CN116039190B

CN116039190B - A temperature/light-sensitive flexible electrochemical gel actuator and its preparation and control method

Info

Publication number: CN116039190B
Application number: CN202310061493.9A
Authority: CN
Inventors: 胡宏伟; 张圣韬; 程广贵; 丁建宁; 张忠强
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2023-01-18
Filing date: 2023-01-18
Publication date: 2025-10-03
Anticipated expiration: 2043-01-18
Also published as: CN116039190A

Abstract

The present invention relates to a temperature/light-sensitive flexible electrochemical gel actuator and a preparation and control method, belonging to the technical field of ionic electroactive polymer preparation. Its structure includes two layers of conductive gel electrode films and a gel electrolyte interlayer film in the middle; the electrode film is prepared by casting a PEDOT:PSS solution into a film, and the electrolyte film is prepared by mixing and dissolving PVDF-HFP and an ionic liquid and then casting it into a film. Finally, the flexible actuator is prepared by hot pressing. The device has the advantages of integrated sensing and driving, high sensitivity, weak voltage drive, low cost, and simple preparation. This flexible actuator has broad application prospects in the fields of soft robots, artificial muscles, biomedicine, and intelligent wearable sensing.

Description

Temperature/photosensitive flexible electrochemical gel actuator and preparation and control method thereof

Technical Field

The invention relates to a temperature/photosensitive flexible electrochemical gel actuator and a preparation and control method thereof, belonging to the technical field of ionic electric actuation polymer preparation.

Background

Sensors and drivers have a wide range of applications in production and life and are extremely important. The flexible driver is a key component of flexible mechatronics, which is one of core technologies in important development fields of human future industries such as bionic robots, artificial intelligence, wearable medical treatment and the like in the emerging scientific technology of the century. Unlike conventional rigid mechatronics, flexible mechatronics eliminate complex mechanical actuators, often based on functional polymers or polymer-based composites to achieve complex end motions. As the ionic electrically actuated polymer of the main body material for the flexible driver, the ionic electrically actuated polymer not only has the advantages of low-voltage driving, quick response, large strain, large stress and the like, but also has the actuating and sensing functions. At present, the material is also used for a great deal of exploratory engineering in the aspect of drivers, and has rich application.

The core of the flexible electronic device is a sensing material, the driver has similar mechanical property and biocompatibility as human skin, and the conductive polymer poly (3, 4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT: PSS) is used as an electrode film to prepare a sensing and driving integrated device, so that the device can be truly close to the motion form of living things in the nature, and the real bionic effect is realized. The device has the advantages of microminiaturization, integrability, high sensitivity, long detection range, convenient signal extraction and the like, and corresponding feedback is timely made through sensing the change of temperature. Has wide application prospect in the fields of soft robots, artificial muscles, biomedical and intelligent wearable sensing and has important practical significance.

Disclosure of Invention

The invention provides a structure, a preparation and a control method of a temperature/photosensitive flexible electrochemical gel actuator, which utilizes the sensing function and the actuating function of an ionic gel material to realize the integration of sensing and driving of temperature, has the advantages of large flexibility, high sensitivity, large working range and good stability, and has important significance for promoting the application of flexible intelligent materials and the development of flexible machine electronic technology.

The structure of the temperature/light-sensitive flexible electrochemical gel actuator comprises an upper electrode film, a lower electrode film and an electrolyte layer positioned between the upper electrode film and the lower electrode film, wherein the electrolyte layer is formed by mixing polyvinylidene fluoride copolymer (PVDF-HFP) and 1-ethyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt (EMIMTFSI). The actuator generates a thermoelectric voltage under the effect of a temperature gradient and at the same time undergoes bending deformation under the application of a voltage.

The preparation of the temperature/photosensitive flexible electrochemical gel actuator comprises the following steps:

the preparation of the electrode film comprises the steps of taking PEDOT, stirring PSS solution, adding an initiator, stirring uniformly, injecting into a customized mold, standing at room temperature to enable the electrode film to naturally volatilize and form, placing the formed electrode film into an oven dryer, heating and drying the electrode film, and then annealing the electrode film at high temperature to finish the preparation of the electrode film.

