MXene / PEDOT: PSS multistage composite conductive ink, and preparation method and application thereof
By preparing MXene/PEDOT:PSS multi-level composite conductive ink, the problems of easy oxidation of MXene and incompatibility of rheological properties were solved, achieving high conductivity, stability and multi-process adaptability, which is suitable for flexible electronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-04
- Publication Date
- 2026-04-10
AI Technical Summary
In existing technologies, MXene is prone to oxidation, it is difficult to balance the conductivity and stability of composite inks, it has poor rheological properties and weak interface compatibility, which limits its application in flexible electronic devices.
By preparing MXene/PEDOT:PSS multi-level composite conductive ink, a core-shell structure design and interface engineering were adopted. MXene nanosheets were coated with PEDOT:PSS to construct a three-dimensional conductive network. The rheological properties were controlled by the solvent system to form a highly efficient conductive ink.
It significantly improves the oxidation resistance and conductivity of MXene, adapts to various printing processes, meets the high-performance requirements of flexible electronic devices, extends service life and improves stability.
Smart Images
Figure CN121825317A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of printed electronics and functional ink materials, and particularly relates to an MXene / PEDOT:PSS multi-level composite conductive ink, its preparation method and application. Background Technology
[0002] In the modern electronics and information industry, flexible electronics technology is rapidly developing towards integration, miniaturization, and multifunctionality. Printed electronics, as its core manufacturing technology, has been widely applied in flexible displays, wearable sensors, smart packaging, and radio frequency identification. Conductive ink, as the "lifeblood" of printed electronics technology, directly determines the function and reliability of printed circuits. Among them, conductive inks that combine high conductivity, good environmental stability, and excellent printability are key materials driving the development of next-generation high-performance flexible electronic devices.
[0003] In recent years, two-dimensional transition metal carbides / nitrides MXene (in the form of Ti3C2T) have been studied. x MXene (represented by titanium dioxide) is considered one of the most promising conductive ink materials due to its excellent metallic conductivity, outstanding hydrophilicity, and rich surface chemical properties. Its aqueous dispersions can achieve stability without complex additives, greatly simplifying formulation. However, MXene materials face two key bottlenecks in practical applications: First, the titanium element in its layered structure is easily oxidized to titanium dioxide in oxygen-containing environments, leading to an irreversible and rapid decline in conductivity, severely damaging the long-term storage and operational stability of the ink and the devices made from it. Second, the rheological behavior of a single MXene dispersion is relatively simple, making it difficult to simultaneously meet the specific requirements of different advanced manufacturing processes such as screen printing, inkjet printing, and direct-write 3D printing regarding ink viscosity, yield stress, and thixotropic recovery, thus limiting its application breadth.
[0004] On the other hand, the conductive polymer poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) has been extensively studied due to its excellent film-forming properties, environmental stability, and tunable conductivity. However, the intrinsic conductivity of PEDOT:PSS is generally lower than that of MXene, which limits its use as a single active material in applications requiring extremely high conductivity or high volumetric energy density.
[0005] Currently, researchers have attempted to combine MXene with PEDOT:PSS to leverage the advantages of both. However, existing composite methods primarily focus on simple physical blending, failing to fundamentally address issues such as weak interfacial compatibility, the potential sacrifice of high conductivity due to complete PEDOT:PSS encapsulation of MXene nanosheets, and imprecise control of rheological behavior after composite formation. Achieving a robust synergistic and structurally ordered composite of MXene and PEDOT:PSS at the nanoscale through innovative material design and fabrication processes, while simultaneously addressing the MXene oxidation challenge and precisely customizing the rheological properties of the ink, ultimately yielding a versatile, high-performance conductive ink with comprehensive performance, adaptability to multiple processes, and high stability, remains an unresolved technological challenge in this field. Summary of the Invention
[0006] The purpose of this invention is to provide an MXene / PEDOT:PSS multi-level composite conductive ink and its preparation method, aiming to solve the technical problems in the prior art, such as the easy oxidation of MXene, the difficulty in balancing the conductivity and stability of composite inks, poor rheological adaptability, and weak interfacial compatibility.
