Integrated pressure and temperature hydrogel array sensor, and preparation method therefor

Abstract

An integrated pressure and temperature hydrogel array sensor, which comprises: a plurality of sensing array units arranged in an array. Each sensing array unit comprises interdigitated electrodes (101) and a hydrogel layer (102) covering the surface of the interdigitated electrodes (101), wherein the hydrogel layer (102) is fixed to the interdigitated electrodes (101) by means of photocuring, and the hydrogel layer (102) is in intimate contact with the surface of the interdigitated electrodes (101); the interdigitated electrodes (101) are two coplanar nested interdigitated electrodes prepared on a flexible circuit board; the hydrogel layer (102) is a hydrogel layer having variations in crosslink density and height; and the hydrogel layer (102) comprises a high-crosslink-density hydrogel region (102a) and a low-crosslink-density hydrogel region (102b). A flexible sensing structure based on photocurable hydrogel that features an arrayed electrode design can simultaneously monitor variations in a pressure signal and a temperature signal by means of an array module acquisition system. Further disclosed is a preparation method for an integrated pressure and temperature hydrogel array sensor.

Description

A pressure-temperature integrated hydrogel array sensor and its fabrication method Technical Field

[0001] This application relates to the field of flexible sensing technology, and in particular to a pressure-temperature integrated hydrogel array sensor and its fabrication method. Background Technology

[0002] The receptors in the human skin system are composed of ion conductors, and their signal transduction is based on ion dynamics. Numerous temperature and mechanoreceptors are distributed in the dermis, clearly sensing the spatial distribution of strain and temperature on the skin. Tactile sensing simulates the functions of human skin, such as temperature, humidity, pressure, and vibration, to respond to external stimuli. In recent years, with the rapid development of the Internet of Things (IoT), flexible tactile sensing has become crucial for the development of many cutting-edge technologies, including wearable devices, brain-computer interfaces, and smart healthcare.

[0003] Sensing structures with integrated pressure and temperature sensing capabilities enable collaborative sensing between electronic devices and skin / tissue, which is crucial for multi-parameter monitoring in complex scenarios. For example, in wound healing, hydrogel dressings with mechanical, temperature, and chemical sensing capabilities can establish comprehensive wound monitoring, including sensing stress changes and monitoring parameters such as wound temperature and reactive oxygen species. Achieving integrated multi-parameter sensing through structural design is a future development trend.

[0004] Utilizing ionic pathways to achieve sensing functions can mimic the information processing methods of biological systems, enabling biomimetic sensing functions with a higher degree of similarity to living organisms. In recent years, ionization sensing mechanisms have relied on the double-layer structure of the ion-electron interface, possessing high sensitivity. The sensing function of devices can be optimized through the design of ionic materials. Hydrogel materials belong to a class of ionic materials, and their ionic function can be tuned through structural design. Simultaneously, they possess the flexibility of large deformation, allowing for highly sensitive feedback to external stimuli when applied to sensing structures. Furthermore, various biopolymers, natural polymers, and synthetic polymers can be used as components of hydrogels, endowing them with excellent biofunctionality and thus enabling diverse sensing functions.

[0005] Existing zwitterionic skin sensor systems utilize temperature-responsive N-isopropylacrylamide and glucose-responsive methacrylamide-phenylboronic acid to design a sandwich-structured hydrogel sensor. The overall sensor is capacitive, with each of the three layers possessing different response characteristics, enabling monitoring of wound temperature, strain, and tissue fluid glucose concentration. It is important to note that the N-isopropylacrylamide hydrogel, when in an asymmetric structure, may buckle and deform due to temperature changes, potentially interfering with the overall capacitive sensing signal.

[0006] Summary of the Invention

[0007] This application provides a pressure and temperature integrated hydrogel array sensor and its preparation method. Based on the double-layer theory of ionization sensing and diffusion layer effect, a flexible sensing structure based on photocurable hydrogel is designed. Through arrayed electrode design and array module acquisition system, pressure and temperature signal changes can be monitored simultaneously.

