High-strength and high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel, and preparation method and application thereof

Abstract

The application discloses a high-strength and high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel as well as a preparation method and application thereof. The method is to use methyl imidazole and chitosan as raw materials, acrylic acid as a crosslinking agent, N, N-methylene bisacrylamide and ammonium persulfate as initiators, and based on the principle of free radical polymerization, to prepare the high-strength and high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel by using physical crosslinking and chemical crosslinking. The prepared hydrogel has a clear three-dimensional structure, rich pore structure, thick pore wall, high specific surface area, high porosity and stable structure, can effectively improve the defects of the existing chitosan-based hydrogel, such as poor mechanical strength, weak molecular chain interaction in the gel network and poor sensing performance, and has good conductive sensing performance. The tensile strength of the hydrogel reaches 0.10-0.13 MPa, the compressive strength reaches 7.46-10.45 MJ / m 2 , the shear adhesion strength reaches 9.45-13.56 kPa, and the conductive strain sensitivity coefficient reaches 4.06-4.16.

Description

Technical Field

[0001] This invention belongs to the technical field of novel composite material synthesis methods, specifically relating to a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel, its preparation method, and its application. Background Technology

[0002] Modern smart materials, such as wearable sensors, solar converters, or feedback sensors for robots, require the development of flexible electrolytes with high tensile strength, compressibility, and ion transport properties. Compared to widely used polyvinyl alcohol electrolytes, hydrogels, with their three-dimensional networks and high water content, are more suitable for fabricating flexible electronic devices due to their higher tensile and compressibility. Hydrogel-based sensors constitute a broad family of innovative smart sensing devices applicable to many different applications. In fact, hydrogels are essentially hydrophilic, biocompatible, and highly water-swellable polymer networks capable of converting chemical energy into mechanical energy, possessing remarkable properties and the ability to respond to external stimuli. Hydrogels based on natural polymers, in particular, offer advantages such as safety, biocompatibility, and sustainability, and can easily achieve conductivity by adding electrolytes, attracting increasing interest from researchers.

[0003] Polymer-based hydrogels, made by mixing synthetic polymers or inorganic components with natural polymers, can achieve tunable mechanical properties and offer numerous advantages in conductive applications. However, these hydrogels cannot fully utilize the advantages of natural polymers, making the development of purely natural polymer-based hydrogels more attractive and an irresistible trend. However, purely natural polymer-based hydrogels typically exhibit low tensile strength (<100%) and compressive strength (<75%), significantly limiting their practical applications. Therefore, preparing hydrogels with high tensile strength, high compressive strength, and high compressive strength using natural polymers remains a significant challenge.

[0004] To address the existing technical problems of poor mechanical strength, weak molecular chain interactions in the gel network, and poor sensing performance of chitosan-based hydrogels, there is an urgent need to conduct modification research to improve their mechanical and conductive sensing properties. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel, its preparation method and application, so as to solve the problems of poor mechanical strength and poor conductive sensing performance of existing chitosan-based hydrogels.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] This invention discloses a high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel, the structural formula of which is as follows:

[0008]

[0009] Where n = 20 to 70.

[0010] Preferably, the tensile strength is 0.10–0.13 MPa, and the compressive strength is 7.46–10.45 MJ / m. 2 The shear adhesion strength reaches 9.45–13.56 kPa.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] This invention discloses a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel with a distinct three-dimensional structure, abundant pores, thick pore walls, high specific surface area, high porosity, rich imidazole ions, and stable structure. It effectively improves the shortcomings of existing chitosan-based hydrogels such as poor mechanical strength and poor sensing performance, and has better mechanical properties and conductive sensing performance.

[0013] Furthermore, this high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel exhibits a tensile strength of 0.10–0.13 MPa and a compressive strength of 7.46–10.45 MJ / m. 2 The shear adhesion strength reaches 9.45–13.56 kPa.

[0014] This invention also discloses a method for preparing the above-mentioned high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel, comprising the following steps:

[0015] 1) First, add methylimidazole to acetone; then add epichlorohydrin, stir to react, remove the solvent by rotary evaporation, and obtain imidazole ionic liquid;

[0016] 2) Dissolve chitosan in water, then add the imidazole ionic liquid obtained in step 1), adjust the pH to 4-5, and after the reaction is complete, add ethanol and filter to obtain imidazole ionic chitosan.

