A two-dimensional conductive polymer bridged by disulfonic acid and a preparation method and application thereof

Abstract

The application relates to a two-dimensional conductive polymer doped by a disulfonic acid bridge, a preparation method and application thereof. The method is realized by solid-liquid interface limited in-situ polymerization and introduction of a disulfonic acid dopant with a double anchoring position function. On the premise of ensuring the continuity, uniformity and controllability of the film, the effective improvement of the overall electrical performance of the two-dimensional conductive polymer film is realized, so as to reduce the anisotropy of the material electric transport. Compared with the prior art, the application can stably obtain a continuous conductive film with a centimeter level or even a larger area, and meets the requirements of the manufacturability and application scale of flexible electronics and functional devices. The preparation method has the advantages of simple process, strong controllability, applicability to various conductive polymer systems, good repeatability and expandability, and the prepared two-dimensional conductive polymer has wide application prospects in the fields of flexible electronic devices, anisotropic conductive films and related electronic functional materials.

Description

Technical Field

[0001] This invention relates to the field of conductive polymer materials technology, and in particular to a disulfonic acid-bridged doped two-dimensional conductive polymer, its preparation method, and its application. Background Technology

[0002] With the rapid development of flexible electronic devices, wearable electronic devices, and novel functional thin-film devices, higher requirements are being placed on conductive materials in terms of continuity, uniformity, flexibility, and processability. Compared to traditional inorganic conductive materials, conductive polymers have attracted widespread attention in fields such as flexible electronics, electrochemical devices, sensors, and functional thin films due to their advantages of good mechanical flexibility, solution processability, and the ability to regulate structure and performance through chemical means.

[0003] In recent years, two-dimensional conductive polymers have gradually attracted the attention of researchers as a novel form of conductive polymer structure. Through confined synthesis and interface-induced growth, conductive polymers can be used to form two-dimensional thin film structures with orientation or layered features on substrate surfaces. Compared with traditional bulk or disordered thin films, two-dimensional conductive polymers exhibit higher structural order at the molecular scale, which is beneficial for forming continuous charge transport paths, thereby improving the in-plane charge transport performance of the material to a certain extent. Simultaneously, thanks to the flexible characteristics of the organic framework, these two-dimensional thin films exhibit good mechanical compliance with flexible or curved substrates.

[0004] However, existing two-dimensional conductive polymer systems still face many problems in practical preparation and application. On the one hand, some studies have obtained high conductivity through single crystals or highly ordered structures, but such methods usually rely on strict growth conditions, are highly sensitive to substrate type and process environment, and the resulting material size is limited, making it difficult to achieve large-area, continuous and uniform thin film preparation, which restricts their application in practical devices.

[0005] On the other hand, two-dimensional conductive polymer systems capable of large-area continuous film formation often exhibit significant imbalances in charge transport across different spatial dimensions. Due to the limited electronic coupling between conductive polymer chains and layers, charge is primarily transported along the polymer chain direction or in-plane direction of the film, while the charge transport capability in the thickness direction is weak. This results in limited overall conductivity of the material and significant anisotropy in charge transport, especially in multilayer stacked or thicker film structures.

[0006] To address the aforementioned issues, existing technologies typically improve the electrical properties of conductive polymers by increasing the doping level, introducing inorganic conductive fillers, or controlling polymerization conditions. However, increasing the doping level primarily increases carrier concentration, with limited effect on improving inter-chain or interlayer charge coupling; introducing inorganic conductive fillers may disrupt the continuity and flexibility of the film; and relying solely on controlling polymerization conditions often makes it difficult to achieve synergistic optimization of charge transport behavior in different spatial dimensions while maintaining two-dimensional structural characteristics and large-area film formation capability.