[0008] To address the aforementioned technical problems, in a first aspect, embodiments of this application provide a pressure-temperature integrated hydrogel array sensor, comprising: multiple sensing array units arranged in an array; each sensing array unit includes interdigitated electrodes and a hydrogel layer covering the surface of the interdigitated electrodes; the hydrogel layer is fixed to the interdigitated electrodes by photocuring, and the hydrogel layer is tightly bonded to the surface of the interdigitated electrodes; the interdigitated electrodes are two coplanar nested interdigitated electrodes fabricated using a flexible circuit board; the hydrogel layer has differences in crosslinking density and height; the hydrogel layer includes a high crosslinking density hydrogel region and a low crosslinking degree hydrogel region.

[0009] In some exemplary embodiments, the high cross-linking density hydrogel region is located at the center of the hydrogel layer, and the low cross-linking density hydrogel region surrounds the high cross-linking density hydrogel region; the high cross-linking density hydrogel region does not deform during the pressure process and is only affected by temperature; the low cross-linking density hydrogel region can be affected by both temperature and pressure at the same time, and achieves single pressure sensing by decoupling from the high cross-linking density hydrogel region.

[0010] In some exemplary embodiments, the hydrogel layer has a cross-linked network structure, within which doped ionic components form ionic pathways; the main network material of the cross-linked network structure includes one or more of acrylamide, hydroxyethyl methacrylate, acrylic acid, isooctyl methacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, and N,N-methylenebisacrylamide hydrogel monomers; the ionic components are ionic liquids or cationic / anionic polyelectrolytes with polymerizable functional groups; the ionic components include: vinylimidazolium sulfonylimide salts, vinylimidazolium phosphates, allylimidazolium sulfonylimide salts, allylimidazolium phosphates, and one or more of sodium alginate, sodium polystyrene sulfonate, sodium polyacrylate, and polydiallyldimethylammonium chloride.

[0011] In some exemplary embodiments, the hydrogel layer further includes a solvent and a photoinitiator; the solvent is deionized water or a doping system of deionized water and a polyol; the polyol includes one or more of ethylene glycol, 1,3-propanediol, glycerol, n-butanol, and 1,2-butanediol; the photoinitiator includes one or more of benzoyl, acetophenone, α-hydroxy ketone, and acylphosphine oxides.

[0012] In some exemplary embodiments, the mass ratio of the network host material to the ionic component is (1-100):1; the mass ratio of the solvent to the network host material is (0.5-10):1; and the mass ratio of the photoinitiator to the network host material is (0-0.5):1.

[0013] In some exemplary embodiments, the sensor array unit is connected to the array module acquisition system, and the sensor array unit performs row and column scanning through the array module acquisition system to acquire array image information under temperature and pressure changes.

[0014] In some exemplary embodiments, the flexible circuit board is one of single-sided, double-sided, or multi-layer circuits; the flexible circuit board includes a flexible substrate and an electrode material disposed on the flexible substrate; the flexible substrate includes one of polyimide and polyethylene terephthalate; the electrode material includes one of gold, platinum, copper, and silver.

[0015] Secondly, embodiments of this application also provide a method for fabricating an integrated pressure and temperature hydrogel array sensor, comprising the following steps: First, a mold is provided; then, a hydrogel material layer is formed on the mold; next, a photocurable mask is used to perform a first photocuring on the hydrogel material layer; then, interdigitated electrodes are covered on the hydrogel material layer after the first photocuring treatment, and a second photocuring is performed to obtain a hydrogel layer with crosslinking density and height differences that is closely attached to the interdigitated electrodes; the hydrogel layer includes a high crosslinking density hydrogel region and a low crosslinking degree hydrogel region; finally, the mold is removed to obtain the hydrogel sensing structure.

[0016] In some exemplary embodiments, the high cross-linking density hydrogel region is located at the center of the hydrogel layer, and the low cross-linking degree hydrogel region surrounds the high cross-linking density hydrogel region.

[0017] In some exemplary embodiments, the time for both primary and secondary photocuring is 0.1 min to 10 min.

