Guar glue hydrogel flexible conductive sensor and preparation method and application thereof

Abstract

The invention belongs to the technical field of flexible sensors, and particularly discloses a guar gum hydrogel flexible conductive sensor and a preparation method and application thereof, and the guar gum hydrogel flexible conductive sensor comprises the following raw materials: 3-6 parts of guar gum, 10-15 parts of polyvinyl alcohol, 5-10 parts of skirt kelp powder, 0.1-1 part of disodium succinate, and 100 parts of water. The guar gum hydrogel flexible conductive sensor has the mechanical properties of high stress, high strain, high elasticity and the like; the cable can bear 65Kg of weight without being snapped, has very strong freezing resistance and drying resistance, and can be normally used in an extremely low temperature environment; the compound has the advantages of compatibility with normal cells of a human body, resistance to cancer cells, simple preparation method and the like.

Description

Technical Field

[0001] The invention relates to the technical field of flexible sensors, and in particular to a guar gum hydrogel flexible conductive sensor and a preparation method and application thereof. Background Art

[0002] Hydrogel flexible conductive sensors are new flexible sensors developed in recent years, which can convert Morse code, deformation, movement, sound vibration, heart and pulse beats into electrical signals. Therefore, they show great application prospects in the fields of strain sensors, wearable devices, flexible supercapacitors, brakes, soft robots, biomedicine, etc. However, it is difficult for existing hydrogel flexible conductive sensors to maintain strong mechanical properties (high stress, high stress, high elasticity) while also being resistant to freezing, drying, anti-cancer and cell compatibility, which seriously limits the application scope of flexible sensors.

[0003] Guar gum is made by grinding the endosperm of the legume plant guar bean. It is a macromolecular natural hydrophilic colloid, mainly composed of galactose and mannose. Guar gum is a raw material for constructing green hydrogels, but pure guar gum aqueous solution cannot form a hydrogel regardless of freezing or heating treatment. It can only be obtained under alkaline conditions and in the presence of chemical crosslinking agents (such as diethylene glycol diglycidyl ether), through chemical reaction crosslinking and complex subsequent de-alkalinization of substances and crosslinking agent residues to obtain a gel product.

[0004] Therefore, it is very necessary to provide a guar gum hydrogel flexible conductive sensor with simple process, short preparation time and significant enhancement of its mechanical properties and freeze-resistance and drying resistance. Summary of the invention

[0005] In view of the above-mentioned shortcomings that currently exist, the present invention provides a guar gum hydrogel flexible conductive sensor and a preparation method and application thereof. The guar gum hydrogel flexible conductive sensor of the present invention has mechanical properties such as high stress, high strain, and high elasticity; can bear a load of 65 kg without being broken, and has strong freezing and drying resistance, and can be used normally in an extremely low temperature environment; has compatibility with normal human cells, resistance to cancer cells, and has the advantages of a simple preparation method, etc.

[0006] In order to achieve the above-mentioned purpose, in a first aspect, the present invention provides a guar gum hydrogel flexible conductive sensor. The raw materials of the guar gum hydrogel flexible conductive sensor are as follows, calculated by weight: 3 to 6 parts of guar gum, 10 to 15 parts of polyvinyl alcohol, 5 to 10 parts of kelp powder, 0.1 to 1 part of disodium succinate, and 100 parts of water.

[0007] According to one aspect of the present invention, the weight average molecular weight of the polyvinyl alcohol is 90,000 to 110,000, and the alcoholysis degree is 99%.

[0008] In a second aspect, the present invention provides a method for preparing the above-mentioned guar gum hydrogel flexible conductive sensor, comprising the following steps:

[0009] S1. Mix 3-6 parts of guar gum, 10-15 parts of polyvinyl alcohol, 5-10 parts of kelp powder, 0.1-1 part of disodium succinate and 100 parts of water, disperse and mix them evenly, and stir them at 90-100° C. for 1-4 hours to obtain a mixed solution;

[0010] S2. Pour the mixed solution into a mold and place it at room temperature for 8 to 50 hours to obtain a finished flexible sensor.