[0007] This invention is achieved by providing a method for preparing an MXene / PEDOT:PSS multi-level composite conductive ink, the method comprising the following steps: S1. Add 1.0g LiF to 30mL 9M HCl solution and stir magnetically at 500rpm for 60 minutes until completely dissolved to form an etching agent; S2. Add 1.0g of Ti3AlC2 powder to the etching agent, and stir at 600-800rpm for 20 hours in a constant temperature water bath at 35℃. After centrifugation, washing, argon bubbling, ultrasonic treatment, and centrifugation separation, a few-layer Ti3C2T is obtained. x The MXene dispersion was freeze-dried and then redispersed to a homogeneous dispersion of 10 mg / mL. S3. Measure Clevios™ PH1000 aqueous solution, add 5-15 vol% ethylene glycol, and stir at 300 rpm at room temperature for 30 minutes. Add the above MXene dispersion dropwise according to the solid content mass ratio of MXene to PEDOT:PSS of 1:0.5-1:5, and stir at 400 rpm for 4 hours under argon protection and in the dark. Concentrate by rotary evaporation at a water bath temperature of 35℃ and a rotation speed of 80 rpm, and monitor the target solid content by weighing to obtain the composite conductive ink.
[0008] A further technical solution of the present invention is as follows: the separation and purification step in step S2 includes: diluting the reaction product with deionized water, centrifuging at 3000-4000 rpm, discarding the supernatant, and washing repeatedly until the pH of the supernatant is >5; redispersing the precipitate in deionized water, centrifuging at 1000-2000 rpm, and collecting the dark green supernatant; after argon bubbling for 15 minutes and sonicating in an ice-water bath for 20 minutes, centrifuging the dispersion at 3000-4000 rpm, collecting the dark green precipitate at the bottom, and dispersing it in an appropriate amount of deionized water to obtain a few-layer Ti3C2T. x MXene dispersion.
[0009] A further technical solution of the present invention is that the solid content mass ratio of MXene to PEDOT:PSS in step S3 is 1:0.5 to 1:5.
[0010] A further technical solution of the present invention is that: in step S3, ethylene glycol accounts for 10 vol of the volume of the PEDOT:PSS aqueous solution.
[0011] A further technical solution of the present invention is that the target solid content of rotary evaporation in step S3 is 15wt% to 35wt%.
[0012] Another objective of this invention is to provide an MXene / PEDOT:PSS multi-level composite conductive ink, wherein the conductive ink comprises a core-shell structure unit formed by MXene nanosheets as the core and PEDOT:PSS molecules coating their surface, and a three-dimensional conductive network structure formed by the PEDOT:PSS molecular chains bridging the MXene nanosheets.
[0013] A further technical solution of the present invention is: the MXene surface is rich in –O, –OH, and –F functional groups, and PEDOT:PSS preferentially adsorbs onto the MXene surface through electrostatic interaction and π-π stacking to form a continuous or semi-continuous coating layer.
[0014] A further technical solution of the present invention is: the solvent system is a mixture of water and ethylene glycol, wherein the volume fraction of ethylene glycol in the solvent system is 2-20 vol.
[0015] A further technical solution of the present invention is that the rheological properties of the conductive ink can be controlled by adjusting the mass ratio of MXene to PEDOT:PSS, and / or adjusting the volume fraction of ethylene glycol in the solvent system, and / or adjusting the final solid content of the ink, so as to adapt to screen printing, inkjet printing or direct writing 3D printing processes, and to prepare flexible display devices, wearable sensor devices or smart packaging devices.
[0016] Another objective of this invention is to provide an application of MXene / PEDOT:PSS multi-level composite conductive ink in the fabrication of flexible electronic devices, wherein the flexible electronic devices include at least one of flexible electrodes, flexible sensors, radio frequency identification antennas, or energy storage devices.