[0018] The technical solution provided in this application has at least the following advantages:

[0019] This application provides a pressure-temperature integrated hydrogel array sensor and its fabrication method. The hydrogel array sensor includes: multiple sensing array units arranged in an array; each sensing array unit includes interdigitated electrodes and a hydrogel layer covering the surface of the interdigitated electrodes; the hydrogel layer is fixed on the interdigitated electrodes by photocuring, and the hydrogel layer is tightly attached to the surface of the interdigitated electrodes; the interdigitated electrodes are two coplanar nested interdigitated electrodes fabricated using a flexible circuit board; the hydrogel layer has differences in crosslinking density and height; the hydrogel layer includes a high crosslinking density hydrogel region and a low crosslinking degree hydrogel region. This application achieves simultaneous pressure and temperature sensing through ion sensing, using a single hydrogel material composition, and can achieve sensing differences in different regions simply by changing the structural design. Based on the double-layer theory, it can simultaneously monitor changes in pressure and temperature signals, and can perform array-based sensing structure design to achieve signal acquisition of temperature and pressure distribution. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0021] Figure 1 is a schematic diagram of the structure of the pressure-temperature integrated hydrogel array sensor provided in the embodiment of this application.

[0022] Figure 2 is a schematic diagram of the array electrode structure provided in an embodiment of this application.

[0023] Figure 3 is a schematic flowchart of the fabrication method of the pressure-temperature integrated hydrogel array sensor provided in the embodiment of this application.

[0024] Figure 4 is a top view of the hydrogel layer provided in the embodiment of this application.

[0025] Figure 5 is a schematic diagram of the integrated hydrogel sensing principle provided in the embodiment of this application.

[0026] Figures 6 and 7 are schematic diagrams of the integrated temperature and pressure sensing response curves provided in the embodiments of this application. Detailed Implementation

[0027] As can be seen from the background technology, in the existing ion skin sensor system based on zwitterions, the N-isopropylacrylamide hydrogel may buckle and deform due to temperature changes when it is in an asymmetric structure, which may interfere with the overall capacitive sensing signal.

[0028] To address the aforementioned technical problems, this application provides an integrated pressure and temperature hydrogel array sensor and its fabrication method. The hydrogel array sensor includes: multiple sensing array units arranged in an array; each sensing array unit includes interdigitated electrodes and a hydrogel layer covering the surface of the interdigitated electrodes; the hydrogel layer is fixed to the interdigitated electrodes by photocuring, and the hydrogel layer is tightly bonded to the surface of the interdigitated electrodes; the interdigitated electrodes are two coplanar nested interdigitated electrodes fabricated using a flexible circuit board; the hydrogel layer has differences in crosslinking density and height; the hydrogel layer includes a high-crosslinking-density hydrogel region and a low-crosslinking-density hydrogel region. This application simultaneously achieves pressure and temperature sensing through ion sensing, using a single hydrogel material composition. Differences in sensing between different regions can be achieved simply by changing the structural design. Based on the double-layer theory, it can simultaneously monitor changes in pressure and temperature signals, enabling array-based sensing structure design to acquire signals from temperature and pressure distributions. This application provides a pressure and temperature integrated hydrogel array sensor and its preparation method. Based on the double-layer theory of ionization sensing and diffusion layer effect, a flexible sensing structure based on photocurable hydrogel is designed. Through arrayed electrode design and array module acquisition system, pressure and temperature signal changes can be monitored simultaneously.

[0029] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0030] Referring to Figure 1, this application embodiment provides a pressure-temperature integrated hydrogel array sensor, including: multiple sensing array units arranged in an array; each sensing array unit includes an interdigital electrode 101 and a hydrogel layer 102 covering the surface of the interdigital electrode 101; the hydrogel layer 102 is fixed on the interdigital electrode 101 by photocuring, and the hydrogel layer 102 is in close contact with the surface of the interdigital electrode 101; the interdigital electrode 101 consists of two coplanar nested interdigital electrodes fabricated using a flexible circuit board; the hydrogel layer 102 is a hydrogel layer with differences in crosslinking density and height; the hydrogel layer 102 includes a high crosslinking density hydrogel region 102a and a low crosslinking degree hydrogel region 102b.

