Pressure and temperature integrated hydrogel array sensor and preparation method thereof

Abstract

The invention relates to the technical field of flexible sensing, in particular to a pressure and temperature integrated hydrogel array sensor and a preparation method thereof, and the hydrogel array sensor comprises a plurality of sensing array units arranged in an array; each sensing array unit comprises an interdigital electrode and a hydrogel layer covering the surface of the interdigital electrode; the hydrogel layer is fixed on the interdigital electrode in a photocuring mode, and the hydrogel layer is tightly attached to the surface of the interdigital electrode; the interdigital electrodes are two coplanar nested interdigital electrodes prepared by adopting a flexible circuit board; the hydrogel layer is a hydrogel layer with crosslinking density difference and height difference; the hydrogel layer comprises a high-crosslinking-density hydrogel area and a low-crosslinking-degree hydrogel area. According to the flexible sensing structure based on the photo-curing hydrogel, through the array electrode design, the changes of a pressure signal and a temperature signal can be monitored at the same time through an array module acquisition system.

Description

Technical Field

[0001] The present application relates to the field of flexible sensing technology, and in particular to a pressure-temperature integrated hydrogel array sensor and a preparation method thereof. Background Art

[0002] The receptors of the human skin system are composed of ionic conductors, and their signal transduction mode is based on ion dynamics. A large number of thermoreceptors and mechanoreceptors are distributed in the dermis, which can clearly sense the spatial distribution of strain and temperature on the skin. Tactile sensing simulates the temperature, humidity, pressure, vibration and other functions of human skin to achieve response to external stimuli. With the rapid development of the Internet of Things in recent years, flexible tactile sensing has important significance for the development of many cutting-edge technologies such as wearable devices, brain-computer interfaces, and smart medical care.

[0003] Sensing structures with integrated pressure and temperature sensing can achieve collaborative sensing between electronic devices and skin and tissues, which is crucial for multi-parameter monitoring in complex scenarios. For example, in wound healing, hydrogel dressings with mechanical, temperature and chemical sensing can establish all-round wound monitoring, including the perception of stress changes, as well as the grasp of parameters such as wound surface temperature and reactive oxygen. Sensing structures that achieve multi-parameter integrated sensing through structural design are the trend of future development.

[0004] Using ionic pathways to achieve sensing functions can simulate the way biological systems process information, and can achieve biomimetic sensing functions that are more similar to living organisms. In recent years, the ion-type sensing mechanism relies on the double-layer structure of the ion-electron interface, which has high sensitivity. The sensing function of the device can be optimized by designing ionic materials. Hydrogel materials belong to a class of ionic materials, and their ionic functions can be adjusted through structural design. At the same time, they have the soft characteristics of large deformation, and can be applied to sensing structures to achieve highly sensitive feedback to external stimuli. In addition, a variety of biopolymers, natural polymers, and synthetic polymers can be used as components of hydrogels, giving them good biological functionality, thereby achieving diversified sensing functions.

[0005] In the prior art, the zwitterion-based ionic skin sensor system selects temperature-responsive N-isopropylacrylamide and glucose-responsive methacrylamide phenylboronic acid to design a sandwich hydrogel sensor, which is a capacitive sensor as a whole. The upper, middle and lower layers all have different response characteristics to monitor wound temperature, strain and glucose concentration in tissue fluid. It should be noted that when N-isopropylacrylamide hydrogel is in an asymmetric structure, it may cause overall buckling deformation due to temperature changes, which may interfere with the overall capacitive sensing signal. Summary of the invention

[0006] The embodiment of the present application provides a pressure-temperature integrated hydrogel array sensor and a preparation method thereof. Based on the ionization sensing and diffusion layer effect of the double-layer theory, a flexible sensing structure based on photocurable hydrogel is designed. Through the arrayed electrode design and the array module acquisition system, the pressure signal and temperature signal changes can be monitored simultaneously.