[0017] The beneficial effects of this invention are: MXene provides a conductive framework, and PEDOT:PSS coating induces a conformational change, constructing a highly efficient conductive network with significantly improved conductivity; the core-shell structure and three-dimensional network formed by PEDOT:PSS effectively block oxygen and moisture, inhibit MXene oxidation, and extend service life; by adjusting the component ratio, ethylene glycol content, and solid content, it is compatible with multiple processes such as screen printing, inkjet printing, and direct-write 3D printing; water is used as the main solvent, and ethylene glycol is low in toxicity, which conforms to the concept of green manufacturing. Attached Figure Description
[0018] Figure 1 This is a flowchart of the preparation method of MXene / PEDOT:PSS multi-level composite conductive ink provided in the embodiments of the present invention. Detailed Implementation
[0019] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0020] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0021] This invention aims to provide a multi-level composite conductive ink based on MXene and PEDOT:PSS, and its preparation method. Through a unique "core-shell" structure design and interface engineering, PEDOT:PSS effectively encapsulates and protects MXene, significantly improving its oxidation resistance. Simultaneously, the charge interaction between the two induces a conformational change in the PEDOT chain, synergistically constructing a three-dimensional, highly efficient conductive network. Ultimately, this invention aims to obtain an advanced conductive ink that possesses high conductivity, excellent environmental stability, and can be flexibly formulated to adapt to various printing processes, meeting the needs of high-end flexible electronics manufacturing.
[0022] like Figure 1 As shown, the preparation method of the MXene / PEDOT:PSS multi-level composite conductive ink provided by the present invention is described in detail below: Step S1, Preparation of etching agent: Add 1.0g LiF to a polytetrafluoroethylene-lined reactor or a well-sealed glass bottle containing 30mL of 9M HCl solution. The reactor has a capacity of 50mL. Stir the mixture magnetically at 500rpm for 60 minutes until the LiF is completely dissolved to obtain the etching agent.
[0023] Step S2, preparation of few-layer Ti3C2T x MXene dispersion: Under continuous stirring, slowly add 1.0 g Ti3AlC2 powder to the etching agent obtained in step S1, place in a 35°C constant temperature water bath, and react vigorously at 600-800 rpm for 20 hours. After the reaction, transfer the mixture to a centrifuge tube, dilute 5 times with deionized water, and centrifuge at 3500 rpm for 8 minutes, discarding the yellow supernatant. Redisperse the resulting black precipitate with deionized water, repeating this centrifugation and washing process until the pH of the supernatant is >5. Disperse the final precipitate in 250 mL of deionized water, centrifuge at 1500 rpm for 5 minutes, and carefully collect the dark green supernatant, i.e., MXene colloid; the precipitate can be repeatedly dispersed and centrifuged at low speed 1-2 times to collect more product. The collected colloidal dispersion was bubbled under argon for 15 minutes, then sonicated in an ice-water bath for 20 minutes. The dispersion was then centrifuged at 3500 rpm for 60 minutes. The supernatant was carefully discarded, and the dark green precipitate at the bottom was redispersed in an appropriate amount of deionized water to obtain a few-layer Ti3C2T. x MXene dispersion. The dispersion was freeze-dried to obtain a few-layer MXene powder; before use, it was redispersed in deionized water to prepare a homogeneous dispersion with a concentration of 10 mg / mL.
[0024] Step S3: Measure out a commercially available Clevios™ PH1000 PEDOT:PSS aqueous solution and add 5–15 vol% ethylene glycol (EG). Stir at 300 rpm at room temperature for 30 minutes. Then, while continuously stirring the PEDOT:PSS / EG mixture at 300 rpm, add dropwise the 10 mg / mL MXene dispersion prepared in step S2 using a pipette, according to an MXene to PEDOT:PSS solid content mass ratio of 1:0.5–1:5. After addition, transfer the mixture to a sealed container under argon protection and stir at 400 rpm in the dark at room temperature for 4 hours to ensure thorough mixing and interaction. Subsequently, transfer the mixture to a flask in a rotary evaporator, set the water bath temperature to 35°C, and the rotation speed to 80 rpm, gradually applying vacuum to begin concentration. Monitor the quality by periodic weighing to obtain a composite conductive ink with the target solid content, suitable for different printing processes. The solid content mass ratio of MXene to PEDOT:PSS is 1:2 to 1:3, which better balances the conductivity and rheological properties of the ink. Ethylene glycol accounts for 10 vol% of the volume of the PEDOT:PSS aqueous solution, optimally inducing the conformational transformation of the PEDOT molecular chain, improving conductivity and optimizing rheological characteristics. The target solid content for rotary evaporation is 15 wt% to 35 wt%, and by adjusting this solid content, the ink can be adapted to different processes such as screen printing, inkjet printing, or direct-write 3D printing.
