Self-repairing ionic gel, self-repairing ionic gel sensor as well as preparation method and application of self-repairing ionic gel sensor

Abstract

The invention provides self-repairing ionic gel, a self-repairing ionic gel sensor and a preparation method and application of the self-repairing ionic gel sensor, and belongs to the field of intelligent high polymer materials. The self-repairing ionic gel sensor sequentially comprises a first electrode layer, a self-repairing ionic gel sensing layer and a second electrode layer from top to bottom, the self-repairing ionic gel comprises a semi-interpenetrating polymer network, a lithium salt dispersed in the semi-interpenetrating polymer network and a solvent; wherein the semi-interpenetrating polymer network is formed by penetrating linear polyacrylic acid into a cross-linked network of poly (hydroxyethyl acrylate-co-hydroxyethyl methylacrylate). The self-repairing ionic gel sensor can convert external pressure, stretching and other mechanical stimuli into measurable resistance or capacitance signal changes, and has the advantages of high sensitivity, wide detection range, low hysteresis and quick response.

Description

Technical Field

[0001] This invention relates to the field of intelligent polymer materials, and in particular to a self-healing ionogel, a self-healing ionogel sensor, its preparation method and application. Background Technology

[0002] With the rapid development of robotics technology, robots have been widely applied in industrial manufacturing, medical assistance, home services, and human-robot collaboration. To enable robots to interact with humans and dynamic environments more safely and intelligently, endowing them with tactile sensing capabilities similar to human skin is crucial. Robotic skin, through the integration of flexible sensors, can detect various physical signals such as external forces, deformation, and temperature in real time, thereby achieving accurate perception and feedback of contacted objects, operational forces, and the external environment. This becomes a key component in enhancing the robot's autonomy and adaptability. Furthermore, to ensure long-term reliable operation, robotic skin must also possess the ability to withstand and recover from mechanical wear and accidental scratches.

[0003] Currently, flexible sensors, with their excellent stretchability, conformability, and mechanical durability, are gradually becoming the ideal choice for robotic skin tactile systems. Among them, ionogels, with their excellent ionic conductivity, elasticity, structural designability, and good environmental stability, exhibit significant advantages in the field of flexible sensing and are considered one of the important materials for constructing multimodal sensing robot skin. Ionogel-based sensors can convert mechanical deformations such as pressure, tension, and bending into measurable electrical signals, enabling robots to recognize grasping force, surface texture, hand gestures, and even complex environmental contact states, thus applying them to various scenarios such as precision grasping, safe interaction, biomimetic manipulation, and emotional expression. However, in practical applications, problems such as limited mechanical strength, susceptibility to damage, and insufficient adhesion still exist. Summary of the Invention

[0004] In view of the above, in order to at least partially solve at least one of the aforementioned technical problems, the present invention provides a self-healing ion gel, a self-healing ion gel sensor, a method for preparing the same and its application. The technical solution provided by the present invention is as follows.

[0005] According to an embodiment of the first aspect of the present invention, a self-healing ionogel sensor is provided, comprising, from top to bottom: a first electrode layer, a self-healing ionogel sensing layer, and a second electrode layer; the self-healing ionogel comprises a semi-interpenetrating polymer network, a lithium salt dispersed in the semi-interpenetrating polymer network, and a solvent; wherein the semi-interpenetrating polymer network is formed by linear polyacrylic acid penetrating a crosslinked network of poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate).

[0006] According to an embodiment of a second aspect of the present invention, a self-healing ionic gel is provided, comprising a semi-interpenetrating polymer network, a lithium salt dispersed in the semi-interpenetrating polymer network, and a solvent; the semi-interpenetrating polymer network is formed by linear polyacrylic acid penetrating a crosslinked network of poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate).

[0007] According to an embodiment of a third aspect of the present invention, a method for preparing a self-healing ionic gel is provided, comprising: mixing acrylic acid, a photoinitiator and a solvent, and reacting them under light irradiation to obtain a polyacrylic acid solution; mixing the polyacrylic acid solution, hydroxyethyl acrylate, hydroxyethyl methacrylate, a crosslinking agent, a thermal initiator and a lithium salt, and reacting them under heating to obtain a self-healing ionic gel.

[0008] According to an embodiment of a fourth aspect of the present invention, an application of a self-healing ionogel or a self-healing ionogel sensor in electronic skin is provided.

[0009] According to embodiments of the present invention, the present invention provides a self-healing ionogel (hereinafter referred to as "gel") sensor, wherein the self-healing ionogel is based on a linear polyacrylic acid and poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) crosslinked network, forming a gel system with a semi-interpenetrating polymer network structure, and lithium salt is used as the ion-conducting medium. This unique semi-interpenetrating polymer network not only enhances the mechanical strength, resilience, and self-healing ability after damage of the gel through dynamic and reversible multiple hydrogen bonds and physical entanglement between polymer chains, but also provides a continuous and stable channel for ion transport, ensuring the stability of the gel's electrical properties. Furthermore, the lithium salt is uniformly dispersed in the semi-interpenetrating polymer network, establishing continuous ion transport channels and dynamic bonding points, endowing the gel with a high (e.g., 2.9 mS / m) and stable ion conductivity. At the same time, its ion interactions further increase the dynamic reversibility of the semi-interpenetrating polymer network, which is beneficial for achieving high-sensitivity sensing and high-efficiency self-healing. This semi-interpenetrating polymer network structure effectively improves the problems of high environmental sensitivity, insufficient elasticity and fatigue resistance, and poor interfacial adhesion of traditional iontophores in practical applications, enabling them to better adapt to the complex and ever-changing working environment and usage requirements in robotic skin applications. Attached Figure Description

[0010] Figure 1 This is a graph showing the weight change of the self-healing ionic gel and ionic hydrogel in Test Example 2 of the present invention after being placed in a natural environment for 30 days.