[0007] Chinese patent CN113929879B discloses a diacetylene-bridged one-dimensional linear or two-dimensional network organic energy storage material, its preparation method, and its applications. This method uses a fused structure of five-membered heterocyclic and eight-membered rings as the basic unit, and prepares the diacetylene-bridged one-dimensional linear or two-dimensional network organic energy storage material through substitution reactions, Sonogashira reactions, deprotection reactions, and Eglinton reactions. In this material, the fused ring structure can undergo planar to saddle-shaped structure transformation during electron gain and loss, overcoming the π-π interactions between molecular layers. Furthermore, the fused ring structure, bridged by diacetylene groups, exhibits good conductivity and high redox stability. In particular, the two-dimensional network structure has a regular porous structure, which is beneficial for ion and electron transport, making it suitable for use as an energy storage material, such as an electrode material for sodium-ion batteries. However, this patent primarily uses rigid covalent bridging units –C≡C–C≡C– to achieve structural connections. Its bridging method focuses on the geometric extension of the molecular skeleton, offering limited control over electronic structure and intermolecular interactions, making it difficult to form continuous and efficient charge transport channels across molecular units. Furthermore, its method of weakening π-π interactions through intramolecular conformational changes is a passive adjustment, failing to fundamentally achieve effective control over interlayer stacking and order.

[0008] Chinese patent CN120271861A discloses a two-dimensional ordered conductive polymer film, its synthesis method, and its applications. The synthesis method includes: adding an oxidant solution to a reaction vessel, then adding a monomer solution while stirring, and mixing thoroughly to obtain a reaction solution; placing a substrate material parallel to the surface of the reaction solution and allowing it to float on the surface, then allowing it to stand for a period of time, resulting in a uniform two-dimensional ordered conductive polymer film adhering to the substrate material at the interface where the reaction solution surface contacts the substrate material. This method is applicable to the preparation of ordered conductive polymers by redox polymerization and has high versatility. The prepared conductive polymer film exhibits excellent photothermal conversion performance and has broad application prospects in fields such as smart buildings and energy management. However, the solid-liquid interface confined polymerization method used in this patent has significant limitations in practical industrial applications. First, this method requires the substrate to float statically on the liquid surface, severely limiting the area prepared in a single operation to the size of the reaction vessel. The process is cumbersome and time-consuming, making it difficult to meet the demands of large-area, continuous industrial production. Second, during interfacial film formation, a large number of monomers and oxidants spontaneously undergo random phase polymerization within the reaction system, resulting in significant waste of raw materials. Furthermore, this static polymerization is highly dependent on the natural diffusion of reactants in the liquid phase, limiting film thickness growth and easily leading to uneven thickness when attempting to expand the prepared area, making precise control of the microstructure of large-area films difficult. More importantly, from the perspective of the invention's intrinsic material properties, this patent relies solely on a single physical interface confinement, lacking a chemical control mechanism at the polymer molecular level (such as introducing specific crosslinking or bridging doping mechanisms). This results in weak inter-chain and interlayer interactions within the generated two-dimensional film, and carriers face extremely high barriers during cross-chain and cross-layer transport. Therefore, although this method endows the material with certain photothermal conversion properties and in-plane conductivity, it severely limits its three-dimensional charge transport capability, especially making it difficult to fundamentally improve its out-of-plane conductivity, thus failing to meet the stringent requirements of modern high-performance electronic devices for omnidirectional and high-efficiency charge transport of conductive polymer materials.

[0009] Therefore, there is an urgent need for a preparation method that can effectively regulate the interactions between polymer chains and layers, thereby improving the overall electrical properties of the material, while ensuring large-area continuous film formation and good process controllability of two-dimensional conductive polymer films, so as to meet the practical application requirements of flexible electronics and related functional devices for high-performance conductive films. Summary of the Invention

[0010] The purpose of this invention is to solve at least one of the above-mentioned problems by providing a disulfonic acid-bridged doped two-dimensional conductive polymer, its preparation method, and its application. The method involves in-situ polymerization of the conductive polymer under solid-liquid interface confinement conditions, and introducing an organic disulfonic acid with two spatially separated sulfonic acid groups as a dopant during the polymerization process. This allows the dopant to interact with adjacent conductive polymer chain segments at multiple points, thereby constructing a controllable inter-chain coupling structure in the two-dimensional polymer system and achieving synergistic optimization of material structural order and charge transport performance.