[0031] This application innovatively proposes a novel integrated pressure and temperature sensing structure. Based on the double-layer theory of ionization sensing and the diffusion layer effect, a flexible sensing structure based on photocurable hydrogel is designed. This flexible sensing structure consists of two coplanar nested interdigital electrodes fabricated on a flexible circuit board, and a hydrogel material with different heights and crosslinking densities covering them. The electrodes in the array sensor structure are obtained by arraying the aforementioned interdigital electrodes, and the hydrogel material covering them is a repetition of the aforementioned units. The hydrogel is fixed to the interdigital electrodes by photocuring, with no gaps or other materials between them.

[0032] This application achieves simultaneous pressure and temperature sensing via ion sensing. An arrayed sensor structure is designed using hydrogel material components. Figure 1 shows an integrated hydrogel array sensing structure using a 5x5 array as an example. Taking the 5x5 array electrodes as an example, the double-sided routing design of the interdigitated electrodes is demonstrated. The row and column leads are located on opposite sides, respectively. Through-holes are drilled at specific locations, and the connection between the two sides' circuits is achieved by plating metal on the hole walls. The hydrogel layer correspondingly has 25 repeating units.

[0033] It should be noted that Figure 1 shows an integrated hydrogel array sensing structure with a 5*5 array as an example, but it is not limited to this. As shown in Figure 2, Figure 2 shows the interdigitated electrodes and array design scheme of an integrated sensing structure with a 3*3 array as an example.

[0034] The sensor array unit is connected to the array module acquisition system. During data acquisition, the temperature and pressure channels of this integrated sensor can be tested by connecting two single-point interdigital electrodes to the same excitation signal. The capacitance change can be converted into an output voltage change by an operational amplifier circuit. The sensor array is scanned row and column by the array module acquisition system to acquire array image information under temperature and pressure changes. Data processing can obtain the pressure and temperature distribution.

[0035] In some embodiments, the flexible electrode is prepared by conventional printing conductive materials or laser etching methods. The prepared flexible circuit board can be single-sided, double-sided or multi-layer circuit. The flexible substrate includes, but is not limited to, polyimide and polyethylene terephthalate. The electrode material includes, but is not limited to, inert metals such as gold and platinum, as well as copper and silver.

[0036] In some embodiments, the thickness of the flexible substrate is 1 to 1000 micrometers, more specifically 10 to 500 micrometers. Specifically, the linewidth of the interdigital strip electrode is 0.1 to 1000 micrometers, more specifically 10 to 300 micrometers; the spacing between adjacent electrodes of the interdigital strip electrode is 0.1 to 1000 micrometers, more specifically 10 to 300 micrometers; and the spacing between each unit of the array electrode is 1 to 10000 micrometers, more specifically 50 to 5000 micrometers.

[0037] The hydrogel layer with differences in crosslinking density and height possesses a crosslinking network structure and ion pathways, and its composition is a photocurable gel system. In some embodiments, the hydrogel layer has a crosslinking network structure, and ionic components are doped within the crosslinking network structure to form ion pathways; the main network material of the crosslinking network structure includes one or more of acrylamide, hydroxyethyl methacrylate, acrylic acid, isooctyl methacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, and N,N-methylenebisacrylamide hydrogel monomers; the ionic components are ionic liquids or cationic / anionic polyelectrolytes with polymerizable functional groups; the ionic components include: vinylimidazolium sulfonylimide salts, vinylimidazolium phosphates, allylimidazolium sulfonylimide salts, allylimidazolium phosphates, and one or more of sodium alginate, sodium polystyrene sulfonate, sodium polyacrylate, and polydiallyldimethylammonium chloride.

[0038] In some embodiments, the hydrogel layer further includes a solvent and a photoinitiator; the solvent is deionized water or a doping system of deionized water and a polyol; the polyol includes one or more of ethylene glycol, 1,3-propanediol, glycerol, n-butanol, and 1,2-butanediol; the photoinitiator includes one or more of benzoyl, acetophenone, α-hydroxy ketone, and acylphosphine oxides.