[0011] Figure 2 This is a microscope image of the self-healing ionogel after it was scratched in Test Example 3 of this invention;

[0012] Figure 3This is a microscope image of the self-healing ion gel in Test Example 3 of the present invention 1 hour after it was scratched;

[0013] Figure 4 This is a microscope image of the self-healing ionogel in Test Example 3 of the present invention, taken 2 hours after it was scratched.

[0014] Figure 5 This is a microscope image of the self-healing ionogel in Test Example 3 of the present invention 12 hours after it was scratched;

[0015] Figure 6 This is a graph showing the sensitivity test results of the self-healing ionogel sensor in Test Example 4 of the present invention;

[0016] Figure 7 The figure shows the dynamic stability test results of the self-healing ion gel sensor in Test Example 5 of the present invention.

[0017] Figure 8 This is a graph showing the pressure test results of the self-healing ionogel sensor in Test Example 6 of the present invention;

[0018] Figure 9 The graph shows the cycle stability test results of the self-healing ionogel sensor in Test Example 7 of this invention. Detailed Implementation

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0020] In this invention, the term "semi-interpenetrating polymer network" refers to a special polymeric material system formed by the interpenetration and entanglement of a linear polymer and a cross-linked network polymer. In this system, only one of the two polymer components forms a cross-linked network structure, while the other is linear, and there are no chemical bonds connecting the two; they are only bonded together by physical interactions (such as chain entanglement, van der Waals forces, hydrogen bonds, etc.).

[0021] In this invention, the term "interfacial double layer modulation effect" refers to the formation of an electrochemical double layer structure (typically composed of charges on the electrode surface and oppositely charged ions in the electrolyte) at the interface when the ion gel comes into contact with the encapsulated electrode. Under external pressure, the gel deforms, causing changes in ion distribution, interfacial contact area, or contact spacing, thereby altering the double layer capacitance or interfacial resistance, and ultimately enabling a sensing response to pressure signals.

[0022] Applying traditional ionogel sensors to robotic skin faces a series of key technological challenges. Regarding material properties, during actual robot operation, the skin is highly susceptible to microcracks and even macroscopic damage due to friction, pressure, or contact with sharp objects. This irreversible damage disrupts the conductive pathways and structural integrity, leading to signal attenuation or even failure, severely impacting sensor lifespan. Simultaneously, the elasticity and resilience of traditional ionogels are ill-suited to the frequent and significant dynamic deformations of robot joints, making them prone to plastic deformation or fatigue damage over long-term use. Furthermore, the adhesion between traditional ionogels and the curved substrate of the robot is insufficient, making them prone to peeling or displacement during dynamic movement, affecting signal acquisition stability. On the other hand, traditional ionogels still fail to fully meet the requirements of robots for real-time, high-precision (e.g., sensing frequency greater than 200Hz) tactile feedback in terms of sensitivity, response speed, and cycle stability. The complexity of the fabrication process, cost control, and feasibility of large-scale production also restrict the practical application and widespread adoption of ionogel sensors in robotic skin.

[0023] In view of this, the present invention provides a self-healing ionogel that combines self-healing capability, excellent environmental stability, reliable mechanical properties, low cost, and high sensitivity (GF=6.1983). Based on this, a self-healing ionogel sensor suitable for robot skin is constructed, and a simple and cost-effective preparation method is also provided. This sensor can achieve stable and conformal fit with the complex curved surfaces of a robot, and can sense contact pressure, sliding, and deformation signals in real time, thereby effectively improving the robot's intelligence level in human-robot interaction, precision operation, and external environment perception.

[0024] Specifically, according to an embodiment of the first aspect of the present invention, a self-healing ionic gel is provided, comprising a semi-interpenetrating polymer network, a lithium salt dispersed in the semi-interpenetrating polymer network, and a solvent; wherein the semi-interpenetrating polymer network is formed by linear polyacrylic acid penetrating a crosslinked network of poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate).

[0025] According to embodiments of the present invention, a semi-interpenetrating polymer network (hereinafter referred to as "semi-interpenetrating network") formed by the interpenetration of linear polyacrylic acid and poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) crosslinking networks is constructed, and combined with dynamic reversible hydrogen bonding and ion-dipole interactions, functional integration is achieved at the molecular level. Specifically, the semi-interpenetrating network is rich in carboxyl and hydroxyl functional groups, which can form a network of multiple, reversible hydrogen bonds. These hydrogen bonds, as dynamic physical crosslinking points, not only enhance the mechanical strength and resilience of the gel, but also provide a self-healing driving force, enabling the gel to self-repair after damage. At the same time, lithium ions generated by the dissociation of lithium salt in the gel form ion-dipole interactions with polar groups, which helps the uniform dispersion and migration of lithium ions in the semi-interpenetrating network, thereby constructing a continuous ion transport pathway and effectively improving the ionic conductivity of the gel. Through the synergy of dynamic reversible hydrogen bonding and ion-dipole interactions, the gel achieves an organic combination of mechanical properties, self-healing characteristics, and ionic conductivity, laying a structural foundation for constructing high-performance flexible sensing materials.

[0026] According to embodiments of the present invention, the mass ratio of linear polyacrylic acid to the poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) can be 0.05:1-0.2:1, for example, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.13:1, 0.15:1, 0.17:1, 0.19:1, 0.2:1, but is not limited to the listed values. A suitable content of linear polyacrylic acid provides sufficient hydrogen bonding sites to support the self-healing properties of the gel, while avoiding excessive swelling of the cross-linked network due to excessive linear chains, which would lead to a decrease in the mechanical properties of the gel. The mass ratio of the total mass of linear polyacrylic acid and poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) to the mass of the solvent is (0.5-2):1, for example, it can be 0.5:1, 0.8:1, 0.9:1, 1:1, 1.2:1, 1.4:1, 1.5:1, 1.7:1, 1.9:1, 2:1, but is not limited to the values ​​listed.

