An MXene-modified conductive water-based ink suitable for screen printing and its preparation method

Abstract

This invention provides an MXene-modified conductive water-based ink suitable for screen printing and its preparation method. The MXene-modified conductive water-based ink possesses both excellent conductivity and good printing stability. The MXene two-dimensional material is uniformly dispersed in the system, resulting in a homogeneous ink texture, good storage stability, and excellent printability for screen printing. The MXene-modified conductive water-based ink may consist only of MXene material as a conductive filler, water, a thixotropic agent, and an emulsifier. Due to its natural hydrophilicity and high conductivity, it can be easily dispersed in water to form a stable and uniform conductive water-based ink. During printing, it constructs a denser conductive network, greatly simplifying the preparation process of the conductive water-based ink, reducing the use of related additives, and avoiding adverse effects on conductivity caused by excessive additives. Simultaneously, the resulting printed products exhibit uniform performance.

Description

Technical Field

[0001] This invention belongs to the field of conductive water-based inks and printing technology, specifically relating to an MXene-modified conductive water-based ink suitable for screen printing processes and its preparation method. Background Technology

[0002] Conductive water-based inks use water as the main solvent and are characterized by low VOC, environmental friendliness, good adhesion, and flexibility. They are currently widely used in printed electronics, flexible circuits, sensing, antistatic, photovoltaic / display, smart packaging, textiles and other fields.

[0003] However, existing conductive water-based inks still face many technical bottlenecks. On the one hand, traditional metal-based inks (such as silver and copper-based inks) are usually expensive and require high-temperature sintering to remove the insulating polymer coating or achieve fusion bonding between metal particles. This process can easily cause thermal damage to flexible substrates such as paper and PET that are not heat-resistant. On the other hand, carbon materials such as graphene and carbon nanotubes are inherently hydrophobic and difficult to disperse stably in aqueous systems. They usually require expensive special solvents or surfactants, which not only increases costs but may also introduce non-conductive impurities. At present, the selection of conductive fillers for conductive water-based inks suitable for screen printing is still mainly limited to the above-mentioned materials, which greatly restricts the use of conductive water-based inks in screen printing. Summary of the Invention

[0004] To address the limitations in selecting conductive fillers and the cumbersome preparation processes in existing conductive water-based inks, this invention provides an MXene-modified conductive water-based ink suitable for screen printing and its preparation method. The MXene-modified conductive water-based ink of this invention possesses both excellent conductivity and good printing stability; the MXene two-dimensional material is uniformly dispersed in the system, resulting in a homogeneous ink texture, good storage stability, and excellent printability for screen printing. The preparation method provided by this invention is simple, environmentally friendly, and suitable for large-scale production.

[0005] The MXene-modified conductive water-based ink of this invention can be used directly at room temperature without high-temperature post-treatment, offering significant advantages such as simple processing, low cost, and minimal damage to the substrate. The MXene-modified conductive water-based ink may consist only of MXene material as a conductive filler, water, a thixotropic agent, and an emulsifier. Due to its natural hydrophilicity and high conductivity, it can be easily dispersed in water to form a stable and uniform conductive water-based ink, constructing a denser conductive network during printing. This greatly simplifies the preparation process of conductive water-based inks, reduces the use of related additives, and avoids adverse effects on conductivity caused by excessive additives. Furthermore, the resulting printed products exhibit uniform performance.

[0006] The objective of this invention is achieved through the following technical solution: An MXene-modified conductive water-based ink, wherein the MXene-modified conductive water-based ink comprises the following components in parts by weight: 2-20 parts by weight of MXene material; 1-8 parts by weight of adhesive; Thixotropic agent 0.5-5 parts by weight; Emulsifier 0.5-2 parts by weight; 100 parts by weight of water.

[0007] According to an embodiment of the present invention, the MXene-modified conductive water-based ink comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 parts by weight of MXene material relative to 100 parts by weight of water.

[0008] According to an embodiment of the present invention, the MXene-modified conductive water-based ink comprises 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, and 8 parts by weight of binder relative to 100 parts by weight of water.

[0009] According to an embodiment of the present invention, the MXene-modified conductive water-based ink comprises 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, or 5 parts by weight of a thixotropic agent relative to 100 parts by weight of water.

