CN106426099A - Electrically driven artificial muscle and preparation method thereof - Google Patents

Abstract

The invention is an electrically driven artificial muscle based on liquid metal, including liquid metal flexible electrodes that can be sprayed, printed or printed, electroactive polymer materials, and flexible packaging materials, wherein the liquid metal flexible electrodes are covered on the electroactive polymer material The surface is the positive electrode and the negative electrode respectively, and the flexible packaging material is wrapped around the liquid metal flexible electrode and the outside of the electroactive polymer material to protect the liquid metal flexible electrode; this artificial muscle can bend or bend under the action of an external electric field. Other deformations; Compared with the existing artificial muscle tissue made of platinum or gold materials, the scheme proposed by the present invention has fewer process steps, lower cost and does not require the use of dangerous compounds. It can be used in medical device design and industrial product manufacturing And robotics and other fields have a wide range of applications.

Description

A kind of electrically driven artificial muscle and its preparation method

technical field

The invention belongs to the technical field of artificial muscles, and in particular relates to an electrically driven artificial muscle and a preparation method thereof.

Background technique

By simulating the movement of organisms, achieving high efficiency and high flexibility in engineering design has always been a hot spot in the field of mechanical engineering. Most of the various movement modes of organisms are realized through muscle contraction and stretching, so artificial muscles have become one of the hot areas in scientific research. Similar to the muscle tissue of a living body, the most important feature of the artificial muscle is that it can produce bending or contraction movement under the action of external electrical excitation, and output a certain force while generating deformation, and place the artificial muscle at the joint of the machine that needs to move , with the control module, it can realize the set action or complete the corresponding task. In the research of intelligent manufacturing and bionic robot, artificial muscle is an important part, which helps to realize the light weight and flexibility of the robot.

The realization of traditional artificial muscles is generally to inject fluid into different chambers through pneumatic or hydraulic devices through variable elastic chambers to make them expand or contract, and to cooperate with valve flow channels and air pumps or liquid pumps to rationally design the chambers Different types of movement such as bending, winding, and stretching can be realized. The advantage of this artificial muscle design is that it has a large driving force and can realize more complex shapes and structures. But its disadvantage is that it cannot achieve complete flexibility, and requires a large number of rigid components such as air pumps, pipes, and valves, and because of the chamber structure, its volume is often large, which is not conducive to some occasions that require micro-instruments.

In addition to traditional artificial muscles, the use of material properties to achieve electro-deformation has become one of the new research directions. The study found that a class of elastic polymer materials can be deformed under the action of electrical stimulation, so they were named electroactive polymers. Electroactive polymers are divided into two categories: electronic and ionic. Among them, electronic electroactive polymers, also known as electric field active materials, induce electrostrictive effects and electrostatic, piezoelectric and ferroelectric effects through the electrostatic force in the electric field. Materials can induce displacement under the action of a DC electric field, such as dielectric elastomers. When a voltage is applied, it will shrink along the direction of the electric force line and expand in a plane perpendicular to the electric force line. This material usually requires a high excitation electric field (>100V/μm), close to the breakdown electric field. Ionic electroactive polymers drive actuators through the movement of ions in the polymer. Ionic electroactive polymers often require relatively low voltage and high current, and their energy efficiency is relatively low, requiring continuous energy supply to maintain their shape. Such polymers typically operate in liquid ionized environments and are therefore commonly used for applications in biological environments.

A typical class of ionic electroactive polymers is ionic polymer-metal composites, which consist of ionic polymer films and metal electrodes coated on the surface of the films. Inside the ionic polymer membrane, a large number of cations are contained to neutralize the anions covalently bonded to the polymer backbone. This composite material can generate large strain at low driving voltage and low impedance. The electric field causes a change in ion concentration, which attracts water molecules to move toward one side of the polymer. The non-uniform distribution of water molecules causes one side of the actuator to swell and the other side to shrink, causing the layered structure to bend toward the electrode side. In the present invention, the artificial muscle is constructed based on the design of this ionic polymer-metal composite material.

Liquid metal is a metal material with a melting point in the room temperature range, usually based on gallium-based alloys, including indium, tin, bismuth and other elements. At present, liquid metal materials can be used to print flexible electronic circuits, which can be applied to skin electronics and wearable devices. Liquid metal can also be combined on the surface of other objects by spraying and other methods.

