Ionic gel diode device and preparation method and application thereof

Abstract

The invention discloses an ionic gel diode device and a preparation method and application thereof, and belongs to the field of resistive sensors. The ionic gel diode device is composed of two layers of ionic gel with opposite free charges, based on the unique p-n junction structural design, the ionic skin can sense various stimuli such as current, pressure and temperature, in addition, the ionic gel diode device has rich synaptic behaviors and a memory function, and the function of the ionic skin is improved. Based on the characteristics, the sensing and storage integrated ionic gel diode artificial skin is successfully realized.

Description

Technical Field

[0001] The present application relates to an ionic gel diode device, a preparation method thereof, and an application, belonging to the field of resistive sensors. Background Art

[0002] The human skin is the largest sensory organ, renowned for its excellent elasticity, moisturizing ability, and antifreeze performance. The skin generates ionic signals through tactile, thermal, and electrical stimuli, thereby realizing signal perception, transmission, processing, and memory. These functions work together to promote humans' conscious perception and decision-making of the external environment. Inspired by these excellent characteristics of the skin, in recent years, bio-inspired ionic flexible sensors have attracted extensive attention. These sensors conduct signals through ions and successfully simulate skin-like characteristics, such as multimodal perception, memory function, and synaptic behavior. Among many research materials, ionic gel has become a promising artificial skin material due to its excellent ionic conductivity, wide electrochemical window, good transparency, superior mechanical properties, and the avoidance of common problems of water evaporation and freezing in hydrogels.

[0003] Despite many advancements, the ionic skins reported currently still face the following several challenges: (1) how to achieve multimodal perception and memory of tactile, thermal, and electrical stimuli; (2) high-sensitivity detection of ultra-low currents at the nanoampere (nA) level; and (3) realizing rich synaptic behaviors required for constructing reservoir computing. These problems urgently need further research and breakthroughs. Summary of the Invention

[0004] According to the first aspect of the present application, an ionic gel diode device is provided. Its core design is based on a bilayer ionic gel with a p-n junction structure. This ionic gel material has remarkable characteristics such as flexibility, transparency, no ion leakage, and excellent biocompatibility. The artificial skin is composed of two ionic gels with opposite free charges respectively. Through the heterojunction of polyanions and polycations, an ionic double layer (IDL) similar to the depletion layer of the p-n semiconductor junction is formed. This ionic gel material can sense various stimuli such as current, pressure, and temperature, showing rich synaptic behaviors and memory functions, thus realizing the design of an ionic gel diode artificial skin that integrates perception and storage.

[0005] An ionic gel diode device, the ionic gel diode includes a flexible electrode and an ionic gel layer;

[0006] The ionic gel layer includes a free anion gel layer and a free cation gel layer;

[0007] The free anion gel layer and the free cation gel layer are attached together;

[0008] The flexible electrodes are attached to both sides of the ionic gel layer;

[0009] The material of the free anion gel layer is poly-1-[2-acryloyloxyethyl]-3-butylimidazolium bis(trifluoromethane)sulfonimide;

[0010] The material of the free cation gel layer is poly-1-ethyl-3-methylimidazolium (3-sulfopropyl) acrylate.

[0011] The material of the free anion gel layer is poly-1-[2-acryloyloxyethyl]-3-butylimidazolium bis(trifluoromethane)sulfonimide (PolyAT), specifically as follows:

[0012]

[0013] The material of the free cation gel layer is poly-1-ethyl-3-methylimidazolium (3-sulfopropyl) acrylate (PolyES), specifically as follows:

[0014]

[0015] The ionic gel diode device has a p-n junction structure and is used as an artificial skin. This artificial skin can sense and store various stimuli such as current, pressure, and temperature. In addition, it also has rich synaptic behaviors and memory functions, thus realizing the integration of sensing and storage.

[0016] Among them, the free anion gel layer is the PolyAT layer, and the free cation gel layer is the PolyES layer. The preparation of the PolyAT layer and the PolyES layer both come from the prior art and can be prepared by the methods disclosed in the prior art.

[0017] Optionally, the thickness of the free anion gel layer and the free cation gel layer is 2 - 5 mm.

[0018] Optionally, the thickness of the free anion gel layer and the free cation gel layer is one of 2 mm, 3 mm, and 5 mm.

[0019] Optionally, the flexible electrode is selected from one of the PI-Cu flexible electrode and the ITO flexible electrode.