[0010] According to an embodiment of the present invention, the MXene-modified conductive water-based ink comprises 0.5 parts by weight, 1 part by weight, 1.2 parts by weight, 1.5 parts by weight, 1.8 parts by weight, or 2 parts by weight of emulsifier relative to 100 parts by weight of water.

[0011] According to embodiments of the present invention, the MXene material is a known MXene material in the art, and the present invention does not particularly limit it; similarly, the present invention does not particularly define the source of the MXene material, which can be a commercially acquired MXene material, or an MXene material prepared using methods known in the art (such as HF etching of MAX), for example, prepared by HF etching using MAX as a raw material. Exemplarily, the MXene material is selected from M... n+1 X nWherein, M represents Ti, Nb, Ta, V, or Cr, X represents C or N, and n is 1, 2, or 3. Also exemplarily, the MXene material is selected from at least one of Ti3C2, Ti2C, Cr2C, Ti2N, Ta4C3, Ta4C3, Nb4C3, Nb2C, V2C, Mo2TiC2, Mo2C, and V4C3. MAX is selected from M... n+1 AX n ; where M, X, and n are defined as described above, and A is Al or Si.

[0012] According to an embodiment of the present invention, the adhesive is selected from at least one of polyvinyl alcohol, CMC-Na, and PVP.

[0013] According to an embodiment of the present invention, the thixotropic agent is selected from at least one of fumed SiO2, organobentonite, and lithium magnesium silicate.

[0014] According to an embodiment of the present invention, the emulsifier is selected from at least one of OP-4, OP-7, OP-10, OP-15 and OP-20.

[0015] According to an embodiment of the present invention, the viscosity of the MXene-modified conductive water-based ink is 2000~12000 cP.

[0016] According to an embodiment of the present invention, the adhesion of the MXene-modified conductive water-based ink is grade 3 or 4.

[0017] According to an embodiment of the present invention, the sheet resistance of the MXene-modified conductive water-based ink is 10. 2 ~10 8 Ω / sq.

[0018] The present invention also provides a method for preparing the above-mentioned MXene-modified conductive water-based ink, comprising: dissolving a binder as a matrix material in water, first adding MXene material, then adding a thixotropic agent and an emulsifier, to prepare the MXene-modified conductive water-based ink.

[0019] According to an embodiment of the present invention, the preparation method includes the following steps: 1) Dissolve the adhesive in deionized water to obtain an aqueous adhesive solution; 2) Add the MXene aqueous dispersion system to the binder aqueous solution in step 1), and perform ultrasonic dispersion and stirring to obtain a mixed solution; 3) Add the thixotropic agent to the mixed solution in step 2), and perform ultrasonic dispersion and stirring to obtain a mixed solution; 4) Add the emulsifier to the mixed solution in step 3), and perform ultrasonic dispersion and stirring to obtain the MXene-modified conductive water-based ink.

[0020] According to an embodiment of the present invention, in step 1), the adhesive is dissolved in deionized water using a method known in the art to obtain an aqueous adhesive solution. Exemplarily, the adhesive is dissolved in deionized water using the following method: first, the adhesive is added to deionized water at room temperature, then stirred under heating conditions. After the adhesive is completely dissolved, it is cooled to room temperature to obtain the aqueous adhesive solution. The heating temperature is not particularly limited, but it is necessary to ensure that the adhesive can quickly dissolve in deionized water under heating conditions to prepare the aqueous adhesive solution, while also ensuring that the adhesive does not decompose under heating conditions.

[0021] According to an embodiment of the present invention, in step 1), the concentration of the binder in the binder aqueous solution is not particularly limited, as long as the mass ratio of binder to water in the prepared MXene modified conductive water-based ink is 1-8:100.

[0022] According to an embodiment of the present invention, in step 2), the concentration of the MXene aqueous dispersion system is 20-300 mg / mL, for example, 20 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, 120 mg / mL, 150 mg / mL, 180 mg / mL, 200 mg / mL, 220 mg / mL, 240 mg / mL, 250 mg / mL, 280 mg / mL or 300 mg / mL.