[0007] To solve the above technical problems, in the first aspect, an embodiment of the present application provides a pressure-temperature integrated hydrogel array sensor, comprising: a plurality of sensor array units arranged in an array; each sensor array unit comprises an interdigitated electrode and a hydrogel layer covering the surface of the interdigitated electrode; the hydrogel layer is fixed on the interdigitated electrode by photocuring, and the hydrogel layer is tightly fitted to the surface of the interdigitated electrode; the interdigitated electrode is two coplanar nested interdigitated electrodes prepared by a flexible circuit board; the hydrogel layer is a hydrogel layer with different cross-linking density and height; the hydrogel layer comprises a high cross-linking density hydrogel area and a low cross-linking degree hydrogel area.

[0008] 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 is surrounded by 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 temperature and pressure at the same time, and a single pressure perception is achieved by decoupling from the high cross-linking density hydrogel region.

[0009] In some exemplary embodiments, the hydrogel layer has a cross-linked network structure, and ionic components are doped in the cross-linked network structure to form ion paths; the network main 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 and cationic polyelectrolyte with a polymerizable functional group structure; the ionic component includes: vinyl imidazole sulfonyl imide salts, vinyl imidazole phosphates, allyl imidazole sulfonyl imide salts, allyl imidazole phosphates, and one or more of sodium alginate, sodium polystyrene sulfonate, sodium polyacrylate, and polydiallyldimethylammonium chloride.

[0010] 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-propylene glycol, glycerol, n-butanol, and 1,2-butanediol; the photoinitiator includes one or more of benzil, acetophenone, α-hydroxy ketone, and acylphosphine oxide.

[0011] 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.

[0012] In some exemplary embodiments, the sensor array unit is connected to an 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.

[0013] In some exemplary embodiments, the flexible circuit board is one of a single-sided, double-sided or multi-layer circuit; the flexible circuit board includes a flexible substrate and an electrode material arranged 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.

[0014] In the second aspect, an embodiment of the present application also provides a method for preparing a pressure-temperature integrated hydrogel array sensor, comprising the following steps: first, providing a mold; then, forming a hydrogel material layer on the mold; next, using a photocuring mask to perform a photocuring on the hydrogel material layer; then, covering the hydrogel material layer after the first photocuring treatment with interdigital electrodes, and performing a secondary photocuring to obtain a hydrogel layer with a cross-linking density difference and a height difference that is tightly fitted with the interdigital electrodes; the hydrogel layer includes a high cross-linking density hydrogel area and a low cross-linking degree hydrogel area; finally, removing the mold to obtain a hydrogel sensing structure.

[0015] 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.

[0016] In some exemplary embodiments, the time for the primary photocuring and the secondary photocuring is 0.1 min to 10 min.

[0017] The technical solution provided by the embodiment of the present application has at least the following advantages:

[0018] The embodiment of the present application provides a pressure-temperature integrated hydrogel array sensor and a preparation method thereof, the hydrogel array sensor comprising: a plurality of sensor array units arranged in an array; each sensor array unit comprises an interdigital electrode and a hydrogel layer covering the surface of the interdigital electrode; the hydrogel layer is fixed on the interdigital electrode by photocuring, and the hydrogel layer is tightly fitted to the surface of the interdigital electrode; the interdigital electrode is two coplanar nested interdigital electrodes prepared by a flexible circuit board; the hydrogel layer is a hydrogel layer with cross-linking density differences and height differences; the hydrogel layer comprises a high cross-linking density hydrogel area and a low cross-linking degree hydrogel area. The present application realizes pressure and temperature perception simultaneously through ion sensing, adopts a hydrogel material component, and can realize perception differences in different regions only by changing the structural design. Based on the double electrical layer theory, it can monitor the changes of pressure signals and temperature signals at the same time, and can design an arrayed sensing structure to realize signal acquisition of temperature and pressure distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0020] Figure 1 This is a schematic diagram of the structure of the pressure-temperature integrated hydrogel array sensor provided in an embodiment of the present application.

[0021] Figure 2 A schematic diagram of the structure of the array electrode provided in an embodiment of the present application.

[0022] Figure 3 A schematic flow chart of a method for preparing a pressure-temperature integrated hydrogel array sensor provided in an embodiment of the present application.

[0023] Figure 4 A top view of the hydrogel layer provided in an embodiment of the present application.

[0024] Figure 5 Schematic diagram of the integrated hydrogel sensing principle provided in the embodiments of the present application.