[0020] Optionally, the ionic gel layers are arranged in an array.

[0021] Among them, the array arrangement of the ionic gel layers can be designed according to actual needs. It can be in the form of an N×N array, where N can take positive integers between 1 and 100, such as 8×8.

[0022] According to a second aspect of the present application, a method for preparing an ion gel diode device is provided.

[0023] The method for preparing the ion gel diode device described above includes:

[0024] S1: Obtain free anion gel and free cation gel respectively;

[0025] S2: Cut the free anion gel and free cation gel into thin slices respectively, process them into the required shapes, stack them together respectively, and perform a lamination operation to make them tightly combined to obtain an ion gel layer;

[0026] S3: Apply flexible electrodes on both sides of the ion gel layer to obtain the ion gel diode device.

[0027] Optionally, in step S2, after designing and laying out the array, stack them together respectively and perform a lamination operation.

[0028] In step S3, the flexible electrodes should be closely attached to the gel, and short circuits caused by contact between the electrodes on both sides should be avoided.

[0029] In step S1, the preparation of the free anion gel and the free cation gel both come from the prior art and can be prepared by the methods disclosed in the prior art.

[0030] PolyAT is prepared by polymerizing the following two monomers:

[0031]

[0032] PolyES is prepared by polymerizing the following two monomers:

[0033]

[0034] The raw materials for preparing PolyAT include 2-bromoethanol, triethylamine, acryloyl chloride, 1-butylimidazole, and lithium bis(trifluoromethanesulfonyl)imide.

[0035] The raw materials for preparing PolyES include 1-ethyl-3-methylimidazolium chloride, 3-acryloyloxypropane sulfonate potassium, and methoxyphenol.

[0036] As a preferred embodiment, the method for preparing the ion gel diode device includes:

[0037] (1) Obtain AT and ES monomers, and add an initiator and a chain transfer agent to obtain a precursor solution for synthesizing PolyAT (poly 1-[2-acryloyloxyethyl]-3-butylimidazole bis(trifluoromethanesulfonyl)imide) and PolyES (poly 1-ethyl-3-methylimidazolium (3-sulfopropyl) acrylate) gels;

[0038] (2) Inject the monomer solutions of AT and ES into the mold respectively. Under the protection of inert gas, react overnight at 60 °C under heating conditions until the polymer liquid solidifies and forms, obtaining two kinds of ion gels.

[0039] (3) After cutting the two kinds of ion gels into squares of the same size, laminate the upper and lower layers together. Subsequently, attach the PI-Cu flexible electrodes in the form of cross electrodes on both sides, and finally obtain an ion gel diode device composed of a PI-Cu / PolyAT / PolyES / PI-Cu structure.

[0040] Optionally, in the step (1), the PolyAT and PolyES gel precursor solutions added with initiator and chain transfer agent are prepared with ethanol.

[0041] Optionally, in the step (2), there may also be the following steps;

[0042] (2-1) Ensure that the amount of ethanol dissolving the monomer is minimized to maximize the concentration as much as possible;

[0043] (2-2) After the curing reaction is completed, first wash the ion gel with dichloromethane liquid to wash the unreacted monomers;

[0044] (2-3) After washing, place the elastomer in a vacuum dryer to remove the residual solvent and water;

[0045] (2-4) The inert gas includes at least one of nitrogen, argon, and helium.

[0046] Optionally, in the step (1), the initiator is selected as azobisisobutyronitrile (AIBN), and the crosslinking agent is selected as polyethylene glycol diacrylate (PEGDA).

[0047] Optionally, in the step (1), the molar ratio of the monomer, initiator, and crosslinking agent is 1:0.005:0.02.

[0048] As a specific implementation manner, the preparation method of the ion gel diode device includes:

[0049] (a) Synthesize the monomers of the PolyAT layer and the PolyES layer;

[0050] (b) Prepare the precursor solution according to the molar ratio of the monomer, initiator, and crosslinking agent of 1:0.005:0.02;

[0051] (c) Inject the precursor solutions for synthesizing PolyAT and PolyES into the mold respectively. Under the protection of inert gas, react overnight at 60 °C under heating conditions until the polymer liquid solidifies and forms, obtaining two kinds of ion gels;

[0052] (d) Cut and laminate AT and ES elastomers of the same size together, and apply PI-Cu electrodes to both sides to complete the preparation of the artificial ion skin.

[0053] Optionally, in the step (a), the AT monomer is a light yellow transparent liquid, and the ES monomer is a viscous yellow oil.