Traditional ionic polymer-metal composite materials need to use materials such as platinum or gold and their compounds to make artificial muscles. The method of chemical deposition is relatively complicated, and the heating and other operations involved in the process are also dangerous.

Contents of the invention

In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide an electrically driven artificial muscle and its preparation method, combined with the printing and spraying performance of liquid metal, using liquid metal as electrode material, made of ion exchange membrane, It is an ion-exchange polymer metal material (IPMC); the invention uses liquid metal materials and electroactive polymers to make artificial muscles. Compared with traditional chemical deposition methods, it simplifies the manufacturing process, reduces costs and improves performance. It is helpful to promote the further expansion of artificial muscle research and application.

In order to achieve the above object, the technical scheme adopted in the present invention is:

An electrically driven artificial muscle, including a liquid metal flexible electrode 2 that can be sprayed, printed or printed, an electroactive polymer material 3 and a flexible packaging material 4, wherein the liquid metal flexible electrode 2 is covered on one of the electroactive polymer materials 3 Or both surfaces, that is, only the positive electrode or the negative electrode adopts the liquid metal flexible electrode 2 or the positive and negative electrodes both adopt the liquid metal flexible electrode 2, and the flexible packaging material 4 is wrapped on the outside of the liquid metal flexible electrode 2 and the electroactive polymer material 3 to act To the protection of liquid metal flexible electrode 2.

The liquid metal flexible electrode 2 can be selected from different liquid metal materials, such as metal gallium, gallium-based alloy with low melting point in different proportions, etc., and the liquid metal electrode material can be selected according to printing performance and environmental adaptability requirements.

The electroactive polymer material 3 is an electroactive polymer capable of deformation including bending and stretching under the action of an external electric field, such as a proton exchange membrane.

The electroactive polymer material 3 can use different types of electroactive polymers, such as proton exchange membranes, etc., which can undergo deformations such as bending and stretching under the action of an external electric field.

When the liquid metal flexible electrode 2 covers one surface of the electroactive polymer material 3 , the other electrode is a thin layer 5 of gold or platinum.

The electroactive polymer material 3 is single-layer or multi-layer. When it is multi-layer, liquid metal flexible electrodes 2 are respectively arranged on each layer, and the artificial muscle tissue with higher thickness and larger bending moment is formed by lamination.

The artificial muscles are placed and combined in three-dimensional space in different directions, thereby forming a complex artificial muscle tissue capable of deforming or bending in multiple directions.

For the electroactive polymer material 3 , before spraying or printing the liquid metal material on the surface, it is necessary to distribute enough ion hydrate inside the electroactive polymer material 3 by soaking or wetting.

The present invention also provides a method for preparing the electrically driven artificial muscle, in which the liquid metal flexible electrode material is uniformly sprayed on the surface of the electroactive polymer material 3 to form a liquid metal flexible electrode 2, and then the liquid metal flexible electrode 2 is connected to the liquid metal flexible electrode 2 with an electrode clip. The external power supply is further sprayed on the surface of the liquid metal to form a flexible packaging material 4 to protect the liquid metal flexible electrode 2 .

The electroactive polymer material 3 selects Nafion 117 proton exchange membrane, after removing surface impurities, soaks in 1 mole per liter of sodium chloride solution for about 1 hour, and sprays liquid metal flexible electrode material after taking it out; the liquid metal The mass fraction of gallium is selected as 75%, and the mass fraction of indium is 25% gallium-indium alloy; After the spraying is completed, the proton exchange membrane is trimmed to avoid the short circuit of the positive and negative electrodes; and then the PVC solution is sprayed on the surface of the liquid metal. After the solvent in the PVC solution evaporates, a layer of PVC film is left, which is the flexible packaging material 4 .

The liquid metal flexible electrode material is sprayed on one or both surfaces of the electroactive polymer material 3, that is, only the positive electrode or the negative electrode uses the liquid metal flexible electrode 2 or both the positive and negative electrodes use the liquid metal flexible electrode 2, when the liquid metal flexible electrode When 2 covers one surface of the electroactive polymer material 3, a thin layer 5 of gold or platinum is formed on the other surface of the electroactive polymer material 3 by chemical deposition as another electrode.