[0025] Figure 6 and Figure 7 This is a schematic diagram of the temperature and pressure integrated sensing response curve provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] As can be seen from the background technology, in the prior art zwitterion-based ionic skin sensor system, N-isopropylacrylamide hydrogel may cause overall buckling deformation due to temperature changes when in an asymmetric structure, which may interfere with the overall capacitive sensing signal.

[0027] In order to solve the above technical problems, the embodiment of the present application provides a pressure-temperature integrated hydrogel array sensor and a preparation method thereof, the hydrogel array sensor comprising: a plurality of sensor array units arranged in an array; each sensor array unit comprises a forked electrode and a hydrogel layer covering the surface of the forked electrode; the hydrogel layer is fixed on the forked electrode by photocuring, and the hydrogel layer is tightly fitted to the surface of the forked electrode; the forked electrode is two coplanar nested forked electrodes prepared by a flexible circuit board; the hydrogel layer is a hydrogel layer with cross-linking density differences and height differences; the hydrogel layer comprises a high cross-linking density hydrogel area and a low cross-linking degree hydrogel area. The present application realizes pressure and temperature perception simultaneously through ion sensing, adopts a hydrogel material component, and can realize perception differences in different regions only by changing the structural design. Based on the double electrical layer theory, it can monitor the changes of pressure signals and temperature signals at the same time, and can design an arrayed sensing structure to realize signal acquisition of temperature and pressure distribution. The embodiment of the present application provides a pressure-temperature integrated hydrogel array sensor and a preparation method thereof. Based on the ionization sensing and diffusion layer effect of the double-layer theory, a flexible sensing structure based on photocurable hydrogel is designed. Through the arrayed electrode design and the array module acquisition system, the pressure signal and temperature signal changes can be monitored simultaneously.

[0028] The following will describe the various embodiments of the present application in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in the present application can be implemented.

[0029] See also Figure 1 The embodiment of the present application provides a pressure-temperature integrated hydrogel array sensor, comprising: a plurality of sensor array units arranged in an array; each sensor array unit comprises an interdigitated electrode 101 and a hydrogel layer 102 covering the surface of the interdigitated electrode 101; the hydrogel layer 102 is fixed on the interdigitated electrode 101 by photocuring, and the hydrogel layer 102 is tightly attached to the surface of the interdigitated electrode 101; the interdigitated electrode 101 is two coplanar nested interdigitated electrodes prepared by a flexible circuit board; the hydrogel layer 102 is a hydrogel layer with a difference in cross-linking density and a difference in height; the hydrogel layer 102 comprises a high cross-linking density hydrogel area 102a and a low cross-linking degree hydrogel area 102b.

[0030] This application innovatively proposes a new integrated pressure and temperature sensing structure, based on the ionization sensing and diffusion layer effect of the double electric layer theory, and designs a flexible sensing structure based on photocurable hydrogel. The flexible sensing structure consists of two coplanar nested interdigitated electrodes made of a flexible circuit board, and a hydrogel material with height differences and crosslinking density differences covered thereon. The electrodes in the array sensor structure are obtained by array design of the above-mentioned interdigitated electrodes, and the hydrogel material covered thereon is a repetition of the above-mentioned unit. The hydrogel is fixed on the interdigitated electrodes by photocuring, and there is no gap or other material between the two.

[0031] This application uses ion sensing to simultaneously realize pressure and temperature perception, and uses hydrogel material components to design an arrayed sensor structure. Figure 1 The integrated hydrogel array sensing structure with a 5*5 array as an example is shown. Taking the 5*5 array electrode as an example, the double-sided routing design of the interdigitated electrode is demonstrated. The row and column routing leads are located on the front and back sides respectively. Holes are drilled at specific locations, and the connection of the two-sided circuits is achieved by metallization on the hole wall. The hydrogel layer has 25 repeating units accordingly.

[0032] It should be noted that Figure 1 The integrated hydrogel array sensing structure is shown as an example of a 5*5 array, but is not limited thereto. Figure 2 As shown, Figure 2 The figure shows the interdigital electrodes and array design of an integrated sensing structure taking 3*3 as an example.

