Conductive organic hydrogel as well as preparation method and application thereof

Abstract

The invention discloses conductive organic hydrogel as well as a preparation method and application thereof, and belongs to the technical field of polymer hydrogel. The preparation method provided by the invention comprises the following steps: dissolving 3-aminophenylboronic acid, acrylamide, an initiator and MXene nanosheets in water for free radical polymerization to obtain a polymer; and soaking the polymer in glycerol to obtain the conductive organic hydrogel. According to the preparation method, the conductive organic hydrogel can be endowed with excellent high elasticity, and stable signal output is kept in the long-term circulation process; no obvious water loss phenomenon exists in the long-term storage process, the mass and the volume of the hydrogel do not change obviously, and meanwhile, the hydrogel has good flexibility and stable sensing capacity at high / low temperature; the system can be used for monitoring electric signal changes generated by human joint movement, can also be used for collecting physiological signals such as electrocardio and myoelectricity, and has a wide application prospect clinically.

Description

Technical Field

[0001] This application belongs to the technical field of polymer hydrogels, and particularly relates to a conductive organic hydrogel, a preparation method thereof, and an application thereof. Background Art

[0002] Conductive hydrogels have shown excellent prospects in fields such as electronic skin, health management, and disease diagnosis due to their excellent flexibility, good biocompatibility, and adjustable conductive network channels. However, traditional conductive hydrogels exhibit high hysteresis and signal drift during use due to the lack of effective non-covalent bond interactions. At the same time, during long-term storage in high / low temperature environments, the water molecules inside the hydrogel will be frozen or evaporated, resulting in a significant decline in the mechanical properties of the hydrogel, severely affecting its practical applications. Therefore, it is crucial to ensure that conductive hydrogels have excellent stability and high elasticity in extreme environments.

[0003] To meet the application requirements, in recent years, researchers have effectively improved the elasticity of hydrogels by introducing stress-dispersing transfer stations and non-covalent bonds into the hydrogel network to achieve signal stability of conductive hydrogels during long-term monitoring. Professor Zhang Ting and his team at the University of Science and Technology of China used a method combining covalent crosslinking and dynamic non-covalent interactions to prepare low-hysteresis polyacrylic acid (PAA) / chitosan (CS) / Ti 3 C 2 TX (MXene) hydrogels (Nano Energy, 126 (2024) 109586). However, these water-based solvent hydrogels, although having good elasticity, also limit the application potential of hydrogels in extreme environments.

[0004] Hydrogels also need to have the ability to work in extreme environments. In recent years, researchers have prepared stable hydrogels under extreme environmental conditions by introducing organic solvents, zwitterions, inorganic salts, and ionic liquids into the hydrogel network. Professor Zhang Lei and his team at Tianjin University replaced the antifreeze - betaine into ammonium chloride / calcium alginate / polyacrylamide hydrogels through a simple solvent replacement strategy to prevent the hydrogel from freezing at low temperatures (Adv. Funct. Mater. 2020, 30, 1907986). However, this organic hydrogel has a high hysteresis problem due to the lack of effective non-covalent bonds. Therefore, there is a huge challenge in developing simple and effective methods to construct conductive organic hydrogels with both stability and high elasticity in extreme environments. Summary of the Invention

[0005] This application discloses a conductive organic hydrogel, a preparation method thereof, and an application thereof, aiming to solve the technical problems of poor stability and poor elasticity of existing conductive organic hydrogels under extreme environmental conditions.

[0006] To achieve the above object, the technical solution of the present application is as follows:

[0007] The first aspect of the present application provides a preparation method of a conductive organic hydrogel, and the preparation method includes:

[0008] Dissolve 3-aminophenylboronic acid, acrylamide, an initiator and MXene nanosheets in water for free radical polymerization to obtain a polymer;

[0009] Soak the polymer in glycerol to obtain the conductive organic hydrogel.

[0010] Preferably in combination with the first aspect, the concentration of the 3-aminophenylboronic acid is 0.02 - 0.1 mol / L.