[0011] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a method for preparing a disulfonic acid-bridged doped two-dimensional conductive polymer, characterized by comprising the following steps: S10: The substrate is pretreated, and conductive polymer monomer solution, bridging dopant solution and oxidant solution are prepared respectively; S20: Under the confined conditions of the solid-liquid interface, the conductive polymer monomer solution, the bridging dopant solution and the oxidant solution are polymerized in situ on the substrate surface to form a two-dimensional conductive polymer film crude product 1 on the substrate surface; S30: The crude two-dimensional conductive polymer film 1 obtained in step S20 is cleaned to remove unreacted monomers and residual oxidants or by-products. After cleaning, crude two-dimensional conductive polymer film 2 is obtained. S40: Dry the two-dimensional conductive polymer film crude product 2 after cleaning in step S30 to obtain the two-dimensional conductive polymer film finished product. The bridging dopant is an organic disulfonic acid with a disulfonic acid group structure.

[0012] Furthermore, the substrate in step S10 is quartz glass, and the pretreatment step of the substrate is as follows: the substrate is ultrasonically cleaned in acetone, ethanol and deionized water in sequence, dried and then subjected to plasma cleaning or UV-ozone treatment for 5–15 min.

[0013] Further, the conductive polymer monomer in step S10 is pyrrole; the conductive polymer monomer solution is prepared by the following steps: adding pyrrole to deionized water at low temperature to prepare the conductive polymer monomer solution; The low temperature condition is 0–5 °C; the concentration of the conductive polymer monomer is 0.02–0.10 mol / L.

[0014] Further, the bridging dopant solution in step S10 is prepared by dissolving organic disulfonic acid in deionized water, and its concentration is 0.01-0.2 mol / L, wherein the organic disulfonic acid includes one or more of methanedisulfonic acid, ethanedisulfonic acid, succinic acid, or naphthalenedisulfonic acid.

[0015] Furthermore, in step S10, the oxidant solution is prepared by dissolving the oxidant in deionized water, and the oxidant is ammonium persulfate, with a concentration of 0.01-0.2 mol / L.

[0016] Furthermore, the in-situ polymerization under solid-liquid interface confinement conditions in step S20 includes the following steps: S21: Place the substrate treated in step S10 into the reaction vessel to form a stable solid-liquid interface with the reaction solution; S22: The conductive polymer monomer solution prepared in step S10 is mixed with the bridging dopant solution and added to the reaction vessel in step S21. Then, an oxidant solution is added dropwise, and an in-situ polymerization reaction is carried out under static conditions so that the conductive polymer preferentially forms a film on the substrate surface. In step S22, the molar ratio of the bridging dopant to the conductive polymer monomer is 0.1-1.0:1; the molar ratio of the oxidant to the conductive polymer monomer is 0.8-1.5:1; the reaction temperature of the in-situ polymerization reaction is 0–5 ℃, and the reaction time is 8–16 h.

[0017] Further, the cleaning step in step S30 includes: after the polymerization is completed, the substrate is removed, the upper reaction solution is removed, and the film on the surface of the substrate is repeatedly washed with deionized water until the washing solution is close to neutral. Then, the substrate is further washed 1–3 times with an organic solvent, wherein the organic solvent is either ethanol or isopropanol.

[0018] Furthermore, the drying temperature is 40–80 °C, the drying time is 2–12 h, and the drying method is vacuum drying.

[0019] In a second aspect, the present invention provides a disulfonic acid-bridged doped two-dimensional conductive polymer, which is prepared by any of the methods described above.

[0020] In a third aspect, the present invention provides an application of a disulfonic acid-bridged doped two-dimensional conductive polymer, wherein the two-dimensional conductive polymer is applied to flexible electronic devices and anisotropic conductive films.

[0021] In this invention, controlling the concentration of the conductive polymer monomer within the aforementioned range helps to ensure the continuity of interfacial film formation while avoiding excessively rapid polymerization in the bulk solution phase. If the monomer concentration is too low, it is difficult to form a continuous and complete two-dimensional conductive polymer film; if the monomer concentration is too high, bulk polymerization is likely to occur, affecting the film uniformity and structural controllability.