[0033] The sensor array unit is connected to the array module acquisition system. During data acquisition, the temperature and pressure channel test of the integrated sensor can be conducted by connecting two single-point interdigitated electrodes to the same excitation signal, and the capacitance change can be converted into the output voltage change through the operational amplifier circuit. The sensor array is scanned in rows and columns through the array module acquisition system to collect array image information under temperature and pressure changes. The pressure and temperature distribution can be obtained through data processing.

[0034] In some embodiments, the flexible electrode is prepared by conventional printing conductive materials or laser etching methods. The prepared flexible circuit board can be a 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, platinum, copper, silver, etc.

[0035] In some embodiments, the thickness of the flexible substrate is 1 to 1000 microns, further 10 to 500 microns. The line width of the interdigitated strip electrodes is specifically 0.1 to 1000 microns, further 10 to 300 microns; the spacing between two adjacent electrodes of the interdigitated strip electrodes is 0.1 to 1000 microns, further 10 to 300 microns; the spacing between each unit of the array electrode is 1 to 10000 microns, further 50 to 5000 microns.

[0036] The hydrogel layer with cross-linking density difference and height difference has a cross-linking network structure and an ion path, and its composition is a photocurable gel system. In some embodiments, the hydrogel layer has a cross-linking network structure, and ion components are doped in the cross-linking network structure to form an ion path; the network main material of the cross-linking 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 ion component is an ionic liquid or an anionic and cationic polyelectrolyte with a polymerizable functional group structure; the ion component includes: vinyl imidazole sulfonyl imide salt, vinyl imidazole phosphate, allyl imidazole sulfonyl imide salt, allyl imidazole phosphate, and one or more of sodium alginate, sodium polystyrene sulfonate, sodium polyacrylate, and polydiallyl dimethyl ammonium chloride.

[0037] 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-propylene glycol, glycerol, n-butanol, and 1,2-butanediol; the photoinitiator includes one or more of benzil, acetophenone, α-hydroxy ketone, and acylphosphine oxide.

[0038] 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; 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; the mass ratio of the photoinitiator to the network host material is (0.01-0.1):1.

[0039] Specifically, the hydrogel preparation process is as follows Figure 3As shown, first, the network main material, ion component, solvent and photoinitiator are mixed evenly, oxygen is excluded, and the hydrogel prepolymer 111 is obtained; the height difference of the hydrogel is prepared by reverse molding, wherein the mold 110 is obtained by mechanical processing, including but not limited to PDMS mold, polytetrafluoroethylene mold, stainless steel mold, and the height difference is controlled at 0.1mm~2mm, and the hydrogel prepolymer 111 is poured into the mold 110; the cross-linking density difference of the hydrogel is controlled by covering the photocuring mask 112, wherein the black area is shielded from light, and the transparent area will be cured preferentially; after the area is exposed to ultraviolet light, the photocuring mask 112 is removed; then, the interdigital electrode 1θ1 is covered on the hydrogel, and the whole is subjected to secondary light curing, and the curing time of the two times is controlled at 0.1~10min. Finally, one side of the hydrogel layer 102 is removed from the mold 110, and the other side is kept directly attached to the interdigital electrode 101, so as to obtain a hydrogel layer 102 with cross-linking density difference and height difference.

[0040] In some embodiments, Figure 4 As shown, the high cross-linking density hydrogel area 102a is located at the center of the hydrogel layer 102, and the low cross-linking degree hydrogel area 102b is surrounded by the high cross-linking density hydrogel area 102a; the high cross-linking density hydrogel area 102a does not deform during the pressure process and is only affected by temperature; the low cross-linking degree hydrogel area 102b can be affected by temperature and pressure at the same time, and a single pressure perception is achieved by decoupling from the high cross-linking density hydrogel area 102a. The schematic diagram of its sensing principle is shown in Figure 5 shown.