[0011] Preferably in combination with the first aspect, the concentration of the acrylamide is 2 - 4 mol / L.

[0012] Preferably in combination with the first aspect, the mass fraction of the MXene nanosheets is 1 - 3 wt%.

[0013] Preferably in combination with the first aspect, the initiator is one or more of potassium persulfate, ammonium persulfate and 2,2'-azobis(2-methylpropionamidine) dihydrochloride.

[0014] Preferably in combination with the first aspect, the addition amount of the initiator is 0.1 - 2% of the total mass of the 3-aminophenylboronic acid and acrylamide monomers.

[0015] Preferably in combination with the first aspect, when dissolving 3-aminophenylboronic acid, acrylamide, an initiator and MXene nanosheets in water for free radical polymerization, the temperature is 25 - 80 °C and the time is 3 - 12 h.

[0016] Preferably in combination with the first aspect, when soaking the polymer in glycerol, the soaking time is 1 - 6 h.

[0017] The second aspect of the present application provides a conductive organic hydrogel prepared by the preparation method described in the first aspect.

[0018] The third aspect of the present application provides the application of the conductive organic hydrogel prepared by the preparation method described in the first aspect or the conductive organic hydrogel described in the second aspect in the technical field of flexible wearable sensors.

[0019] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application at least include:

[0020] The preparation method provided by this application dissolves 3-aminophenylboronic acid, acrylamide, an initiator, and MXene nanosheets in water for free radical polymerization, and then immerses them in glycerol to obtain a conductive organic hydrogel. On the one hand, 3-aminophenylboronic acid and acrylamide undergo free radical polymerization reaction through an initiator to generate a polymer hydrogel. The MXene nanosheets interact with it through hydrogen bonds, enabling the MXene nanosheets to be uniformly dispersed in the polymer. Then, glycerol is compounded into the hydrogel, which can endow the conductive organic hydrogel with excellent comprehensive properties. On the other hand, it can endow the conductive organic hydrogel with excellent high elasticity and maintain stable signal output during long-term cycling. There is no obvious water loss phenomenon during long-term storage, and neither the mass nor the volume of the hydrogel will change significantly. At the same time, it has good flexibility and stable sensing ability at high / low temperatures. It can monitor the change of electrical signals generated by human joint activities and can also be used to collect physiological signals such as electrocardiogram and electromyogram, showing broad application prospects in clinical practice. Meanwhile, this preparation method is simple to operate and easy to scale up production. Description of the Drawings

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a comparison chart of the tensile results of B1-organic hydrogel, B2-organic hydrogel, and B3-organic hydrogel prepared in the embodiments of this application;

[0023] Figure 2 It is a comparison chart of the tensile results of B2-organic hydrogel, B4-organic hydrogel, and B5-organic hydrogel prepared in the embodiments of this application;

[0024] Figure 3 It is a comparison chart of the tensile results of B6-conductive organic hydrogel, B7-conductive organic hydrogel, B8-conductive organic hydrogel, and B9-conductive organic hydrogel prepared in the embodiments of this application;

[0025] Figure 4 It is a comparison chart of the tensile results of A1-conductive organic hydrogel, A2-conductive organic hydrogel, and A3-conductive organic hydrogel prepared in the embodiments of this application;

[0026] Figure 5 It is an infrared test result chart of A2-conductive organic hydrogel, B2-organic hydrogel, and B8-conductive organic hydrogel prepared in the embodiments of this application;

[0027] Figure 6Comparison chart of the tensile results of the A2-conductive organic hydrogel, B2-organic hydrogel, and B8-conductive organic hydrogel prepared in the embodiments of the present application;

[0028] Figure 7 Continuous cyclic loading and unloading diagram of the A2-conductive organic hydrogel prepared in the embodiments of the present application;

[0029] Figure 8 Flexibility result diagram of the A2-conductive organic hydrogel prepared in the embodiments of the present application at high / low temperatures;

[0030] Figure 9 Water retention rate test result diagram of the A2-conductive organic hydrogel prepared in the embodiments of the present application at room temperature;

[0031] Figure 10 Water retention rate test result diagram of the A2-conductive organic hydrogel prepared in the embodiments of the present application at high temperature;

[0032] Figure 11 Result diagram of the sensing test of the A2-conductive organic hydrogel prepared in the embodiments of the present application. Detailed implementation manners

[0033] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0034] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may indicate: the situation of A existing alone, B existing alone, and A and B existing simultaneously. Where A and B may be singular or plural. The character " / " generally indicates that the associated objects before and after are an "or" relationship.