[0025] The PEDOT:PSS solution needs to be premixed with a high-boiling-point co-solvent (such as ethylene glycol) to initially adjust the conformation of the PEDOT chains before slowly adding the MXene dispersion. If MXene is mixed in first and then EG is added, it is easy to cause local aggregation of MXene; pre-adjusting the PEDOT:PSS system is beneficial for its uniform adsorption on the MXene surface.
[0026] The solid content mass ratio of MXene to PEDOT:PSS is 1:0.5 to 1:5. EG accounts for 5 to 15 vol% of the PEDOT:PSS solution volume.
[0027] Argon protection: MXene is highly sensitive to dissolved oxygen in solution; an argon environment significantly reduces the partial pressure of oxygen in the solution, slowing down oxidation.
[0028] Stirring in the dark: Light exposure can easily induce photocatalytic oxidation of MXene surface, and PEDOT:PSS may also undergo photoinduced structural changes.
[0029] In the concentration process of this invention, rotary evaporation is carried out under gradually applied vacuum conditions, and the endpoint can be determined by monitoring and judging the state of the system. Specifically, the initial mass of the container and materials can be recorded before rotary evaporation, and the theoretical endpoint mass can be calculated based on the target solid content. During rotary evaporation, the degree of concentration can be judged by intermittently stopping the vacuum and weighing the overall mass, which serves as the basis for judging the endpoint of rotary evaporation.
[0030] In conductive polymer-based ink systems, a single PEDOT:PSS solution typically exhibits predominantly viscous fluid characteristics, making it difficult to maintain a stable shape after extrusion or printing. Introducing MXene two-dimensional nanosheets with a high aspect ratio allows MXene, as a structural filler, to interact with the PEDOT:PSS molecular chains at multiple points, forming a physical network structure where the sheets and polymer synergistically support each other. This significantly improves the ink's storage modulus, yield stress, and thixotropic recovery capability.
[0031] As the relative content of MXene in the composite system increases, a continuous physical contact network gradually forms between the MXene nanosheets. The ink system gradually shifts from being primarily viscous to being primarily elastic, with significantly enhanced viscoelastic characteristics. This also facilitates the construction of continuous conductive pathways, improving overall conductivity. However, when the MXene content is too high, excessive stacking or aggregation of the layers can easily occur, leading to decreased system fluidity and even affecting printing continuity and film uniformity.
[0032] Therefore, by controlling the solid content mass ratio of MXene to PEDOT:PSS within a reasonable range, synergistic optimization between rheological properties and electrical conductivity can be achieved. In this invention, it is preferable to control the solid content mass ratio of MXene to PEDOT:PSS within the range of 1:0.5 to 1:5, more preferably 1:2 to 1:3, so that the ink system has both good printability and stable electrical conductivity.
[0033] In the conductive ink system of this application, the composition of the solvent system, especially the ratio of water to co-solvent, has a significant impact on the rheological behavior, surface tension, and drying characteristics of the ink. The introduction of the co-solvent can weaken the strong electrostatic interaction between the PSS chains and PEDOT chains in PEDOT:PSS, and induce the conformation of the PEDOT molecular chains to change from a coiled state to a more linear extended state, thereby improving the conductivity while changing the rheological characteristics of the ink system.
[0034] As the proportion of co-solvent increases, the surface tension of the ink system gradually decreases, the fluidity and spreadability of the system are enhanced, and the drying rate slows down accordingly, which is conducive to the formation of a more uniform conductive film. When the co-solvent content is low, the ink dries faster, which is suitable for process scenarios that require rapid film formation or high-throughput processing.
[0035] Therefore, by controlling the volume fraction of the co-solvent in the solvent system within the range of 2 to 20 vol%, preferably 5 to 15 vol%, the rheological behavior, drying speed, and film quality of the ink can be effectively adjusted without changing the proportion of conductive components, thereby enabling the composite conductive ink to flexibly adapt to different types of printing and coating processes.
