An ion gel based on phase separation regulation and a preparation method and application thereof

Abstract

This invention belongs to the field of sensor technology and discloses an ion gel based on phase separation control, its preparation method, and its applications. The ion gel of this invention contains a polar polymer network and a binary solvent system filled within the polar polymer network; the binary solvent system includes a hydrophilic first ionic liquid and a hydrophobic second ionic liquid; structurally, the ion gel includes at least one first region and at least one second region, the first and second regions being connected to form an integral structure, and a topologically continuous chemically bonded interface being formed between the first and second regions through the polar polymer network; the elastic modulus of the first region is greater than that of the second region. The ion gel of this invention achieves intrinsic decoupling of mechanical strain and temperature signals, reducing the complexity of signal processing, and possesses excellent fatigue resistance and high-resolution multimodal sensing performance over a wide temperature range.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, and specifically relates to an ion gel based on phase separation regulation, its preparation method, and its application. Background Technology

[0002] Flexible ionic conductors are showing revolutionary potential in wearable electronics and artificial skin by bridging the gap between biological compliance and electronic functionality. To realistically simulate the somatosensory system of human skin, flexible sensors must be able to simultaneously and accurately sense multiple external stimuli, the most critical of which is the simultaneous sensing of mechanical deformation and temperature.

[0003] However, existing flexible ion-electronic devices face a severe challenge of signal cross-interference when achieving high-fidelity, independent multimodal signal detection. In traditional ion-conducting media, temperature fluctuations alter polymer chain relaxation and ion mobility, while mechanical deformation reshapes the geometry of the ion-conducting channels. These two physical mechanisms are essentially overlapping and coupled within the same continuous phase, leading to entanglement of strain and temperature signals, severely compromising the accuracy and reliability of the sensing.

[0004] Currently, there are two main strategies for solving signal crosstalk, but both have inherent limitations: The first strategy involves physical isolation at the device level, which involves stacking or heterogeneously splicing temperature and strain sensors made of different materials. While this method can suppress signal interference to some extent, the mismatch in elastic modulus between different material layers is inevitable. Under repeated high-strain tension, these heterogeneous interfaces are prone to stress concentration, leading to interface delamination, microcracks, and fatigue failure, severely limiting the durability of the device.

[0005] The second strategy involves using machine learning and other algorithms at the software level to mathematically decouple the mixed signals generated by a single homogeneous sensor. However, this algorithmic compensation scheme is not only computationally intensive but also extremely sensitive to environmental drift. Once the sensing baseline shifts due to material aging or environmental changes, the pre-trained algorithm model often fails directly.

[0006] Furthermore, some cutting-edge research attempts to introduce different sensing microregions within the material, but this often creates fragile internal interfaces that are prone to slippage or delamination. Moreover, since ion conduction and elastic support in traditional gel materials typically originate from the same continuous phase, ion mobility and mechanical modulus are difficult to independently control, and the problem of mechanical-transport coupling remains.

[0007] Therefore, there is an urgent need in this field for a solution that can achieve intrinsic decoupling of strain and temperature signals at the hardware level, while maintaining the chemical homogeneity and structural integrity of the material and avoiding mechanical failure risks such as interface delamination. Summary of the Invention

[0008] This invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the object of this invention is to provide an ionic gel based on phase separation control, its preparation method, and its applications. The ionic gel of this invention achieves intrinsic decoupling of mechanical strain and temperature signals, and avoids the risk of interface delamination caused by heterogeneous splicing, making it suitable for smart wearables and multimodal flexible electronic devices.

[0009] In a first aspect, the present invention provides an ionic gel comprising a polar polymer network and a binary solvent system filled in the polar polymer network. The binary solvent system comprises a hydrophilic first ionic liquid and a hydrophobic second ionic liquid; The polar polymer network is obtained by polymerization of polar monomers, photoinitiators, and crosslinking agents; The ion gel structurally includes at least one first region and at least one second region, the first region and the second region being connected to form an integral structure, and the first region and the second region forming a topologically continuous chemical bonding interface through the polar polymer network; The elastic modulus of the first region is greater than that of the second region.