[0041] Figure 5 The pressure and temperature sensing principle is demonstrated. The high cross-linking density hydrogel area (area I) does not deform during the pressure process and is only affected by temperature. The low cross-linking density hydrogel area (area II) is affected by both temperature and pressure, but can be decoupled from area I to achieve single pressure sensing. Principle: According to Stern theory, the double-layer capacitance is mainly composed of the Helmholtz layer capacitance (C H ) and diffusion layer capacitance (C D ), where C H It is only related to the ion contact area and the capacitance per unit area. Since the ion material and the electrode are in full contact in this application, C H It is only related to the capacitance per unit area, that is, temperature. D It is positively correlated with the thickness of the ion material. The increase in pressure causes the thickness to decrease, resulting in C D The value is reduced, and the empirical formula can be obtained by collecting experimental data. The capacitance of region I and region II are expressed as:

[0042] C I =C H(I) =UAC×S I (1)

[0043]

[0044] In the formula, C I and C II The capacitance values ​​collected in two areas are C H(I) and C H(II) is the Helmholtz layer capacitance of the two regions, UAC is the capacitance per unit area, and the two regions are assumed to be consistent. I and S II are the effective contact areas of the sensing electrodes in the two regions, which are fixed constants in this application. It can be seen that after the capacitive decoupling of region I, region II can be transformed into a region that is only affected by C D , that is, the pressure effect.

[0045] In addition, the present invention also provides a method for preparing a pressure-temperature integrated hydrogel array sensor. Figure 3 , specifically comprising the following steps: first, providing a mold; then, forming a hydrogel material layer on the mold; next, using a photocuring mask to perform a photocuring on the hydrogel material layer; then, covering the hydrogel material layer after the photocuring treatment with interdigital electrodes, and performing a secondary photocuring to obtain a hydrogel layer with a cross-linking density difference and a height difference that is tightly fitted with the interdigital electrodes; the hydrogel layer includes a high cross-linking density hydrogel area and a low cross-linking degree hydrogel area; finally, removing the mold to obtain a hydrogel sensing structure.

[0046] 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.

[0047] In some embodiments, the time for the primary photocuring and the secondary photocuring is 0.1 min to 10 min.

[0048] The present application realizes pressure and temperature perception simultaneously through ion sensing, adopts a hydrogel material component, and can realize perception differences in different areas only by changing the structural design. Based on the double layer theory, it can monitor the changes of pressure signals and temperature signals at the same time, and can perform arrayed sensing structure design to realize signal collection of temperature and pressure distribution.

[0049] The preparation method of the pressure-temperature integrated hydrogel array sensor provided in the present application is described in detail below through specific examples.

[0050] First, prepare the hydrogel prepolymer. Select acrylamide and polyethylene glycol diacrylate as the main body of the hydrogel, dope sodium alginate as the ion component, use pure water as the solvent, and select 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone as the photoinitiator. Among them, the mass ratio of acrylamide: polyethylene glycol diacrylate: sodium alginate: water: photoinitiator is controlled to be 1:0.05:0.1:3:0.03, and after stirring evenly, remove oxygen and set aside.

[0051] Then, the electrode selection is performed. A flexible printed circuit board is used, the substrate is polyimide, and a dual-channel interdigital electrode is printed, where the line width and line spacing of the interdigital electrode are both 200 microns, and the overall size of the electrode is a circle with a diameter of 10 mm, where the temperature sensing part electrode size is a circle with a diameter of 5 mm, and the pressure sensing part is the remaining area.

[0052] Next, build an integrated sensing structure. The processed polytetrafluoroethylene circular mold has an overall size of 15mm diameter, 1mm depth, 5mm center cone diameter, and 0.5mm height. Pour the hydrogel prepolymer into the mold; cover it with a mask, the central circular area has a light-transmitting diameter of 5mm, and perform the first photocuring (365nmUV) for 1min; remove the mask and cover the gel with interdigital electrodes, and perform the second photocuring for 30s; finally, remove one side of the hydrogel from the mold, and keep the other side in direct contact with the interdigital electrodes to obtain an integrated sensing structure.

[0053] Finally, the performance is characterized. The inductance-capacitance-resistance detection system is used to deduce the pressure at a certain moment. The data acquisition card detection system is used to measure the change of dual-channel capacitance under different water pressures and different contact forces underwater. Figure 6 and Figure 7 Figure 2 shows a schematic diagram of the temperature and pressure integrated sensing response curve, where: Figure 6 and Figure 7 The horizontal axis represents the temperature change of the sensor and the thickness change of the hydrogel after being compressed, and the vertical axis represents the output capacitance of the sensor.