The mass percentage concentration of the PEDOT to the PSS solution is 1.2%, the initiator is 1-butyl-3-methylimidazole p-toluenesulfonate, the addition amount of the initiator is 1% of the solid content of the PEDOT to the PSS solution, the standing time at room temperature is 24 hours, the heating and drying temperature is 60 ℃, the time is 120 minutes, the high-temperature annealing temperature is 150 ℃, and the time is 30 minutes.

The preparation of the electrolyte layer comprises the steps of taking PVDF-HFP, adding N, N-dimethylformamide, stirring at 80 ℃ until the PVDF-HFP and the N-dimethylformamide are fully dissolved, taking ionic liquid EMIMTFSI, adding the ionic liquid into the fully dissolved solution, stirring at room temperature until the ionic liquid is uniformly dispersed, injecting the ionic liquid into a mold, placing the mold in a fume hood, and fully volatilizing an organic solvent through heating to complete the preparation of the electrolyte layer.

The ratio of PVDF-HFP, N-dimethylformamide to ionic liquid EMIMTFSI was 1g:10ml:4g.

Preferably, the 1-butyl-3-methylimidazole p-toluenesulfonate is used as an initiator, so that the interaction between PEDOT and PSS can be weakened, the separation and recombination of PEDOT and PSS molecular chains can be promoted, and the electrode conductivity can be improved to improve the electrode conductivity.

Preferably, PVDF-HFP is selected as a raw material for the electrolyte layer, has outstanding properties of high mechanical strength, thermal stability, chemical resistance, high hydrophobicity, etc., as compared to other commercial polymer materials, has higher mechanical and impact strength, and has excellent creep resistance under long-term stress and cyclic loading fatigue, as compared to perfluorocarbon polymers that are softer and lower in mechanical strength.

Preferably, the thickness of the electrolyte layer is 190 mu m, the thicknesses of the electrode layers on the upper surface and the lower surface are 35 mu m, and the prepared electrode film and the electrolyte layer are pressed and molded in a hot pressing mode to obtain the flexible driver.

Preferably, the connection part of the flexible driver and an external circuit adopts an Au electrode as a contact, so that the corrosion of the ionic liquid to the metal electrode at the connection part is avoided.

Preferably, the excitation source of the flexible driver adopts an electric field of 1-2V to electrically drive the flexible driver.

Preferably, the custom mold is a polytetrafluoroethylene mold, and has the characteristics of high temperature resistance, acid resistance, alkali resistance and resistance to various organic solvents.

The control method of the temperature/photosensitive flexible electrochemical gel actuator is characterized in that when a heat source is close to a driver, temperature difference is generated on the upper surface and the lower surface of the driver, and thermoelectric force is generated due to the diffusion phenomenon of ions. The device is connected to an external circuit control system, and when the thermoelectric voltage reaches a certain threshold value, voltage is applied to the driver, so that bending and straightening actions are realized, and feedback to external stimulus is realized.

According to the technical principle of the invention, as shown in figure 2, according to the Soxhlet effect, ions are diffused under the action of temperature gradient, and because of inconsistent migration rates of positive and negative ions, thermoelectric potential can be generated under the condition that temperature difference exists between the upper surface and the lower surface, the ion diffusion device can be used for temperature sensing. Under the action of an electric field, positive and negative ions can migrate, and one side of the positive and negative ions expands and one side of the positive and negative ions contracts due to different volumes, so that the positive and negative ions are in a bent state, and can be used as a driver. The conductive polymer flexible driver material provided by the invention is prepared from commercially available PEDOT (polymer electrolyte) PSS solution serving as a main material for preparing the electrode film by adopting a pouring method, and compared with the traditional flexible electrode preparation, the conductive polymer flexible driver material is low in preparation cost, simple in technical process, greatly improves the conductivity and tensile property of the prepared electrode film by adding the conductive agent and the initiator, and prepares the electrolyte layer by mixing PVDF-HFP and EMIMTFSI according to a certain proportion. The method can realize the advantages of larger strain, stress, high response speed, large swing displacement and the like in the low voltage (1-2V) range. The device has higher sensitivity, the Seebeck coefficient reaches 2mv/k, and smaller temperature change can be perceived. The conductive polymer flexible driver has important practical significance in the fields of soft robots, artificial muscles, biomedical and intelligent wearable sensing.