[0010] Specifically, the ion gel of the present invention utilizes the difference in elastic modulus between the first region and the second region, making the first region insensitive to strain but sensitive to temperature, and making the second region sensitive to strain, thereby achieving in-situ synchronous measurement of temperature and strain signals without interference between them.

[0011] In some embodiments of the present invention, the first ionic liquid includes at least one of 1-ethyl-3-methylimidazolium ethyl sulfate and 1-butyl-3-methylimidazolium ethyl sulfate.

[0012] In some embodiments of the present invention, the second ionic liquid includes at least one of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.

[0013] In some embodiments of the present invention, the monomer includes at least one of acrylic acid, acrylamide, and N-acryloylglycamide.

[0014] In some embodiments of the present invention, the photoinitiator includes an ultraviolet photoinitiator.

[0015] In some embodiments of the present invention, the ultraviolet photoinitiator includes Irgacure 2959.

[0016] In some embodiments of the present invention, the crosslinking agent includes at least one of N,N-methylenebisacrylamide and ethylene glycol dimethacrylate.

[0017] In some embodiments of the present invention, the elastic modulus of the first region is at least one order of magnitude higher than that of the second region, preferably the ratio of the elastic modulus of the first region to that of the second region is greater than 40. By controlling a suitable difference in elastic modulus, a significant strain shielding effect is achieved against external deformation.

[0018] In some embodiments of the present invention, ion transport within the first region follows the Vogel-Tammann-Fulcher kinetic model, and its activation energy changes non-monotonically with the mass ratio of the first ionic liquid to the second ionic liquid and / or the content of the polar polymer. The non-monotonic change in activation energy is positively correlated with the mass ratio of the first ionic liquid to the second ionic liquid and / or the content of the polar polymer.

[0019] A second aspect of the present invention provides a method for preparing the ionogel described in the first aspect of the present invention, which is prepared by a stepwise in-situ photopolymerization method, comprising the following steps: The first ionic liquid and the second ionic liquid were mixed separately to obtain binary solvent A and binary solvent B. The monomer, crosslinking agent, initiator and binary solvent A are mixed to obtain the first precursor solution; The monomer, crosslinking agent, initiator and binary solvent B are mixed to obtain the second precursor solution; A mold with a first region cavity and a second region cavity is used, with a partition between the first region cavity and the second region cavity. The first precursor liquid is injected into the first region cavity of the mold. After the partition is removed, the second precursor liquid is immediately injected into the second region cavity, so that the first precursor liquid and the second precursor liquid come into contact at the boundary. The first and second precursor solutions in the mold are solidified and then demolded to obtain the ion gel.

[0020] In some embodiments of the present invention, the mass ratio of the first ionic liquid to the second ionic liquid in the binary solvent A is 2:8 to 6:4. By controlling the content of the first and second ionic liquids in the first region, the polar polymer network undergoes phase separation and forms an aggregated structure, thereby resulting in a higher elastic modulus than that of the second region.

[0021] In some embodiments of the present invention, the mass ratio of the first ionic liquid to the second ionic liquid in the binary solvent B is 7:3 to 10:0. By controlling the content of the first and second ionic liquids in the second region, the polar polymer network is in a solvated or microphase-separated state, thereby exhibiting a lower elastic modulus.

[0022] In some embodiments of the present invention, the first precursor solution contains 50%-70% by mass of monomers.

[0023] In some embodiments of the present invention, the crosslinking agent and the initiator in the first precursor liquid each account for 0.1%-1% of the mass percentage of the monomer.

[0024] In some embodiments of the present invention, the second precursor liquid contains 20%-40% by mass of monomer.

[0025] In some embodiments of the present invention, the crosslinking agent and the initiator in the second precursor liquid each account for 0.1%-1% of the mass percentage of the monomer.