[0017] 3) Dissolve the imidazole ion chitosan obtained in step 2) in acetic acid solution, first add N,N-methylenebisacrylamide and ammonium persulfate and stir evenly, then add acrylic acid to continue the reaction. After ultraviolet irradiation, a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel is obtained.

[0018] Preferably, in step 1), the mass ratio of methylimidazole:acetone:epoxychloropropane is (3-4):(10-30):(5-6); wherein the mass fraction of methylimidazole is 99%, the mass fraction of acetone is 99.5%, and the mass fraction of epichlorohydrin is 99.5%.

[0019] Preferably, in step 1), the reaction conditions are: stirring at 70-90°C for 1-2 hours.

[0020] Preferably, in step 2), the mass ratio of chitosan to imidazole ionic liquid is (3-4):(10-20); the molecular weight of chitosan is 20,000-300,000.

[0021] Preferably, in step 2), the mass fraction of the dilute hydrochloric acid solution is 12% to 17%; and the mass fraction of the acetic acid solution is 3% to 5%.

[0022] Preferably, in step 3), the mass ratio of imidazole ion-chitosan: N,N-methylenebisacrylamide: ammonium persulfate: acrylic acid is (0.1-0.3):(0.02-0.06):(0.06-0.08):(2-6); wherein the mass fraction of acrylic acid is 99.5% and the mass fraction of N,N-methylenebisacrylamide is 99.8%.

[0023] Preferably, in step 3), after adding acrylic acid, the reaction continues for 10-15 minutes; and then the mixture is irradiated under ultraviolet light for 10-15 minutes.

[0024] The present invention also discloses the application of the above-mentioned high-strength and high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel in conductive sensing, with a conductive strain sensitivity coefficient of 4.06 to 4.16.

[0025] This invention also discloses a method for preparing the aforementioned high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel. Using methylimidazolium and chitosan as raw materials, imidazole ions undergo a ring-opening reaction with the amino groups in the chitosan structure via epoxy groups. Acrylic acid is used as a crosslinking agent, and N,N-methylenebisacrylamide and ammonium persulfate are used as initiators. Based on the principle of free radical polymerization, imidazole ion chitosan / acrylic hydrogels are prepared through physical and chemical crosslinking. The introduction of imidazole ions gives the hydrogel excellent conductive sensing properties. The prepared hydrogel exhibits a distinct three-dimensional structure with abundant pores, good mechanical strength, excellent sensing performance, and structural stability.

[0026] Furthermore, in step 2), the chitosan has a molecular weight of 20,000 to 300,000 and a degree of deacetylation of 80% to 95%.

[0027] The present invention also discloses the application of the above-mentioned high-strength and high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel in conductive sensing, with a conductive strain sensitivity coefficient of 4.06 to 4.16. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the synthesis of imidazole ion chitosan obtained in Example 1 of the present invention; wherein, (a) is a schematic diagram of the synthesis of imidazole ions, and (b) is a schematic diagram of the synthesis of imidazole ion chitosan.

[0029] Figure 2 This is a schematic diagram illustrating the synthesis of the high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel obtained in Example 1 of the present invention.

[0030] Figure 3 The infrared spectrum of the imidazole ion chitosan obtained in Example 1 of this invention;

[0031] Figure 4 The infrared spectrum of the high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel prepared in Example 1 of this invention. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0033] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0034] The present invention will now be described in further detail with reference to the accompanying drawings:

[0035] This invention discloses a method for preparing a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel. The method first uses methylimidazolium and chitosan as raw materials, acrylic acid as a crosslinking agent, and N,N-methylenebisacrylamide and ammonium persulfate as initiators. Based on the principle of free radical polymerization, imidazole ion chitosan / acrylic hydrogel is prepared by physical crosslinking and chemical crosslinking.

[0036] A method for preparing a high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel specifically includes the following steps:

[0037] 1) By mass, add 3.0-4.0 parts of methylimidazole to 10-30 parts of acetone and stir; slowly add 5-6 parts of epichlorohydrin dropwise, continue stirring at 70-90℃ for 1-2 hours, remove the solvent by rotary evaporation to obtain imidazole ionic liquid;

[0038] 2) By mass, add 50-70 parts of H2O to 3.0-4.0 parts of chitosan and stir at 70-90℃. Add 10-20 parts of the imidazole ionic liquid obtained in step 1), adjust the pH to 4-5 with hydrochloric acid solution, and then continue the reaction for 4-5 hours. Add 50-60 parts of ethanol and filter to obtain imidazole ionic chitosan.

