electrode, the diameter distribution of the metal particles 201 preferably has a unimodal distribution, and the average diameter of the metal particles is preferably 1 nm to 50 μm. . In this case, the metal particles 202 include aggregates in which a plurality of metal particles are aggregated.

The metal particles 201 may be platinum, gold, silver, copper, aluminum, or a mixture thereof, but in terms of ease of deformation and low contact resistance with carbon nanotubes, silver (Ag), gold (Au), and platinum ( Pt), or a mixture thereof, is preferred.

The metal paste electrode layer 200 preferably contains 0.001 to 30 parts by weight of carbon nanotubes 201 based on 100 parts by weight of the metal particles 202, and the parts by weight rearrange the carbon nanotubes. By increasing the connection point between the carbon nanotubes and between the carbon nanotubes and the metal particles, it is a weight part to prevent the reduction in the electrical conductivity in the plane direction (p) due to the deformation of the elastomeric actuator.

As shown in FIG. 4, in the elastomeric actuator according to the present invention, the metal paste electrode layer 200 further includes graphene 203 together with the metal particles 202 and the carbon nanotubes 201. It is characterized in that it further contains 0.001 to 30 parts by weight of graphene 203 based on 100 parts by weight of the metal particles 202.

As shown in FIG. 4, the graphene 203 is optionally formed by the compressive stress in the thickness direction t caused by the electrostatic force and the tensile stress in the plane direction p together with the carbon nanotubes 201. The graphene 203 having the direction of is rearranged in parallel with the plane direction p of the dielectric elastomer film 100.

By rearranging the carbon nanotubes 201 and the graphene 203, between the carbon nanotubes and the carbon nanotubes in the plane direction p, between the carbon nanotubes and the metal particles, between the carbon nanotubes and the graphene, The contact point between the graphene and the graphene and the graphene and the metal particles is increased to prevent the electrical conductivity in the plane direction (p) due to the deformation of the elastomeric actuator.

The physical deformation caused by the application of electrical energy of the elastomeric actuator is dependent on the magnitude of the voltage applied to the metal paste electrode layer 200, the dielectric constant of the dielectric elastomeric film 100 and the thickness of the dielectric elastomeric film 100. It is mainly controlled by the following, and in detail, it is controlled by the following equation (2).

(Relationship 2)

(P _el is the electrostatic pressure, ε is the dielectric constant of the dielectric elastomeric film, ε ₀ is the dielectric constant of the vacuum, U is the voltage applied to the electrode layer, and z is the thickness of the dielectric elastomer film to be)

As described above, the present invention improves the electrical conductivity of the metal paste electrode layer 200 included in the elastomeric actuator by using the physical deformation of the elastomeric actuator, thereby maintaining stable and reproducible electrical conductivity of the electrode layer 200. For the purpose, the thickness of the elastomeric film is characterized by satisfying the following relation 2.

(Relationship 1)

(z is the dielectric elastomer film thickness when no voltage is applied to the electrode layer, and z ^v is the dielectric elastomer film thickness when voltage is applied to the electrode layer.)

The dielectric elastomer film 100 satisfies Equation 2 above at a constant voltage applied to the elastomeric actuator, and a dielectric elastomer commonly used in the elastomeric actuator may be used. In one example, the dielectric elastomer film 100 is a silicone rubber or an acrylate polymer. The carbon nanotubes 201 may include metallic single-walled carbon nanotubes, double-walled carbon nanotubes, or multi-walled carbon nanotubes, and the graphene 203 may include single layer graphene or multilayer graphene.

The elastomeric actuator may be manufactured by applying a metal paste on two opposite surfaces of the dielectric elastomer film using a metal paste in which metal particles and carbon nanotubes are dispersed in an oil or a gel, and then drying them. The coating may be performed by a spray method, a screen printing method, an inkjet method, spin coating, or the like.

In this case, not only the aspect ratio distribution of the carbon nanotubes and the aspect ratio of the carbon nanotubes described above, but also the amount of conductive particles (metal particles, carbon nanotubes, graphene) contained in the dispersion medium of the metal paste, etc. are adjusted to apply the electrode paste. By controlling the distance, surface density, and distance distribution between two conductive particles selected from metal particles, carbon nanotubes, and graphene of the metal paste electrode layer formed by the electrode, the rate of contact point increase between the conductive particles due to the deformation of the dielectric elastomer film can be controlled. have.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all the things that are equivalent to or equivalent to the claims as well as the following claims will belong to the scope of the present invention. .

Claims (8)

Dielectric elastomer films; And an electrode layer formed of a metal paste containing metal particles and carbon nanotubes on opposite sides of the dielectric elastomer film. The method of claim 1,
The carbon nanotubes have a bimodal (trimodal) or trimodal (trimodal) distribution on the basis of the distribution of the aspect ratio of the carbon nanotubes (Elastomer Actuator). The method of claim 2,
The elastic ratio of the carbon nanotubes has two or more peaks selected from a first peak of 10 to 10 ² , a second peak of 10 ³ to 10 ⁴ , and a third peak of 10 ⁵ to 10 ⁶ . Polymer actuators. The method of claim 3,
The metal particles are elastomeric actuators, characterized in that the precious metal particles are silver (Ag), gold (Au), platinum (Pt), or a mixture thereof having an average diameter of 1 nm to 50 ㎛. The method of claim 2,
The electrode layer is an elastomeric actuator, characterized in that containing 0.001 to 30 parts by weight of carbon nanotubes based on 100 parts by weight of the metal particles. The method of claim 2,
The electrode layer is an elastomeric actuator, characterized in that it further contains 0.001 to 30 parts by weight of graphene (graphene) based on 100 parts by weight of the metal particles. The method of claim 1,
The elastomeric actuator is contracted in the thickness direction of the elastomeric actuator by the voltage applied to the electrode layer and elastic deformation occurs in the plane direction of the electrode layer, and when the elastic actuator of the elastomeric actuator, the carbon nanotube Elastomer actuator, characterized in that the contact point between the carbon nanotubes and carbon nanotubes or between the carbon nanotubes and the metal particles is increased to prevent a decrease in the surface electrical conductivity of the elastomeric actuator. The method of claim 1,
The elastomeric actuator is an elastomeric actuator, characterized in that the following relation 1.
(Relationship 1)

(z is the dielectric elastomer film thickness when no voltage is applied to the electrode layer, and z ^v is the dielectric elastomer film thickness when voltage is applied to the electrode layer.)

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