[0026] In some embodiments of the present invention, the curing includes ultraviolet light curing.

[0027] In some embodiments of the present invention, the ultraviolet curing uses ultraviolet light with a wavelength of 340-380nm.

[0028] In some embodiments of the present invention, the ultraviolet curing time is 1-2 hours.

[0029] A third aspect of the present invention provides a multimodal flexible sensor, comprising a sensitive element, wherein the sensitive element comprises the ion gel described in the first aspect of the present invention.

[0030] In some embodiments of the present invention, the multimodal flexible sensor further includes a first measuring electrode and a second measuring electrode. The first measuring electrode is connected to a first region of the ionogel to form a first resistance measuring circuit, and the second measuring electrode is connected to a second region of the ionogel to form a second resistance measuring circuit. Since the migration velocity of ions in the first region changes with temperature, the temperature signal is read by the change in resistance value of the first resistance measuring circuit. When the second region is stretched, its internal ion pathway lengthens, and the strain signal is read by the change in resistance value of the second resistance measuring circuit.

[0031] A fourth aspect of the present invention provides the application of the ion gel described in the first aspect of the present invention or the multimodal flexible sensor described in the third aspect of the present invention in a multimodal sensor array, constructing a flexible sensor array comprising multiple alternating first regions and multiple second regions; the first regions serve as rigid nodes for temperature distribution detection; the second regions connecting adjacent first regions serve as strain channels, used to identify the stretching direction and contraction direction by the difference in resistance change trends of strain channels in different directions, thereby realizing multimodal detection of temperature signals and strain signals.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Intrinsic decoupling of mechanical strain and temperature signals is achieved, reducing the complexity of signal processing and avoiding the signal cross-interference problem faced by traditional multimodal flexible sensors. The ion gel of this invention comprises a polar polymer network and a binary ionic liquid solvent system with hydrophilic and hydrophobic differences. Utilizing phase separation driven by solubility differences, a wide range of material modulus control is achieved within the same chemical system, constructing a one-step "hard-soft-hard" integral modulus partitioning architecture with chemically bonded interfaces. Among them, the first region (high elastic modulus hard region) uses the strain shielding effect as a temperature sensing unit, and the second region (low elastic modulus soft region) serves as a strain sensing unit. When the ion gel of this invention is used in a sensor, when the sensor is subjected to external tension, the deformation is mainly borne by the soft region, while the local strain generated in the hard region is extremely small, with a deformation of ≤0.04%, thus producing a significant strain shielding effect. This ion gel structure physically blocks the interference of mechanical deformation on the temperature sensing channel, enabling independent and accurate extraction of multimodal signals without relying on complex software algorithm compensation.

[0033] (2) Improved bonding strength at multilayer heterogeneous interfaces significantly extends device lifespan. Traditional physically stacked sensors are prone to interlayer delamination and microcracks under repeated high strain. In the ion gel provided by this invention, the polymer matrices of the first and second regions are homologous, and a topologically continuous covalent bond network is formed at the interface through in-situ copolymerization. This monolithic structure effectively avoids stress concentration at modulus abrupt changes, eliminating the risk of interlayer slippage and delamination. Experiments show that the sensor fabricated based on the ion gel of this invention maintains stable electrical output and extremely low mechanical hysteresis after 3000 load-unload cycles under 50% tensile strain, exhibiting excellent fatigue resistance.

[0034] (3) It possesses high-resolution multimodal sensing performance over a wide temperature range. The first region of the ion gel of this invention serves as a temperature sensing unit, optimized based on the Vogel-Tammann-Fulcher mechanism of ion transport within the first region. Its thermal hysteresis is as low as 1.6%, and its temperature resolution reaches 0.01℃. It can also operate stably within the range of -60℃ to 100℃. Meanwhile, the second region serves as a strain sensing unit, with a detection limit as low as 0.01%. The ion gel of this invention overcomes the bottleneck of temperature and strain mutual constraint in traditional hydrogels and ion gels. When used in sensors, it can meet the high-precision and high-fidelity monitoring requirements of human physiological and kinematic characteristics under complex environments. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the ionogel prepared in Example 1 of the present invention.