[0039] 3) By mass, add 0.1 to 0.3 parts of the imidazole ion chitosan obtained in step 2) to 15 to 25 parts of acetic acid solution, stir and clarify, then add 0.02 to 0.06 parts of N,N-methylenebisacrylamide and 0.06 to 0.08 parts of ammonium persulfate and stir evenly. Slowly add 2 to 6 parts of acrylic acid and continue stirring for 10 to 15 minutes. Irradiate under ultraviolet light for 10 to 15 minutes to obtain a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel.

[0040] The composition of the methylimidazole is 99%, the composition of acetone is 99.5%, and the composition of epichlorohydrin is 99.5%.

[0041] Chitosan has a molecular weight of 20,000 to 300,000 and a degree of deacetylation of 80% to 95%.

[0042] The mass ratio of methylimidazole to epichlorohydrin is (3-4):(5-6).

[0043] The mass fraction of the dilute hydrochloric acid solution is 12%–17%.

[0044] The acetic acid solution has a mass fraction of 3% to 5%.

[0045] The mass ratio of imidazole ion-chitosan to acrylic acid is (0.1-0.3):(2-6).

[0046] The mass fraction of acrylic acid is 99.5%, and the mass fraction of N,N-methylenebisacrylamide is 99.8%.

[0047] Example 1

[0048] A method for preparing a high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel includes the following steps:

[0049] 1) By mass, 3.0 parts of methylimidazole were added to 10 parts of acetone and stirred; 5 parts of epichlorohydrin were slowly added dropwise, and stirring was continued at 70°C for 1 hour. The solvent was removed by rotary evaporation to obtain an imidazole ionic liquid.

[0050] 2) By mass, add 50 parts of H2O to 3.0 parts of chitosan and stir at 70°C. Add 10 parts of the imidazole ionic liquid obtained in step 1), adjust the pH to 4 with 15% hydrochloric acid solution, and continue the reaction for 4 hours. Add 50 parts of ethanol and filter to obtain imidazole ionic chitosan.

[0051] 3) By mass, add 0.1 parts of the imidazole ion chitosan obtained in step 2) to 15 parts of 3% acetic acid solution, stir and clarify, then add 0.02 parts of N,N-methylenebisacrylamide and 0.06 parts of ammonium persulfate to continue the reaction, slowly add 2 parts of acrylic acid and continue stirring for 10 min, then irradiate under ultraviolet light for 10 min to obtain a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel.

[0052] A high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel prepared according to the above method exhibits significant performance and characteristics in conductive sensing. When used in an electrochemical workstation, the imidazole ion-chitosan / acrylic hydrogel showed a conductivity strain sensitivity coefficient (GF) of 4.06. Mechanical properties of the imidazole ion-chitosan / acrylic hydrogel were tested using a universal testing machine, yielding a tensile strength of 0.11 MPa and a compressive strength of 8.56 MJ / m. 2 Shear adhesion strength: 11.38 kPa.

[0053] See Figure 1 This is a schematic diagram of the synthesis of imidazole ion chitosan obtained in Example 1 of the present invention; wherein, (a) is a schematic diagram of the synthesis of imidazole ions, and (b) is a schematic diagram of the synthesis of imidazole ion chitosan; as can be seen from the figure, imidazole ions are used to prepare novel imidazole ion chitosan by ring-opening reaction between the epoxy group and the amino group in the chitosan structure, and imidazole ion groups are successfully introduced into the imidazole ion chitosan structure.

[0054] See Figure 2This is a schematic diagram of the synthesis of the high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel obtained in Example 1 of the present invention. As can be seen from the figure, imidazole ion chitosan, acrylic acid, and N,N-methylenebisacrylamide were polymerized and crosslinked under the action of ammonium persulfate to prepare the imidazole ion chitosan / acrylic hydrogel. The introduction of imidazole ions gives the hydrogel excellent conductive sensing properties.

