Preparation method of anti-rust and anti-freezing flexible conductive composite gel

Abstract

The invention belongs to the technical field of flexible conductive materials, and discloses a preparation method of anti-rust and anti-freezing flexible conductive composite gel, which comprises the following steps: S1, dissolving choline chloride in glycerol to prepare a choline chloride glycerol solution; s2, sodium salt and ammonium salt are added into the choline chloride glycerin solution, and a mixed solution is prepared; s3, adding a carbon nanotube into the mixed solution prepared in S2; and S4, placing the solution prepared in the step S3 in a constant-temperature box at 70-95 DEG C, standing for 15-35 hours, taking out, and recovering to room temperature. The preparation process is simple and convenient, the network reversibility is good, the response speed is high, the biocompatibility is good, the conductivity is excellent, and the moisturizing freezing resistance and the corrosion resistance are excellent.

Description

Technical Field

[0001] The invention belongs to the technical field of flexible conductive materials, and in particular relates to a method for preparing a rust-proof and frost-resistant flexible conductive composite gel. Background Art

[0002] Conductive gels, as cutting-edge soft matter materials, possess interdisciplinary applications due to their unique multiscale composite structure. Conductive gels utilize a three-dimensional cross-linked hydrophilic polymer network as their backbone, incorporating active media such as ionic liquids, conductive nanoparticles, or conductive polymers to create composite systems that combine mechanical flexibility with charge transport properties. This three-dimensional network structure not only imparts excellent deformation recovery and environmental adaptability, but also allows for precise control of mechanical strength, conductivity, and interfacial properties by adjusting the component ratios.

[0003] Conductive gels can simulate the characteristics of biological tissues in the fields of flexible sensing and wearable electronic skin, and show good biocompatibility in tissue engineering scaffolds and bioelectric signal monitoring. At the same time, they show unique interface advantages in flexible energy storage devices and intelligent response systems, becoming one of the core research directions of the new generation of smart materials. Therefore, the functional expansion and engineering application of conductive gels are also accelerating. By introducing dynamic bonding networks or biomimetic adhesion groups, the material can achieve multifunctional integration such as self-repair, antifreeze and underwater adhesion, significantly improving the service stability under complex working conditions. For example, hydrogel electrodes modified with dopamine derivatives can still maintain stable interfacial impedance in humid environments, providing reliable protection for long-term monitoring of wearable devices. In addition, gradient structure hydrogels prepared by combining microfluidic technology can achieve precise control of ion transmission paths, and show excellent performance of fast response and large deformation in the field of flexible actuators.

[0004] Although water-based conductive gels have made breakthrough progress, their inherent aqueous phase system still has obvious limitations in extreme environments. When the ambient humidity is lower than 30% or the temperature exceeds 60°C, the hydrogel will lose water, resulting in a sharp drop in ionic conductivity, and the mechanical properties will deteriorate significantly. To address this technical pain point, the present invention uses glycerol, a green solvent, as a matrix, and first utilizes specific interactions between specific molecules to construct a glycerol-based small molecule gel. On this basis, conductive particles such as carbon nanotubes are introduced to achieve stable ion transport in a wide temperature range of -50°C to 150°C. Compared with traditional polymer gels, this glycerol-based small molecule conductive gel significantly improves ionic conductivity while maintaining excellent mechanical flexibility, showing irreplaceable application value in special scenarios such as aerospace sensors and deep-sea exploration equipment, and opening up a new material system for the development of flexible electronic devices in extreme environments.

[0005] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0006] The object of the present invention is to provide a method for preparing a rust-proof and frost-resistant flexible conductive composite gel, thereby overcoming the above-mentioned defects in the prior art.

[0007] In order to achieve the above object, the present invention provides a method for preparing a rust-proof and frost-resistant flexible conductive composite gel, comprising the following steps: S1: dissolving choline chloride in glycerol to prepare choline chloride glycerol solution; S2: adding sodium salt and ammonium salt to the choline chloride glycerol solution to prepare a mixed solution; S3: adding carbon nanotubes to the mixed solution prepared in S2; S4: Place the solution prepared in S3 in a constant temperature box at 70-95°C for 15-35 hours, then take it out and return it to room temperature.