[0035] In the following description of this embodiment, the term "at least one" means one or more, and "a plurality" means two or more. "At least one of the following items (pieces)" or its similar expressions refer to any combination of these items, including any combination of single items (pieces) or plural items (pieces). For example, "at least one of a, b, or c", or, "at least one of a, b, and c" can both indicate: a, b, c, a - b (that is, a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0036] Those skilled in the art should understand that in the following description of the embodiments of the present application, the sequence numbers do not imply the order of execution, and some or all steps can be executed in parallel or sequentially. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0037] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0038] It should be noted that all raw materials and reagents in the embodiments of the present application are purchased on the market or prepared by conventional methods well-known to those skilled in the art. For example, proso millet starch, pullulanase, etc. are all obtained by purchasing on the market or prepared by conventional methods well-known to those skilled in the art.

[0039] In a first aspect, an embodiment of the present application provides a method for preparing a conductive organic hydrogel, and the preparation method includes:

[0040] Dissolve 3-aminophenylboronic acid, acrylamide, an initiator, and MXene nanosheets in water for free radical polymerization to obtain a polymer;

[0041] Soak the polymer in glycerol to obtain the conductive organic hydrogel.

[0042] Wherein, on the one hand, 3-aminophenylboronic acid and acrylamide undergo free radical polymerization reaction through an initiator to generate a polymer hydrogel. MXene nanosheets interact with it through hydrogen bonds, so that the MXene nanosheets are uniformly dispersed in the polymer. Then, glycerol is compounded into the hydrogel, which can endow the conductive organic hydrogel with excellent comprehensive properties; on the other hand, it can endow the conductive organic hydrogel with excellent high elasticity and maintain stable signal output during long-term cycling; there is no obvious water loss phenomenon during long-term storage, and neither the mass nor the volume of the hydrogel will change significantly; it has good flexibility and stable sensing ability at high / low temperatures; it can monitor the change of electrical signals generated by human joint activities, and can also be used to collect physiological signals such as electrocardiogram and electromyogram, and has broad application prospects in clinical practice. At the same time, this preparation method is simple in operation and easy to scale up production.

[0043] In the embodiments of the present application, the concentration of the 3-aminophenylboronic acid (APBA) is preferably 0.02 - 0.1 mol / L. The concentration of the acrylamide (AM) is preferably 2 - 4 mol / L. Among them, by controlling the concentrations of 3-aminophenylboronic acid and acrylamide, the best mechanical strength and elongation at break of the hydrogel can be achieved.

[0044] In the embodiments of the present application, the mass fraction of the MXene nanosheets is preferably 1-3 wt%. Among them, by controlling the addition amount of the MXene nanosheets, the conductive hydrogel can have excellent electrical conductivity and excellent high elasticity at the same time.

[0045] In the embodiments of the present application, the initiator is preferably one or more of potassium persulfate, ammonium persulfate, and 2,2'-azobis(2-methylpropionamidine) dihydrochloride. The addition amount of the initiator is preferably 0.1-2% of the total mass of 3-aminophenylboronic acid and acrylamide monomers. Among them, the initiator will decompose to generate free radicals under certain conditions, thereby initiating the polymerization reaction. If the amount of the initiator used is too small, the number of free radicals generated is insufficient, which may cause the polymerization reaction to be difficult to initiate, or the reaction rate is too slow and incomplete, affecting the performance and yield of the polymer; if the amount of the initiator used is too large, the reaction rate will be too fast, and the heat in the system will accumulate rapidly and be difficult to dissipate, which may lead to explosive polymerization, making the reaction difficult to control. At the same time, it may also cause the molecular weight distribution of the polymer to become wider, affecting the product quality.