[0011] According to one aspect of the present invention, the preparation method of the kelp powder is:

[0012] T1. According to the mass fraction, put 1 part of washed kelp and 0.5 parts of water into a wall breaking machine, start the wall breaking machine 10 to 15 times, each time for 3 to 5 minutes, to obtain kelp slurry;

[0013] T2. Filter the Laminaria japonica slurry through fine gauze to collect the filtrate; then let the collected filtrate stand for precipitation to obtain wet Laminaria japonica powder; freeze-dry the wet Laminaria japonica powder to obtain dry Laminaria japonica powder.

[0014] According to one aspect of the present invention, in step S1, the stirring speed is 1000-1800 r / min.

[0015] According to one aspect of the present invention, in step S2, the mold is any one of a standard dumbbell-shaped mold and a plastic tube mold.

[0016] According to one aspect of the present invention, the inner diameter of the plastic tube mold is 1.5 to 2 cm and the length is 4 to 5 cm.

[0017] In a third aspect, the present invention also provides an application of the guar gum hydrogel flexible conductive sensor in a flexible conductive sensor.

[0018] In a fourth aspect, the present invention also provides application of the above-mentioned guar gum hydrogel flexible conductive sensor in conductive materials.

[0019] In a fifth aspect, the present invention also provides the application of the above-mentioned guar gum hydrogel flexible conductive sensor in smart screen touch screen materials.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) Compared with the existing pure guar gum aqueous solution, which needs to be cross-linked by chemical reaction and complicated subsequent de-alkaline substances and cross-linking agent residues under alkaline conditions and in the presence of chemical cross-linking agents (such as diethylene glycol diglycidyl ether) to obtain a gel product, the present invention uses the hydroxyl groups on the polyvinyl alcohol molecular chain and the carboxyl groups on the disodium succinate molecular structure to form hydrogen bonds with the hydroxyl groups on the guar gum molecular chain, accelerates the formation of guar gum hydrogel, shortens the preparation time, simplifies the preparation process, and significantly strengthens its mechanical properties (high stress, high strain, high elasticity). At the same time, the super interaction between guar gum, polyvinyl alcohol, disodium succinate, kelp, and water molecules is used to reduce the freezing point of the hydrogel, inhibit the evaporation of water in the hydrogel, thereby significantly improving the freezing resistance and drying resistance of the guar gum-based hydrogel.

[0022] (2) The flexible conductive sensor of the present invention can carry a weight of 65 kg without being broken. A hole is punched on the film-shaped flexible conductive sensor or an incision is made on the side of the film. The flexible conductive sensor is not damaged under 300% strain stretching and has strong mechanical properties. At the same time, the flexible conductive sensor of the present invention still has good elasticity and conductivity in an environment of minus 120°C, has strong freeze resistance, and can be used in low temperature and severe cold environments. Moreover, the flexible conductive sensor of the present invention still has good elasticity, toughness, and conductivity after being placed at room temperature for 6 months. It can be used for a long time in an open environment, has a longer service life, and has strong dryness resistance. In addition, the flexible conductive sensor of the present invention also has good cancer cell killing ability and good cell compatibility.

[0023] (3) The flexible conductive sensor of the present invention realizes the effective integration of multiple advantages such as simplified preparation process, green, strong mechanical properties (high stress, high strain, high elasticity), strong freezing resistance, strong drying resistance, cancer cell killing ability, and cell compatibility, overcoming the defects of traditional flexible sensors with good single performance and poor other performance. The flexible conductive sensor of the present invention can be used for wearable flexible materials, conductive materials, smart screen touch screen materials, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flexibility test graph of the flexible sensor prepared in Example 1 of the present invention after being frozen at -80°C for 8 hours;

[0025] Figure 2 This is a test graph of the conductivity of the flexible sensor prepared in Example 1 of the present invention after being frozen at -80°C for 8 hours. DETAILED DESCRIPTION

[0026] To make the present invention easier to understand, the present invention is further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by professional and technical personnel in the field; unless otherwise specified, the raw materials and reagents involved in this article can be purchased from the market or prepared by known methods.