[0008] Furthermore, as a preference, the amount of choline chloride added is 5%-10% of the glycerol; more preferably, the amount added is 5%, 6%, 7%, 8%, 9%, 10%. Furthermore, preferably, the sodium salt is one or a mixture of two or more of sodium laurate, sodium stearate, sodium salicylate, sodium lactobionate, and sodium cinnamate.

[0009] Furthermore, preferably, the ammonium salt is one of dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, polyquaternary ammonium salt, or a mixture of two or more of the above.

[0010] Further, preferably, the amount of sodium salt added is 0.3-2.5mM; more preferably, the amount added is 0.3mM, 0.4mM, 0.5mM, 0.6mM, 0.7mM, 0.8mM, 0.9mM, 1.0mM, 1.1mM, 1.2mM, 1.3mM, 1.4mM, 1.5mM, 1.6mM, 1.7mM, 1.8mM, 1.9mM, 2.0mM, 2.1mM, 2.2mM, 2.3mM, 2.4mM, 2.5mM.

[0011] Furthermore, preferably, the amount of the ammonium salt added is 0.5-1.5 mM; more preferably, the amount added is 0.5 mM, 0.6 mM, 0.7 mM, 0.8 mM, 0.9 mM, 1.0 mM, 1.1 mM, 1.2 mM, 1.3 mM, 1.4 mM, or 1.5 mM.

[0012] Furthermore, preferably, the amount of carbon nanotubes added in step S3 is 0.1%-1% of the glycerol; more preferably, the amount added is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1.0%.

[0013] Furthermore, preferably, the steps S1 and S2 are mixed at 60-80°C; more preferably, they are mixed at 60°C, 65°C, 70°C, 75°C, or 80°C.

[0014] Furthermore, preferably, the mixing in step S3 is carried out at 45-60°C; more preferably, the mixing is carried out at 45°C, 50°C, 55°C, or 60°C.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses sodium salt and ammonium salt as two surfactants to form a three-dimensional conductive network in combination with carbon nanotubes, and achieves rapid gelation through weak intermolecular interactions. The two surfactants can effectively adsorb on the surface of carbon nanotubes, reducing agglomeration. The constructed conductive network structure is uniform and has the characteristics of simple preparation process, good network reversibility, fast response speed, good biocompatibility and excellent conductivity. (2) The present invention replaces the traditional aqueous phase medium with glycerol and adds a very small amount of compound surfactant to construct a small molecule gel network with excellent moisturizing, antifreeze and corrosion resistance; (3) The ammonium salt surfactant in the present invention can also give the gel antibacterial properties, so that the material has mechanical properties, conductive properties and antibacterial properties, which can expand its application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a magnified microscope view of the composite gel prepared in Examples 1-3 of the present invention; Figure 2 1 is an appearance diagram of the samples prepared in Comparative Examples 1-4 and Example 1 of the present invention; Figure 3 Schematic diagram of the microscopes obtained in comparative examples 1-4 and example 1 of the present invention; Figure 4 These are inverted appearance diagrams of Comparative Example 2, Comparative Example 3, and Example 1 of the present invention; Figure 5 Graph showing the change in storage modulus G' (solid symbols) and loss modulus G" (open symbols) versus shear frequency (ω) for samples prepared in Examples 1-4 of the present invention; Figure 6This is a diagram showing the difference in conductivity of the samples prepared in Examples 2-4 of the present invention at -10°C and 25°C; Figure 7 This is a schematic diagram of the sample prepared in Example 1 of the present invention being immersed in a pure iron block. DETAILED DESCRIPTION

[0017] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0018] The following is a brief summary of one or more aspects to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceivable aspects and is neither intended to identify key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that will be provided later. Example 1

[0019] A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM sodium stearate and 1.0 mM cetyltrimethylammonium bromide to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 0.1 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Place the solution obtained in S3 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature. Example 2

[0020] A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM sodium stearate and 1.0 mM cetyltrimethylammonium bromide to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 0.3 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Place the solution obtained in S3 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature. Example 3

[0021] A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM sodium stearate and 1.0 mM cetyltrimethylammonium bromide to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 0.5 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Place the solution obtained in S3 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature. Example 4

[0022] A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM sodium stearate and 1.0 mM cetyltrimethylammonium bromide to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 1.0 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Place the solution obtained in S3 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature. Example 5