[0023] According to an embodiment of the present invention, in step 2), the MXene aqueous dispersion system comprises MXene material and deionized water. The MXene aqueous dispersion system can be obtained commercially or prepared using methods known in the art. Exemplarily, the MXene aqueous dispersion system is prepared by the following method: a) Add LiF to HCl solution and stir until homogeneous to obtain HF solution; b) Add MAX powder to the HF solution obtained in step a) to carry out a stripping reaction and obtain a dispersion; c) The collected dispersion was centrifuged and washed multiple times, the supernatant was collected and freeze-dried to prepare MXene material; d) Add the MXene material obtained in step c) to deionized water at the required concentration to prepare the MXene aqueous dispersion system.

[0024] According to an embodiment of the present invention, in step 2), the ultrasonic dispersion and stirring treatment is first mechanically stirred at 800-1000 rpm for 8-10 min, then ultrasonically treated in an ice water bath for 20-30 min, and then mechanically stirred at 800-1000 rpm for 20-30 min; the ultrasonic dispersion and stirring treatment in step 2) can ensure that MXene is uniformly dispersed in the binder aqueous solution.

[0025] According to an embodiment of the present invention, in step 3), the ultrasonic dispersion and stirring treatment is first mechanically stirred at 800-1000 rpm for 3-5 min, then ultrasonically treated in an ice-water bath for 3-5 min, and then mechanically stirred at 800-1000 rpm for 3-5 min; the ultrasonic dispersion and stirring treatment in step 3) can ensure that the thixotropic agent is uniformly dispersed in the solution system and maintain the uniformity of the ink's thixotropic properties.

[0026] According to an embodiment of the present invention, in step 4), the ultrasonic dispersion and stirring treatment is first mechanically stirred at 800-1000 rpm for 3-5 min, then ultrasonically treated in an ice-water bath for 3-5 min, and then mechanically stirred at 800-1000 rpm for 3-5 min; the ultrasonic dispersion and stirring treatment in step 4) can ensure that the emulsifier is uniformly dispersed in the solution system and maintain the stability of the ink performance.

[0027] This invention also provides the application of the above-mentioned MXene-modified conductive water-based ink in screen printing processes.

[0028] The MXene-modified conductive water-based ink of this invention uses MXene as the conductive functional component, a binder as the structural framework, a thixotropic agent as the rheological modifier and anti-settling medium, and an emulsifier as the interface optimizer and stabilizer. It is a high-performance conductive water-based ink suitable for screen printing, constructed through the stepwise addition of each component and multiple ultrasonic / stirring synergistic treatments. This conductive water-based ink for screen printing simultaneously solves common problems in existing technologies such as MXene's tendency to agglomerate, poor ink storage stability, poor printability, and weak adhesion to flexible substrates. It embodies the design philosophy of multi-component synergy, controllable process, and adjustable performance.

[0029] The beneficial effects of this invention are: (1) The process is simple, the conditions are mild, and no high-temperature treatment is required, making it suitable for large-scale production. The entire process of preparing conductive water-based ink and the curing process after printing do not involve high-temperature sintering (traditional metal inks require heat treatment at 150~300 ℃) or high-pressure homogenization and other high-energy-consuming steps. The operation is simple, green and environmentally friendly, and it is easy to transition from laboratory to industrial mass production.

[0030] (2) The stepwise strategy of “preparing the MXene aqueous dispersion system first and then mixing it with the binder matrix” is adopted, that is, the stepwise preparation strategy of “exfoliation-concentration-mixing” is adopted, which greatly improves the dispersion of MXene in the binder system. The subsequent combination of ultrasonication and stirring makes the two-dimensional MXene sheets fully exfoliated and uniformly distributed in the system, avoiding the agglomeration and sedimentation problems that are easy to occur in the conventional one-step mixing method.

[0031] (3) The addition of additives improves the antioxidant properties of MXene, resulting in a significant improvement in the stability and printability of the conductive water-based ink. MXene is easily oxidized under normal conditions, leading to a significant decrease in conductivity. This invention effectively solves this technical problem by introducing thixotropic agents and emulsifiers in specific mass proportions into the conductive water-based ink. This is mainly because thixotropic agents and emulsifiers can form a physical adsorption or weak gel network on the surface of the two-dimensional MXene sheets, slowing down the oxidation of MXene by water and oxygen, and improving the stability of the ink during long-term storage. Specifically, the addition of thixotropic agents endows the conductive water-based ink with excellent thixotropy and anti-settling properties, while emulsifiers further improve the compatibility between the components. The conductive water-based ink obtained in this way has a uniform texture, good storage stability (no obvious stratification or precipitation after standing at room temperature for 30 days), and excellent printability.