[0054] Optionally, in the step (b), azobisisobutyronitrile is selected as the initiator, and polyethylene glycol diacrylate is selected as the crosslinking agent.

[0055] Optionally, in the step (b), ethanol is selected as the solvent for dissolving the ionic polymer solution.

[0056] Optionally, in the step (b), ensure that the amount of ethanol for dissolving the polymer is minimized to maximize the concentration.

[0057] Optionally, in the step (c), after the curing reaction is completed, first wash the ion gel with dichloromethane liquid to wash away the unreacted monomers.

[0058] Optionally, in the step (c), after washing with dichloromethane, place the elastomer in a vacuum drying chamber to remove the residual solvent and water.

[0059] Optionally, the inert gas in the step (c) includes at least one of nitrogen, argon, and helium.

[0060] According to the third aspect of the present application, an application of an ion gel diode device as a sensor is provided.

[0061] The application of the above-mentioned ion gel diode device as a sensor.

[0062] Prepare it into an 8×8 ion gel array, and accurately sense and store the temperature and pressure distribution of an object by monitoring the current changes at different positions. By combining the long-term memory (LTM) and short-term memory (STM) storage behaviors triggered by electrical pulses, the ion gel diode is used as a storage unit in the readout layer of the reservoir computing system, and can directly learn and infer from electrical signals without the need for dedicated electrical sensors or digital computers.

[0063] According to the fourth aspect of the present application, there is provided an application of an ionic gel diode device as an artificial skin. The artificial skin is an ionic gel diode artificial skin that combines multimodal sensing and reservoir computing. Its multimodal perception and memory are mainly based on the balance between the drift current caused by mobile ions and the internal electric field caused by fixed polymer chains; due to the movement of free ions, the disruption and restoration of the balance, it exhibits strong synaptic behaviors, including excitatory post-synaptic current (EPSC), paired-pulse facilitation (PPF), short-term plasticity (STP), long-term plasticity (LTP), short-term memory (STM), long-term memory (LTM), and multi-bit enhancement and inhibition, which can realize a fully memristive reservoir computing system.

[0064] The application of the above-mentioned ionic gel diode device as an artificial skin.

[0065] The beneficial effects that the present application can produce include:

[0066] The ionic gel diode device, its preparation method, and application provided by the present application. The ionic gel diode device is applied as an artificial skin. Thanks to the built-in potential, the artificial skin realizes highly sensitive perception and memory functions for ultra-low electrical stimuli (about 1 nA), a wide pressure range (0.075 Pa to 400 kPa), and a wide temperature range (-80 to 120 °C). Based on the strong synaptic behaviors exhibited by the ionic gel, including EPSC, PPF, STP, LTP, STM, LTM, and multi-bit enhancement and inhibition functions, this system can realize a fully memristive reservoir computing (RC) system within a sensor. This design provides a new approach for the development of multifunctional artificial skin. Description of the Drawings

[0067] Figure 1 Schematic structural diagram of the ionic gel diode artificial skin for the embodiment;

[0068] Figure 2 Output voltage graph of the ionic gel diode artificial skin for the embodiment under different current intensities with a constant number of pulses;

[0069] Figure 3 EPSC graph of the ionic gel diode artificial skin for the embodiment triggered by different pressure pulses;

[0070] Figure 4 Detection diagram of the ionic gel diode artificial skin of the embodiment by applying two consecutive pressure pulses (1.9 kPa, 0.2 s);

[0071] Figure 5 Current change diagram of the ionic gel diode artificial skin of the embodiment in a wide temperature range from -80 °C to 120 °C;

[0072] Figure 6 Detection diagram of the ionic gel diode artificial skin of the embodiment by applying two consecutive temperature pulses (0 °C, 2.3 s);

[0073] Figure 7 Current diagram generated by multiple sensing units when a steel ruler at 50 °C approaches the sensor array of the 8×8 sensing array made of the ionic gel diode artificial skin of the embodiment;

[0074] Figure 8 Diagram for positioning and identifying the position and size of a weight by analyzing the current change in each sensor unit of the 8×8 sensing array made of the ionic gel diode artificial skin of the embodiment;

[0075] Figure 9 Process photos of the ionic gel diode artificial skin of the embodiment when a robot imitates humans to select a suitable object;

[0076] Figure 10 Process diagram and accuracy rate diagram for handwritten digit recognition using the ionic gel diode artificial skin of the embodiment as a storage unit in the readout layer of an RC system. Detailed implementation manners

[0077] The present application will be described in detail below in conjunction with embodiments, but the present application is not limited to these embodiments.