[0036] Figure 2 This is a schematic diagram illustrating the microscopic principle of phase separation driven by the solubility difference in a binary solvent system, as described in this invention.

[0037] Figure 3 The images shown are SEM images and physical photos of the ion gels prepared according to different ion liquid ratios of the present invention.

[0038] Figure 4 This is a test image of the ionogel prepared in Example 1 of the present invention under a stretched state.

[0039] Figure 5 The figure shows the results of the fracture test of the ion gel prepared in Example 1 of the present invention.

[0040] Figure 6 The resistivity response diagrams of the first and second regions in the ionogel prepared in Example 1 of the present invention under temperature and strain stimulation are shown.

[0041] Figure 7 This is a schematic diagram of the flexible multimodal sensor array prepared by Example 2 of the present invention, and a fitting curve of the relative resistance change rate of different channels of the array under uniaxial tension. Detailed Implementation

[0042] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, apparatus, or molds used in the embodiments can be obtained from conventional commercial sources or by existing technical methods. Unless otherwise specified, the testing or experimental methods are conventional methods in the art.

[0043] In this invention, "room temperature" refers to 25±2℃.

[0044] In this invention, "about" means an error of less than 2%.

[0045] Example 1 An ionic gel comprising a polar polymer network and a binary solvent system filled within the polar polymer network; wherein the binary solvent system comprises a hydrophilic first ionic liquid and a hydrophobic second ionic liquid.

[0046] This embodiment presents a monolithic hard-soft-hard (HSH) ionogel with high modulus contrast, prepared using a stepwise in-situ photopolymerization method, comprising the following steps: (1) Preparation of the first precursor solution (for constructing the high modulus hard region): The hydrophilic 1-ethyl-3-methylimidazolium ethyl sulfate (EMIES) and the hydrophobic 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMITFSI) are mixed at a mass ratio of 5:5 to obtain binary solvent A; Acrylic acid (AA) monomer was added to binary solvent A to achieve a mass fraction of 60 wt%, and crosslinking agent N,N'-methylenebisacrylamide (MBAA) and photoinitiator Irgacure 2959 were added at a mass of 0.21 wt% of the monomer. The mixture was then magnetically stirred (500 rpm) at room temperature for 10 minutes until fully dissolved and homogeneous.

[0047] (2) Preparation of the second precursor solution (for constructing low-modulus soft regions): Mix EMIES and EMITFSI at a mass ratio of 8:2 to obtain binary solvent B; Add AA monomer to binary solvent B to achieve a mass fraction of 30 wt%, and add 0.21 wt% of MBAA and 0.47 wt% of Irgacure 2959. Then, stir magnetically (500 rpm) at room temperature for 10 minutes until fully dissolved and homogeneous.

[0048] (3) In-situ stepwise copolymerization molding: A glass mold with a removable polytetrafluoroethylene (PTFE) spacer is used, which divides the inner cavity of the mold into three parts: left, middle and right. First, the first precursor liquid is injected into the island-shaped cavities (first region cavity) with a size of 1.5cm×1.0cm in the left and right parts of the mold. Then, the PTFE spacer is removed and the second precursor liquid is injected into the bridging island-shaped cavity (second region cavity) with a size of 3.0cm×1.0cm in the middle part, so that the first and second precursor liquids come into natural physical contact at the boundary. The mold is immediately placed under ultraviolet light with a wavelength of 365nm for 1 hour to initiate free radical polymerization. After obtaining the ion gel, it is demolded and taken out for use. Because the first precursor liquid has a high mass fraction of AA monomer and a high viscosity, and the first region is a pre-designed shallow island cavity, the first precursor liquid can basically remain in place after the separator is removed; after the second precursor liquid is injected, it only has limited contact with the first precursor liquid at the boundary and is then cured by ultraviolet light. Therefore, macroscopic mixing will not occur, but a topologically continuous chemical bonding interface will be formed at the interface.