[0027] In some embodiments, the mass content of lithium salt can be 1%-10% based on the total mass of the self-healing ionogel, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, but not limited to the listed values. A suitable lithium salt content ensures sufficient migratable ions within the gel while avoiding lithium ion aggregation or localized crystallization caused by excessively high concentrations (e.g., greater than 10%), thereby maintaining the gel's flexibility and mechanical integrity. The lithium salt is at least one of lithium chloride and lithium bis(trifluoromethanesulfonate)imine, and can be used alone or in combination depending on specific performance requirements.

[0028] In some embodiments, the solvent can be polyethylene glycol (PEG), with an average molecular weight of 200-600, such as 200, 400, or 600. Traditional hydrogels often dry out and harden due to water evaporation; while using ionic liquids as solvents can improve gel stability to some extent, it also significantly increases material costs. Therefore, this invention selects non-volatile, low-molecular-weight PEG as the solvent, whose terminal hydroxyl groups can form dynamic hydrogen bonds with carboxyl and hydroxyl groups in the semi-interpenetrating network. This not only further enhances the compactness and dynamic reversibility of the semi-interpenetrating network but also synergistically improves the gel's self-healing efficiency, mechanical properties, and structural stability. While improving the environmental stability of the gel, it also provides a feasible path for its low-cost and large-scale preparation. It is understood that this invention is not limited to this; in other embodiments, the solvent can still be a protic solvent such as water, or an ionic liquid.

[0029] According to an embodiment of a second aspect of the present invention, a method for preparing a self-healing ionic gel is provided, comprising: mixing acrylic acid, a photoinitiator and a solvent, and reacting them under light irradiation to obtain a polyacrylic acid solution; mixing the polyacrylic acid solution, hydroxyethyl acrylate, hydroxyethyl methacrylate, a crosslinking agent, a thermal initiator and a lithium salt, and reacting them under heating to obtain a self-healing ionic gel.

[0030] According to embodiments of the present invention, a semi-interpenetrating network is constructed through a programmed stepwise polymerization and ion-coordinated control mechanism. First, acrylic monomers are photopolymerized under the action of a photoinitiator to prepare linear polyacrylic acid. Subsequently, under thermal initiation conditions, hydroxyethyl acrylate and hydroxyethyl methacrylate undergo a copolymerization reaction under the action of a crosslinking agent to form a crosslinked network, which interpenetrates with the linear polyacrylic acid to form a semi-interpenetrating network. Simultaneously, lithium salt and solvent are introduced synchronously during the polymerization process and uniformly dispersed in the semi-interpenetrating network. Through the above stepwise and controllable polymerization process, a self-healing ionogel combining a semi-interpenetrating network, dynamic hydrogen bonding, and stable ion transport pathways is formed.

[0031] In some embodiments, the photoinitiator is at least one selected from 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, and benzophenone. The crosslinking agent is at least one selected from poly(ethylene glycol) dimethacrylate and divinylbenzene. The thermal initiator is at least one selected from azobisisobutyronitrile, azobisisobutyramidoline hydrochloride, 4-4'-azobis(4-cyanopentanoic acid), benzoyl peroxide, hydroperoxide, dialkyl peroxide, peroxide ester, and dicarbonate peroxide. These thermal initiators have moderate initiation activity, enabling uniform copolymerization and stable crosslinking of hydroxyethyl acrylate and hydroxyethyl methacrylate, which is beneficial for forming a structurally uniform crosslinked network.

[0032] In some embodiments, the mass ratio of acrylic acid, hydroxyethyl acrylate, and hydroxyethyl methacrylate to the solvent can be 0.5:1 to 2:1, for example, 0.5:1, 1:1, 1.5:1, or 2:1, but is not limited to the listed values. A suitable ratio range ensures the complete formation of the semi-interpenetrating structure while avoiding problems such as excessive cross-linking of the gel or insufficient solvation due to excessively high monomer concentrations (e.g., greater than 2:1).

[0033] The mass ratio of the crosslinking agent to the total mass of hydroxyethyl acrylate and hydroxyethyl methacrylate is 0.001:1-0.05:1, for example, 0.001:1, 0.015:1, 0.02:1, 0.025:1, 0.03:1, 0.035:1, 0.04:1, 0.045:1, 0.05:1, but not limited to the listed values. This range of crosslinking agent dosage can enable the gel to possess good mechanical strength, resilience, and self-healing ability while forming a stable poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) crosslinking network.

[0034] In some embodiments, a polyacrylic acid solution, hydroxyethyl acrylate, hydroxyethyl methacrylate, a crosslinking agent, a thermal initiator, and a lithium salt are mixed and heated to 40-60°C for 7-9 hours. The heating temperature can be 40°C, 45°C, 50°C, 55°C, or 60°C, but is not limited to the listed values. This temperature range effectively activates the thermal initiator (such as azobisisobutyrazoline hydrochloride) while avoiding excessively high temperatures (e.g., above 60°C) that could lead to the decomposition of poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) or other side reactions. The reaction time can be 7 hours, 8 hours, or 9 hours, but is not limited to the listed values. Sufficient reaction time ensures complete polymerization of the monomers and the complete formation of the semi-interpenetrating network, improving product conversion and the structural integrity of the semi-interpenetrating network.

[0035] According to an embodiment of a third aspect of the present invention, a self-healing ion gel sensor is provided, comprising, from top to bottom: a first electrode layer, a self-healing ion gel sensing layer, and a second electrode layer; wherein the self-healing ion gel sensing layer uses the self-healing ion gel as described above.