[0023] A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM sodium stearate and 1.0 mM cetyltrimethylammonium bromide to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 0.1 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Add 0.01 mM polyquaternium-7 (PQA-7) to the mixed solution prepared in S3 and mix well; S5: Place the solution prepared in S4 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature. Example 6

[0024] A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM sodium stearate and 1.0 mM cetyltrimethylammonium bromide to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 0.1 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Add 0.05 mM polyquaternium-7 (PQA-7) to the mixed solution prepared in S3 and mix well; S5: Place the solution prepared in S4 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature. Example 7

[0025] A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM sodium stearate and 1.0 mM cetyltrimethylammonium bromide to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 0.1 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Add 0.1 mM polyquaternium-7 (PQA-7) to the mixed solution prepared in S3 and mix well; S5: Place the solution prepared in S4 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature.

[0026] Comparative Example 1: A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 0.1 g of carbon nanotubes to the mixed solution prepared in S1 and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S3: Place the solution prepared in S2 in a thermostat at 85°C for 24 hours, then take it out and return it to room temperature.

[0027] Comparative Example 2: A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM sodium stearate to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 1.0 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Place the solution obtained in S3 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature.

[0028] Comparative Example 3: A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of glycerol solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM hexadecyltrimethylammonium bromide to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 1.0 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Place the solution obtained in S3 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature.

[0029] Comparative Example 4: A method for preparing a rust-proof and frost-resistant flexible conductive composite gel comprises the following steps: S1: Weigh 100g of deionized water solution and 8g of choline chloride, dissolve the choline chloride in glycerol, and place in a thermostat at 70°C to disperse evenly to prepare a choline chloride glycerol solution; S2: Add 1.0 mM sodium stearate and 1.0 mM cetyltrimethylammonium bromide to the above choline chloride solution, place in a 70°C thermostat and disperse evenly to prepare a mixed solution; S3: Add 1.0 g of carbon nanotubes to the mixed solution prepared in S2, and homogenize at 55°C with a homogenizer at 10,000 rpm for 10 min; S4: Place the solution obtained in S3 in a thermostat at 85°C for 24 hours and then take it out and return it to room temperature.

[0030] The raw material ratios of Examples 1-7 are shown in Table 1 below:

[0031] The raw material proportions of the above comparative examples 1-4 are shown in Table 2 below:

[0032] The above Examples 1 to 7 and Comparative Examples 1 to 4 were tested, and the test results are as follows: like Figure 1 As shown, a microscope-enlarged schematic diagram of the composite gel prepared in Examples 1-3 is magnified at 200X. The second row in the figure is a microscope-enlarged schematic diagram of Example 1, Example 2, and Example 3, respectively. The difference between the first and second rows in the figure is that step S2 is removed in the preparation method (i.e., sodium stearate and cetyltrimethylammonium bromide are not added). It can be seen from the figure that the addition of ammonium salt and sodium salt can effectively promote the dispersion of carbon nanotubes.

[0033] like Figure 2 As shown, the appearance pictures of the samples prepared in Comparative Examples 1-4 and Example 1 were taken after standing in a constant temperature box at 25°C for 24 hours. It can be seen from the pictures that Comparative Examples 1 and 4 have obvious stratification phenomenon, and Comparative Examples 2 and 3 have uneven distribution in the macroscopic view. Similarly, the sample prepared in the water system of Comparative Example 4 has uneven distribution.

[0034] like Figure 3 As shown, the microscopic images of the samples prepared in Comparative Examples 1-4 and Example 1 were taken after standing in a constant temperature box at 25°C for 24 hours, and the images were magnified at 200X. It can be clearly seen from the microscopic images that the carbon nanotubes in Comparative Example 1 without adding a surfactant and Comparative Example 4 of the aqueous system have obvious aggregation behavior; the dispersibility of the carbon nanotubes in Comparative Example 2 with only sodium stearate added and Comparative Example 3 with only cetyltrimethylammonium bromide added are enhanced, but their dispersibility is significantly weaker than that in Example 1 with the addition of a compound surfactant.

[0035] like Figure 4As shown, the inverted appearance of Comparative Example 2, Comparative Example 3 and Example 1 is shown. It can be seen that Comparative Example 2 and Comparative Example 3 cannot form glycerol gel by adding only a single surfactant. Only by adding a combination of anionic sodium stearate and hexadecyltrimethylammonium bromide (as in Example 1) can a glycerol gel system be formed.