[0046] In the embodiments of the present application, when 3-aminophenylboronic acid, acrylamide, the initiator, and MXene nanosheets are dissolved in water for free radical polymerization, the temperature is 25-80 °C and the time is 3-12 h. Among them, by controlling the time and temperature of the polymerization reaction, polymers with a target molecular weight can be controlled, thereby endowing the polymers with excellent comprehensive properties.

[0047] In the embodiments of the present application, when the polymer is immersed in glycerol, the immersion time is 1-6 h. Among them, by controlling the impregnation time in glycerol, the composite amount of glycerol in the conductive hydrogel can be controlled, thereby affecting the mechanical properties of the hydrogel.

[0048] The second aspect of the present application provides a conductive organic hydrogel prepared by the preparation method described in the first aspect. Among them, based on the above preparation method, the conductive hydrogel can be endowed with excellent high elasticity, excellent flexibility and sensing ability in extreme environments, structural stability and conductive signal stability during long-term storage.

[0049] The third aspect of the present application provides the application of the conductive organic hydrogel described in the second aspect in the field of flexible wearable sensors. Among them, based on the excellent high elasticity, excellent flexibility and sensing ability in extreme environments, structural stability and signal stability of the above conductive hydrogel, it has broad application prospects in the field of flexible wearable sensors.

[0050] The technical solutions of the present application will be further elaborated below in conjunction with specific embodiments.

[0051] Example 1

[0052] This embodiment provides a method for preparing A1-conductive organic hydrogel (PAPB / M-Gly-1), specifically including:

[0053] S101: Dissolve 11.46 mg of APBA, 213.3 mg of AM, and 5.62 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.24 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to initially obtain a polymer hydrogel;

[0054] S102: Immerse the above polymer hydrogel in a glycerol solution for 1 h to finally obtain A1-conductive organic hydrogel (PAPB / M-Gly-1).

[0055] Example 2

[0056] This embodiment provides a method for preparing A2-conductive organic hydrogel (PAPB / M-Gly-3), specifically including:

[0057] S201: Dissolve 11.46 mg of APBA, 213.3 mg of AM, and 5.62 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.24 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to initially obtain a polymer hydrogel;

[0058] S202: Immerse the above polymer hydrogel in a glycerol solution for 3 h to finally obtain A2-conductive organic hydrogel (PAPB / M-Gly-3).

[0059] Example 3

[0060] This embodiment provides a method for preparing A3-conductive organic hydrogel (PAPB / M-Gly-6), specifically including:

[0061] S301: Dissolve 11.46 mg of APBA, 213.3 mg of AM, and 5.62 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.24 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to initially obtain a polymer hydrogel;

[0062] S302: Immerse the above polymer hydrogel in a glycerol solution for 3 h to finally obtain A3-conductive organic hydrogel (PAPB / M-Gly-6).

[0063] Meanwhile, to verify the comprehensive performance of the conductive organic hydrogel prepared in the above embodiments, the present application provides the following comparative examples for detailed description.

[0064] Comparative Example 1

[0065] This comparative example provides a preparation method of B1-organic hydrogel (P(AM 3 -APBA 0.02 ), which specifically includes:

[0066] Dissolve 3.83 mg of APBA, 213.3 mg of AM, and 0 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.02 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.17 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to obtain B1-organic hydrogel (P(AM 3 -APBA 0.02 ).

[0067] Comparative Example 2

[0068] This comparative example provides a preparation method of B2-organic hydrogel (P(AM 3 -APBA 0.06 ), which specifically includes:

[0069] Dissolve 11.5 mg of APBA, 213.3 mg of AM, and 0 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.24 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to obtain B2-organic hydrogel (P(AM 3 -APBA 0.06 ).