[0036] A self-healing ionogel sensing layer, serving as the sensitive functional layer, is encapsulated between the first and second electrodes, constituting a self-healing ionogel sensor (hereinafter referred to as the "sensor"). In the self-healing ionogel sensing layer, a semi-interpenetrating network forms the physical support framework, while lithium salt provides freely moving ions. When the self-healing ionogel sensor is subjected to external mechanical stimuli such as pressure or tension, the semi-interpenetrating network deforms, altering the geometry of the ion conduction channels and modulating the distribution of the interfacial double layer. This linearly converts the deformation into a change in electrical signal (such as resistance or capacitance), which is output by the first and second electrodes. By detecting the change in the electrical signal, the type and degree of the external mechanical stimulus can be inferred, achieving quantitative sensing of deformations such as pressure and tension. This sensor can convert external mechanical stimuli such as pressure and tension into measurable changes in resistance or capacitance signals, exhibiting high sensitivity (GF=6.1983), a wide detection range (0-500mm / min), low hysteresis, fast response (e.g., 50-100ms), and good recovery characteristics, making it suitable for constructing robotic tactile sensing arrays.

[0037] In some embodiments, the thickness of the first electrode layer and the second electrode layer is independently 0.01-0.1 mm, for example, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, or 0.1 mm, but not limited to the listed values. The thickness of the self-healing ionogel is 0.5-1 cm, for example, 0.5 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, or 1 cm, but not limited to the listed values. Exemplarily, the first electrode layer and the second electrode layer are each independently connected to a wire to transmit electrical signals generated in response to deformation of the self-healing ionogel sensing layer.

[0038] According to an embodiment of a fourth aspect of the present invention, an application of a self-healing ionogel or a self-healing ionogel sensor in electronic skin is provided.

[0039] According to embodiments of the present invention, a preparation method employing "photopolymerization pre-preparation - simultaneous thermal polymerization crosslinking" achieves precise control over the gel's microstructure. The linear polyacrylic acid pre-formed during the photopolymerization stage lays the structural foundation for the subsequent construction of the semi-interpenetrating network, while simultaneously introducing abundant dynamic hydrogen bond sites. During the thermal polymerization stage, while initiating the copolymerization crosslinking reaction, lithium salt is uniformly dispersed within the growing semi-interpenetrating network, simultaneously constructing continuous ion transport channels. This preparation method ensures that the formed semi-interpenetrating network structure is uniform and dense, with a rational distribution of dynamic hydrogen bonds, thereby endowing the gel with high sensitivity (GF=6.1983), rapid response (e.g., 50-100ms), excellent environmental stability (resistance to temperature and humidity changes), and self-healing properties. By constructing a semi-interpenetrating polymer network formed by linear polyacrylic acid penetrating a crosslinked network of poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) (P(HEA-co-HEMA)), and synergistically with uniformly dispersed lithium salts therein, a synergistic system of "mechanically stable semi-interpenetrating network" and "efficient ionic conductivity pathway" is built, which effectively improves the overall performance of the sensor in terms of sensitivity, dynamic response stability, wide-range pressure response and cycle durability.

[0040] In terms of sensitivity, the sensor exhibits high and stable sensitivity characteristics over a wide compressive strain range of 0-80%, with a sensitivity (GF) reaching 6.1983. Lithium salt, acting as the ion-conducting medium, is uniformly dispersed within a semi-interpenetrating network. Under compressive strain, the elastic deformation of the semi-interpenetrating network not only alters the geometry and effective length of the ion migration channels but also significantly affects the interfacial contact resistance between the gel and the encapsulated electrode, resulting in a significant change in resistance and achieving a high-sensitivity (GF=6.1983) electrical response. Compared to piezoresistive sensors that rely on electronic conductors (such as carbon materials and metal nanowires) or traditional ion gels employing loose dynamic networks for self-healing performance, the former, while achieving higher sensitivity, is difficult to repair after damage; the latter often suffers from insufficient network structure strength and ion transport efficiency, leading to limitations in sensitivity and stability. This invention effectively alleviates the challenge of balancing sensitivity and self-healing performance by constructing a synergistic system of a "mechanically robust semi-interpenetrating network" and a "highly efficient ion-conducting pathway." This design enables the sensor to exhibit a sensitive and stable response over a wide compressive strain range (e.g., 0-80%), while maintaining the gel's inherent self-healing properties, achieving a balance between sensing performance and durability. This demonstrates the gel's significant advantages in developing robotic skin that combines highly sensitive tactile perception with long-term stability.

[0041] In terms of dynamic stability, the sensor's excellent dynamic response characteristics are attributed to its synergistic structural design of a "highly efficient ion-conducting pathway" and a "mechanically robust semi-interpenetrating network." Specifically, the elasticity and fatigue resistance of the semi-interpenetrating network endow the sensor with excellent resistance to plastic deformation, allowing the gel to maintain structural integrity under high speed (e.g., 500 mm / min) and repeated compression. Uniformly dispersed lithium ions provide a stable and continuous ion-conducting pathway, whose migration rate can quickly respond to the deformation of the semi-interpenetrating network. Simultaneously, this semi-interpenetrating network can adaptively adapt to the external loading rate, enabling real-time modulation of electrical performance. This invention, by constructing a synergistic system of a "mechanically robust semi-interpenetrating network" and a "highly efficient ion-conducting pathway," achieves the tracking and stability of the sensing signal to the loading rate. This not only demonstrates the high sensitivity of the gel in static conditions (GF=6.1983), but more importantly, in simulated rapid, dynamic interactions with robots (e.g., grasping, sliding, light touching), the sensor can still provide real-time, reliable, and high-fidelity tactile feedback. This is of great significance for the precise perception and control of robot skin in complex, unsteady working environments.

[0042] In terms of pressure response, the uniform and dense semi-interpenetrating network ensures the uniform transmission of external compressive stress, inducing proportional deformation of the semi-interpenetrating network structure. This results in stable and repeatable ion channel geometry and interface double-layer modulation effects under different degrees of compression. The lithium-ion migration path can respond to macroscopic compressive strain in real time and accurately, achieving a linear conversion between strain and resistance signal changes. The excellent elasticity and rapid dynamic hydrogen bond recombination capability of the semi-interpenetrating network enable the sensor to quickly recover to its initial microstructure and electrical state after loading / unloading cycles, exhibiting low hysteresis and high repeatability response characteristics. This provides a stable and reliable electrical signal foundation for robot skin to achieve precise force feedback, quantify grasping force, and identify the hardness and softness of objects, fully demonstrating the sensor's sensing consistency and comprehensive performance advantages in complex interactive scenarios.