[0032] (4) Clear synergistic effect of components and wide performance control window. This invention can flexibly adjust the rheological behavior of conductive water-based ink by adjusting the amount of thixotropic agent, meeting the differentiated requirements of conductive water-based ink for different screen meshes and different substrates; the addition of emulsifier further reduces surface tension, avoiding printing defects such as pinholes and broken lines. By establishing a synergistic rheological control system of thixotropic agent and emulsifier, key performance indicators such as viscosity, adhesion and sheet resistance of conductive water-based ink can be controlled, thereby adapting to the application needs of different screen meshes and different substrates. Attached Figure Description

[0033] Figure 1 SEM images of the MXene material prepared for Example 1.

[0034] Figure 2 SEM image of the MXene-modified conductive water-based ink prepared in Example 1.

[0035] Figure 3 A comparison image of the MXene-modified conductive water-based ink prepared in Example 1 (right) and the MXene-modified conductive water-based ink prepared in Comparative Example 3 (left) after standing for 30 days. Detailed Implementation

[0036] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0037] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0038] Preparation Example 1 Step (1): Dissolve 1.6 g LiF (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) in 20.0 mL dilute hydrochloric acid (purchased from Sinopharm Chemical Reagent Co., Ltd.) and stir evenly at room temperature to form solution A; Step (2): Weigh 1.0 g of MAX (Ti3AlC2, purchased from Jilin 11 Technology Co., Ltd.) powder and add it to solution A in small amounts several times to obtain solution B; Step (3): Transfer solution B to an oil bath magnetic stirring vessel, maintain the temperature at 55 ℃, and process for 24 h to obtain solution C; Step (4): Centrifuge the obtained solution C multiple times, shaking it continuously before centrifugation, controlling the rotation speed at 4500 rpm, and the centrifugation time for each centrifugation to be 3 min. A total of 20 centrifugations are performed to obtain solution D. Step (5): Sonicate solution D in an ice-water bath for 60 min to obtain solution E. Centrifuge at 3500 rpm for 60 min, extract the supernatant of the obtained solution, freeze-dry and collect MXene powder. Step (6): Disperse 0.1 g of the collected MXene powder into 1 mL of deionized water to obtain an MXene dispersion system with a concentration of 0.1 g / mL; disperse 0.3 g of the collected MXene powder into 1 mL of deionized water to obtain an MXene dispersion system with a concentration of 0.3 g / mL.

[0039] Example 1 Step (1): Weigh 4.4 g of PVA powder (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) and dissolve it in 40 mL of deionized water. After stirring and dispersing at room temperature, transfer it to an oil bath and stir at 90 °C for more than 6 h. After standing for 30 min, a transparent and uniform PVA aqueous solution is obtained. Step (2): After the PVA aqueous solution from step (1) has cooled to room temperature, add 60 mL of the MXene dispersion system with a concentration of 0.1 g / mL prepared above, and perform ultrasonic dispersion and stirring treatment. Specifically, first perform mechanical stirring treatment at 800-1000 rpm for 8-10 min, then perform ultrasonic treatment in an ice water bath for 20-30 min, and then perform mechanical stirring treatment at 800-1000 rpm for 20-30 min. Step (3): Add 1.0 g of hydrophilic vapor phase SiO2 (thixotropic agent, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) to the solution obtained in step (2), and perform ultrasonic dispersion and stirring treatment. Specifically, first perform mechanical stirring treatment at 800-1000 rpm for 3-5 min, then perform ultrasonic treatment in an ice water bath for 3-5 min, and then perform mechanical stirring treatment at 800-1000 rpm for 3-5 min. Step (4): Add 1.0 g of emulsifier (equal mass of OP-4 and OP-10, both purchased from Shandong Yousuo Chemical Technology Co., Ltd.) to the solution obtained in step (3), and perform ultrasonic dispersion and stirring treatment. Specifically, first perform mechanical stirring treatment at 800-1000 rpm for 3-5 min, then perform ultrasonic treatment in an ice water bath for 3-5 min, and then perform mechanical stirring treatment at 800-1000 rpm for 3-5 min to obtain the MXene modified conductive water-based ink.