[0027] Example 1

[0028] A method for preparing a guar gum hydrogel (guar gum / kelp powder / polyvinyl alcohol / disodium succinate water-resistant type) flexible conductive sensor comprises the following steps:

[0029] (1) According to the weight percentage (based on the weight of water), the concentration of guar gum is 3%, the concentration of polyvinyl alcohol is 15%, the concentration of kelp powder is 10%, and the concentration of disodium succinate is 1%. Weigh 1.5 g of guar gum, 7.5 g of polyvinyl alcohol, 5 g of kelp powder, and 0.5 g of disodium succinate, add 50 g of deionized water, and stir at 90° C. (speed of 1500 r / min) for 4 h to obtain a guar gum / kelp powder / polyvinyl alcohol / disodium succinate mixed solution for later use;

[0030] (2) pouring the guar gum / kelp powder / polyvinyl alcohol / disodium succinate mixed solution prepared in step (1) into a standard dumbbell-shaped mold at room temperature;

[0031] (3) placing the mold containing the mixed solution in step (2) at room temperature for 48 hours to obtain a finished flexible sensor.

[0032] The results show that the stress of the finished flexible sensor obtained in this embodiment is 14 MPa, the strain is 600%, the Young's modulus is 0.3 MPa, and the toughness is 7 MJ m -3 . Please refer to Table 1 for details.

[0033] Example 2

[0034] A method for preparing a guar gum hydrogel (guar gum / kelp powder / polyvinyl alcohol / disodium succinate water-resistant type) flexible conductive sensor comprises the following steps:

[0035] (1) According to the weight percentage (based on the weight of water), the concentration of guar gum is 4%, the concentration of polyvinyl alcohol is 10%, the concentration of kelp powder is 10%, and the concentration of disodium succinate is 1%. Weigh 2g of guar gum, 5g of polyvinyl alcohol, 5g of kelp powder, and 0.5g of disodium succinate, add 50g of deionized water, and stir at 90°C (speed of 1500r / min) for 4h to obtain a guar gum / kelp powder / polyvinyl alcohol / disodium succinate mixed solution for later use;

[0036] (2) pouring the guar gum / kelp powder / polyvinyl alcohol / disodium succinate mixed solution prepared in step (1) into a standard dumbbell-shaped mold at room temperature;

[0037] (3) placing the mold containing the mixed solution in step (2) at room temperature for 24 hours to obtain a finished flexible sensor.

[0038] The results show that the stress of the finished flexible sensor obtained in this embodiment is 12 MPa, the strain is 550%, the Young's modulus is 0.4 MPa, and the toughness is 6 MJ m -3 . Please refer to Table 1 for details.

[0039] Example 3

[0040] A method for preparing a guar gum hydrogel (guar gum / kelp powder / polyvinyl alcohol / disodium succinate water-resistant type) flexible conductive sensor comprises the following steps:

[0041] (1) According to the weight percentage (based on the weight of water), the concentration of guar gum is 3%, the concentration of polyvinyl alcohol is 15%, the concentration of kelp powder is 10%, and the concentration of disodium succinate is 0.8%. Weigh 1.5 g of guar gum, 7.5 g of polyvinyl alcohol, 5 g of kelp powder, and 0.4 g of disodium succinate, add 50 g of deionized water, and stir at 90° C. (speed of 1500 r / min) for 4 h to obtain a guar gum / kelp powder / polyvinyl alcohol / disodium succinate mixed solution for later use;

[0042] (2) pouring the guar gum / kelp powder / polyvinyl alcohol / disodium succinate mixed solution prepared in step (1) into a standard dumbbell-shaped mold at room temperature;

[0043] (3) placing the mold containing the mixed solution in step (2) at room temperature for 24 hours to obtain a finished flexible sensor.

[0044] The results show that the stress of the finished flexible sensor obtained in this embodiment is 13 MPa, the strain is 610%, the Young's modulus is 0.5 MPa, and the toughness is 6 MJ m -3 . Please refer to Table 1 for details.