[0043] In terms of cyclic stability, the linear polyacrylic acid (PAA) and P(HEA-co-HEMA) cross-linked networks interpenetrate each other, forming a semi-interpenetrating network that combines toughness and elasticity, endowing the gel with excellent fatigue and deformation resistance. The lithium salt is uniformly dispersed and stably present in the semi-interpenetrating network, constructing an ionic conductivity pathway independent of physical contact, thereby mitigating signal attenuation caused by the shedding or migration of conductive fillers. More importantly, the dense dynamic hydrogen bonds in the semi-interpenetrating network can undergo reversible breakage and recombination under cyclic stress. This mechanism not only dissipates energy promptly and delays the formation of microcracks, but also actively repairs microscopic damage formed during cyclic loading, thus maintaining the integrity of the ionic conductivity pathway and the semi-interpenetrating network over a long period. Compared with existing flexible sensors that rely on physically blended conductive fillers or pure covalently cross-linked networks, the former is prone to sensitivity drift due to interface failure during cyclic loading, while the latter suffers irreversible performance degradation after damage accumulation. This invention, through the synergistic design of a "mechanically robust semi-interpenetrating network" and an "ion-conducting pathway," enables the sensor to maintain a highly consistent signal output waveform even after long-term, high-frequency cyclic loading. This lays the foundation for robotic skin to continuously and stably provide high-fidelity tactile signals during long-term, dynamic interactive tasks, effectively alleviating the contradiction between sensitivity and long service life in traditional sensors, and demonstrating the sensor's advantages in cyclic durability and reliability.

[0044] The present invention will be described in detail below with reference to specific embodiments. It should be noted that the described embodiments are merely some, not all, of the embodiments of the present invention. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0045] Unless otherwise expressly stated, the experimental materials, raw materials and reagents used in the following examples and the specification of this invention are all commercially available conventional products.

[0046] Example 1

[0047] 50g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 5g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173) were added sequentially. The mixture was irradiated under 365nm ultraviolet light for 1h to obtain a polyacrylic acid solution. To the polyacrylic acid solution obtained above, 20g of hydroxyethyl acrylate (HEA), 20g of hydroxyethyl methacrylate (HEMA), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044), and 5g of lithium chloride (LiCl) were added sequentially. After thoroughly mixing the system, it was sealed and reacted at 50℃ for 8h to finally obtain a self-healing ionic gel.

[0048] Example 2

[0049] 50g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 5g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173) were added sequentially. The mixture was irradiated under 365nm ultraviolet light for 1h to obtain a polyacrylic acid solution.

[0050] To the polyacrylic acid solution obtained in the previous step, 20g of hydroxyethyl acrylate (HEA), 20g of hydroxyethyl methacrylate (HEMA), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044), and 5g of lithium bis(trifluoromethanesulfonate) imine (LiTFSI) were added sequentially. After thoroughly mixing the system, it was sealed and reacted at 50°C for 8 hours to finally obtain a self-healing ionic gel.

[0051] Example 3

[0052] 50g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 5g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173) were added sequentially. The mixture was irradiated under 365nm ultraviolet light for 1h to obtain a polyacrylic acid solution. To the polyacrylic acid solution obtained above, 17.5g of hydroxyethyl acrylate (HEA), 17.5g of hydroxyethyl methacrylate (HEMA), 5g of polyethylene glycol (PEG400), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044), and 5g of lithium chloride (LiCl) were added sequentially. After thoroughly mixing the system, it was sealed and reacted at 50℃ for 8h to finally obtain a self-healing ionic gel.

[0053] Example 4

[0054] 45g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 5g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173) were added sequentially. The mixture was irradiated under 365nm ultraviolet light for 1 hour to obtain a polyacrylic acid solution. To the polyacrylic acid solution obtained above, 22.5g of hydroxyethyl acrylate (HEA), 22.5g of hydroxyethyl methacrylate (HEMA), 5g of polyethylene glycol (PEG400), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044), and 5g of lithium chloride (LiCl) were added sequentially. After thoroughly mixing the system, it was sealed and reacted at 50℃ for 8 hours to finally obtain a self-healing ionic gel.

[0055] Example 5

[0056] 53g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 5g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173) were added sequentially. The mixture was irradiated under 365nm ultraviolet light for 1 hour to obtain a polyacrylic acid solution. To the polyacrylic acid solution obtained above, 20g of hydroxyethyl acrylate (HEA), 20g of hydroxyethyl methacrylate (HEMA), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044), and 2g of lithium chloride (LiCl) were added sequentially. After thoroughly mixing the system, it was sealed and reacted at 50℃ for 8 hours to finally obtain a self-healing ionic gel.

[0057] Example 6

[0058] 50g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 15g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173) were added sequentially. The mixture was irradiated under 365nm ultraviolet light for 1h to obtain a polyacrylic acid solution. To the polyacrylic acid solution obtained above, 15g of hydroxyethyl acrylate (HEA), 15g of hydroxyethyl methacrylate (HEMA), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044), and 5g of lithium chloride (LiCl) were added sequentially. After thoroughly mixing the system, it was sealed and reacted at 50℃ for 8h to finally obtain a self-healing ionic gel.

[0059] Example 7: Preparation of Ionized Hydrogels

[0060] Weigh 50g of deionized water as a solvent, add 5g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173), and irradiate under 365nm ultraviolet light for 1 hour to obtain a polyacrylic acid solution. Add 20g of hydroxyethyl acrylate (HEA), 20g of hydroxyethyl methacrylate (HEMA), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044), and 5g of lithium chloride (LiCl) to the above polyacrylic acid solution sequentially. After thoroughly mixing the system, seal and react at 50℃ for 8 hours to obtain an ionized hydrogel.