[0040] Example 2 Step (1): Weigh 2.0 g of CMC-Na (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) and dissolve it in 40 mL of deionized water. After stirring and dispersing at room temperature, transfer it to an oil bath and stir at 60 °C for more than 2 h. After standing for 30 min, a transparent and uniform CMC-Na aqueous solution is obtained. Step (2): After the CMC-Na aqueous solution from step (1) has cooled to room temperature, add 60 mL of the MXene dispersion system with a concentration of 0.1 g / mL prepared above, and perform ultrasonic dispersion and stirring treatment. Specifically, first perform mechanical stirring treatment at 800-1000 rpm for 8-10 min, then perform ultrasonic treatment in an ice water bath for 20-30 min, and then perform mechanical stirring treatment at 800-1000 rpm for 20-30 min. Step (3): Add 1.0 g of organic sodium bentonite (thixotropic agent, purchased from Dongguan Runheng New Environmental Protection Materials Co., Ltd.) to the solution obtained in step (2), and perform ultrasonic dispersion and stirring treatment. Specifically, first perform mechanical stirring treatment at 800-1000 rpm for 3-5 min, then perform ultrasonic treatment in an ice water bath for 3-5 min, and then perform mechanical stirring treatment at 800-1000 rpm for 3-5 min. Step (4): Add 1.0 g of emulsifier (equal mass of OP-4 and OP-10, both purchased from Shandong Yousuo Chemical Technology Co., Ltd.) to the solution obtained in step (3), and perform ultrasonic dispersion and stirring treatment. Specifically, first perform mechanical stirring treatment at 800-1000 rpm for 3-5 min, then perform ultrasonic treatment in an ice water bath for 3-5 min, and then perform mechanical stirring treatment at 800-1000 rpm for 3-5 min to obtain the MXene modified conductive water-based ink.

[0041] Example 3 Step (1): Weigh 2.0 g of PVP (molecular weight K90, purchased from Alfaesa (China) Chemical Co., Ltd.) and dissolve it in 40 mL of deionized water. After stirring and dispersing at room temperature, transfer it to an oil bath and stir at 60 °C for more than 2 h. After standing for 30 min, a transparent and uniform PVP aqueous solution is obtained. Step (2): After the PVP aqueous solution from step (1) has cooled to room temperature, add 60 mL of the MXene dispersion system with a concentration of 0.1 g / mL prepared above, and perform ultrasonic dispersion and stirring treatment. Specifically, first perform mechanical stirring treatment at 800-1000 rpm for 8-10 min, then perform ultrasonic treatment in an ice water bath for 20-30 min, and then perform mechanical stirring treatment at 800-1000 rpm for 20-30 min. Step (3): Add 1.0 g of lithium magnesium silicate (thixotropic agent, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) to the solution obtained in step (2), and perform ultrasonic dispersion and stirring treatment. Specifically, first perform mechanical stirring treatment at 800-1000 rpm for 3-5 min, then perform ultrasonic treatment in an ice water bath for 3-5 min, and then perform mechanical stirring treatment at 800-1000 rpm for 3-5 min. Step (4): Add 1.0 g of emulsifier (equal mass of OP-4 and OP-10, both purchased from Shandong Yousuo Chemical Technology Co., Ltd.) to the solution obtained in step (3), and perform ultrasonic dispersion and stirring treatment. Specifically, first perform mechanical stirring treatment at 800-1000 rpm for 3-5 min, then perform ultrasonic treatment in an ice water bath for 3-5 min, and then perform mechanical stirring treatment at 800-1000 rpm for 3-5 min to obtain the MXene modified conductive water-based ink.

[0042] Example 4 The other operations are the same as in Example 1, except that 60 mL of MXene dispersion system with a concentration of 0.3 g / mL is added. By adjusting the proportion of MXene in the conductive water-based ink, the conductivity of the final ink is improved.

[0043] Comparative Example 1 The other operations are the same as in Example 1, except that MXene material is not added, that is, 100 mL of deionized water is added in step (1), and step (2) is omitted.

[0044] Comparative Example 2 The other operations are the same as in Example 1, except that no binder is added, i.e., step (1) is omitted and 40 mL of deionized water is added in step (2). At this time, due to the low viscosity of the system, the ink flows uncontrollably and penetrates severely during the screen printing process, making it impossible to obtain the expected design pattern. At the same time, due to the failure to form a continuous conductor layer on the glass fiber, its conductivity is extremely poor.