[0045] Example 4

[0046] A method for preparing a guar gum hydrogel (guar gum / kelp powder / polyvinyl alcohol / disodium succinate water-resistant type) flexible conductive sensor comprises the following steps:

[0047] (1) According to the weight percentage (based on the weight of water), the concentration of guar gum is 3%, the concentration of polyvinyl alcohol is 15%, the concentration of kelp powder is 10%, and the concentration of disodium succinate is 1%. Weigh 1.5 g of guar gum, 7.55 g of polyvinyl alcohol, 5 g of kelp powder, and 0.5 g of disodium succinate, add 50 g of deionized water, and stir at 90° C. (speed of 1500 r / min) for 4 h to obtain a guar gum / kelp powder / polyvinyl alcohol / disodium succinate mixed solution for later use;

[0048] (2) at room temperature, pour the guar gum / kelp powder / polyvinyl alcohol / disodium succinate mixed solution prepared in step (1) into a plastic tube mold with a diameter of 2 cm and a length of 4 cm;

[0049] (3) placing the mold containing the mixed solution in step (2) at room temperature for 48 hours to obtain a finished flexible sensor.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 1 is that polyvinyl alcohol is replaced by polyacrylamide, and the other steps and parameters are the same as those in Example 1.

[0052] The results show that the stress of the finished flexible sensor obtained in this embodiment is 0.002 MPa, the strain is 260%, the Young's modulus is 0.2 MPa, and the toughness is 1 MJ m -3 . Please refer to Table 1 for details.

[0053] Comparative Example 2

[0054] The difference between this comparative example and Example 3 is that the kelp powder is replaced with DMSO, and the other steps and parameters are the same as those in Example 3.

[0055] The results show that the stress of the finished flexible sensor obtained in this embodiment is 0.0011 MPa, the strain is 140%, the Young's modulus is 0.35 MPa, and the toughness is 1.5 MJ m -3 . Please refer to Table 1 for details.

[0056] Comparative Example 3

[0057] The difference between this comparative example and Example 4 is that disodium succinate is replaced by sodium glycinate, and the other steps and parameters are the same as those of Example 4.

[0058] Performance testing and result analysis

[0059] The stress, strain, Young's modulus and toughness properties of the finished flexible sensors prepared in Examples 1 to 3 of the present application and Comparative Examples 1 to 2 are shown in Table 1 below.

[0060] Table 1:

[0061] Stress / MPa strain / % Young's modulus / MPa <![CDATA[Toughness / MJm -3 > Example 1 14 600 0.3 7 Example 2 12 550 0.4 6 Example 3 13 610 0.5 6 Comparative Example 1 0.002 260 0.2 1 Comparative Example 2 0.0011 140 0.35 1.5

[0062] (1) Freeze resistance test

[0063] The flexible sensor prepared in Example 1 of the present invention was subjected to a freeze resistance test, specifically: the flexible sensor was placed in a freezer at -80 degrees Celsius for 8 hours. Figure 1 As shown. Figure 1 It can be seen that the flexible sensor prepared in Example 1 of the present application has good flexibility and is not frozen solid after being frozen at -80°C for 8 hours. When the above-frozen flexible sensor is connected to a circuit at -80°C, the LED bulb still maintains a high brightness. Figure 2 As shown. Figure 2 It can be seen that the flexible sensor prepared in Example 1 of the present application has a strong freeze resistance and can be used normally in an extremely low temperature environment.

[0064] (2) Strong mechanical properties (high stress, high strain, high elasticity) capability test

[0065] The flexible sensor prepared in Example 4 of the present invention was used to perform a mechanical property test: the flexible sensor can bear a weight of 65 kg without being broken. This proves that the flexible sensor has strong mechanical properties (high stress, high stress, high elasticity). The flexible sensors in Comparative Examples 1-3 cannot bear a weight of 65 kg.