[0049] The structure of the ionogel prepared in this embodiment is as follows: Figure 1 As shown, the left and right parts are both first regions (hard regions) formed by curing the first precursor liquid, with an elastic modulus of several megapascals (about 7.5 MPa), which can be used as temperature sensing units of the sensor; the middle part is a second region (soft region) formed by curing the second precursor liquid, with an elastic modulus of about 71 kPa, which can be used as strain sensing units of the sensor. The modulus of the hard region is more than 40 times higher than that of the soft region, and the two regions are seamlessly covalently bonded at the interface through a PAA network to form a topologically continuous whole.

[0050] In this invention, the core of constructing a binary solvent system lies in utilizing the differences in solubility and interaction between different ionic liquids and polar polymer networks (such as polyacrylic acid PAA). The hydrophilic first ionic liquid mainly acts as a solvator, while the hydrophobic second ionic liquid mainly induces phase separation of polymer segments and the formation of aggregated structures. A schematic diagram of the microscopic principle of phase separation driven by the solubility difference in a binary solvent system is shown below. Figure 2 As shown.

[0051] Phase separation mechanism and basic material verification: This invention tests and verifies the phase separation mechanism of the material bulk, such as... Figure 3 As shown; where (a) are cross-sectional scanning electron microscope (SEM) images at different ratios, with a scale bar of 10 μm in each SEM image; (b) are macroscopic images of the corresponding ratios, with a scale bar of 1 cm in each macroscopic image. This invention prepared homogeneous ionogel samples with a polar monomer (AA) mass fraction of 30 wt% but containing 6 different ion liquid ratios. Figure 3The letter E represents the first ionic liquid EMIES, and T represents the second ionic liquid EMITFSI. The following number represents the mass ratio of the two ionic liquids. For example, E8T2 means that the mass ratio of the first ionic liquid to the second ionic liquid is 8:2. Figure 3 This demonstrates intuitively that as the proportion of the hydrophobic second ionic liquid increases, the polymer network gradually transitions from a continuous liquid phase to a microphase-separated state, and eventually evolves into an aggregated solid phase. This fundamental material-level morphological evolution provides a direct basis for formulation design in selecting specific parameters to construct high-modulus "hard regions" and low-modulus "soft regions" in this invention.

[0052] Example 2 The same preparation process and raw material types as in Example 1 were used, with the only difference being the formulation parameters: the mass fraction of AA monomer in the first precursor solution was adjusted to 50 wt%, and the mass ratio of EMIES to EMITFSI was adjusted to 4:6; the mass fraction of AA monomer in the second precursor solution was adjusted to 20 wt%, and the mass ratio of EMIES to EMITFSI was adjusted to 7:3. The ionogel prepared according to these parameters also exhibited a significant soft-hard partitioned phase separation structure, enabling basic multimodal signal decoupling monitoring.

[0053] Example 3 Using the same preparation process as in Example 1, the boundary conditions for phase separation were explored by changing the concentration of the precursor solution: the mass fraction of AA monomer in the first precursor solution was adjusted to 70 wt%, and the mass ratio of EMIES to EMITFSI was 2:8; the mass fraction of AA monomer in the second precursor solution was adjusted to 40 wt%, and pure hydrophilic ionic liquid EMIES (i.e., the ratio of EMIES to EMITFSI was 10:0) was used as the solvent. Due to the extreme hydrophilic-hydrophobic contrast, the ionic gel prepared with these parameters exhibited a highly dense aggregated solid phase in the hard region and a completely continuous liquid phase in the soft region, while maintaining a good chemical cross-linking network at the interface.