[0022] When the molar ratio of disulfonic acid dopant to conductive polymer monomer is controlled within the aforementioned range, charge compensation and structural regulation can be achieved simultaneously during polymerization. When the content of disulfonic acid dopant is too low, its regulatory effect on the inter-chain or interlayer structure of polymers is not significant; when the content of disulfonic acid dopant is too high, it may introduce too many non-conductive components, which is detrimental to the stability of the film structure and the overall electrical properties.

[0023] Controlling the in-situ polymerization temperature within the range of 0–10 °C helps suppress rapid bulk reactions and promotes the preferential growth of conductive polymers at the solid-liquid interface, thereby forming conductive polymer films with two-dimensional structural features. Proper control of the reaction time contributes to obtaining structurally complete and thickness-controllable two-dimensional conductive polymer films.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention introduces organic disulfonic acid with a disulfonic acid group structure as a bridging dopant to construct a multi-point electrostatic coupling structure in a two-dimensional conductive polymer system, which effectively enhances the electronic coupling ability between adjacent polymer chain segments. Thus, while maintaining the two-dimensional structural characteristics and the ability to form a large-area continuous film, it reduces the transport barrier of charge carriers in different spatial dimensions, thereby improving the overall electrical performance of the material and optimizing the transport anisotropy.

[0025] 2. This invention performs in-situ polymerization under the confined conditions of the solid-liquid interface. The electric field strength at the interface is enhanced by the double electric layer present at the solid-liquid interface, which allows the bridging dopant to be embedded into the polymer chain more efficiently, thereby obtaining a two-dimensional conductive polymer with a higher doping degree. This provides more charge carriers, which enables the two-dimensional conductive polymer prepared by this invention to improve its charge transport capability in the thickness direction while maintaining the structural order of the two-dimensional conductive polymer, reducing the anisotropy of electric transport, and improving the overall electrical performance of the material.

[0026] 3. The preparation method described in this invention does not require the introduction of additional inorganic conductive fillers, the process is simple and highly controllable, it is applicable to a variety of conductive polymer systems, has good repeatability and scalability, and is convenient for preparing large-area continuous two-dimensional conductive polymer films. Attached Figure Description

[0027] Figure 1 This is a flowchart of the method for preparing the disulfonic acid-bridged doped two-dimensional conductive polymer of the present invention. Figure 2 The images shown are of the two-dimensional conductive polymer film prepared in Example 1 of the present invention, wherein Figure (a) is a macroscopic photograph, Figure (b) is a scanning electron microscope (SEM) morphology image, and Figure (c) is an atomic force microscope (AFM) step thickness image. Figure 3 The images shown are high-resolution transmission electron microscope (HRTEM) images and selected area electron diffraction (SAED) images of Embodiment 1 and Comparative Example 1 of the present invention. Figure 4 The temperature-dependent conductivity curves of Comparative Example 1 and Example 1 of this invention were tested using the van der Burg method. Figure 5 The images show the surface current distribution diagrams and corresponding out-of-plane current distribution curves of Comparative Example 1 and Example 1 of this invention using conductive atomic force microscopy (C-AFM). Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0029] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, although not explicitly stated, each point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can be used as its own lower or upper limit and combined with any other point or individual value, or combined with other lower or upper limits, to form a range not explicitly stated. In the description of this application, it should be noted that, unless otherwise stated, "above" includes the stated number, and "multiple" in "one or more" means two or more.

[0030] The foregoing description of this application is not intended to describe every disclosed implementation or method. Instead, the following description provides more specific examples of exemplary embodiments. Throughout the application, guidance is provided through a series of embodiments that can be used in various combinations. The examples listed are representative only and should not be construed as exhaustive.

[0031] Numerous details are explored in the following description to provide a more thorough explanation of embodiments of this application; however, it will be apparent to those skilled in the art that embodiments of this application may be practiced without these specific details.

[0032] This invention involves in-situ polymerization of conductive polymers under confined conditions at the solid-liquid interface, and the introduction of an organic disulfonic acid with two spatially separated sulfonic acid groups as a dopant during the polymerization process. This allows the dopant to interact with adjacent conductive polymer chains at multiple points, thereby constructing a controllable inter-chain coupling structure in a two-dimensional polymer system and achieving synergistic optimization of material structural order and charge transport performance.

