Preparation method and application of flexible stretchable electrode with double conductive networks

Abstract

The invention discloses a preparation method and application of a flexible stretchable electrode with double conductive networks, and relates to the technical field of flexible electronics, electrochemistry and material scientificity, the electrode comprises a conductive nano material and a high-molecular polymer material, the high-molecular polymer elastic material is thermoplastic polyurethane (TPU), and the conductive filler is a carbon nano tube (CNT) and poly (3, 4-difluorophenyl)-1, 3, 4-trimethyl-1, 3-pentanediol monoisobutyrate. The flexible stretchable electrode is in the shape of a thin film, and the flexible stretchable electrode is in the shape of a thin film and is made of polystyrolsulfon acid (PEDOT: PSS); according to the invention, when the mass ratio of the thermoplastic polyurethane (TPU) solution is 0.4: 2.6: 1.0, the film-shaped double-conductive-network flexible stretchable electrode obtains high stretchability (1100%); the double-conductive-network flexible stretchable electrode film can be deformed at will in a state and also has excellent conductivity in a stretching deformation state; the composite material has the characteristics of high stretchability, high conductivity, strain insensitivity, good electrochemical performance, excellent biocompatibility and the like, and human joint movement can be monitored in real time under large deformation of human movement; the preparation method is simple, easy to operate and low in cost.

Description

Technical Field

[0001] The present invention relates to the fields of flexible electronics, electrochemistry and material science and technology, and in particular to a preparation method and application of a flexible stretchable electrode with a double conductive network. Background Art

[0002] In recent years, with the development of flexible electronics, the preparation and application of flexible wearable electrodes have received widespread attention. Researchers have found that the application of flexible wearable electrodes in human motion monitoring has great advantages. They can detect stimuli such as pressure, temperature and strain applied by the external environment; studies have shown that these materials can be widely used in human motion monitoring, medical health monitoring, human-computer interaction, flexible supercapacitors, electronic skin and tattoos.

[0003] But so far, commercialized flexible wearable electrodes are mainly composed of metal and semiconductor materials. However, due to the inherent rigidity of the materials themselves, their stretchability is poor. Secondly, there are disadvantages of low resolution and limited sensing range, which leads to the fact that the flexible wearable electrodes composed of metal and semiconductor materials cannot meet the detection requirements of flexible wearable electrodes. Based on the requirements for flexible wearable electrodes, in order to meet the monitoring of joint movement and temperature changes under human motion, this requires that the flexible stretchable electrodes must have the function of strain and temperature monitoring and have a wide sensing range and high sensitivity. In order to improve the stretchability and sensitivity of flexible wearable electrodes to meet the requirements of wearable electronic products, a large amount of conductive nanomaterials are doped into the elastomer to form a sensing film, which is of great significance to the research on flexible wearable electrodes.

[0004] In view of this, a preparation method and application of a flexible stretchable electrode with a double conductive network are provided to overcome the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation method and application of a flexible stretchable electrode with a double conductive network, aiming to solve the problems of limited detection range, complex process and high cost of the flexible stretchable electrode; the double conductive network electrode of the present invention has excellent stretchability, stretchable conductivity, biocompatibility and is non-toxic to the human body, and can stably realize continuous monitoring of human body movement.

[0006] To solve the above technical problems, the present invention provides a flexible stretchable electrode with a double conductive network, wherein the electrode has a double conductive network, wherein the first conductive network is formed by poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) and thermoplastic polyurethane (TPU), and the second conductive network is formed by carbon nanotubes (CNTs), poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) and thermoplastic polyurethane (TPU). Finally, a fibrous conductive network is formed, and hydrogen bonds are formed due to the reaction between groups, thereby enhancing the mechanical and electrical properties.

[0007] A flexible stretchable electrode with a double conductive network, the electrode comprises a conductive nano material and a high molecular polymer material, the conductive nano material filler is a carbon nanotube (CNT), the high molecular polymer material is poly (3,4 ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) and thermoplastic polyurethane (TPU), and the mass ratio of the three solutions is 0.4:2.6:1.0. The flexible stretchable electrode is in the form of a film.

[0008] The conductive nanomaterial described in the present invention is a multi-walled carbon nanotube (CNT). The special chemical structure determines many special physical and chemical properties of the carbon nanotube, which has excellent mechanical, electrical and thermal properties. It is an ideal reinforcing agent and conductive nanofiller for preparing stretchable strain sensors with elastomers.

[0009] The poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) described in the present invention is a conductive polymer solution having high conductivity and good compatibility with elastomers.

[0010] The elastomer described in the present invention is thermoplastic polyurethane (TPU) with high tensile properties.