[0054] Comparative Example 1 (Homogeneous ionic gel without partitioning) The same raw materials as in Example 1 were used, but without modulus partitioning design. In the specific preparation, the first precursor liquid and the second precursor liquid in Example 1 were mixed uniformly according to the total volume ratio of the first region to the second region in Example 1, preferably at a volume ratio of 1:1, to obtain a homogeneous mixed precursor liquid; then the mixed precursor liquid was directly injected into an integral mold without spacers and cured under 365nm ultraviolet light for 1 hour to prepare a single homogeneous ionogel without a hard-soft-hard partitioning structure.

[0055] Comparative Example 2 (Physically assembled multilayer ionic gel) Using the same formulation as in Example 1, but separately curing the first and second regions, respectively. Subsequently, the cured first and second regions were assembled together from top to bottom by physical bonding to obtain a non-monolithic multilayer ionic gel.

[0056] Performance testing (1) Strain shielding and interface strength: Uniaxial tensile and fracture tests were performed on the ionogel prepared in Example 1, and the results are as follows: Figure 4 and Figure 5 As shown. Figure 4 The results show that in the uniaxial tensile test, the deformation of Example 1 was almost entirely absorbed by the soft region (tensile strain of about 264%), while the hard region remained almost undeformed (local strain of about 0.04%), confirming a significant strain shielding effect. Figure 5 The results show that in the fracture test, the failure occurred within the soft bulk rather than at the interface between the soft and hard phases, demonstrating that the monolithic chemically bonded interface of Example 1 has high bonding strength. Comparative Example 2, a multilayered ionogel with physical bonding, exhibits a greater difference in elastic modulus between its soft and hard phases. Under tensile loads, stress concentration is more likely to occur at the interface, leading to interlayer delamination, microcracks, and even delamination failure, making it difficult to maintain a long-term stable mechanical connection.

[0057] (2) Intrinsic decoupling of multimodal signals: The ionogel prepared in Example 1 was used as a sample, and the resistance response of its first and second regions under temperature and strain stimuli was tested respectively. The results are as follows: Figure 6 As shown in Example 1, the hard region exhibits minimal resistance change under global stretching but a significant response to temperature changes; the soft region, on the other hand, is highly sensitive to strain changes. This demonstrates that the present invention achieves spatial separation of temperature and strain responses through an integral modulus partitioning design, thereby realizing intrinsic decoupling of multimodal signals. In contrast, Comparative Example 1, a homogeneous ionogel without partitioning, lacks the functional differentiation structure of hard and soft regions. Its temperature and mechanical stimuli act simultaneously within the same ion conduction network, making it more prone to signal cross-interference and hindering the independent identification of temperature and strain signals.

[0058] Application Example 1 Fabrication of a multimodal flexible sensor: The ion gel prepared in Example 1 is used as the sensing element, and a flexible copper foil electrode is attached to the corresponding test area of ​​the ion gel as the measuring electrode, with lead wires extending from it. The measuring electrode electrically connected to the first area forms a temperature measurement circuit, and the measuring electrode electrically connected to the second area forms a strain measurement circuit. In addition to the sensing element and measuring electrode, the sensor can also be connected to flexible lead wires, a packaging substrate, and an external signal acquisition unit according to actual usage requirements.

[0059] Application Example 2 Fabrication of a flexible multimodal sensor array: Based on the ionogel of Example 1, a 3×3 multimodal sensor array was fabricated using a mesh patterned mold. A rigid hard region (1.0cm×1.0cm) composed of 60wt% PAA and E5T5 served as the array nodes. Due to its extreme insensitivity to strain, it was used as a high-precision temperature sensing node and a stable anchor point for electrode interconnections. The region connecting adjacent rigid nodes was bridged by a soft region (1.0cm×1.0cm) composed of 30wt% PAA and E8T2, serving as a directional strain sensing element.

[0060] The flexible multimodal sensor array fabricated above is as follows: Figure 7 As shown in the figure, (a) is a schematic diagram of the array structure, and (b) is a fitting curve of the relative resistance change rate of different channels of the array under uniaxial tension. This array can not only eliminate motion artifacts to achieve accurate temperature spatial distribution mapping, but also effectively distinguish between longitudinal tension under uniaxial loading and transverse contraction induced by Poisson effect by different trends in the transverse and longitudinal soft zone resistance, thereby realizing vector strain identification.