[0055] See Figure 3 The image shows the infrared spectrum of imidazole ion-chitosan obtained in Example 1 of this invention; as can be seen from the image, chitosan exhibits high activity at 3697 cm⁻¹. -1 The position belongs to the stretching vibration of the hydroxyl and amino groups, at 1577 cm⁻¹. -1 The peak belongs to the CN stretching vibration; the peak of imidazole ion chitosan is at 1656 cm⁻¹. -1 and 1577cm -1 The peaks belong to the C=N double bond and CN stretching vibrations, indicating that imidazole ions were successfully introduced into chitosan and chitosan with imidazole ions was successfully prepared.

[0056] See Figure 4 The image shows the infrared spectrum of the high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel prepared in Example 1 of this invention; as can be seen from the image, the imidazole ion-chitosan / acrylic hydrogel exhibits high strength at 1586 cm⁻¹. -1 The CN stretching vibration peak, 2924 cm⁻¹, belongs to the imidazole ion chitosan structure. -1 The peak at 1241 cm⁻¹ belongs to the skeletal peak of polymeric acrylic acid. -1 The peak at the specified location belongs to the carboxyl bending vibration peak of polymeric acrylic acid. Combined with the mechanical properties of the high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel, it indicates that the hydroxyl groups in the imidazole ion chitosan in this hydrogel structure form a hydrogen bond cross-linking network with the carboxyl groups of polymeric acrylic acid. This demonstrates that the high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel has been successfully prepared.

[0057] Example 2

[0058] A method for preparing a high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel includes the following steps:

[0059] 1) By mass, 3.2 parts of methylimidazole were added to 20 parts of acetone and stirred; 5.5 parts of epichlorohydrin were slowly added dropwise, and the mixture was stirred at 80°C for 2 hours. The solvent was removed by rotary evaporation to obtain an imidazole ionic liquid.

[0060] 2) By mass, add 60 parts of H2O to 3.2 parts of chitosan and stir at 80°C. Add 15 parts of the imidazole ionic liquid obtained in step 1), adjust the pH to 5 with 17% hydrochloric acid solution, and continue the reaction for 5 hours. Add 60 parts of ethanol and filter to obtain imidazole ionic chitosan.

[0061] 3) By mass, add 0.2 parts of the imidazole ion chitosan obtained in step 2) to 20 parts of 5% acetic acid solution, stir and clarify, then add 0.04 parts of N,N-methylenebisacrylamide and 0.08 parts of ammonium persulfate to continue the reaction, slowly add 3 parts of acrylic acid and continue stirring for 15 min, then irradiate under ultraviolet light for 15 min to obtain a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel.

[0062] A high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel prepared according to the above method exhibits significant application performance and characteristics, particularly its conductive sensing capability. When used in an electrochemical workstation, the imidazole ion-chitosan / acrylic hydrogel showed a conductivity strain sensitivity coefficient (GF) of 4.16. Mechanical properties of the imidazole ion-chitosan / acrylic hydrogel were tested using a universal testing machine, yielding a tensile strength of 0.12 MPa and a compressive strength of 7.46 MJ / m. 2 Shear adhesion strength: 12.53 kPa.

[0063] Example 3

[0064] A method for preparing a high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel includes the following steps:

[0065] 1) By mass, 3.4 parts of methylimidazole were added to 20 parts of acetone and stirred; 5.5 parts of epichlorohydrin were slowly added dropwise, and stirring was continued at 80°C for 1.2 h. The solvent was removed by rotary evaporation to obtain an imidazole ionic liquid.

[0066] 2) By mass, add 60 parts of H2O to 3.4 parts of chitosan and stir at 80°C. Add 15 parts of the imidazole ionic liquid obtained in step 1), adjust the pH to 4 with 15.5% hydrochloric acid solution, and continue the reaction for 4.2 hours. Add 52 parts of ethanol and filter to obtain imidazole ionic chitosan.

[0067] 3) By mass, add 0.2 parts of the imidazole ion chitosan obtained in step 2) to 20 parts of 3.5% acetic acid solution, stir and clarify, then add 0.04 parts of N,N-methylenebisacrylamide and 0.065 parts of ammonium persulfate to continue the reaction, slowly add 4 parts of acrylic acid and continue stirring for 11 min, then irradiate under ultraviolet light for 11 min to obtain a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel.