[0078] Unless otherwise specified, the raw materials in the embodiments of the present application are all purchased through commercial channels.

[0079] Unless otherwise specified, the test methods are all conventional methods, and the instrument settings are all the settings recommended by the manufacturers.

[0080] 2-Bromoethanol, triethylamine, acryloyl chloride, 1-ethyl-3-methylimidazolium chloride were purchased from Shanghai Bide Pharmaceutical Technology Co., Ltd.; 1-butylimidazole, lithium bis(trifluoromethane)sulfonimide, 3-acryloyloxypropanesulfonic acid potassium salt, methoxyphenol were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0081] The analysis methods in the embodiments of the present application are as follows:

[0082] The current and voltage of the ionic gel diode artificial skin were tested and analyzed using a semiconductor analyzer (Keithley SC-4200).

[0083] Synthesis of AT: It includes the following three steps: First, the synthesis of C1. 2-Bromoethanol and acryloyl chloride were reacted in dichloromethane in the presence of triethylamine. 7.09 mL (0.1 mol) of 2-bromoethanol and 13.9 mL of triethylamine were used. Acryloyl chloride (9.72 mL, 0.1 mol) dissolved in 10 mL of CH 2 Cl 2 was added dropwise through a constant pressure funnel. After stirring at room temperature for 16 hours, it was extracted, dried, and rotary evaporated to obtain a clear liquid with a yield of 80%. Second, the synthesis of C2. C1 and 1-butylimidazole (0.73 g, 5.86 mmol) were stirred in acetonitrile at 60 °C under nitrogen protection for 16 hours. After the reaction, the solvent was removed by rotary evaporation, and then it was dissolved in water and washed with dichloromethane. Finally, the synthesis of AT. An ion exchange reaction was carried out between C2 and lithium bis(trifluoromethanesulfonyl)imide (1.6 g, 5.59 mmol) in water. After stirring at room temperature for 48 hours, it was extracted and dried to obtain a light yellow transparent liquid AT with a yield of 40%. Characterized by 1H NMR and 19F NMR, the product met the expectations.

[0084] Synthesis of ES: 1-Ethyl-3-methylimidazolium chloride (3.15 g, 21.5 mmol), potassium 3-acryloyloxypropane sulfonate (5.0 g, 21.5 mmol), and methoxyphenol (5.0 mg, 0.04 mmol) were dissolved in acetonitrile (20 mL) and stirred vigorously at room temperature for 16 hours. After the reaction, potassium chloride was removed by filtration. The filtrate was concentrated and dried under vacuum. The resulting liquid was dissolved in dichloromethane and stored overnight at below 0 °C. It was filtered and concentrated to obtain a viscous yellow oil ES with a yield of 50% (3.3 g), which met the expectations as characterized by 1H NMR.

[0085] Synthesis of PolyAT ionic gel: First, 0.4 g of AT was weighed and mixed with 2 mol% PEGDA. Then, a 0.5 mol% AIBN ethanol solution (10 mg / mL) was added to the mixture. Among them, the molar ratio of AT monomer, AIBN, and PEGDA was 1:0.005:0.02. After thorough mixing, ethanol was removed using a vacuum pump. The resulting mixture was transferred to a glass mold using a pipette and reacted overnight at 60 °C under a nitrogen atmosphere. After the reaction was completed, the elastomer was taken out of the mold and any unreacted monomer was washed off with dichloromethane. Then, the elastomer was placed in a vacuum drying chamber to remove the residual solvent and water. The PolyAT ionic gel was prepared.

[0086] Synthesis of PolyES ion gel: First, weigh 0.4 g of ES and mix it with 2 mol% PEGDA. Then, add 0.5 mol% AIBN ethanol solution (10 mg / mL) to the mixture. Among them, the molar ratio of ES monomer, AIBN, and PEGDA is 1:0.005:0.02. After thorough mixing, remove ethanol using a vacuum pump. Transfer the resulting mixture to a glass mold using a pipette and react overnight in a nitrogen atmosphere at 60 °C. After the reaction is completed, take out the elastomer from the mold, wash away any unreacted monomers with dichloromethane, and then place the elastomer in a vacuum drying chamber to remove residual solvents and water. The PolyES ion gel is prepared.