Compared with the prior art, the electrically driven artificial muscle based on liquid metal realized by the present invention can produce bending or other deformation under the action of an external electric field by printing or spraying liquid metal material on the surface of the electroactive polymer. Compared with the existing artificial muscles of mechanical devices, the product volume and control portability are simplified. Compared with the existing artificial muscle tissue formed by chemical deposition of platinum or gold materials, the process steps of the scheme proposed by the present invention are less , lower cost and does not require the use of dangerous compounds, and has a wide range of applications in medical device design, industrial product manufacturing, and robotics.

Description of drawings

Fig. 1 is a schematic structural diagram of an electrically driven artificial muscle provided by the present invention, the positive and negative electrodes on both sides of the electroactive polymer material are liquid metal flexible electrodes.

Fig. 2 is a schematic structural diagram of an electro-driven artificial muscle provided by the present invention. The positive electrode material of the electroactive polymer material is a liquid metal flexible electrode, and the negative electrode material is an electroless gold element plating layer.

Fig. 3 is a schematic diagram of directional bending of the electro-driven artificial muscle of the present invention after voltage is applied.

Fig. 4 is a schematic diagram of the composite structure of the electro-driven artificial muscle provided by the present invention, in which multiple layers of electro-driven artificial muscles are superimposed to increase the driving torque of the artificial muscle.

Fig. 5 is a schematic diagram of the composite structure of the electro-driven artificial muscle provided by the present invention. The artificial muscle is placed in three-dimensional space in different directions to form a complex artificial muscle tissue that can deform or bend in multiple directions.

detailed description

The implementation of the present invention will be described in detail below in conjunction with the drawings and examples.

Fig. 1 and Fig. 2 are schematic structural diagrams of an electrically driven artificial muscle provided by the present invention, which are also two embodiments of the present invention.

First, the electroactive polymer material 3 is heated and soaked in hydrogen peroxide for about 10 minutes. Specifically, in this embodiment, the electroactive polymer material 3 is selected from Nafion 117 proton exchange membrane. After removing surface impurities, the Nafion 117 membrane is then soaked in 1 mole about 1 hour per liter of sodium chloride solution. Take out the Nafion 117 proton exchange membrane, and evenly spray liquid metal flexible electrode material on the surface of the exchange membrane. Specifically, in this embodiment, the liquid metal is a gallium-indium alloy with a mass fraction of gallium of 75% and a mass fraction of indium of 25%. After spraying, trim the proton exchange membrane to avoid short circuit between positive and negative electrodes. Then the liquid metal flexible electrode material is connected with an external power source with an electrode clip. Then spray PVC solution on the surface of the liquid metal, and after the solvent in the PVC solution evaporates, a layer of PVC film, that is, the flexible packaging material 4 is left to protect the liquid metal flexible electrode 2 .

The liquid metal flexible electrode material can be sprayed on both surfaces of the electroactive polymer material 3 , that is, the liquid metal flexible electrode 2 is used for both the positive and negative electrodes, as shown in FIG. 1 .

The liquid metal flexible electrode material can be sprayed on one surface of the electroactive polymer material 3, that is, the positive electrode adopts the liquid metal flexible electrode 2, and the other surface of the electroactive polymer material 3 is a thin layer of gold or platinum formed by chemical deposition. 5, as the negative electrode, as shown in Figure 2.

After the electro-driven artificial muscle is assembled, apply a DC voltage of 5V to 10V on the electrode, and the artificial muscle will bend in the positive direction, as shown in Figure 3.

After making a single-layer liquid metal electro-driven artificial muscle, multiple artificial muscles can be stacked to form a multi-layer artificial muscle, and the multi-layer artificial muscle can be packaged with a flexible packaging material 4 as a whole. Multi-layer artificial muscles can improve the output torque of artificial muscles, and are used in occasions with high requirements for strength, as shown in Figure 4.

Two pieces of electro-driven artificial muscles 1 are fixed end to end in opposite directions, and four groups of such artificial muscles are connected end to end in space to form a rectangle. After voltage is applied, a single group of artificial muscles bends in opposite directions, and The length of this group of artificial muscles is reduced and the width is increased. Four groups of artificial muscles can be combined to control the size of the rectangle. As shown in Figure 5. Electro-actuated artificial muscles can also be combined in other morphologies to achieve more complex shape changes or actuation morphologies.