[0045] Comparative Example 3 The other operations are the same as in Example 1, except that thixotropic agents and emulsifiers are not added, i.e., steps (3) and (4) are omitted. Although there is no significant difference in performance compared to Example 1, as... Figure 3 As shown, the prepared conductive water-based ink does not meet the basic requirements for long-term storage.

[0046] Comparative Example 4 Step (1): Weigh 4.4 g of PVA powder (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) and dissolve it in 40 mL of deionized water. After stirring and dispersing at room temperature, transfer it to an oil bath and stir at 90 °C for more than 6 h. After standing for 30 min, a transparent and uniform PVA aqueous solution is obtained. Step (2): After the PVA aqueous solution from step (1) has cooled to room temperature, add 60 mL of the MXene dispersion system with a concentration of 0.1 g / mL prepared above, and mechanically stir at 800-1000 rpm for 8-10 min. Step (3): Add 1.0 g of hydrophilic vapor phase SiO2 (thixotropic agent, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.) to the solution obtained in step (2) and mechanically stir at 800-1000 rpm for 3-5 min. Step (4): Add 1.0 g of emulsifier (equal mass of OP-4 and OP-10, both purchased from Shandong Yousuo Chemical Technology Co., Ltd.) to the solution obtained in step (3), and mechanically stir at 800-1000 rpm for 3-5 min to obtain the MXene modified conductive water-based ink.

[0047] In the MXene-modified conductive water-based ink prepared in Comparative Example 4, the MXene was not uniformly dispersed, resulting in significant differences in sheet resistance values ​​at different locations (with orders of magnitude differences) after the prepared conductive water-based ink was coated onto the surface of the substrate, which seriously affected its practical application value.

[0048] Comparative Example 5 The other operations are the same as in Example 1, except that in step (2), 60 mL of MXene dispersion system with a concentration of 0.6 g / mL is added. At this time, after MXene combines with PVA, the system will seriously agglomerate, and it will be impossible to obtain uniformly dispersed MXene-modified conductive water-based ink. Moreover, the adhesion effect is extremely poor, and it will peel off after drying.

[0049] Figure 1 SEM images of the MXene material prepared for Example 1. Figure 2 SEM image of the MXene-modified conductive water-based ink prepared in Example 1. Figure 1 This demonstrates the actual dimensions of dispersed, few-layer MXene, while Figure 2 This demonstrates that the components in the conductive water-based ink are uniformly dispersed without any defects such as clumping.

[0050] Figure 3 The image shows a comparison of the MXene-modified conductive water-based ink prepared in Example 1 and the MXene-modified conductive water-based ink prepared in Comparative Example 3 after being left to stand for 30 days. The MXene-modified conductive water-based ink prepared in Comparative Example 3 showed significant stratification after prolonged storage, while the MXene-modified conductive water-based ink prepared in Example 1 remained stable with minimal impact on its viscosity, adhesion, and sheet resistance.

[0051] Performance testing Viscosity tests were performed on the conductive water-based inks prepared in Examples 1-4 and Comparative Examples 1-5. Adhesion was tested according to GB / T9286-2021 "Cross-cut Test for Paints and Varnishes". Sheet resistance was measured using the four-probe method to obtain film layers from screen printing of the conductive water-based inks prepared in Examples 1-4 and Comparative Examples 1-5. The film layers obtained from screen printing of the conductive water-based inks from Examples 1-4 and Comparative Examples 1-4 were subjected to a high-temperature treatment at 110 °C for 24 h, and the sheet resistance of the film layers after the high-temperature treatment was measured. The test results are shown in Table 1.

[0052] Table 1. Performance test results of MXene-modified conductive water-based inks in the examples and comparative examples.

[0053] Therefore, it can be seen that the conductive water-based ink of the present invention, suitable for screen printing, exhibits characteristics such as non-agglomeration of MXene, good ink storage stability, moderate viscosity, strong printability, and strong adhesion to flexible substrates. More importantly, since MXene is easily oxidized under normal conditions, leading to a significant decrease in conductivity, the conductive water-based ink of the present invention can significantly improve the oxidation resistance of MXene, thereby significantly enhancing the stability and printability of the conductive water-based ink. The use of the conductive water-based ink of the present invention can effectively solve the problem of decreased conductivity caused by high-temperature drying treatment that may be encountered during the application of conductive water-based inks.