[0061] Comparative Example 1: Preparation of a lithium-free self-healing gel

[0062] 50g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 5g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173) were added sequentially. The mixture was irradiated under 365nm ultraviolet light for 1 hour to obtain a polyacrylic acid solution. To the polyacrylic acid solution prepared above, 22.5g of hydroxyethyl acrylate (HEA), 22.5g of hydroxyethyl methacrylate (HEMA), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, and 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044) were added. After thorough mixing, the mixture was reacted at 50℃ under sealed conditions for 8 hours to finally obtain a self-healing gel.

[0063] Comparative Example 2: Preparation of a lithium-free self-healing gel

[0064] 50g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 5g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173) were added sequentially. The mixture was irradiated under 365nm ultraviolet light for 1 hour to obtain a polyacrylic acid solution. To the polyacrylic acid solution obtained above, 20g of hydroxyethyl acrylate (HEA), 20g of hydroxyethyl methacrylate (HEMA), 5g of polyethylene glycol (PEG400), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, and 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044) were added sequentially. After thoroughly mixing the system, it was sealed and reacted at 50℃ for 8 hours to finally obtain a self-healing gel.

[0065] Comparative Example 3: Preparation of a lithium-free self-healing gel

[0066] 45g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 5g of acrylic acid (AA) and 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173) were added sequentially. The mixture was irradiated under 365nm ultraviolet light for 1 hour to obtain a polyacrylic acid solution. To the polyacrylic acid solution obtained above, 25g of hydroxyethyl acrylate (HEA), 25g of hydroxyethyl methacrylate (HEMA), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, and 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044) were added sequentially. After thoroughly mixing the mixture, it was sealed and reacted at 50℃ for 8 hours to finally obtain a self-healing gel.

[0067] Comparative Example 4: Preparation of One-Step Ion Gel

[0068] 50g of polyethylene glycol (PEG400) with a molecular weight of 400 was weighed as a solvent, and 5g of acrylic acid (AA), 0.05g of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (I1173), 20g of hydroxyethyl acrylate (HEA), 20g of hydroxyethyl methacrylate (HEMA), 0.8g of crosslinking agent poly(ethylene glycol) diacrylate, 0.4g of initiator azobisisobutyrazoline hydrochloride (VA044), and 5g of lithium chloride (LiCl) were added sequentially. After the system was thoroughly stirred and mixed, it was irradiated under 365 nm ultraviolet light for 1 h to obtain a one-step ionogel.

[0069] Test Example 1: Mechanical Property Test

[0070] The self-healing ionogels prepared in Examples 1-6, the ionogel prepared in Example 7, the self-healing gels prepared in Comparative Examples 1-3, and the one-step ionogel prepared in Comparative Example 4 were cured in dumbbell-shaped polytetrafluoroethylene molds to obtain standard gel tensile specimens. Tensile tests were performed using a universal testing machine at a constant tensile rate of 50 mm / min to obtain the corresponding stress-strain curves, and the tensile strength and elongation at break, among other mechanical properties, were calculated accordingly. The test results are shown in Table 1 below.

[0071] Table 1 Results of mechanical and electrical performance tests

[0072]

[0073] As shown in Table 1, in terms of mechanical properties, the tensile strength of Examples 1-7 is generally better than that of Comparative Examples 1-4. Among them, Example 5 (increased HEA / HEMA, reduced PEG400) exhibits the highest tensile strength (620 kPa) and hardness (45), but its elongation at break is relatively low (650%). In contrast, Example 4 (reduced HEA / HEMA, increased PEG400) has the highest elongation at break (1200%), while its tensile strength (450 kPa) and hardness (20) are moderate, demonstrating the key role of component adjustment in balancing mechanical properties. Comparative Examples 1-3, due to the absence of lithium salt, generally have lower tensile strength and hardness, indicating the necessity of lithium salt in improving mechanical properties.

[0074] Regarding electrical performance, the examples using lithium chloride exhibited high ionic conductivity (2.1-3.8 mS / m), while the conductivity of Example 2 (0.2 mS / m) using LiTFSI and Example 6 (0.4 mS / m) with half the amount of lithium salt were significantly reduced. This indicates that the high mobility of chloride ions and an appropriate lithium salt concentration are key to maintaining high conductivity (e.g., 2.1-3.8 mS / m). The conductivity of Comparative Examples 1-3 could not be measured because they contained no lithium salt at all, further illustrating that lithium salt is a necessary condition for ionic conductivity.

[0075] Regarding the influence of structure and process, Example 6 (increased AA ratio) achieved a moderate elongation (800%) while maintaining high strength (600 kPa), indicating that an appropriate amount of carboxyl groups helps to enhance the crosslinking of the semi-interpenetrating network. Furthermore, Comparative Example 4 (one-step preparation) showed similar mechanical properties to Example 1, but its electrical conductivity (2.9 mS / m) was slightly lower than Example 1 (3.3 mS / m), indicating that the two-step process is more conducive to the formation of regular ion channels, thus having an advantage in overall performance. In summary, by adjusting the type and content of lithium salt and the ratio of monomer to solvent, the mechanical and electrical properties of self-healing ionogels can be controlled within a wide range, achieving designability of gel properties and meeting the diverse needs of flexible sensing materials in different application scenarios.

[0076] Test Example 2: Comprehensive Performance Test of Self-Healing Ionic Gel

[0077] The self-healing ionic gel prepared in Example 1 was subjected to comprehensive performance testing, as follows:

[0078] 1. Tensile properties: When the self-healing ionogel was stretched to 8 times its original length, no visible cracks or damage occurred, indicating that it has excellent tensile properties and toughness.

[0079] 2. Puncture resistance: The self-healing ion gel was punctured using a sharp probe. The results showed that the gel maintained its structural integrity after puncture, with no visible damage or tearing, proving that it has good puncture resistance.