[0033] To further understand the present invention, the following embodiments are provided. It is worth noting that, unless otherwise specified, all raw materials used in the present invention are commercially available; and all methods and equipment employed are common in the art.

[0034] Example 1 like Figure 1 As shown, this embodiment provides a method for preparing a two-dimensional conductive polymer, including the following steps: Step S1: Select quartz glass as the reaction substrate, and place the substrate in acetone, ethanol and deionized water in sequence for ultrasonic cleaning. The cleaning time for each step is 10 min. After the cleaned substrate is dried, the surface is activated by plasma cleaning or UV-ozone treatment for 15 minutes, and then set aside.

[0035] Step S2, preparing a conductive polymer monomer solution, includes the following steps: Using pyrrole as a conductive polymer monomer, a monomer solution was prepared by adding pyrrole to deionized water at 0°C. The concentration of the pyrrole solution is 0.02 mol / L. After preparation, it is left to stand at 0°C for later use.

[0036] Step S3: Prepare the bridging dopant solution.

[0037] The bridging dopant is dissolved in deionized water. The bridging dopant is naphthalene disulfonic acid, wherein the molar ratio of naphthalene disulfonic acid to pyrrole is 1:1.

[0038] The concentration of the naphthalene disulfonic acid solution is 0.1 mol / L.

[0039] Step S4: Prepare the oxidant solution.

[0040] An oxidant solution was prepared by dissolving an oxidant in deionized water. The oxidant was ammonium persulfate, and its molar ratio with pyrrole was 1:1. The solution was then pre-cooled at 0 °C for later use.

[0041] The concentration of the ammonium persulfate solution is 0.02 mol / L.

[0042] Step S5 involves an in-situ polymerization reaction conducted under confined conditions at the solid-liquid interface. The process includes: The pretreated substrate is placed in a glass beaker so that it can form a stable solid-liquid interface with the reaction solution; The pyrrole solution and the bridging dopant solution are mixed evenly and then added to the reaction vessel. Under static conditions, ammonium persulfate solution is added to the reaction system by slow dropwise addition, so that the conductive polymer undergoes in-situ polymerization on the substrate surface and forms a crude two-dimensional conductive polymer film 1.

[0043] Step S6: After the polymerization reaction is complete, remove the substrate and remove the upper reaction liquid.

[0044] The crude two-dimensional conductive polymer film 1 obtained in step S5 was then washed with deionized water, repeated 5 times until the washing solution was neutral. To ensure complete removal of acidic bridging dopants and amorphous polypyrrole powder byproducts generated by free polymerization, the filtrate (or washing solution) was tested with precision pH paper or a pH meter after each wash until the washing solution was neutral (pH value between 6.8 and 7.2). Then, ethanol was used for further washing 3 times to remove residual unreacted monomers and oligomer impurities, yielding crude two-dimensional conductive polymer film 2.

[0045] Step S7: The cleaned two-dimensional conductive polymer film crude product 2 undergoes post-processing. The two-dimensional conductive polymer film crude product 2 obtained in step S6 is placed in a vacuum drying oven and dried at 80 ℃ for 12 h to stabilize the film structure and electrical properties.

[0046] After the above steps, a two-dimensional conductive polymer film is obtained.

[0047] Comparative Example 1 This comparative example is largely the same as Example 1, except that no bridging dopant was introduced during the preparation process to prepare an unbridged two-dimensional conductive polymer film as a control sample.

[0048] In this comparative example, the preparation method of the two-dimensional conductive polymer film includes the following steps: Step S1: Prepare the substrate, pyrrole solution, and ammonium persulfate solution respectively.

[0049] Step S2: In-situ polymerization reaction is carried out under the confined conditions of solid-liquid interface to form a two-dimensional conductive polymer film on the substrate surface.

[0050] Step S3: After the polymerization reaction is completed, the obtained two-dimensional conductive polymer film is cleaned and dried to finally obtain a two-dimensional conductive polymer film without the introduction of bridging dopants, which is the sample of Comparative Example 1.