[0039] In some embodiments, the mass ratio of the network host material to the ionic component is (1-100):1; the mass ratio of the solvent to the network host material is (0.5-10):1; and the mass ratio of the photoinitiator to the network host material is (0-0.5):1. Preferably, the mass ratio of the network host material to the ionic component is (5-50):1; the mass ratio of the solvent to the network host material is (1-5):1; and the mass ratio of the photoinitiator to the network host material is (0.01-0.1):1.

[0040] Specifically, the hydrogel preparation process is shown in Figure 3. First, the network substrate material, ionic components, solvent, and photoinitiator are mixed uniformly to remove oxygen, obtaining hydrogel prepolymer 111. The height difference of the hydrogel is obtained through molding, where mold 110 is obtained through machining, including but not limited to PDMS molds, polytetrafluoroethylene molds, and stainless steel molds, with the height difference controlled between 0.1 mm and 2 mm. The hydrogel prepolymer 111 is poured into mold 110. The crosslinking density difference of the hydrogel is controlled by covering it with a photocurable mask 112, where the black area is protected from light and the transparent area is cured preferentially. After the area is irradiated with ultraviolet light, the photocurable mask 112 is removed. Then, the interdigitated electrode 101 is covered on the hydrogel, and the whole is subjected to a second photocuring, with the curing time controlled between 0.1 and 10 min for both curing times. Finally, one side of the hydrogel layer 102 is removed from mold 110, while the other side remains in direct contact with the interdigitated electrode 101, obtaining a hydrogel layer 102 with crosslinking density and height differences.

[0041] In some embodiments, as shown in FIG4, the high cross-linking density hydrogel region 102a is located at the center of the hydrogel layer 102, and the low cross-linking density hydrogel region 102b surrounds the high cross-linking density hydrogel region 102a. The high cross-linking density hydrogel region 102a does not deform during the pressure process and is only affected by temperature. The low cross-linking density hydrogel region 102b can be affected by both temperature and pressure at the same time. By decoupling from the high cross-linking density hydrogel region 102a, a single pressure sensing is achieved. The schematic diagram of its sensing principle is shown in FIG5.

[0042] Figure 5 illustrates the pressure and temperature sensing principles. The high-crosslink density hydrogel region (Region I) does not deform under pressure and is only affected by temperature. The low-crosslink density hydrogel region (Region II) is affected by both temperature and pressure, but pressure sensing can be achieved by decoupling it from Region I. Brief explanation of the principle: According to Stern theory, the double-layer capacitance is mainly composed of the Helmholtz layer capacitance (C0). H ) and diffusion layer capacitance (C D Composed of, where, C H Only related to the ionized contact area and capacitance per unit area, since the ionized material and the electrode are in complete contact in this application, C H It is only related to the capacitance per unit area, i.e., temperature. C D The thickness of the ionic material is positively correlated with the pressure; increased pressure causes a decrease in thickness, leading to C. D The value decreases, and an empirical formula can be obtained by collecting experimental data. The capacitances of region I and region II are expressed as: C I =C H(I) =UAC×S I (1)

[0043] In the formula, C I and C II The capacitance values ​​C were collected from two different regions. H(I) and C H(II) The values ​​represent the Helmholtz layer capacitances of the two regions, where UAC is the capacitance per unit area. It is assumed that the two regions are identical. S I and S II These represent the effective contact areas of the sensing electrodes in the two regions, which are fixed constants in this application. Therefore, it can be seen that after capacitive decoupling in region I, region II can be transformed into a region only affected by C. D That is, the effect of stress.

[0044] Furthermore, this application embodiment also provides a method for fabricating an integrated pressure and temperature hydrogel array sensor. The flowchart is shown in Figure 3, and the method specifically includes the following steps: First, a mold is provided; then, a hydrogel material layer is formed on the mold; next, a photocurable mask is used to perform a first photocuring on the hydrogel material layer; then, interdigitated electrodes are covered on the hydrogel material layer after the first photocuring treatment, and a second photocuring is performed to obtain a hydrogel layer with differences in crosslinking density and height that is closely attached to the interdigitated electrodes; the hydrogel layer includes a high crosslinking density hydrogel region and a low crosslinking degree hydrogel region; finally, the mold is removed to obtain the hydrogel sensing structure.