[0070] Comparative Example 3

[0071] This example provides a preparation method of B3-organic hydrogel (P(AM 3 -APBA 0.1 ), which specifically includes:

[0072] Dissolve 31 mg of APBA, 213.3 mg of AM, and 0 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.1 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.32 mg of ammonium persulfate as an initiator, mix well, and then place it in an oven at 60 °C and let it stand for 3 h to obtain B3-organic hydrogel (P(AM 3 -APBA 0.1 ))

[0073] The differences between Comparative Examples 1, 2, and 3 of this application lie in gradually increasing the addition amount of APBA to explore the effect of the addition amount of APBA on the mechanical properties of the hydrogel. Use a universal electronic tensile testing machine (CMT-1503) to conduct uniaxial tensile testing on the hydrogel. The calculation formula for stress is F / A 0 , where F is the force acting on the hydrogel and A 0 is the initial cross-sectional area of the hydrogel. The elongation at break is defined as the percentage increase in the tensile distance at the time of specimen fracture relative to the original gauge length

[0074] Conduct tensile property testing on the hydrogels prepared in Comparative Examples 1, 2, and 3, and the test results are as Figure 1 shown. According to Figure 1 it can be seen that as the addition amount of APBA gradually increases, more hydrogen bonds are formed between polymer chains, so the strength increases. However, when the addition concentration of APBA reaches 0.1 mol / L, the elongation at break of the hydrogel decreases significantly. The optimal addition concentration of APBA is 0.06 mol / L

[0075] Comparative Example 4

[0076] This comparative example provides a preparation method for B4-organic hydrogel (P(AM 2 -APBA 0.06 ))

[0077] Dissolve 11.5 mg of APBA, 142.2 mg of AM, and 0 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 2 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.24 mg of ammonium persulfate as an initiator, mix well, and then place it in an oven at 60 °C and let it stand for 3 h to obtain B4-organic hydrogel (P(AM 2 -APBA 0.06 ))

[0078] Comparative Example 5

[0079] This comparative example provides a preparation method for B5-organic hydrogel (P(AM 4 -APBA 0.06 )) as follows:

[0080] Dissolve 11.46 mg of APBA, 284.4 mg of AM, and 0 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 4 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.95 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to obtain B5-organic hydrogel (P(AM 4 -APBA 0.06 ))).

[0081] The differences between comparative examples 2, 4, and 5 of this application lie in gradually increasing the addition amount of AM to explore the influence of the addition amount of AM on the mechanical properties of the hydrogel.

[0082] Conduct tensile property tests on the hydrogels prepared in comparative examples 2, 4, and 5, and the test results are as Figure 2 shown. According to Figure 2 it can be seen that as the addition amount of AM gradually increases, the entanglement between polymer chains becomes denser, so the strength increases. However, when the addition concentration of AM reaches 4 mol / L, the elongation at break of the hydrogel decreases significantly. The optimal addition concentration of AM is 3 mol / L.

[0083] Comparative example 6

[0084] This comparative example provides a preparation method for B6-conductive organic hydrogel (PAPB / M -1％ ), which specifically includes:

[0085] Dissolve 11.46 mg of APBA, 213.3 mg of AM, and 2.24 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.24 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to obtain B6-conductive organic hydrogel (PAPB / M -1％ ).

[0086] Comparative example 7

[0087] This example provides a preparation method for B7-conductive organic hydrogel (PAPB / M -2％ ), which specifically includes:

[0088] Dissolve 11.46 mg of APBA, 213.3 mg of AM, and 4.49 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.24 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to obtain B7-conductive organic hydrogel (PAPB / M -2％ ).

[0089] Comparative Example 8

[0090] This comparative example provides a preparation method of B8-conductive organic hydrogel (PAPB / M -2.5％ ), which specifically includes:

[0091] Dissolve 11.46 mg of APBA, 213.3 mg of AM, and 5.62 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.24 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to obtain B8-conductive organic hydrogel (PAPB / M -2.5％ ).