[0068] A high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel prepared according to the above method exhibits significant performance and characteristics in conductive sensing. When used in an electrochemical workstation, the imidazole ion-chitosan / acrylic hydrogel showed a conductivity strain sensitivity coefficient (GF) of 4.08. Mechanical properties of the high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel were tested using a universal testing machine, yielding a tensile strength of 0.10 MPa and a compressive strength of 9.23 MJ / m. 2 Shear adhesion strength: 9.45 kPa.

[0069] Example 4

[0070] A method for preparing a high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel includes the following steps:

[0071] 1) By mass, 3.6 parts of methylimidazole were added to 20 parts of acetone and stirred; 5.5 parts of epichlorohydrin were slowly added dropwise, and stirring was continued at 80°C for 1.4 h. The solvent was removed by rotary evaporation to obtain an imidazole ionic liquid.

[0072] 2) By mass, add 60 parts of H2O to 3.6 parts of chitosan and stir at 80°C. Add 15 parts of the imidazole ionic liquid obtained in step 1), adjust the pH to 4 with 16% hydrochloric acid solution, and continue the reaction for 4.5 h. Add 55 parts of ethanol and filter to obtain imidazole ionic chitosan.

[0073] 3) By mass, add 0.2 parts of the imidazole ion chitosan obtained in step 2) to 20 parts of 4% acetic acid solution, stir and clarify, then add 0.04 parts of N,N-methylenebisacrylamide and 0.07 parts of ammonium persulfate to continue the reaction, slowly add 5 parts of acrylic acid and continue stirring for 13 min, then irradiate under ultraviolet light for 13 min to obtain a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel.

[0074] A high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel prepared according to the above method exhibits significant application performance and characteristics, particularly its conductive sensing capability. When used in an electrochemical workstation, the imidazole ion-chitosan / acrylic hydrogel showed a conductivity strain sensitivity coefficient (GF) of 4.10. Mechanical properties of the imidazole ion-chitosan / acrylic hydrogel were tested using a universal testing machine, yielding a tensile strength of 0.11 MPa and a compressive strength of 8.47 MJ / m. 2 Shear adhesion strength: 10.42 kPa.

[0075] Example 5

[0076] A method for preparing a high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel includes the following steps:

[0077] 1) By mass, 4.0 parts of methylimidazole were added to 30 parts of acetone and stirred; 6 parts of epichlorohydrin were slowly added dropwise, and stirring was continued at 90°C for 1.8 h. The solvent was removed by rotary evaporation to obtain an imidazole ionic liquid.

[0078] 2) By mass, add 70 parts of H2O to 4.0 parts of chitosan and stir at 90°C. Add 20 parts of the imidazole ionic liquid obtained in step 1), adjust the pH to 5 with 16.5% hydrochloric acid solution, and continue the reaction for 4.8 h. Add 58 parts of ethanol and filter to obtain imidazole ionic chitosan.

[0079] 3) By mass, add 0.3 parts of the imidazole ion chitosan obtained in step 2) to 25 parts of 4.5% acetic acid solution, stir and clarify, then add 0.06 parts of N,N-methylenebisacrylamide and 0.075 parts of ammonium persulfate to continue the reaction, slowly add 6 parts of acrylic acid and continue stirring for 14 min, then irradiate under ultraviolet light for 14 min to obtain a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel.

[0080] A high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel prepared according to the above method exhibits significant application performance and characteristics, particularly its conductive sensing capability. When used in an electrochemical workstation, the imidazole ion-chitosan / acrylic hydrogel showed a conductivity strain sensitivity coefficient (GF) of 4.12. Mechanical properties of the high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel were tested using a universal testing machine, yielding a tensile strength of 0.13 MPa and a compressive strength of 10.45 MJ / m. 2 Shear adhesion strength: 13.56 kPa.

[0081] Comparison Example

[0082] A method for preparing chitosan hydrogel includes the following steps:

[0083] By mass, 0.1 parts of chitosan were added to 15 parts of 3% acetic acid solution. After stirring and clarifying, 0.04 parts of N,N-methylenebisacrylamide and 0.08 parts of ammonium persulfate were added to continue the reaction. 2 parts of acrylic acid were slowly added dropwise and stirring was continued for 15 minutes. The mixture was then irradiated under ultraviolet light for 15 minutes to obtain chitosan hydrogel.