[0054] Based on the above technical scheme, the embodiment of the present application provides a pressure-temperature integrated hydrogel array sensor and a preparation method thereof, the hydrogel array sensor comprising: a plurality of sensor array units arranged in an array; each sensor array unit comprises a forked electrode and a hydrogel layer covering the surface of the forked electrode; the hydrogel layer is fixed on the forked electrode by photocuring, and the hydrogel layer is tightly fitted to the surface of the forked electrode; the forked electrode is two coplanar nested forked electrodes prepared by a flexible circuit board; the hydrogel layer is a hydrogel layer with cross-linking density differences and height differences; the hydrogel layer comprises a high cross-linking density hydrogel area and a low cross-linking degree hydrogel area. The present application realizes pressure and temperature perception simultaneously through ion sensing, adopts a hydrogel material component, and can realize perception differences in different regions only by changing the structural design. Based on the double electric layer theory, it can monitor the changes of pressure signals and temperature signals at the same time, and can perform arrayed sensing structure design to realize signal acquisition of temperature and pressure distribution.

[0055] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art can make their own changes and modifications without departing from the spirit and scope of the present application, so the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A pressure-temperature integrated hydrogel array sensor, characterized in that: include: A plurality of sensor array units arranged in an array; Each sensing array unit includes an interdigital electrode and a hydrogel layer covering the surface of the interdigital electrode; The hydrogel layer is fixed on the interdigital electrode by photocuring, and the hydrogel layer is closely attached to the surface of the interdigital electrode; The interdigital electrodes are two coplanar nested interdigital electrodes made of a flexible circuit board; The hydrogel layer is a hydrogel layer with cross-linking density difference and height difference; the hydrogel layer includes a high cross-linking density hydrogel region and a low cross-linking 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 area does not deform during the pressure process and is only affected by temperature; the low cross-linking degree hydrogel area can be affected by temperature and pressure at the same time, and single pressure perception is achieved by decoupling from the high cross-linking density hydrogel area.

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 ion components are doped into the cross-linked network structure to form ion 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 component is an ionic liquid or anionic and cationic polyelectrolyte with a polymerizable functional group structure; the ionic component includes: vinyl imidazole sulfonyl imide salt, vinyl imidazole phosphate, allyl imidazole sulfonyl imide salt, allyl imidazole phosphate, and one or more of sodium alginate, sodium polystyrene sulfonate, sodium polyacrylate, and polydiallyl dimethyl ammonium chloride.

4. The pressure-temperature integrated hydrogel array sensor according to claim 3, characterized in that: The hydrogel layer also includes a solvent and a photoinitiator; The solvent is deionized water or a doping system of deionized water and polyols; the polyols include one or more of ethylene glycol, 1,3-propylene glycol, glycerol, n-butanol, and 1,2-butanediol; The photoinitiator includes one or more of benzil, acetophenone, α-hydroxyketone and acylphosphine oxide.

5. The pressure-temperature integrated hydrogel array sensor according to claim 4, characterized in that: 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 main material is (0.5-10):1; The mass ratio of the photoinitiator to the network main material is (0-0.5):

1.

6. The pressure-temperature integrated hydrogel array sensor according to claim 1, characterized in that: 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 a single-sided, double-sided or multi-layer circuit; The flexible circuit board includes a flexible substrate and an electrode material arranged on the flexible substrate; The flexible substrate comprises 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 in that: The following steps are involved: Provide molds; forming a layer of hydrogel material on the mold; Using a photocuring mask, photocuring the hydrogel material layer once; Covering the interdigital electrodes on the hydrogel material layer after the primary photocuring treatment, and performing secondary photocuring to obtain a hydrogel layer with different crosslinking density and height that is closely attached to the interdigital electrodes; the hydrogel layer includes a high crosslinking density hydrogel area and a low crosslinking degree hydrogel area; The mold was removed to obtain the hydrogel sensing structure.

9. The method for preparing 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 for preparing the pressure-temperature integrated hydrogel array sensor according to claim 8, characterized in that: The time for the first light curing and the second light curing is 0.1min to 10min.

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