[0061] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. An ionogel, characterized in that, The ion gel contains a polar polymer network and a binary solvent system filled in the polar polymer network. The binary solvent system comprises a hydrophilic first ionic liquid and a hydrophobic second ionic liquid; The polar polymer network is obtained by polymerization of polar monomers, photoinitiators, and crosslinking agents; The ion gel structurally includes at least one first region and at least one second region, the first region and the second region being connected to form an integral structure, and the first region and the second region forming a topologically continuous chemical bonding interface through the polar polymer network; The elastic modulus of the first region is greater than that of the second region.

2. The ionogel according to claim 1, characterized in that, The first ionic liquid comprises at least one of 1-ethyl-3-methylimidazolium ethyl sulfate and 1-butyl-3-methylimidazolium ethyl sulfate; and / or, the second ionic liquid comprises at least one of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; and / or, the monomer comprises at least one of acrylic acid, acrylamide, and N-acryloylglycine; and / or, the photoinitiator comprises an ultraviolet photoinitiator; and / or, the crosslinking agent comprises at least one of N,N-methylenebisacrylamide and ethylene glycol dimethacrylate.

3. The ionogel according to claim 1, characterized in that, The ratio of the elastic modulus of the first region to that of the second region is greater than 40.

4. The ionogel according to claim 1, characterized in that, Ion transport within the first region follows the Vogel-Tammann-Fulcher kinetic model, and its activation energy changes non-monotonically with the mass ratio of the first ionic liquid to the second ionic liquid and / or the content of the polar polymer. The non-monotonic change in activation energy is positively correlated with the mass ratio of the first ionic liquid to the second ionic liquid and / or the content of the polar polymer.

5. A method for preparing an ion gel as described in any one of claims 1-4, characterized in that, The method of stepwise in-situ photopolymerization is used for preparation, including the following steps: The first ionic liquid and the second ionic liquid were mixed separately to obtain binary solvent A and binary solvent B. The monomer, crosslinking agent, initiator and binary solvent A are mixed to obtain the first precursor solution; The monomer, crosslinking agent, initiator and binary solvent B are mixed to obtain the second precursor solution; A mold with a first region cavity and a second region cavity is used, with a partition between the first region cavity and the second region cavity. The first precursor liquid is injected into the first region cavity of the mold. After the partition is removed, the second precursor liquid is immediately injected into the second region cavity, so that the first precursor liquid and the second precursor liquid come into contact at the boundary. The first and second precursor solutions in the mold are solidified and then demolded to obtain the ion gel.

6. The preparation method according to claim 5, characterized in that, In the binary solvent A, the mass ratio of the first ionic liquid to the second ionic liquid is 2:8 to 6:

4.

7. The preparation method according to claim 5, characterized in that, In the binary solvent B, the mass ratio of the first ionic liquid to the second ionic liquid is 7:3 to 10:

0.

8. A multimodal flexible sensor, characterized in that, Includes a sensitive element, said sensitive element comprising the ion gel according to any one of claims 1-4.

9. The multimodal flexible sensor according to claim 8, characterized in that, It also includes a first measuring electrode and a second measuring electrode. The first measuring electrode is connected to a first region of the ion gel to form a first resistance measuring circuit, and the second measuring electrode is connected to a second region of the ion gel to form a second resistance measuring circuit.

10. The application of an ionogel as described in any one of claims 1-4 or a multimodal flexible sensor as described in claim 8 in a multimodal sensor array, characterized in that, A flexible sensor array is constructed, comprising multiple alternating first regions and multiple second regions. The first regions serve as rigid nodes for temperature distribution detection. The second regions, connecting adjacent first regions, serve as strain channels, used to identify the stretching and contraction directions by the differences in resistance change trends of strain channels in different directions, thereby achieving multimodal detection of temperature and strain signals.

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