[0084] The chitosan hydrogel prepared according to the above method exhibits significant application performance and characteristics, particularly its conductive sensing capability. When used in an electrochemical workstation, the chitosan hydrogel showed a conductivity strain sensitivity coefficient (GF) of 0.60. Mechanical properties of the imidazole ion-chitosan / acrylic hydrogel were tested using a universal testing machine, yielding a tensile strength of 0.05 MPa and a compressive strength of 3.46 MJ / m.2 The shear adhesion strength was 5.58 kPa. The results of the hydrogel conductivity strain sensitivity coefficient (GF) are compared in Table 1.

[0085] Table 1. Comparison of conductivity strain sensitivity coefficient (GF) of high-strength, high-sensitivity conductive imidazole ion-modified chitosan / acrylic hydrogels prepared in Examples 1-5 and chitosan hydrogels prepared in the comparative examples.

[0086] Example number GF Example 1 4.06 Example 2 4.16 Example 3 4.08 Example 4 4.10 Example 5 4.12 Comparison Example 0.60

[0087] Table 1 compares the conductivity strain sensitivity coefficient (GF) of the high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogels prepared in Examples 1-5 and the chitosan hydrogels prepared in the comparative examples. As can be seen from the table, the high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogels prepared in this invention have far superior conductivity sensing performance compared to the control examples, and therefore have excellent conductivity sensing performance.

[0088] Table 2. Mechanical properties of imidazole ion-chitosan / acrylic hydrogels

[0089]

[0090]

[0091] Table 2 shows the mechanical properties of the high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel. As can be seen from the table, the high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic hydrogel has excellent tensile properties, compressive strength, and adhesion properties, which are far superior to the control example. Therefore, it has better mechanical properties.

[0092] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel, characterized in that, Includes the following steps: 1) First, add methylimidazolium to acetone; then add epichlorohydrin, stir the reaction, remove the solvent by rotary evaporation, and obtain imidazolium ionic liquid; the reaction conditions are: stirring at 70~90 ℃ for 1~2 h. 2) Dissolve chitosan in water, then add the imidazole ionic liquid obtained in step 1), adjust the pH to 4-5, and after the reaction is complete, add ethanol and filter to obtain imidazole ionic chitosan. 3) Dissolve the imidazole ion chitosan obtained in step 2) in acetic acid solution, first add N,N-methylenebisacrylamide and ammonium persulfate and stir evenly, then add acrylic acid and continue the reaction for 10-15 min. After irradiation with ultraviolet light for 10-15 min, a high-strength, high-sensitivity conductive imidazole ion chitosan / acrylic acid hydrogel is obtained. The high-strength, high-sensitivity conductive imidazole ion-exchange chitosan / acrylic hydrogel exhibits a tensile strength of 0.10~0.13 MPa and a compressive strength of 7.46~10.45 MJ / m. 2 The shear adhesion strength reaches 9.45~13.56 kPa; The conductivity strain sensitivity coefficient reaches 4.06~4.

16.

2. The method for preparing the high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel according to claim 1, characterized in that, In step 1), the mass ratio of methylimidazole: acetone: epichlorohydrin is (3~4):(10~30):(5~6); wherein the mass fraction of methylimidazole is 99%, the mass fraction of acetone is 99.5%, and the mass fraction of epichlorohydrin is 99.5%.

3. The method for preparing the high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel according to claim 1, characterized in that, In step 2), the mass ratio of chitosan to imidazole ionic liquid is (3~4):(10~20); the molecular weight of chitosan is 20,000~300,000.

4. The method for preparing imidazole ion-chitosan / acrylic hydrogel according to claim 1, characterized in that, In step 2), the pH value is adjusted using a dilute hydrochloric acid solution with a mass fraction of 12% to 17%; in step 3), the mass fraction of the acetic acid solution is 3% to 5%.

5. The method for preparing the high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel according to claim 1, characterized in that, In step 3), the mass ratio of imidazole ion chitosan: N,N-methylenebisacrylamide: ammonium persulfate: acrylic acid is (0.1~0.3):(0.02~0.06):(0.06~0.08):(2~6); wherein the mass fraction of acrylic acid is 99.5% and the mass fraction of N,N-methylenebisacrylamide is 99.8%.

6. The application of the high-strength, high-sensitivity conductive imidazole ion-chitosan / acrylic hydrogel prepared by the method according to any one of claims 1 to 5 in conductive sensing, characterized in that, The conductivity strain sensitivity coefficient reaches 4.06~4.16.

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