[0045] In some embodiments, the high cross-linking density hydrogel region is located at the center of the hydrogel layer, and the low cross-linking degree hydrogel region surrounds the high cross-linking density hydrogel region.

[0046] In some embodiments, the time for both the first and second photocuring is 0.1 min to 10 min.

[0047] This application achieves simultaneous pressure and temperature sensing through ion sensing. It uses a hydrogel material composition and can achieve sensing differences in different regions simply by changing the structural design. Based on the double-layer theory, it can simultaneously monitor changes in pressure and temperature signals and can perform array-based sensing structure design to achieve signal acquisition of temperature and pressure distribution.

[0048] The fabrication method of the pressure-temperature integrated hydrogel array sensor provided in this application will be described in detail below through specific embodiments.

[0049] First, the hydrogel prepolymer was prepared. Acrylamide and polyethylene glycol diacrylate were selected as the main components of the hydrogel, with sodium alginate as the ionic component. Pure water was used as the solvent, and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylphenylacetone was selected as the photoinitiator. The mass ratio of acrylamide:polyethylene glycol diacrylate:sodium alginate:water:photoinitiator was controlled to be 1:0.05:0.1:3:0.03. After stirring evenly, oxygen was removed before use.

[0050] Next, electrode selection was performed. A flexible printed circuit board with a polyimide substrate was used to print dual-channel interdigitated electrodes. The linewidth and spacing of the interdigitated electrodes were both 200 micrometers. The overall electrode size was a circle with a diameter of 10 mm. The temperature sensing electrode was a circle with a diameter of 5 mm, and the pressure sensing electrode was in the remaining area.

[0051] Next, an integrated sensing structure was constructed. A circular polytetrafluoroethylene mold was fabricated, with an overall diameter of 15mm, a depth of 1mm, a central frustum diameter of 5mm, and a height of 0.5mm. The hydrogel prepolymer was poured into the mold; a mask was applied, with a light-transmitting diameter of 5mm in the central circular area, and a first photocuring (365nm UV) was performed for 1 minute; the mask was removed, and interdigitated electrodes were placed on the gel, followed by a second photocuring for 30 seconds; finally, one side of the hydrogel was removed from the mold, while the other side remained in direct contact with the interdigitated electrodes, thus obtaining the integrated sensing structure.

[0052] Finally, performance characterization was performed. An inductor-capacitor-resistance sensing system was used to deduce the magnitude of the pressure applied at a given moment. A data acquisition card was used to measure the dual-channel capacitance changes under different water pressures and contact forces underwater. Figures 6 and 7 show schematic diagrams of the integrated temperature and pressure sensor response curves, where the horizontal axis in Figures 6 and 7 represents the sensor temperature change and the thickness change of the hydrogel after pressure, respectively, and the vertical axis represents the sensor output capacitance.

[0053] Based on the above technical solutions, this application provides a pressure-temperature integrated hydrogel array sensor and its fabrication method. The hydrogel array sensor includes: multiple sensing array units arranged in an array; each sensing array unit includes interdigitated electrodes and a hydrogel layer covering the surface of the interdigitated electrodes; the hydrogel layer is fixed to the interdigitated electrodes by photocuring, and the hydrogel layer is tightly bonded to the surface of the interdigitated electrodes; the interdigitated electrodes are two coplanar nested interdigitated electrodes fabricated using a flexible circuit board; the hydrogel layer has differences in crosslinking density and height; the hydrogel layer includes a high-crosslinking-density hydrogel region and a low-crosslinking-density hydrogel region. This application simultaneously achieves pressure and temperature sensing through ion sensing, using a single hydrogel material composition. Different sensing differences in different regions can be achieved simply by changing the structural design. Based on the double-layer theory, it can simultaneously monitor changes in pressure and temperature signals, enabling array-based sensing structure design to acquire signals of temperature and pressure distribution.