Drawings

The structure of the driver of fig. 1 is schematically shown;

FIG. 2 is a schematic diagram of the device sensing driving principle, wherein (a) is the principle of driver thermal sensing;

FIG. 3 shows the complete process of "trending away" a bionic flower;

figure 4 is a view of the azimuth perception of the arrayed distributed driver.

Detailed Description

In the specific implementation process, in order to make the technical solution of the present invention more clear and complete, the present invention will be clearly and completely described below with reference to specific examples. The described examples are only some of the examples of the present invention and are not intended to represent all examples.

Materials, reagents and the like not specifically mentioned in the examples, unless otherwise specified, are commercially available or can be obtained by a method well known to those of ordinary skill in the art. The specific experimental methods, operating conditions involved are generally as set forth in conventional process conditions as well as in handbooks, or as recommended by the manufacturer.

Embodiment 1. A method for preparing a high conductive polymer flexible driver with a layered structure comprises the specific steps of taking out a prepared electrode film, soaking the electrode film in organic solvent alcohol for 30 minutes, soaking the electrode film in deionized water for 30 minutes, cutting the electrode film soaked in deionized water into regular strips by scissors, soaking the electrode film in ionic liquid EMIMTFSI for 30 minutes, and heating in an oven to remove redundant moisture in the film, so that the ionic liquid can enter the film better. The manufacturing of the driver adopts a hot-pressing method, the three-layer structure of the driver is respectively an electrode film (upper) 1, an electrolyte layer (middle) 2 and an electrode film (lower) 3, after the three layers of the driver are placed layer by layer, the three-layer structure is transferred onto glass slides, the three-layer structure is tightly pressed by two glass slides, then the glass slides are placed into an 80 ℃ oven for heating for 60min, the glass slides are taken out after heating is finished, the glass slides are cut into the shape of flowers, flexible electrodes are clamped on the upper surface and the lower surface of the center of the device, and in order to avoid corrosion of ionic liquid to the joint, an Au electrode is used as a contact electrode, and a copper wire is used for connecting to an external electrical control system. The simulated bionic flower opens and closes, as shown in fig. 3, when the palm is close to the upper surface of the flower, the upper surface and the lower surface generate temperature difference at the moment, so that thermoelectric potential is generated, the controller captures a voltage signal, and the excitation source provides 1-2v of voltage according to the voltage, so that the purpose of driving is achieved, and the complete process of' trending away the harmful is completed.

In example 2, the structure, preparation and control method of the temperature/light-sensitive flexible electrochemical gel actuator are the same as those of example 1, and the specific steps are that the prepared electrode film is taken out and soaked in organic solvent alcohol for 30 minutes, then soaked in deionized water for 30 minutes, the electrode film soaked in deionized water is cut into regular strip shapes by scissors, and is placed into ionic liquid EMIMTFSI to be soaked and simultaneously placed into a blast drying box at 60 ℃ to be heated for 3 hours, so that redundant moisture in the film is removed, and the ionic liquid is better led into the film. The manufacturing of the driver adopts a hot-pressing method, the three-layer structure of the driver is respectively an electrode film (upper), an electrolyte layer (middle) and an electrode film (lower), the three layers of the driver are placed layer by layer and then transferred onto a glass slide, the three-layer structure is pressed by two glass slides, then the glass slide is placed into an 80 ℃ oven for heating for 60min, and the glass slide is taken out after heating is completed. The device was cut into four strips of 30mm by 6mm in size and 260 μm in thickness (electrolyte layer thickness 190 μm, electrode layers on the upper and lower surfaces were each 35 μm thick) and a screen printing plate was custom made and the film was placed under the plate. And printing by taking the silver paste as a conductive medium, and waiting for drying after printing is finished to obtain the flexible circuit board.

The cut devices are arranged at four directions of the flexible circuit board, and are packaged and connected to an external electric appliance control system. See fig. 4.