The electro-driven artificial muscle design proposed by the present invention can be used for the clamping of objects, especially biological samples, the control of flow channels in microfluids, and the power devices of micro-robots. The process is safe and convenient, and has a wide range of application space and value.

Finally, it should be noted that the above embodiment of an electrically driven artificial muscle based on liquid metal is only used to illustrate the technical solution of the present invention and not limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent replacements to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all of them should be included in the scope of the present invention. within the scope of the claims.

Claims (10)

1. a kind of electrically driven (operated) artificial-muscle is it is characterised in that include sprayable, printing or the liquid metal flexible electrode printing (2), electroactive polymer material (3) and flexible encapsulant material (4), wherein liquid metal flexible electrode (2) cover lives in electricity Property polymeric material (3) one or two surfaces, that is, only negative or positive electrode adopts liquid metal flexible electrode (2) or just All using liquid metal flexible electrode (2), flexible encapsulant material (4) is wrapped in liquid metal flexible electrode (2) and electricity to negative pole The outside of active polymer material (3), plays the protective effect to liquid metal flexible electrode (2).

2. electrically driven (operated) artificial-muscle according to claim 1 is it is characterised in that described liquid metal flexible electrode (2) Using the low melting point gallium-base alloy under gallium or different ratio, described electroactive polymer material (3) adopts PEM.

3. electrically driven (operated) artificial-muscle according to claim 1 is it is characterised in that described electroactive polymer material (3) It is the electroactive polymer that the deformation including bending, stretching can occur in the presence of extra electric field.

4. electrically driven (operated) artificial-muscle according to claim 1 is it is characterised in that when liquid metal flexible electrode (2) covers Cover when a surface of electroactive polymer material (3), another electrode is the thin layer (5) of gold or platinum.

5. electrically driven (operated) artificial-muscle according to claim 1 is it is characterised in that described electroactive polymer material (3) For monolayer or multilamellar, when for multilamellar, each layer is respectively provided with liquid metal flexible electrode (2), stacking composition thickness The bigger artificial-muscle tissue of higher moment of flexure.

6. electrically driven (operated) artificial-muscle according to claim 1 is it is characterised in that described artificial-muscle exists in different directions Combination is placed in three dimensions, thus formed can be in the deformed or bent complicated artificial muscular tissue of multiple directions.

7. the preparation method of the electrically driven (operated) artificial-muscle described in claim 1 is it is characterised in that in electroactive polymer material (3) surface even application liquid metal flexible electrode material, forms liquid metal flexible electrode (2), is then connected with electrode holder Liquid metal flexible electrode (2) and external power source, and then spray formation flexible encapsulant material (4) in liquid metal surface, play Protective effect to liquid metal flexible electrode (2).

8. the preparation method of electrically driven (operated) artificial-muscle according to claim 7 is it is characterised in that described electroactive polymerization Thing material (3) selects Nafion 117 PEM, after removing surface impurity, is immersed in 1 mole every liter of sodium chloride solution Middle about 1 hour, sprays liquid metal flexible electrode material after taking-up；Described liquid metal select gallium mass fraction be 75%, the mass fraction of indium is 25% gallium-indium alloy；After the completion of spraying, trimming process is carried out to PEM, it is to avoid positive and negative Electric pole short circuit；So liquid metal surface spray PVC solution, after in PVC solution solvent evaporation after, stay one layer of PVC thin Film is flexible encapsulant material (4).

9. the preparation method of electrically driven (operated) artificial-muscle according to claim 7 is it is characterised in that described liquid metal is soft Property electrode material is sprayed on one or two surfaces of electroactive polymer material (3), and that is, only negative or positive electrode adopts liquid Metal flexible electrode (2) or both positive and negative polarity all using liquid metal flexible electrode (2), when liquid metal flexible electrode (2) covers When a surface of electroactive polymer material (3), chemical deposition is passed through on another surface of electroactive polymer material (3) Gold or the thin layer (5) of platinum that method is formed, as another electrode.

10. electrically driven (operated) artificial-muscle according to claim 7 preparation method it is characterised in that in surface spraying or Before print liquid metal flexible electrode material, distribution foot inside electroactive polymer material (3) is made by immersion or moistening Enough ion hydrates.