[0051] Since no rigid bridging dopant with dual anchoring points was introduced in the sample of Comparative Example 1, there is no effective structural coupling between conductive polymer chain segments and between layers. This is used to illustrate the role of bridging dopant regulation in improving the structure and electrical properties of two-dimensional conductive polymers.

[0052] Comparative Example 2 This comparative example is largely the same as Example 1, except that the polymerization reaction of the conductive polymer is carried out in the bulk solution phase, rather than under solid-liquid interface confinement conditions.

[0053] Step S1: Prepare pyrrole solution, bridging dopant solution and ammonium persulfate solution respectively.

[0054] Step S2: Slowly add the bridging dopant solution and ammonium persulfate solution dropwise into the pyrrole solution to carry out the in-situ polymerization reaction.

[0055] Step S3: After the polymerization reaction is completed, the obtained conductive polymer powder is cleaned and dried to obtain the conductive polymer prepared under non-interface confinement conditions, which is the sample of Comparative Example 2.

[0056] This comparative example is used to illustrate the role of solid-liquid interface confinement conditions in forming two-dimensional conductive polymer structures and improving charge transport properties.

[0057] Performance testing (1) Sample description: The two-dimensional conductive polymer film prepared in Example 1 is referred to as Sample 1; the two-dimensional conductive polymer film without bridging dopant prepared in Comparative Example 1 is referred to as Control Sample 1; and the non-interface confined conductive polymer powder prepared in Comparative Example 2 is referred to as Control Sample 2.

[0058] (2) Thin film conductivity test: Since both Sample 1 and Control Sample 1 benefit from the solid-liquid interface confinement strategy and have a continuous two-dimensional thin film morphology, the in-plane and out-of-plane conductivity of the fabricated devices were tested. Control Sample 2, due to its non-interface confinement system, resulted in a severely agglomerated powder morphology, making it impossible to form a film. To avoid testing errors caused by the huge contact resistance between powder particles, the same thin film conductivity comparison test was not performed on it.

[0059] Experimental verification shows that sample 1 can be obtained by using the polymerization reaction method on the substrate provided in the embodiments of the present invention, as shown in the figure. Figure 2 As shown, the product can form a macroscopically continuous two-dimensional thin film, with a single-batch film area reaching 324 cm². 2In stark contrast, control sample 2, prepared using traditional polymerization methods, failed to form a film at all, yielding only discrete powdery agglomerates. This fundamental morphological difference fully demonstrates that the method of this invention effectively overcomes the bottleneck of traditional processes in constructing continuous two-dimensional macroscopic thin films. Furthermore, to further verify the universality and reproducibility of this method, this invention successfully extended the polymerization reaction to various substrates of different materials (e.g., glass, flexible PET, silicon wafers, and ITO glass) under the same experimental conditions. This method exhibits excellent substrate independence, stably generating macroscopically continuous two-dimensional thin films on different types of substrate surfaces, with highly consistent film area, thickness, and film quality. Morphological structure and electrical properties of the above samples were tested. Macroscopic photographs, scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to demonstrate the high quality and uniformity of the materials at multiple scales. Simultaneously, the in-plane conductivity of the samples was determined using a physical property measurement system (PPMS) combined with the van der Berg method, and the out-of-plane conductivity was determined using a conductive atomic force microscope (c-AFM) based on vertical testing.

[0060] Combination Figure 2 and Figure 3 It can be clearly seen that this invention achieves high-quality growth of materials across the entire scale, from the macroscopic wafer level to the atomic level microstructure, by optimizing the preparation process.

[0061] Figure 2 Images of the two-dimensional conductive polymer film prepared in Example 1 of this invention are shown below. Figure 2 As shown, the film prepared in Example 1 not only maintains high uniformity on an 8-inch large-size substrate ( Figure 2 a), and possesses excellent mechanical continuity and surface smoothness. AFM results ( Figure 2 c) shows a uniform thickness of approximately 200 nm and SEM ( Figure 2 b) The fact that the thin film perfectly spans the micropore array without damage indicates that the thin film has excellent structural integrity.