[0080] 3. Interfacial adhesion performance: When the self-healing ionogel is bonded to the surface of a 200g metal weight, there is no detachment or peeling between the gel and the metal weight while it is suspended, indicating that it has excellent interfacial adhesion performance.

[0081] 4. Environmental Stability: The self-healing ionogel and the ion hydrogel prepared in Example 7 were compared after being exposed to the natural environment for 3 days. The experimental results showed that the mechanical properties of the self-healing ionogel did not change significantly compared to its initial state; while the ion hydrogel, under the same conditions, became significantly drier, harder, and easier to break, indicating that the self-healing ionogel using polyethylene glycol as a solvent provided by this invention possesses superior environmental stability and drying resistance. The weight changes of the self-healing ionogel and the ion hydrogel were continuously observed for 30 days and recorded. The results are shown below. Figure 1 .

[0082] Figure 1 This is a graph showing the weight change of the self-healing ionic gel and ionic hydrogel in Test Example 2 of the present invention after being placed in a natural environment for 30 days.

[0083] Depend on Figure 1It can be seen that the self-healing ionogel maintains a highly stable weight over 30 days, with its weight ratio consistently remaining within the range of 98%-102%, indicating its excellent environmental stability. In contrast, the ion hydrogel exhibits rapid water loss in the initial exposure period (0-5 days), with its weight ratio dropping to approximately 50%, and continues to fluctuate and decrease over the subsequent period, eventually reaching only about 32% of its initial weight ratio, demonstrating significant moisture sensitivity and environmental instability.

[0084] Test Example 3: Self-healing performance test of self-healing ionic gel

[0085] A wound was made on the surface of the self-healing ion gel prepared in Example 1 of this invention using a sharp blade, and the self-healing process of the wound was observed under a microscope in a natural environment. The test results are shown below. Figures 2-5 .

[0086] Figure 2 This is a microscope image of the self-healing ionogel after it was scratched in Test Example 3 of the present invention.

[0087] Figure 3 This is a microscope image of the self-healing ionogel in Test Example 3 of the present invention, taken 1 hour after it was scratched.

[0088] Figure 4 This is a microscope image of the self-healing ionogel in Test Example 3 of the present invention, taken 2 hours after it was scratched.

[0089] Figure 5 This is a microscope image of the self-healing ionogel in Test Example 3 of the present invention, taken 12 hours after it was scratched.

[0090] Depend on Figures 2-5 It is known that the self-healing ionic gel with a semi-interpenetrating polymer network prepared by the photo / thermal synergistic polymerization process of the present invention can achieve autonomous healing of the cut surface within 12 hours at room temperature after being subjected to macroscopic cutting.

[0091] Example 8: Fabrication of a self-healing ionogel sensor

[0092] Two copper foils are respectively attached to the upper and lower surfaces of the self-healing ionogel prepared in Example 1, and each copper foil is connected to a wire to form a self-healing ionogel sensor. The thickness of the copper foil is 0.02 mm, and the thickness of the self-healing ionogel is 0.5 cm.

[0093] Test Example 4: Sensitivity Test of Self-Healing Ion Gel Sensor

[0094] The self-healing ionogel sensor prepared in Example 8 was fixed on the testing platform of an E44.104 electronic universal testing machine and connected to a Keithley 2400 device. Subsequently, pressure was applied to the sensor surface at a set compression rate, and the real-time pressure signal (converted to pressure ΔP based on the effective contact area of ​​the sensor) and resistance signal were recorded simultaneously. The sensitivity was calculated based on the recorded signals using the formula: GF = (ΔR / R0) / ΔP, where GF is the sensitivity (kPa). -1 ); ΔR is the relative change in resistance; R0 is the initial resistance value (Ω); ΔP is the applied pressure (kPa). Test results are shown in [reference needed]. Figure 6 .

[0095] Figure 6 The graph shows the sensitivity test results of the self-healing ionogel sensor in Test Example 4 of this invention.

[0096] Depend on Figure 6 As can be seen, the relative rate of change of resistance (ΔR / R0) of the self-healing ionogel sensor continuously increases as the stretching ratio gradually increases from 0% to 100%, indicating that its resistance changes stably with deformation and has good tensile sensitivity. The calculated sensitivity (GF) is 6.1983, indicating that the self-healing ionogel sensor provided by this invention exhibits high and stable sensitivity characteristics within a wide compressive strain range of 0-80%.

[0097] Test Example 5: Dynamic Stability Test of Self-Healing Ion Gel Sensor

[0098] Using an electronic universal testing machine, under a set force condition, different compression rates were adjusted to test the relationship between the response output signal of the self-healing ionogel sensor prepared in Example 8 and frequency. The results are as follows: Figure 7 As shown.

[0099] Figure 7 The figure shows the dynamic stability test results of the self-healing ionogel sensor in Test Example 5 of this invention.

[0100] Depend on Figure 7 It can be seen that within the compression rate range of 50-500 mm / min, the relative resistance change rate (ΔR / R0) of the self-healing ionogel sensor exhibits a significant, synchronous, and stable increase, with a clear and repeatable output waveform. This indicates that during compression, ion migration and dynamic network reconstruction within the self-healing ionogel can fully respond to changes in external stress, resulting in a significant change in resistance. Furthermore, under all compression rate conditions, ΔR / R0 generally increases with loading time, indicating that the self-healing ionogel sensor maintains a consistent resistance response direction during continuous loading, without signal reversal or drift, demonstrating good signal stability and reliability.

[0101] Test Example 6: Pressure Test of Self-Healing Ion Gel Sensor

[0102] Using an electronic universal testing machine at a fixed compression rate, the relationship between the response output signal and the compression ratio of the self-healing ionogel sensor prepared in Example 8 was detected by setting different force magnitudes. The test results are shown below. Figure 8 .

[0103] Figure 8 The graph shows the pressure test results of the self-healing ionogel sensor in Test Example 6 of the present invention.