[0092] Comparative Example 9

[0093] This comparative example provides a preparation method of B9-conductive organic hydrogel (PAPB / M -3％ ), which specifically includes:

[0094] Dissolve 11.46 mg of APBA, 213.3 mg of AM, and 6.74 mg of MXene nanosheets in 1 mL of deionized water by heating at 60 °C, ultrasonic treatment, vortex oscillation, etc., so that the concentration of APBA is 0.06 mol / L and the concentration of AM is 3 mol / L. After complete dissolution, wait for the temperature of the mixed solution to cool to room temperature, add 2.24 mg of ammonium persulfate as an initiator, mix evenly, and then place it in an oven at 60 °C and let it stand for 3 h to obtain B9-conductive organic hydrogel (PAPB / M -3％ ).

[0095] The differences between Comparative Examples 6, 7, 8, and 9 of this application lie in gradually increasing the addition amount of MXene nanosheets to explore the influence of the addition amount of MXene nanosheets on the mechanical properties of the hydrogel.

[0096] Conduct tensile property tests on the hydrogels prepared in Comparative Examples 6, 7, 8, and 9, and the test results are as Figure 3 shown. According toFigure 3 It can be seen that as the addition amount of MXene nanosheets gradually increases, the entanglement between polymer chains becomes denser, so the strength increases. However, when the addition amount of MXene nanosheets is 3%, the elongation at break of the hydrogel decreases significantly. The optimal addition amount of MXene nanosheets is 2.5%.

[0097] After selecting the optimal addition amounts of APBA, AM, and MXene nanosheets, the effect of the soaking time in glycerol on the mechanical properties of the conductive hydrogel was further verified, and the results are shown in Figure 4.

[0098] According to Figure 4 what is known, as the soaking time in glycerol increases, more hydrogen bonds are formed between glycerol and polymer chains, so the strength increases. However, when the soaking time is longer (6 h), the amount of glycerol entering is more, and the elongation at break decreases significantly. The optimal soaking time in glycerol is 3 h.

[0099] The examples with the optimal addition amounts selected were compared, namely Example 2 (PAPB / M-Gly-3), Comparative Example 2 (P(AM 3 -APBA 0.06 )) and Comparative Example 8 (PAPB / M -2.5％ ) were subjected to structural characterization, and the test results are as Figure 5 shown.

[0100] According to Figure 5 what is known, it was found that the -NH stretching vibration peak of the PAPB hydrogel is at 1610 cm -1 . After adding MXene nanosheets, the -NH stretching vibration peak of the PAPB / M -2.5％ hydrogel shifts to 1606 cm -1 . After performing glycerol solvent replacement, the -NH stretching vibration peak of the PAPB / M-Gly-3 organic hydrogel shifts to 1600 cm -1 . These results prove that hydrogen bond interactions are formed between Mxene nanosheets, glycerol molecules, and acrylamide chains.

[0101] The conductive hydrogels prepared in the examples were subjected to mechanical property tests, and the test results are as Figure 6 shown.

[0102] According to Figure 6 what is known, "Strain" represents the elongation at break, and "Stress" represents the tensile strength. Since more hydrogen bonds are formed between Mxene nanosheets, glycerol molecules, and acrylamide chains, the mechanical strength of Example 2 (PAPB / M-Gly-3) is the best.

[0103] The conductive hydrogel prepared in Example 2 was subjected to continuous cyclic loading and unloading, and a universal electronic tensile testing machine (CMT-1503) was used to conduct cyclic tensile tests on the hydrogel at a fixed strain. The test results are as follows Figure 7 shown

[0104] According to Figure 7 it can be known that its hysteresis rate is within 12% (hysteresis rate = area of loading-unloading curve / area of loading curve). Each curve in the figure represents the tensile cyclic curve under different numbers of cycles. After multiple tensile cycles, the conductive hydrogel has excellent cyclic stability

[0105] The flexibility of the conductive hydrogel prepared in Example 2 was tested at high and low temperatures. The test results are as follows Figure 8 shown