[0087] Example 1

[0088] First, process each ion gel material into a square shape of the specified size using precise cutting tools to ensure dimensional accuracy and morphological consistency. Cut the PolyAT and PolyES ion gels into square sheets of 0.5 cm × 0.5 cm as the elastomer substrate, with a thickness of 5 mm. Then, stack the sheets of these two materials together and perform a lamination operation to make them closely combined to form a composite structure. To ensure stable and efficient transmission of electrical properties, select PI-Cu electrode materials and apply them to both sides of the ion gel respectively. An ion gel diode is obtained.

[0089] Example 2

[0090] Precisely cut the PolyAT and PolyES ion gels into squares of 0.5 cm × 0.5 cm respectively, with a thickness of 5 mm, ensuring that the size of each unit is consistent. Next, design and layout the array, which is an 8×8 array with a spacing of 100 mm. Laminate 64 ion gel units in a predetermined manner to ensure that each unit is closely combined to form a uniform composite structure. Subsequently, cover each unit with a layer of PI-Cu electrode and connect each row and each column of the array by wire welding to ensure effective acquisition and transmission of signals. After the electrode access is completed, perform performance tests on the array through an external circuit to ensure the stable electrical performance of each unit. Finally, perform packaging treatment on the entire array to improve its mechanical stability and environmental adaptability. Eventually, a high-performance 8×8 sensing array is obtained, which has broad application potential and is suitable for fields such as flexible electronics and intelligent sensors.

[0091] Figure 1 It is a schematic diagram of the structure of an ion gel diode artificial skin. The middle two layers are the PolyAT ion gel layer and the PolyES ion gel, and the outermost two layers are the polyimide-copper electrodes.

[0092] Test Example 1

[0093] The ion gel diode fabricated in Example 1 was connected to a semiconductor analyzer (Keithley SC-4200), and different intensities of current were applied to observe its voltage changes. During the experiment, by precisely controlling the current range, the response characteristics of the ion gel device to current were detected. As Figure 2 shown, the results indicate that the ion gel device can effectively detect and respond to minute current changes in the range of 1 to 200 nA, and exhibits obvious voltage changes throughout the measurement range. Both the output voltage and retention time increase with the increase in current intensity. In addition, the device also demonstrates complex synaptic behaviors, that is, as the current changes, its voltage response not only shows a linear change, but also exhibits non-linear characteristics and memory effects similar to those of biological synapses. These synaptic behaviors enable the ion gel device to possess the ability to mimic biological nervous systems, showing great application potential in the fields of flexible electronics, artificial neural networks, and intelligent sensors.

[0094] Test Example 2

[0095] The ion gel diode fabricated in Example 1 was connected to a semiconductor analyzer (Keithley SC-4200), and a constant voltage of 0.5 V was applied. Subsequently, different intensities of pressure stimuli were applied to the device to observe its current changes. As Figure 3 shown, the EPSCs triggered by different pressure pulses in the ion gel diode artificial skin are different. By adjusting the pressure intensity, the EPSC value can be easily adjusted. After the pressure pulse is removed, the EPSC rapidly decays and gradually returns to the baseline. As Figure 4 shown, the ion gel diode artificial skin exhibits PPF behavior by applying two consecutive pressure pulses (1.9 kPa, 0.2 s).

[0096] The experimental results show that the ion gel device can accurately detect pressure changes in a wide pressure range from 0.075 Pa to 400 kPa and present corresponding current responses. This characteristic indicates that the ion gel device has high sensitivity and accuracy in multiple pressure ranges. At the same time, the current response of the device not only shows a certain linear relationship with the pressure change, but also exhibits complex non-linear behaviors, demonstrating rich synaptic characteristics, such as memory effects and step-by-step recovery phenomena after pressure stimulation. These synaptic behaviors make the ion gel device have great potential in simulating the functions of biological nervous systems.

[0097] Test Example 3

[0098] The ion gel diode fabricated in Example 1 was connected to a semiconductor analyzer (Keithley SC-4200), and a constant voltage of 0.5 V was applied. Subsequently, different temperature stimuli were applied to the device to observe its current changes. As Figure 5 shown, the ion gel device can accurately respond to temperature changes in a wide temperature range from -80 °C to 120 °C, has high detection ability, exhibits good temperature sensitivity, and has excellent repeatability in non-contact sensing mode. As the temperature changes, the current response of the device shows obvious changes, indicating that it can effectively sense and track temperature fluctuations. As Figure 6 shown, the ion gel diode artificial skin exhibited PPF behavior by applying two consecutive temperature pulses (0 °C, 2.3 s). In addition, the device also demonstrated synaptic behavior, such as non-linear current responses triggered by temperature changes and memory effects after temperature stimuli. These synaptic characteristics enable the ion gel device not only to detect temperature but also to possess adaptive and learning abilities similar to biological nervous systems. This temperature-sensitive and synaptic-behavioral property is particularly suitable for high-tech application scenarios that require sensing temperature changes and making complex responses.