[0066] (3) Drying resistance test

[0067] The flexible sensor prepared in Example 2 of the present invention was tested for its drying resistance: after being placed in an open environment for 3 months, the flexible sensor had good flexibility and was not dried into a solid. Moreover, after the flexible sensor was placed in an open environment for 3 months, it was connected to a circuit and the LED bulb still maintained a high brightness. This proves that the flexible sensor has a strong drying resistance and can be used for a long time in an open environment.

[0068] (4) Anti-cancer ability test

[0069] The flexible sensor prepared in Example 3 of the present invention was tested for its cancer cell killing ability: the MTT cytotoxicity test was used to analyze the effect of the flexible sensor on human liver cancer HepG2 cells. The survival rate of cancer cells after 24 hours was only 74%, indicating that the flexible sensor had a strong cancer cell killing ability.

[0070] (5) Cytocompatibility test

[0071] The flexible sensor prepared in Example 1 of the present invention was subjected to a cell compatibility test: the MTT cytotoxicity test was used to analyze the effect of the flexible sensor on human renal epithelial 293T cells. The cell survival rate after 24 hours was as high as 98%, indicating strong cell compatibility.

[0072] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A guar gum hydrogel flexible conductive sensor, characterized in that: The raw materials of the guar gum hydrogel flexible conductive sensor are as follows, measured by weight: 3-6 parts of guar gum, 10-15 parts of polyvinyl alcohol, 5-10 parts of kelp powder, 0.1-1 part of disodium succinate, and 100 parts of water.

2. The guar gum hydrogel flexible conductive sensor according to claim 1, characterized in that: The weight average molecular weight of the polyvinyl alcohol is 90,000-110,000, and the alcoholysis degree is 99%.

3. The method for preparing the guar gum hydrogel flexible conductive sensor according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1. Mix 3-6 parts of guar gum, 10-15 parts of polyvinyl alcohol, 5-10 parts of kelp powder, 0.1-1 part of disodium succinate and 100 parts of water, disperse and mix them evenly, and stir them at 90-100° C. for 1-4 hours to obtain a mixed solution; S2. Pour the mixed solution into a mold and place it at room temperature for 8 to 50 hours to obtain a finished flexible sensor.

4. The method for preparing the guar gum hydrogel flexible conductive sensor according to claim 3, characterized in that: The preparation method of the kelp powder is as follows: T1. According to the mass fraction, put 1 part of washed kelp and 0.5 parts of water into a wall breaking machine, start the wall breaking machine 10 to 15 times, each time for 3 to 5 minutes, to obtain kelp slurry; T2. Filter the Laminaria japonica slurry through fine gauze to collect the filtrate; then let the collected filtrate stand for precipitation to obtain wet Laminaria japonica powder; freeze-dry the wet Laminaria japonica powder to obtain dry Laminaria japonica powder.

5. The method for preparing the guar gum hydrogel flexible conductive sensor according to claim 3, characterized in that: In step S1, the stirring speed is 1000-1800 r / min.

6. The method for preparing the guar gum hydrogel flexible conductive sensor according to claim 3, characterized in that: In step S2, the mold is any one of a standard dumbbell-shaped mold and a plastic tube mold.

7. The method for preparing the guar gum hydrogel flexible conductive sensor according to claim 6, characterized in that: The inner diameter of the plastic tube mold is 1.5 to 2 cm, and the length is 4 to 5 cm.

8. Use of the guar gum hydrogel flexible conductive sensor according to any one of claims 1 to 2 or the guar gum hydrogel flexible conductive sensor prepared by the preparation method according to any one of claims 3 to 7 in wearable flexible materials.

9. Use of the guar gum hydrogel flexible conductive sensor according to any one of claims 1 to 2 or the guar gum hydrogel flexible conductive sensor prepared by the preparation method according to any one of claims 3 to 7 in conductive materials.

10. Use of the guar gum hydrogel flexible conductive sensor according to any one of claims 1 to 2 or the guar gum hydrogel flexible conductive sensor prepared by the preparation method according to any one of claims 3 to 7 in smart screen touch screen materials.

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