[0062] Figure 3 High-resolution transmission electron microscopy (HRTEM) images and selected area electron diffraction (SAED) images are shown, for example. Figure 3 As shown, further characterization by HRTEM and SAED revealed that this large-area uniform thin film possesses the microstructure basis for achieving excellent conductivity. Example 1 ( Figure 3a) It exhibits locally highly ordered lattice fringes (interplanar spacing 0.375 nm) and clear diffraction spots, presenting a microstructure that interweaves order and disorder. This locally regular arrangement with specific spacing can effectively reduce carrier scattering, providing a continuous and efficient channel for charge transition and transport, thereby significantly improving the overall conductivity of the material.

[0063] In contrast, Comparative Example 1 ( Figure 3 (b) At the microscopic level, the crystal lattice arrangement is highly disordered (local interplanar spacing is 0.258 nm), and the diffraction pattern exhibits diffuse polycrystalline or near-amorphous diffraction rings. This highly disordered internal structure generates a large number of defects and interface barriers, severely hindering the transport of charge carriers. This demonstrates that the process of this invention successfully constructs a microscopically ordered network conducive to efficient conductivity while growing over a large area.

[0064] Combination Figure 4 and Figure 5 The electrical test results show that the strategy adopted in this invention not only significantly improves the basic conductivity of the material, but also successfully breaks through the traditional charge transport barrier in the thickness direction of thin films, and significantly reduces the anisotropy of electrical transport. Figure 4 The graphs show the temperature-dependent conductivity curves of Example 1 and Comparative Example 1. Figure 4 As shown in the in-plane temperature-varying conductivity, both Comparative Example 1 and Example 1 employed a solid-liquid interface confinement strategy. Although interface confinement can induce the molecular chains to form a locally ordered arrangement (exhibiting a microstructure of ordered and disordered interweaving), relying solely on the confinement effect (Comparative Example 1), there is a lack of effective charge connections between adjacent conductive domains, resulting in an in-plane conductivity of only 1.9 S / cm at room temperature. In contrast, Example 1 introduced disulfonic acid molecules as a bridging dopant on the basis of confinement, resulting in a significant increase in in-plane conductivity to 64 S / cm, and a significant reduction in charge transport activation energy (ln( σ ) for 1000 / T The absolute value of the fitting slope decreased from 0.85 to 0.255. This indicates that the bridging agent successfully connected the locally ordered micro-regions generated by the confinement, constructing a smoother two-dimensional planar transport channel.

[0065] More importantly, the out-of-plane test results directly demonstrate the "wall-breaking" effect of the bridging dopant in the vertical direction. While traditional interface confinement strategies can improve in-plane crystallinity, they often exacerbate the layered characteristics of the material, leading to severe obstruction of charge transport between layers (out-of-plane direction) and significant anisotropy. To address this issue, the disulfonic acid dopant in Example 1 utilizes its two active groups to exert a crucial "double-hook" bridging effect between adjacent polymer layers.

[0066] Figure 5This is a test image from out-of-plane conductivity atomic force microscopy (c-AFM). For example... Figure 5 As shown, under the same solid-liquid interface confinement criterion, Comparative Example 1, lacking bridging, exhibits a local current response of only 0–20 nA in the vertical direction, with an average current of 4.08 nA and an out-of-plane conductivity of 2.59 S / cm. In contrast, Example 1, which incorporates a bridging agent, achieves an out-of-plane local current response range of 0–200 nA, representing an approximately 10-fold improvement, with an average current of 52.2 Na and an out-of-plane conductivity of 33.23 S / cm.

[0067] The above results demonstrate that introducing bridging dopants under solid-liquid interface confinement conditions for bridging regulation can effectively improve the charge transport performance of two-dimensional conductive polymers in different spatial dimensions, thus verifying the effectiveness and superiority of the technical solution of this invention.