[0036] Ultimately, the solid content not only determines the absolute content of conductive components in the ink, but is also one of the key parameters determining the ink's rheological properties, especially viscosity and thixotropic behavior. With increasing solid content, the interactions between MXene nanosheets and between MXene and PEDOT:PSS are enhanced, promoting the formation of a continuous and stable three-dimensional network structure, thereby significantly improving the ink's viscosity and storage modulus. Conversely, under lower solid content conditions, the interactions between particles in the ink system weaken, resulting in a system with lower viscosity and better flowability.
[0037] Therefore, by controlling the endpoint of the concentration process, the composite conductive ink can reach different final solid content ranges. This allows for effective control of ink viscosity without changing the material composition, enabling inks with the same basic formulation to be adapted to different types of printing or coating processes.
[0038] Synergistic Enhancement Achieves Performance Breakthrough: By constructing a multi-level composite system of MXene nanosheets and PEDOT:PSS molecules, a synergistic effect of "1+1>2" was achieved. On the one hand, MXene provides an excellent conductive framework; on the other hand, the coating and modification of PEDOT:PSS not only effectively inhibits the oxidative degradation of MXene, but also transforms its molecular chain from a benzene structure to a quinone structure with better conductivity through interaction. The synergy of these two factors greatly improves the conductivity of the composite ink and significantly enhances its electrochemical activity, laying a material foundation for the preparation of high-performance energy storage and sensor devices.
[0039] The bridging structure provides superior stability: the uniform and stable coating layer formed by PEDOT:PSS on the MXene surface effectively blocks the erosion of water molecules and oxygen, thus solving the problem of instability of two-dimensional MXene materials in the environment. Material lifespan and device reliability are significantly improved.
[0040] Precise rheological control adapts to various processes: By precisely designing the compound ratio and solvent system (such as adjusting the water / ethylene glycol ratio), the rheological properties of the ink, such as viscosity, yield stress, and thixotropy, can be controlled. This allows the same base formulation to flexibly adapt to vastly different manufacturing processes, from high-precision direct-write 3D printing to large-area screen printing, breaking through the limitations of traditional single inks on specific printing methods.
[0041] Green process and good processability: The entire preparation process uses water as the main solvent, combined with low-toxicity ethylene glycol, avoiding the use of large amounts of organic solvents, which is in line with the development direction of green manufacturing.
[0042] Another objective of this invention is to provide an MXene / PEDOT:PSS multi-level composite conductive ink, wherein the conductive ink comprises a core-shell structure unit formed by MXene nanosheets as the core and PEDOT:PSS molecules coating their surface, and a three-dimensional conductive network structure formed by the PEDOT:PSS molecular chains bridging the MXene nanosheets.
[0043] The MXene surface is rich in –O, –OH, and –F functional groups. PEDOT:PSS preferentially adsorbs onto the MXene surface through electrostatic interactions and π-π stacking to form a continuous or semi-continuous coating layer.
[0044] The solvent system is a mixture of water and ethylene glycol, with the volume fraction of ethylene glycol in the solvent system being 2–20 vol.
[0045] The rheological properties of the conductive ink can be controlled by adjusting the mass ratio of MXene to PEDOT:PSS, and / or adjusting the volume fraction of ethylene glycol in the solvent system, and / or adjusting the final solid content of the ink, to adapt to screen printing, inkjet printing or direct-write 3D printing processes, and to prepare flexible display devices, wearable sensor devices or smart packaging devices.
[0046] MXene / PEDOT:PSS composite conductive inks form a multi-level composite system with well-defined structural characteristics under controlled mixing sequence and interface regulation conditions. MXene two-dimensional nanosheets serve as the conductive core, while PEDOT:PSS acts as the interface coating and network building unit. Specifically, the MXene nanosheets are rich in functional groups such as –O, –OH, and –F and exhibit negative charge, while also possessing a graphite-like two-dimensional layered structure. Driven by electrostatic interactions and π-π stacking, the PEDOT conjugated backbone of PEDOT:PSS preferentially adsorbs and arranges itself on the MXene nanosheet surface, while the PSS side chains face the solvent phase. This results in continuous or semi-continuous polymer coating layers at the scale of individual MXene nanosheets, forming a core-shell composite structure with MXene as the core and PEDOT:PSS as the shell. As the number of MXene nanosheets in the system increases, the PEDOT:PSS coating layers on adjacent nanosheet surfaces further undergo multi-point molecular chain interactions, gradually constructing a three-dimensional conductive network encapsulation structure that permeates the system, embedding the MXene nanosheets within the polymer network. This continuous coating and three-dimensional network structure forms an effective physical barrier between MXene and the external environment. On the one hand, it significantly reduces the opportunity for oxygen and water molecules to directly contact the active surface of MXene, and on the other hand, it extends their diffusion path in the system, thereby reducing the oxidation reaction rate. At the same time, the occupation of active sites on the MXene surface by PEDOT:PSS and the spatial confinement of the nanosheets by the network structure jointly inhibit the environmental oxidation and structural instability of MXene, achieving long-term stable protection of the conductivity of MXene.