[0106] According to Figure 8 it is known that when the mechanical properties of the conductive hydrogel were tested at -30 °C and 80 °C, it has excellent anti-freezing performance and high-temperature resistance, and has excellent mechanical properties under extreme environmental conditions

[0107] The change in water retention rate of the conductive hydrogel prepared in Example 2 during long-term storage at 25 °C and 60 °C was tested. The test results are as follows Figure 9 and Figure 10 shown

[0108] According to Figure 9 and Figure 10 it is known that "Time and Storage time" represent time, and "W t / W 0 " represents the water retention rate. The change in water retention rate during long-term storage at 25 °C is as follows Figure 9 shown, and the water retention rate is 90% (water retention rate = initial weight / weight at a certain moment). The change in water retention rate during long-term storage at 60 °C is as follows Figure 10 shown, and the water retention rate is 75%. The hydrogel has excellent water retention rate during long-term storage. This is because hydrogen bonding is formed between glycerol and water molecules, reducing the loss rate of water molecules, and having excellent structural stability during long-term storage

[0109] The sensing signal of the conductive hydrogel prepared in Example 2 was tested after being placed for 7 days. The test results are as follows Figure 11 shown

[0110] According to Figure 11 it is known that "Time" represents time, and "△R / R 0" represents the relative resistance change. Among them, the conductive hydrogel obtained in Example 2 was clamped on the fixture of an electronic tensile machine and stretched with different strains. The results showed that when the stretching and bending angle changed, a significant change in the relative resistance could be precisely observed, and after multiple cycles, the resistance of the hydrogel could recover to the original resistance.

[0111] Therefore, the preparation method provided in this application dissolves 3-aminophenylboronic acid, acrylamide, an initiator, and MXene nanosheets in water for free radical polymerization to obtain a polymer; then immerses it in glycerol to obtain the conductive organic hydrogel. It can endow the conductive hydrogel with excellent high elasticity, excellent flexibility and sensing ability in extreme environments, structural stability and signal stability during long-term storage, and has broad application prospects in the field of flexible wearable sensor technology.

[0112] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments.

[0113] The above embodiments are only used to illustrate the technical solutions of this application, rather than limiting this application; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of this application.

Claims

1. A method for preparing a conductive organic hydrogel, characterized in that: The preparation method comprises: 3-aminophenylboronic acid, acrylamide, an initiator and MXene nanosheets are dissolved in water to perform free radical polymerization to obtain a polymer; The conductive organic hydrogel is obtained by soaking the polymer in glycerol.

2. The method for preparing a conductive organic hydrogel according to claim 1, characterized in that: The concentration of the 3-aminophenylboronic acid is 0.02-0.1 mol / L.

3. The method for preparing the conductive organic hydrogel according to claim 1, characterized in that: The concentration of the acrylamide is 2-4 mol / L.

4. The method for preparing a conductive organic hydrogel according to claim 1, characterized in that: The mass fraction of the MXene nanosheets is 1-3 wt %.

5. The method for preparing the conductive organic hydrogel according to claim 1, characterized in that: The initiator is one or more of potassium persulfate, ammonium persulfate and azobisisobutylimidazoline hydrochloride.

6. The method for preparing a conductive organic hydrogel according to claim 1, characterized in that: The added amount of the initiator is 0.1-2% of the total mass of the 3-aminophenylboronic acid and acrylamide monomers.

7. The method for preparing a conductive organic hydrogel according to claim 1, characterized in that: When 3-aminophenylboronic acid, acrylamide, initiator and MXene nanosheets are dissolved in water for free radical polymerization, the temperature is 25-80° C. and the time is 3-12 hours.

8. The method for preparing a conductive organic hydrogel according to claim 1, characterized in that: When the polymer is immersed in glycerol, the immersion time is 1-6 hours.

9. A conductive organic hydrogel prepared by the preparation method according to any one of claims 1 to 8.

10. Use of a conductive organic hydrogel prepared by the preparation method according to any one of claims 1 to 8 or a conductive organic hydrogel according to claim 9 in the field of flexible wearable sensor technology.

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