[0068] The foregoing has shown and described the basic process, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a two-dimensional conductive polymer doped with a disulfonic acid bridge, characterized by, Includes the following steps: S10: The substrate is pretreated, and conductive polymer monomer solution, bridging dopant solution and oxidant solution are prepared respectively; S20: Under the confined conditions of the solid-liquid interface, the conductive polymer monomer solution, the bridging dopant solution and the oxidant solution are polymerized in situ on the substrate surface to form a two-dimensional conductive polymer film crude product 1 on the substrate surface; S30: The crude two-dimensional conductive polymer film 1 obtained in step S20 is cleaned to remove unreacted monomers and residual oxidants or by-products. After cleaning, crude two-dimensional conductive polymer film 2 is obtained. S40: Dry the two-dimensional conductive polymer film crude product 2 after cleaning in step S30 to obtain the two-dimensional conductive polymer film finished product. The bridging dopant is an organic disulfonic acid with a disulfonic acid group structure.

2. A process for the preparation of a two-dimensional conducting polymer doped with a disulfonic acid bridge according to claim 1, characterized in that, The substrate in step S10 is quartz glass. The pretreatment steps for the substrate are as follows: the substrate is ultrasonically cleaned in acetone, ethanol and deionized water in sequence, dried and then subjected to plasma cleaning or UV-ozone treatment for 5–15 min.

3. The method for preparing a disulfonic acid-bridged doped two-dimensional conductive polymer according to claim 1, characterized in that, The conductive polymer monomer in step S10 is pyrrole; the conductive polymer monomer solution is prepared by the following steps: pyrrole is added to deionized water at low temperature to prepare the conductive polymer monomer solution; The low temperature condition is 0–5 °C; the concentration of the conductive polymer monomer is 0.02–0.1 mol / L.

4. The method for preparing a disulfonic acid-bridged doped two-dimensional conductive polymer according to claim 1, characterized in that, The bridging dopant solution in step S10 is prepared by dissolving organic disulfonic acid in deionized water, and its concentration is 0.01-0.2 mol / L. The organic disulfonic acid includes one or more of methanedisulfonic acid, ethanedisulfonic acid, succinic acid, or naphthalenedisulfonic acid.

5. The method for preparing a disulfonic acid-bridged doped two-dimensional conductive polymer according to claim 1, characterized in that, In step S10, the oxidant solution is prepared by dissolving an oxidant in deionized water. The oxidant is ammonium persulfate, and the concentration of the oxidant solution is 0.01-0.2 mol / L.

6. The method for preparing a disulfonic acid-bridged doped two-dimensional conductive polymer according to claim 1, characterized in that, The in-situ polymerization under the confined conditions at the solid-liquid interface in step S20 includes the following steps: S21: Place the substrate treated in step S10 into the reaction vessel to form a stable solid-liquid interface with the reaction solution; S22: The conductive polymer monomer solution prepared in step S10 is mixed with the bridging dopant solution and added to the reaction vessel in step S21. Then, an oxidant solution is added dropwise, and an in-situ polymerization reaction is carried out under static conditions so that the conductive polymer preferentially forms a film on the substrate surface. In step S22, the molar ratio of the bridging dopant to the conductive polymer monomer is 0.1-1.0:1; the molar ratio of the oxidant to the conductive polymer monomer is 0.8-1.5:1; the reaction temperature of the in-situ polymerization reaction is 0–5 ℃, and the reaction time is 8–16 h.

7. The method for preparing a disulfonic acid-bridged doped two-dimensional conductive polymer according to claim 1, characterized in that, The cleaning step in step S30 includes: after the polymerization is completed, the substrate is removed, the upper reaction solution is removed, and the film on the surface of the substrate is repeatedly washed with deionized water until the washing solution is close to neutral. Then, the substrate is further washed 1–3 times with an organic solvent, wherein the organic solvent is either ethanol or isopropanol.

8. The method for preparing a disulfonic acid-bridged doped two-dimensional conductive polymer according to claim 1, characterized in that, The drying temperature is 40–80 °C, the drying time is 2–12 h, and the drying method is vacuum drying.

9. A disulfonic acid-bridged doped two-dimensional conductive polymer prepared by the method described in any one of claims 1-8.

10. Use of a two-dimensional electrically conductive polymer doped with two disulfonic acids as claimed in claim 10, characterized in that, The two-dimensional conductive polymer is applied to flexible electronic devices and anisotropic conductive films.

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