[0047] Another objective of this invention is to provide an application of MXene / PEDOT:PSS multi-level composite conductive ink in the fabrication of flexible electronic devices, wherein the flexible electronic devices include at least one of flexible electrodes, flexible sensors, radio frequency identification antennas, or energy storage devices.
[0048] Example 1 Take a pH 1000 aqueous solution (solid content of 1.3 wt%), add ethylene glycol at 10% of the volume of the PEDOT:PSS solution, and mix with magnetic stirring at room temperature for 30 min to obtain a PEDOT:PSS / ethylene glycol mixed solution.
[0049] Take an MXene aqueous dispersion with a concentration of 10 mg / mL and calculate the amount to be added based on a solid content mass ratio of MXene:PEDOT:PSS = 1:5. Under argon protection and light-proof conditions, slowly add the MXene dispersion dropwise to the PEDOT:PSS / EG mixture, and continuously stir the system at 300–500 rpm. After the addition is complete, continue stirring for 2–4 hours to promote the interfacial interaction between MXene and PEDOT:PSS.
[0050] The resulting mixture was transferred to a rotary evaporator and concentrated under vacuum at a water bath temperature of about 35°C. The concentration endpoint was determined by monitoring the changes in system mass and flow state until the final solid content reached about 15 wt%, thus obtaining the composite conductive ink.
[0051] The prepared MXene / PEDOT:PSS composite conductive ink exhibits good dispersion stability, with no obvious sedimentation or phase separation observed during standing and processing. During screen printing, the ink achieves continuous and stable output, forming uniform and continuous conductive patterns with low resistance and stable conductivity.
[0052] Example 2 Except for adjusting MXene:PEDOT:PSS=1:2 in Example 1, the other PEDOT:PSS pretreatment steps, ethylene glycol addition amount, mixing conditions and rotary evaporation process are the same as in Example 1. Finally, the system is concentrated to about 15wt% solid content to obtain composite conductive ink.
[0053] The prepared composite conductive ink also exhibited good dispersion and processing stability. Compared with Example 1, the contribution of the MXene conductive network in this ink was more significant, which is beneficial for constructing continuous conductive pathways while maintaining good film-forming properties.
[0054] During the printing process, the ink can form a continuous and uniform conductive structure, further improving its conductivity, making it suitable for printed electronics applications with high conductivity requirements.
[0055] Example 3 Except for adjusting the concentration endpoint of rotary evaporation to achieve a final solid content of approximately 35 wt%, the mass ratio of MXene to PEDOT:PSS (1:5), the amount of ethylene glycol added, and the mixing conditions were the same as in Example 1, resulting in a high solid content composite conductive ink.
[0056] The resulting composite conductive ink exhibits good dispersion stability, demonstrating more pronounced viscoelastic characteristics and shape retention. Compared to Example 1, this ink exhibits stronger structural stability during the forming process. During direct-write printing, the ink maintains the integrity and continuity of the printed structure, forming a stable conductive structure with low resistance and stable conductivity.
[0057] Comparative Example 1 The MXene aqueous dispersion and the original PEDOT:PSS solution were directly mixed at a solid content mass ratio of 1:5. After rapid stirring and mixing under air conditions, the system was concentrated to a solid content of approximately 15 wt% by rotary evaporation to obtain conductive ink.
[0058] The ink exhibited uneven dispersion or slight sedimentation during preparation, resulting in poor viscosity stability. Continuous and uniform film formation was difficult to achieve during printing, and the conductivity and environmental stability of the resulting conductive patterns were significantly lower than those in Examples 1-3.