When a finger approaches one of the devices, a thermoelectric voltage corresponding to the finger is generated, and the specific orientation of the finger can be distinguished according to the magnitude of the thermoelectric voltage. The multichannel voltage monitoring control module is adopted, an independent control unit and an electric field are not needed, the independent collection and control of the electric signals of each device can be realized, corresponding feedback is made according to the height of the electric potential, and an excitation source applies voltage to the device to complete the driving process.

Although the embodiments of the present application are described above, the embodiments are only used for facilitating understanding of the present application, and are not intended to limit the present application. Any person skilled in the art can make any modification and variation in form and detail without departing from the spirit and scope of the present disclosure, but the scope of the present disclosure is to be determined by the appended claims.

Claims

1. A control method for a temperature/light-sensitive flexible electrochemical gel actuator, characterized in that the temperature/light-sensitive flexible electrochemical gel actuator includes an upper electrode film, a lower electrode film, and an electrolyte layer located between the upper electrode film and the lower electrode film, wherein the electrolyte layer is formed by a mixture of polyvinylidene fluoride copolymer (PVDF-HFP) and 1-ethyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide (EMIMTFSI); the temperature/light-sensitive flexible electrochemical gel actuator generates thermoelectric potential under the action of a temperature gradient and bends and deforms when a voltage is applied; when a heat source approaches the actuator, a temperature difference is generated between the upper and lower surfaces of the actuator, and a thermoelectric potential is generated due to the diffusion of ions; the device is connected to an external circuit control system, and when the thermoelectric potential reaches a certain threshold, a voltage is applied to the actuator to achieve bending and straightening actions, thereby realizing feedback to external stimuli.

2 . The control method of a temperature/light-sensitive flexible electrochemical gel actuator according to claim 1 , wherein the electrolyte layer has a thickness of 190 μm.

3. The control method of a temperature/light-sensitive flexible electrochemical gel actuator according to claim 1, wherein the thickness of the upper electrode film and the lower electrode film are both 35 μm.

4. A control method for a temperature/light-sensitive flexible electrochemical gel actuator as described in claim 1, characterized in that Au electrodes are used as contacts at the connection between the temperature/light-sensitive flexible electrochemical gel actuator and the external circuit to avoid corrosion of the metal electrodes at the connection by ionic liquid.

5. The control method of a temperature/light-sensitive flexible electrochemical gel actuator according to claim 1, wherein the excitation source of the temperature/light-sensitive flexible electrochemical gel actuator adopts an electric field of 1-2V to electrically drive the actuator.

6. The control method of a temperature/light-sensitive flexible electrochemical gel actuator according to claim 1, wherein the preparation method of the temperature/light-sensitive flexible electrochemical gel actuator comprises the following steps:

(1) Preparation of electrode film: Take the PEDOT:PSS solution, stir it, add the initiator, stir it evenly, and inject it into a customized mold. Let it stand at room temperature to allow it to evaporate naturally and form. Place the formed electrode film in an oven dryer, heat and dry it, and then anneal it at high temperature. The electrode film is prepared.

(2) Preparation of the electrolyte layer: Take PVDF-HFP, add N,N-dimethylformamide, place it at 80°C and stir until it is fully dissolved; take the ionic liquid EMIMTFSI and add it to the fully dissolved solution, stir it at room temperature until it is evenly dispersed, then inject it into the mold, place it in a fume hood, and heat it to fully evaporate the organic solvent. The electrolyte layer is prepared;

(3) The prepared electrode film and electrolyte layer are pressed together by hot pressing to obtain a flexible actuator.

7. A control method for a temperature/light-sensitive flexible electrochemical gel actuator according to claim 6, characterized in that, in step (1), the mass percentage concentration of the PEDOT:PSS solution is 1.2%, the initiator is 1-butyl-3-methylimidazole p-toluenesulfonate; the standing time at room temperature is 24 hours, the heating and drying temperature is 60°C for 120 minutes, and the high-temperature annealing temperature is 150°C for 30 minutes; and the customized mold is a polytetrafluoroethylene mold.

8. The control method of a temperature/light-sensitive flexible electrochemical gel actuator according to claim 6, characterized in that in step (2), the ratio of PVDF-HFP, N,N-dimethylformamide and ionic liquid EMIMTFSI is 1g:10ml:4g.