[0011] Therefore, a flexible electrode with high stretchability and high conductivity can be prepared by mixing carbon nanotubes (CNTs), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and thermoplastic polyurethane (TPU) in a reasonable ratio.

[0012] The ratio of carbon nanotubes (CNT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) and thermoplastic polyurethane (TPU) is set. When the content of the conductive component is too high, the stretchability of the electrode is poor; when the content of the elastic substrate is too high, the conductivity of the electrode is poor.

[0013] When the mass ratio of carbon nanotubes (CNT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) and thermoplastic polyurethane (TPU) solution is 0.4:2.6:1.0, the prepared electrode has high stretchability and high conductivity. The prepared electrode can be deformed at will and has stretchable conductivity to meet the monitoring of human motion signals.

[0014] The present invention also provides a method for preparing a flexible and stretchable electrode with a double conductive network, the preparation method comprising the following steps:

[0015] (1) A magnet was placed in an unused screw-capped transparent glass sample bottle, 1.0 g of thermoplastic polyurethane (TPU) solution was first added to obtain solution A, and then 2.6 g of poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) solution was added to obtain solution B.

[0016] (2) Place solution B on a constant temperature stirring table for 3 h to carry out solution reaction at a rotation speed of 300 rpm / min to 600 rpm / min.

[0017] (3) After the reaction in step (2) is completed, solution B is added with 0.4 g of carbon nanotube (CNT) solution to obtain solution C, which is placed on a constant temperature stirring table for 2 h for solution reaction, and the rotation speed is adjusted to 500 rpm / min to 550 rpm / min.

[0018] (4) Place the mixed solution C after the reaction in step (3) in a refrigerator and let it stand at low temperature for 12-24 hours to remove bubbles in the solution.

[0019] (5) The mixed solution C after standing in step (4) is evenly dropped on the surface of the I TO glass sheet and placed in a vacuum drying oven for 2.5 hours to remove moisture.

[0020] (6) The flexible stretchable electrode with a double conductive network obtained in step (5) is removed from the surface of the ITO glass sheet, cut into electrodes of a certain size as required, welded with copper wires and connected with leads to obtain a flexible stretchable electrode used in the test to monitor human motion signals.

[0021] Preferably, in the solution B of step (1), the mass fraction of the poly(3,4-ethylenedioxythiophene)polystyrenesulfonic acid (PEDOT:PSS) solution is about 1.3%, and the mass fraction of the thermoplastic polyurethane (TPU) solution is about 40%.

[0022] Preferably, in the solution B of step (1), the solid mass ratio of poly(3,4-ethylenedioxythiophene)polystyrene sulfonic acid (PEDOT:PSS) to thermoplastic polyurethane (TPU) is 0.338:4.

[0023] Preferably, in the solution C of step (3), the mass fraction of the carbon nanotube (CNT) solution is 10%.

[0024] Preferably, in the solution C of step (3), the solid mass ratio of carbon nanotubes (CNT) to poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) to thermoplastic polyurethane (TPU) is 0.04:0.338:4.

[0025] Preferably, in the solution C of step (4), the set temperature of the refrigerator is generally 3-5°C.

[0026] Preferably, in the solution C of step (6), the glass sheet material component is indium tin oxide; the electrode size is generally 1.5*2 cm; the copper wire has a diameter of 0.3-0.5 mm and a length of about 10-15 cm.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The dual conductive network flexible stretchable electrode of the present invention not only has high conductivity, but also has high tensile strength (1100%).

[0029] 2. The dual conductive network flexible stretchable electrode of the present invention has good strain insensitivity.

[0030] 3. The dual-conductive network flexible stretchable electrode of the present invention can stably and continuously monitor the physiological signals of human movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a microscopic (SEM) morphology of the flexible stretchable electrode conductive network with double conductive networks in Example 1 of the present invention.

[0032] Figure 2 This is a diagram showing the conductivity changes of the flexible stretchable electrode with a double conductive network under different strains in Example 2 of the present invention.

[0033] Figure 3 This is a monitoring diagram of the ECG signal of a human body in motion using a flexible stretchable electrode with a double conductive network in Example 3 of the present invention.

[0034] Figure 4 This is a graph of myoelectric signal monitoring of the flexible stretchable electrode with double conductive networks in Example 3 of the present invention when the human finger is bent at different angles (0°, 30°, 45° and 90°). DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Embodiment 1:

[0037] like Figure 1 As shown, a flexible stretchable electrode with a double conductive network, the electrode includes a conductive nanomaterial and a high molecular polymer material, the conductive nanomaterial filler is a carbon nanotube (CNT), the high molecular polymer material is poly (3,4 ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) and thermoplastic polyurethane (TPU), the mass ratio of the three solutions is 0.4: (2.2-3.0): 1.0; the flexible stretchable electrode is a film; the carbon nanotubes are multi-walled carbon nanotube dispersions, the mass fraction of which is 10%; the poly (3,4 ethylenedioxythiophene) polystyrene sulfonic acid is an aqueous solution, the mass fraction of which is 1.3%-1.5%; the mass fraction of the thermoplastic polyurethane solution is about 40%.