[0054] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A pressure-temperature integrated hydrogel array sensor, characterized in that, include: Multiple sensor array units arranged in an array; Each sensing array unit includes interdigitated electrodes and a hydrogel layer covering the surface of the interdigitated electrodes; The hydrogel layer is fixed on the interdigital electrode by photocuring, and the hydrogel layer is in close contact with the surface of the interdigital electrode; The interdigital electrodes are two coplanar nested interdigital electrodes fabricated using a flexible circuit board. The hydrogel layer is a hydrogel layer with differences in crosslinking density and height; the hydrogel layer includes a high crosslinking density hydrogel region and a low crosslinking degree hydrogel region.

2. The pressure-temperature integrated hydrogel array sensor according to claim 1, characterized in that, The high cross-linking density hydrogel region is located at the center of the hydrogel layer, and the low cross-linking degree hydrogel region surrounds the high cross-linking density hydrogel region. The high cross-linking density hydrogel region does not deform under pressure and is only affected by temperature; the low cross-linking degree hydrogel region can be affected by both temperature and pressure simultaneously, and achieves single pressure sensing by decoupling from the high cross-linking density hydrogel region.

3. The pressure-temperature integrated hydrogel array sensor according to claim 1, characterized in that, The hydrogel layer has a cross-linked network structure, and the doped ionic components within the cross-linked network structure form ion pathways. The network host material of the cross-linked network structure includes one or more of acrylamide, hydroxyethyl methacrylate, acrylic acid, isooctyl methacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, and N,N-methylenebisacrylamide hydrogel monomers. The ionic component is an ionic liquid or anionic / cationic polyelectrolyte with a polymerizable functional group structure; the ionic component includes: vinylimidazolium sulfonylimide salt, vinylimidazolium phosphate, allylimidazolium sulfonylimide salt, allylimidazolium phosphate, and one or more of sodium alginate, sodium polystyrene sulfonate, sodium polyacrylate, and polydiallyldimethylammonium chloride.

4. The integrated pressure-temperature hydrogel array sensor of claim 3, wherein, The hydrogel layer also includes a solvent and a photoinitiator; The solvent is deionized water or a doping system of deionized water and polyol; the polyol includes one or more of ethylene glycol, 1,3-propanediol, glycerol, n-butanol, and 1,2-butanediol. The photoinitiator includes one or more of the following: benzoyl, acetophenone, α-hydroxy ketone, and acylphosphine oxide.

5. The integrated pressure-temperature hydrogel array sensor of claim 4, wherein, The mass ratio of the network main material to the ionic component is (1-100):1; The mass ratio of the solvent to the network substrate material is (0.5–10):1; The mass ratio of the photoinitiator to the network host material is (0-0.5):

1.

6. The integrated pressure and temperature hydrogel array sensor of claim 1, wherein, The sensor array unit is connected to the array module acquisition system. The sensor array unit performs row and column scanning through the array module acquisition system to acquire array image information under temperature and pressure changes.

7. The pressure-temperature integrated hydrogel array sensor according to claim 1, characterized in that, The flexible circuit board is one of single-sided, double-sided, or multi-layer circuits; The flexible circuit board includes a flexible substrate and an electrode material disposed on the flexible substrate; The flexible substrate includes one of polyimide and polyethylene terephthalate; The electrode material includes one of gold, platinum, copper, and silver.

8. A method for preparing a pressure-temperature integrated hydrogel array sensor, characterized by, Includes the following steps: Provide molds; A hydrogel material layer is formed on the mold; A photocurable mask is used to perform a single photocuring of the hydrogel material layer; Interdigitated electrodes are covered on a hydrogel material layer that has undergone a first photocuring process, and then a second photocuring process is performed to obtain a hydrogel layer with differences in crosslinking density and height that is closely attached to the interdigitated electrodes; the hydrogel layer includes a high crosslinking density hydrogel region and a low crosslinking degree hydrogel region. Remove the mold to obtain the hydrogel sensing structure.

9. The method for fabricating the pressure-temperature integrated hydrogel array sensor according to claim 8, characterized in that, The high cross-linking density hydrogel region is located at the center of the hydrogel layer, and the low cross-linking degree hydrogel region surrounds the high cross-linking density hydrogel region.

10. The method of claim 8, wherein the array of pressure-temperature integrated hydrogel sensors is prepared by the steps of: The time for both the first and second photocuring cycles is 0.1 min to 10 min.

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