[0054] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An MXene-modified conductive water-based ink, wherein, The MXene-modified conductive water-based ink comprises the following components in parts by weight: 2-20 parts by weight of MXene material; 1-8 parts by weight of adhesive; Thixotropic agent 0.5-5 parts by weight; Emulsifier 0.5-2 parts by weight; 100 parts by weight of water.

2. The MXene-modified conductive water-based ink according to claim 1, wherein, The MXene material is selected from M n+1 X n Wherein, M represents Ti, Nb, Ta, V, or Cr, X represents C or N, and n is 1, 2, or 3. Preferably, the MXene material is selected from at least one of Ti3C2, Ti2C, Cr2C, Ti2N, Ta4C3, Ta4C3, Nb4C3, Nb2C, V2C, Mo2TiC2, Mo2C, and V4C3. And / or, the adhesive is selected from at least one of polyvinyl alcohol, CMC-Na and PVP; And / or, the thixotropic agent is selected from at least one of fumed SiO2, organobentonite, and lithium magnesium silicate; And / or, the emulsifier is selected from at least one of OP-4, OP-7, OP-10, OP-15 and OP-20.

3. The MXene-modified conductive water-based ink according to claim 1 or 2, wherein, The viscosity of the MXene-modified conductive water-based ink is 2000~12000 cP; And / or, the adhesion of the MXene-modified conductive water-based ink is grade 3 or 4; And / or, the sheet resistance of the MXene-modified conductive water-based ink is 10. 2 ~10 8 Ω / sq.

4. A method for preparing the MXene-modified conductive water-based ink according to any one of claims 1-3, comprising: The binder is dissolved in water as a matrix material, and MXene material is added first, followed by thixotropic agent and emulsifier to prepare the MXene-modified conductive water-based ink.

5. The preparation method according to claim 4, wherein, The preparation method includes the following steps: 1) Dissolve the adhesive in deionized water to obtain an aqueous adhesive solution; 2) Add the MXene aqueous dispersion system to the binder aqueous solution in step 1), and perform ultrasonic dispersion and stirring to obtain a mixed solution; 3) Add the thixotropic agent to the mixed solution in step 2), and perform ultrasonic dispersion and stirring to obtain a mixed solution; 4) Add the emulsifier to the mixed solution in step 3), and perform ultrasonic dispersion and stirring to obtain the MXene-modified conductive water-based ink.

6. The preparation method according to claim 5, wherein, In step 1), the adhesive is dissolved in deionized water using the following method: First, the adhesive is added to deionized water at room temperature, then stirred under heating conditions. After the adhesive is completely dissolved, it is cooled to room temperature to obtain an aqueous solution of the adhesive.

7. The preparation method according to claim 5 or 6, wherein, In step 2), the concentration of the MXene aqueous dispersion system is 20-300 mg / mL.

8. The preparation method according to any one of claims 5-7, wherein, In step 2), the MXene aqueous dispersion system is prepared by the following method: a) Add LiF to HCl solution and stir until homogeneous to obtain HF solution; b) Add MAX powder to the HF solution obtained in step a) to carry out a stripping reaction and obtain a dispersion; c) The collected dispersion was centrifuged and washed multiple times, the supernatant was collected and freeze-dried to prepare MXene material; d) Add the MXene material obtained in step c) to deionized water at the required concentration to prepare the MXene aqueous dispersion system.

9. The preparation method according to any one of claims 4-8, wherein, In step 2), the ultrasonic dispersion and stirring treatment is first mechanically stirred at 800-1000 rpm for 8-10 min, then ultrasonically treated in an ice water bath for 20-30 min, and then mechanically stirred at 800-1000 rpm for 20-30 min. And / or, in step 3), the ultrasonic dispersion and stirring treatment is first mechanically stirred at 800-1000 rpm for 3-5 min, then ultrasonically treated in an ice water bath for 3-5 min, and then mechanically stirred at 800-1000 rpm for 3-5 min. And / or, in step 4), the ultrasonic dispersion and stirring treatment is first mechanically stirred at 800-1000 rpm for 3-5 min, then ultrasonically treated in an ice water bath for 3-5 min, and then mechanically stirred at 800-1000 rpm for 3-5 min.

10. The application of the MXene-modified conductive water-based ink according to any one of claims 1-3 in screen printing process.

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