[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing an MXene / PEDOT:PSS multi-level composite conductive ink, characterized in that, The preparation method includes the following steps: S1. Add 1.0g LiF to 30mL 9M HCl solution and stir magnetically at 500rpm for 60 minutes until completely dissolved to form an etching agent; S2. Add 1.0g of Ti3AlC2 powder to the etching agent, and stir at 600-800rpm for 20 hours in a constant temperature water bath at 35℃. After centrifugation, washing, argon bubbling, ultrasonic treatment, and centrifugation separation, a few-layer Ti3C2T is obtained. x The MXene dispersion was freeze-dried and then redispersed to a homogeneous dispersion of 10 mg / mL. S3. Measure Clevios™ PH1000 aqueous solution, add 5-15 vol% ethylene glycol, and stir at 300 rpm at room temperature for 30 minutes. Add the above MXene dispersion dropwise according to the solid content mass ratio of MXene to PEDOT:PSS of 1:0.5-1:5, and stir at 400 rpm for 4 hours under argon protection and in the dark. Concentrate by rotary evaporation at a water bath temperature of 35℃ and a rotation speed of 80 rpm, and monitor the target solid content by weighing to obtain the composite conductive ink.
2. The preparation method of the MXene / PEDOT:PSS multi-level composite conductive ink according to claim 1, characterized in that, The separation and purification steps in step S2 include: diluting the reaction product with deionized water, centrifuging at 3000-4000 rpm, discarding the supernatant, and washing repeatedly until the pH of the supernatant is >5; redispersing the precipitate in deionized water, centrifuging at 1000-2000 rpm, and collecting the dark green supernatant; bubbling with argon for 15 minutes, sonicating in an ice-water bath for 20 minutes, centrifuging the dispersion at 3000-4000 rpm, collecting the dark green precipitate at the bottom, and dispersing it in an appropriate amount of deionized water to obtain the few-layer Ti3C2T. x MXene dispersion.
3. The method for preparing the MXene / PEDOT:PSS multi-level composite conductive ink according to claim 2, characterized in that, In step S3, the solid content mass ratio of MXene to PEDOT:PSS is 1:0.5 to 1:
5.
4. The preparation method of the MXene / PEDOT:PSS multi-level composite conductive ink according to claim 3, characterized in that, In step S3, ethylene glycol accounts for 10 vol of the volume of the PEDOT:PSS aqueous solution.
5. The preparation method of the MXene / PEDOT:PSS multi-level composite conductive ink according to claim 4, characterized in that, The target solid content for rotary evaporation in step S3 is 15wt% to 35wt%.
6. An MXene / PEDOT:PSS multi-level composite conductive ink obtained by the preparation method according to any one of claims 1-5, characterized in that, The conductive ink comprises a core-shell structure unit with MXene nanosheets as the core and PEDOT:PSS molecules coating their surface, and a three-dimensional conductive network structure formed by the PEDOT:PSS molecular chains bridging the MXene nanosheets.
7. The MXene / PEDOT:PSS multi-level composite conductive ink according to claim 6, characterized in that, The MXene surface is rich in –O, –OH, and –F functional groups. PEDOT:PSS preferentially adsorbs onto the MXene surface through electrostatic interactions and π-π stacking to form a continuous or semi-continuous coating layer.
8. The MXene / PEDOT:PSS multi-level composite conductive ink according to claim 7, characterized in that, The solvent system is a mixture of water and ethylene glycol, with the volume fraction of ethylene glycol in the solvent system being 2–20 vol.
9. The MXene / PEDOT:PSS multi-level composite conductive ink according to claim 8, characterized in that, The rheological properties of the conductive ink can be controlled by adjusting the mass ratio of MXene to PEDOT:PSS, and / or adjusting the volume fraction of ethylene glycol in the solvent system, and / or adjusting the final solid content of the ink, to adapt to screen printing, inkjet printing or direct-write 3D printing processes, and to prepare flexible display devices, wearable sensor devices or smart packaging devices.
10. The application of the MXene / PEDOT:PSS multi-level composite conductive ink according to any one of claims 6-9 in the fabrication of flexible electronic devices, characterized in that, The flexible electronic device includes at least one of flexible electrodes, flexible sensors, radio frequency identification antennas, or energy storage devices.