[0036] like Figure 5 As shown, the storage modulus G' (solid symbols) and loss modulus G" (open symbols) of the composite gels prepared in Examples 1-4 are plotted as a function of shear frequency (ω), as measured using a rotational rheometer at 25 °C. It can be seen from the figure that the storage modulus G' is always greater than the loss modulus G", and the solution behaves as an elastic fluid, indicating that a gel can be formed by adding a very small amount of surfactant to the glycerol system.

[0037] like Figure 6 As shown, the conductivity difference diagram of the composite gel prepared in Example 2-4 at -10°C and 25°C conditions is shown. During the test, the composite gel was evenly coated on the conductivity test probe before it was gelled. The samples were stabilized in a constant temperature bath at -10°C and 25°C for 15 minutes, respectively, and the readings were started after gelation. Each sample was tested three times and the average value was taken. From the test results, the conductivity difference of the composite gel at -10°C and 25°C was small, and the conductivity at -10°C only decreased slightly, indicating that it has good antifreeze properties, so that it still has excellent conductive properties at low temperatures.

[0038] like Figure 7 As shown in FIG. 1 , a schematic diagram of a pure iron block soaked in the composite gel prepared in Example 1 is shown. The left side of the figure is a photo of the iron block before soaking, and the right side is a photo of the iron block after soaking for 15 days. It can be seen that the gel prepared by the present invention has good corrosion resistance.

[0039] As shown in Table 3, the antibacterial test results of the composite gels prepared in Examples 5-7 are shown. During the test, the conductive gel was evenly coated on an agar plate, inoculated with a certain concentration of bacterial solution (106 CFU / mL), and cultured at 37°C for 24 hours. The diameter of the inhibition zone was measured. The conductive gel was co-cultured with the bacterial solution using the microdilution method to observe the minimum inhibitory concentration of bacterial growth. The experimental results showed that the conductive gel exhibited excellent antibacterial effects against Escherichia coli and Staphylococcus aureus, and the antibacterial performance was further enhanced with increasing PQA-7 concentration, indicating that it has potential antibacterial advantages.

[0040]

[0041] The invention is prepared by mixing less than 3% of a long-chain carboxylate surfactant, a long-chain quaternary ammonium surfactant, and a small amount of choline chloride, and then adding carbon nanotubes and other additives. The preparation process is simple.

[0042] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing a rust-proof and frost-resistant flexible conductive composite gel, characterized in that: The following steps are involved: S1: dissolving choline chloride in glycerol to prepare choline chloride glycerol solution; S2: adding sodium salt and ammonium salt to the choline chloride glycerol solution to prepare a mixed solution; S3: adding carbon nanotubes to the mixed solution prepared in S2; S4: Place the solution prepared in S3 in a constant temperature box at 70-95°C for 15-35 hours, then take it out and return it to room temperature.

2. The method for preparing a rust-proof and frost-resistant flexible conductive composite gel according to claim 1, characterized in that: The added amount of the choline chloride is 5%-10% of the glycerol.

3. The method for preparing a rust-proof and frost-resistant flexible conductive composite gel according to claim 1, characterized in that: The sodium salt is one of sodium laurate, sodium stearate, sodium salicylate, sodium lactobionate, and sodium cinnamate, or a mixture of two or more thereof.

4. The method for preparing a rust-proof and frost-resistant flexible conductive composite gel according to claim 1, characterized in that: The ammonium salt is one of dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, polyquaternary ammonium salt, and a mixture of two or more of the above.

5. The method for preparing a rust-proof and frost-resistant flexible conductive composite gel according to claim 3, characterized in that: The added amount of the sodium salt is 0.3-2.5 mM.

6. The method for preparing a rust-proof and frost-resistant flexible conductive composite gel according to claim 4, characterized in that: The amount of ammonium salt added is 0.5-1.5 mM.

7. The method for preparing a rust-proof and frost-resistant flexible conductive composite gel according to claim 1, characterized in that: In step S3, the amount of carbon nanotubes added is 0.1%-1% of the glycerol.

8. The method for preparing a rust-proof and frost-resistant flexible conductive composite gel according to claim 1, characterized in that: The steps S1 and S2 are mixed at 60-80°C.

9. The method for preparing a rust-proof and frost-resistant flexible conductive composite gel according to claim 1, characterized in that: The step S3 is mixing at 45-60°C.

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