[0104] Depend on Figure 8 It can be seen that within a fixed test period of 0-240 seconds, the relative change rate of resistance (ΔR / R0) of the self-healing ionogel sensor increases significantly with the increase of the stretching ratio. Specifically, as the stretching ratio gradually increases from 10% to 60%, the corresponding ΔR / R0 value also increases sequentially, and the two show a stable positive correlation trend within the range of 10%-60%. All curves remain stable under the corresponding stretching ratios, without significant drift or fluctuation, indicating that the self-healing ionogel sensor has consistent signal output and high reliability under different deformation conditions, while also exhibiting rapid response and stable output, demonstrating good immediate responsiveness and long-term stability.

[0105] Test Example 7: Cyclic Stability Test of Self-Healing Ion Gel Sensor

[0106] The self-healing ionogel sensor prepared in Example 8 was tested to determine the maximum number of cycles it could withstand to maintain a stable and undiminished signal output response when repeatedly subjected to periodically changing pressure. The test results are shown in [link to test results]. Figure 9 .

[0107] Figure 9 The graph shows the cycle stability test results of the self-healing ionogel sensor in Test Example 7 of this invention.

[0108] Depend on Figure 9 It can be seen that, under a constant compression ratio of 15%, the self-healing ionogel sensor exhibits a consistent periodic change in its relative resistance (ΔR / R0) during 3000 consecutive cycles, without significant attenuation or baseline drift. This indicates that the self-healing ionogel sensor can maintain the stability and repeatability of its output signal under long-term, repeated mechanical strain, demonstrating excellent fatigue resistance and cyclic stability.

[0109] In summary, this invention develops a self-healing ionic gel by constructing a system combining a semi-interpenetrating polymer network and dynamic reversible hydrogen bonding. Using a semi-interpenetrating polymer network formed by linear polyacrylic acid penetrating a crosslinked network of poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) as the matrix framework not only endows the gel with excellent elasticity but also achieves self-healing properties through interchain entanglement and dynamic reversible hydrogen bonding. Lithium salt is uniformly dispersed in the semi-interpenetrating network, forming efficient ion transport channels. While achieving high-sensitivity sensing, the ion-dipole interaction further enhances the dynamic reversible properties of the semi-interpenetrating network. By synergistically integrating self-healing properties with the application scenarios of robotic skin, long-term reliable sensing capabilities are achieved: the prepared self-healing ionogel sensor not only has high sensitivity (GF=6.1983) and a wide compressive strain range (0-80%), but its unique self-healing properties can effectively restore the sensing performance deteriorated by mechanical damage, enabling the robotic skin to withstand long-term friction, compression and other complex working conditions, stably adhere to the curved surface of the robotic arm, and continuously and reliably monitor grasping force, contact status and texture features, significantly improving the durability and practicality of the robotic tactile system in interactive operations.

[0110] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-healing ionogel sensor, characterized in that, From top to bottom, it includes: a first electrode layer, a self-healing ion gel sensing layer, and a second electrode layer; The self-healing ion gel sensing layer includes a self-healing ion gel, which includes a semi-interpenetrating polymer network, a lithium salt dispersed in the semi-interpenetrating polymer network, and a solvent. The semi-interpenetrating polymer network is formed by linear polyacrylic acid penetrating a cross-linked network of poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate).

2. The self-healing ionogel sensor according to claim 1, characterized in that, The thickness of the first electrode layer and the second electrode layer are each independently 0.01-0.1 mm; The thickness of the self-healing ion gel sensing layer is 0.5-1cm.

3. A self-healing ionic gel, characterized in that, It includes a semi-interpenetrating polymer network, a lithium salt dispersed in the semi-interpenetrating polymer network, and a solvent; The semi-interpenetrating polymer network is formed by linear polyacrylic acid penetrating a cross-linked network of poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate).

4. The self-healing ionic gel according to claim 3, characterized in that, The mass ratio of the linear polyacrylic acid to the poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) is 0.05:1-0.2:1; The total mass ratio of the linear polyacrylic acid and the poly(hydroxyethyl acrylate-co-hydroxyethyl methacrylate) to the solvent is (0.5-2):

1.

5. The self-healing ionic gel according to claim 3, characterized in that, Based on the total mass of the self-healing ionogel, the mass content of the lithium salt is 1%-10%; The lithium salt is at least one of lithium chloride and lithium bis(trifluoromethanesulfonate); The solvent is polyethylene glycol, and the average molecular weight of the polyethylene glycol is 200-600.

6. A method for preparing the self-healing ionic gel according to any one of claims 3 to 5, characterized in that, include: Acrylic acid, photoinitiator and solvent are mixed and reacted under light to obtain polyacrylic acid solution; The polyacrylic acid solution, hydroxyethyl acrylate, hydroxyethyl methacrylate, crosslinking agent, thermal initiator, and lithium salt are mixed and reacted by heating to obtain the self-healing ionic gel.

7. The preparation method according to claim 6, characterized in that, The photoinitiator is at least one of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, and benzophenone; The crosslinking agent is at least one of poly(ethylene glycol) dimethacrylate and divinylbenzene; The thermal initiator is at least one of azobisisobutyronitrile, azobisisobutyramidoline hydrochloride, 4-4'-azobis(4-cyanopentanoic acid), benzoyl peroxide, hydroperoxide, dialkyl peroxide, peroxide ester, and dicarbonate peroxide.

8. The preparation method according to claim 6, characterized in that, The ratio of the total mass of acrylic acid, hydroxyethyl acrylate, and hydroxyethyl methacrylate to the mass of the solvent is 0.5:1-2:1; The mass ratio of the crosslinking agent to the total mass of the hydroxyethyl acrylate and hydroxyethyl methacrylate is 0.001:1-0.05:

1.

9. The preparation method according to claim 6, characterized in that, The heating temperature for the heating reaction is 40-60℃, and the heating time is 7-9h.

10. The application of a self-healing ionogel sensor as described in any one of claims 1 to 2 or a self-healing ionogel as described in any one of claims 3 to 5 in electronic skin.

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