[0038] The above-mentioned method for preparing a flexible stretchable electrode with a double conductive network comprises the following steps:

[0039] (1) Place a magnet in an unused screw-capped transparent glass sample bottle, first add 1.0 g of thermoplastic polyurethane (TPU) solution to obtain solution A, and then add 2.2 g of poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) solution to obtain solution B. Place solution B on a constant temperature stirring table for 3 h for solution reaction at a rotation speed of 300 rpm / min to 600 rpm / min.

[0040] (2) Add 0.4 g of carbon nanotube (CNT) solution to the solution B after the reaction in step (1) to obtain solution C, and place it on a constant temperature stirring table for 2 hours for solution reaction, and adjust the rotation speed to 500 rpm / min to 550 rpm / min. Place the mixed solution C after the reaction in a refrigerator and let it stand at low temperature for 12-24 hours to remove bubbles in the solution. Evenly drop the mixed solution C after standing on the surface of the I TO glass sheet and place it in a vacuum drying oven for 2.5 hours to remove moisture.

[0041] (3) The flexible stretchable electrode with double conductive network obtained in step (2) is removed from the surface of the ITO glass sheet and cut into electrodes with a size of 1*2 cm to test the stretchability.

[0042] (4) Repeat step (1) to prepare (2.4 g, 2.6 g, 2.8 g and 3.0 g) poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) solution to obtain solution B. Then repeat (2) and (3) to test the optimal stretchability under different conductive component ratios. Figure 2 .

[0043] After the above steps, the experimental results show that when the mass ratio of carbon nanotube (CNT): poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS): thermoplastic polyurethane (TPU) solution is 0.4:2.6:1.0, the prepared flexible stretchable electrode with a double conductive network has high stretchability (1100%), which can be attributed to the existence of hydrogen bonds and cross-linking networks between polymer chains, which enhance the mechanical and electrical properties of the electrode; at this time, the electrode also has excellent conductivity (3465S / m).

[0044] Embodiment 2:

[0045] like Figure 3 As shown, a flexible stretchable electrode with a double conductive network, the electrode includes a conductive nanomaterial and a high molecular polymer material, the conductive nanomaterial filler is a carbon nanotube (CNT), the high molecular polymer material is poly (3,4 ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) and thermoplastic polyurethane (TPU), and the mass ratio of the three solutions is 0.4:2.6:1.0; the flexible stretchable electrode is a film; the carbon nanotubes are multi-walled carbon nanotube dispersions with a mass fraction of 10%; the poly (3,4 ethylenedioxythiophene) polystyrene sulfonic acid is an aqueous solution with a mass fraction of 1.3%-1.5%; the mass fraction of the thermoplastic polyurethane solution is about 40%.

[0046] Preparation of a flexible stretchable electrode with double conductive networks:

[0047] Example 1 was repeated with the same steps, but the difference was that in step (1), only 2.6 g of poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) solution was prepared to obtain a flexible stretchable electrode with a mass ratio of carbon nanotube (CNT): poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS): thermoplastic polyurethane (TPU) of 0.4:2.6:1.0, which was then cut into small electrodes of 1.5*2.5 cm and tested for conductivity under different strains. Figure 3 .

[0048] After the above steps, the experimental results show that the initial square resistance (R) of the flexible stretchable electrode with a double conductive network is 4.5Ω. When stretched by 25%, the square resistance change rate of the electrode is 33.58%, when stretched by 50%, the square resistance change rate of the electrode is 61.51%, when stretched by 75%, the square resistance change rate of the electrode is 79.81%, and when stretched by 100%, the square resistance change rate of the electrode is 105.66%. The results show that it still has high conductivity under large deformation, the electrode has stretchable conductivity, and the flexible electrode can convert the physiological signals of the human body into electrical signals and can be used as a sensor.

[0049] Example 3

[0050] like Figure 4 As shown, a flexible stretchable electrode with a double conductive network, the electrode includes a conductive nanomaterial and a high molecular polymer material, the conductive nanomaterial filler is a carbon nanotube (CNT), the high molecular polymer material is poly (3,4 ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) and thermoplastic polyurethane (TPU), and the mass ratio of the three solutions is 0.4:2.6:1.0; the flexible stretchable electrode is a film; the carbon nanotubes are multi-walled carbon nanotube dispersions with a mass fraction of 10%; the poly (3,4 ethylenedioxythiophene) polystyrene sulfonic acid is an aqueous solution with a mass fraction of 1.3%-1.5%; the mass fraction of the thermoplastic polyurethane solution is about 40%.