[0099] Test Example 4

[0100] A constant voltage of 0.5 V was applied to each unit of the 8×8 sensing array in Example 2. In the experiment, by placing objects of different weights and shapes on the array, the response of the array was observed using current changes. As Figure 7 shown, when a steel ruler at 50 °C approached the sensor array, multiple sensing units generated different currents, achieving non-contact localization of the spatial distribution of the object. As Figure 8 shown, by analyzing the current changes in each sensor unit, the position and size of the weight can be successfully located and identified, achieving contact localization of the spatial distribution of the object.

[0101] The results show that the array can sensitively sense the weight of the object and accurately infer the shape of the object based on the pressure changes applied to each sensing unit. This indicates that the array has high sensitivity and accuracy in sensing mechanical forces and shape recognition.

[0102] In addition, the array can also non-contact sense temperature changes. When objects of different temperatures and shapes approach or are applied to the surface of the array, the current of the array will also change accordingly, further demonstrating its sensitivity to temperature stimuli. Whether through direct contact with the object or in a non-contact manner, the array can accurately identify the weight and shape of the object through current changes.

[0103] As Figure 9As shown, the ion gel diode artificial skin is connected to a robotic hand. The robotic hand can detect the temperature and pressure of an object and select an object with a suitable temperature and desired weight, effectively mimicking the process of a human selecting a suitable object.

[0104] Test Example 5

[0105] Based on the ion gel diode RC system fabricated in Example 1, it is used for handwritten digit recognition. This system combines LTM and STM behaviors and can learn and reason directly from electrical pulse signals without the need for dedicated sensors or digital computers. The ion gel diode serves as a memory unit, achieving multi-level potential and decay states through different current pulse sequences, providing the RC system with real-time learning capabilities. As Figure 10 shown, the ion gel diode artificial skin, as a storage unit in the readout layer of the RC system, performs sensing, decoding, and learning through electrical stimulation. In the experiment, the system binarizes the handwritten digit images of the Modified National Institute of Standards and Technology database (MNIST) with 28×28 pixels and inputs them into the visual neural network composed of ion gel diodes for classification, achieving an accuracy of 91.3%, slightly higher than 90.2% of traditional software.

[0106] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. An ion gel diode device, characterized in that: The ion gel diode comprises a flexible electrode and an ion gel layer; The ion gel layer includes a free anion gel layer and a free cation gel layer; The free anion gel layer and the free cation gel layer are attached together; The flexible electrodes are attached to both sides of the ion gel layer; The material of the free anion gel layer is poly 1-[2-acryloxyethyl]-3-butylimidazole bis(trifluoromethane)sulfonimide; The material of the free cationic gel layer is poly 1-ethyl-3-methylimidazolium (3-sulfopropyl) acrylate.

2. The ion gel diode device according to claim 1, characterized in that: The thickness of the free anion gel layer and the free cation gel layer is 2 to 5 mm.

3. The ion gel diode device according to claim 1, characterized in that: The flexible electrode is selected from a PI-Cu flexible electrode and an ITO flexible electrode.

4. The ion gel diode device according to claim 1, characterized in that: The ion gel layers are arranged in an array.

5. The method for preparing an ion gel diode device according to any one of claims 1 to 4, characterized in that: include: S1 obtained free anion gel and free cation gel respectively; S2 cuts the free anion gel and the free cation gel into thin sheets respectively, processes them into required shapes, and stacks them together to perform lamination operations to make them tightly combined to obtain an ion gel layer; S3 applies flexible electrodes to both sides of the ion gel layer to obtain the ion gel diode device.

6. The preparation method according to claim 5, characterized in that: In step S2, the arrays are designed and laid out and then stacked together for lamination.

7. Use of the ion gel diode device according to any one of claims 1 to 4 as a sensor.

8. Use of the ion gel diode device according to any one of claims 1 to 4 as artificial skin.

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