[0051] Preparation of a flexible stretchable electrode with double conductive networks:

[0052] Repeat Example 2 with the same steps, and then cut into small electrodes of 1*2cm. After welding the copper wires and connecting the small electrodes with the leads, test the ECG signals of the human body in motion and the acute myoelectric signals of the finger movements respectively. However, the difference is that when testing the ECG signals, two small electrodes need to be attached to the wrists of the two hands of the human body. Figure 4 When measuring the electromyographic signal of a human finger in motion, only a single electrode needs to be attached to the finger joint.

[0053] After the above steps, the experimental results show that the flexible stretchable electrode with dual conductive networks has a good response to the ECG signal monitoring in human motion state and the EMG signal monitoring in human finger bending motion at different angles (0°, 30°, 45° and 90°).

Claims

1. A flexible and stretchable electrode with a double conductive network, characterized in that: The electrode includes conductive nanomaterials and high molecular polymer materials, the high molecular polymer elastic material is thermoplastic polyurethane (TPU), the conductive filler is carbon nanotube (CNT) and poly (3,4 ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS), and the flexible and stretchable electrode is in the form of a film.

2. A flexible stretchable electrode with double conductive networks as claimed in claim 1, characterized in that: The mass ratio of carbon nanotube (CNT): poly (3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS): thermoplastic polyurethane (TPU) solution is 0.4:2.6:1.

0.

3. A flexible stretchable electrode with double conductive networks as claimed in claim 2, characterized in that: The conductive filler is a carbon nanotube (CNT) solution and poly (3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS), the carbon nanotube (CNT) is a multi-walled carbon nanotube aqueous dispersion, the solid content of the carbon nanotube (CNT) is 10wt%, and the solid content of the high molecular polymer PEDOT:PSS solution is 1.3%.

4. A flexible stretchable electrode with double conductive networks as claimed in claim 2, characterized in that: The polymer elastomer material is a thermoplastic polyurethane (TPU) solution, and the solid content of the thermoplastic polyurethane (TPU) is 40%.

5. The flexible stretchable electrode with double conductive networks as claimed in claim 1, characterized in that: The glass sheet is made of indium tin oxide (ITO); the diameter of the external electrode copper wire lead is 0.3-0.5 mm and the length is 10-15 cm.

6. A method for preparing a flexible stretchable electrode with a double conductive network, characterized in that: The following steps are involved: (1) placing a magnet in an unused screw-mouth transparent glass sample bottle, first adding 1.0 g of thermoplastic polyurethane (TPU) solution to obtain solution A, then adding 2.6 g of poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS) solution, and stirring the two to mix them evenly to obtain solution B; placing solution B on a constant temperature stirring table and stirring at a speed of 300 rpm / min to 600 rpm / min for 3 hours to allow PEDOT:PSS to fully react with TPU to form a first conductive network; (2) After the reaction in step (1) is completed, 0.4 g of carbon nanotube (CNT) solution is added to solution B and stirring is continued; the stirring table speed is adjusted to 500 rpm / min to 550 rpm / min, and stirring is continued for 2 hours to allow the CNT to further react with the PEDOT:PSS / TPU system to form a second conductive network, thereby obtaining a mixed solution C; (3) evenly coating the mixed solution C that has reacted completely in step (2) on the surface of the indium tin oxide (ITO) glass sheet to ensure that the coating is uniform and has no obvious bubbles; Subsequently, the ITO glass sheet coated with the solution was placed in a vacuum drying oven and dried under appropriate conditions for 2.5 hours to remove moisture, obtaining a flexible and stretchable electrode film based on PEDOT:PSS and CNT; (4) The flexible stretchable electrode with a double conductive network removed from the surface of the ITO glass sheet in step (3) is cut into a desired size, and a copper wire with a diameter of 0.3 to 0.5 mm and a length of 10 to 15 cm is welded on its surface as an external electrode lead to complete the preparation of the electrode.

7. Use of the flexible stretchable electrode with double conductive networks as claimed in any one of claims 1 to 5 in monitoring human motion signals.

8. A method for monitoring human motion signals using the flexible stretchable electrode with double conductive networks as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Cutting the flexible stretchable electrode with double conductive network into an electrode with a size suitable for the joint to be tested; S2. Attach the cut electrodes to the joints to be tested and fix them with conductive tape. Connect them to the test system to monitor the joint movement signals of the human body in motion in real time.

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