Method for in-situ growth of large-area polyaniline film on surface
By pre-constructing self-assembled molecular layers on the substrate surface, the growth of polyaniline films on the substrate surface is controlled by chemical oxidative polymerization, which solves the problems of film uniformity and adhesion in large-area preparation and realizes the preparation of high-quality and stable polyaniline films suitable for a variety of substrate materials.
Patent Information
- Application Number
- CN202511708045.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-02-24
AI Technical Summary
Existing technologies make it difficult to prepare uniform and stable polyaniline films on large-area substrates. Traditional solution processing methods suffer from weak interfacial bonding, low mechanical strength, and uneven electrical properties, while chemical oxidation methods result in random polymerization reactions that lead to easy peeling and poor uniformity of the films.
By pre-constructing a self-assembled molecular layer on the substrate surface, a polyaniline film is grown in situ on the substrate surface using chemical oxidative polymerization. The self-assembled molecular layer forms a strong covalent or ionic bond with the substrate, providing dense nucleation sites and controlling the polymerization reaction to grow at the interface, forming a uniform and dense film.
It has achieved the growth of large-area, high-quality polyaniline films. The films remain intact under repeated bending or stretching, exhibit excellent mechanical and chemical stability, high consistency in electrical properties, and are suitable for a variety of substrate materials. The process is simple and low-cost.
Smart Images
Figure CN121554735A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of conductive polymer material preparation technology, specifically relating to a method for in-situ preparation of polyaniline films on a substrate surface, particularly a chemical oxidation in-situ polymerization method for polyaniline films with large-area substrates and uniform heterogeneous growth. Background Technology
[0002] Polyaniline (PANI), a typical conductive polymer, has attracted much attention in fields such as smart windows, flexible displays, and infrared control due to its high conductivity, rich electrochromic effects, and low cost. Traditional solution processing methods typically involve mixing polyaniline powder with highly polar solvents and binders, followed by coating or spraying to form a film. However, due to the high rigidity and poor solubility of polyaniline molecular chains, traditional solution processing methods struggle to produce high-quality, large-area, uniform films. These films often suffer from weak interfacial adhesion, low mechanical strength, performance degradation due to binder introduction, and uneven electrical properties, affecting charge transport and final device performance, thus limiting their practical applications.
[0003] To overcome the limitations of solution processing, existing technologies mainly employ in-situ polymerization methods, including electrochemical polymerization and chemical oxidative polymerization.
[0004] Electrochemical polymerization can form thin films with good adhesion on conductive substrates, but its fabrication area is limited by electrode size and it is difficult to apply to insulating or flexible substrates, which greatly restricts its application in large-area scenarios. Even the introduction of soft templates such as potassium polyvinyl sulfate (PVSK) to assist polyaniline growth has not completely solved the problem of heterogeneous growth.
[0005] Chemical oxidative polymerization (COP) is considered a feasible route for large-area fabrication due to its advantages of simple equipment requirements, low cost, and theoretical suitability for large-area preparation. However, the problem with this method lies in the random polymerization reaction. Monomers preferentially undergo homogeneous polymerization in the bulk solution to generate powder, rather than heterogeneous growth on the substrate surface. This directly leads to easily peelable and unevenly uniform films, failing to meet the requirements of interfacial stability and performance consistency for practical devices. Some researchers have attempted to use deposited metal oxides as seed layers to assist in the in-situ chemical growth of polyaniline and obtain high-quality films, but this strategy requires sophisticated equipment, involves complex processes, and also faces difficulties in large-area preparation. Summary of the Invention
[0006] The purpose of this invention is to address the problems existing in the prior art by proposing a method for in-situ growth of large-area polyaniline films. This invention first utilizes a self-assembled monolayer to amino-functionalize a substrate, using this monolayer as an anchoring point and interfacial bonding layer for polymer growth. Then, by controlling the reaction conditions of chemical oxidative polymerization, a polyaniline film is grown in situ on the surface of the functionalized substrate. Large-area, high-quality polyaniline films can be prepared by growing on different substrates.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for in-situ growth of large-area polyaniline films includes the following steps: Substrate preparation and cleaning; Based on the substrate material, anchoring groups that are chemically bonded to the substrate surface and end groups that polymerize with aniline are selected as self-assembly molecules to form a self-assembly molecular layer on the substrate. A aniline monomer solution and an oxidant solution were prepared, and in-situ polymerization was carried out on a substrate with a self-assembled molecular layer to obtain a large-area polyaniline film.
[0008] A method for in-situ growth of large-area polyaniline films includes the following steps: Step 1. Substrate preparation and cleaning; Step 2. Preparation of self-assembled molecular layers; 2.1 Based on the substrate material, select anchoring groups that simultaneously have chemical bonds with the substrate surface and end groups that polymerize with aniline as self-assembly molecules; 2.2 The self-assembled molecules were added to a solvent to prepare a self-assembled molecule solution with a concentration of 2-10 mmol / L; 2.3 The cleaned substrate is immersed in a self-assembly molecular solution and the self-assembly reaction is carried out under light-protected conditions for 16-24 hours. After the reaction is completed, the substrate is removed and rinsed with ethanol or water to remove physically adsorbed molecules and form a self-assembly layer on the substrate surface to obtain a functionalized substrate. Step 3. Preparation of polyaniline film; 3.1 Aniline and an acidic medium were added to a solvent to prepare an aniline monomer solution with an aniline concentration of 0.01~0.1 mol / L and an acid concentration of 0.1~1 mol / L; An oxidant solution with a concentration of 0.1 ~ 1 mol / L is prepared by adding the oxidant to the solvent. 3.2 Immerse the functionalized substrate treated in step 2 into an aniline monomer solution. Under stirring conditions, slowly add an oxidant solution to the aniline monomer solution. The oxidant in the added oxidant solution is equimolar with aniline. After the addition is complete, continue stirring for 1 to 4 hours. After the reaction is complete, remove the substrate and wash it with ethanol and deionized water to obtain a large-area polyaniline film grown in situ.
[0009] Furthermore, the substrate mentioned in step 1 can be selected from one of the following: metal (Au, Ag, Pt, etc.), conductive metal oxide (ITO, FTO, AZO), and semiconductor (Si, Ge, GaAs, etc.).
[0010] Furthermore, the substrate mentioned in step 1 can also be a composite substrate formed by preparing metal, transparent conductive metal oxide, and semiconductor on the surface of non-conductive metal oxides (Al2O3, TiO2, CuO, etc.) and polymer films (PVDF film, Nylon film, PET film, etc.) through physical vapor deposition, chemical vapor deposition, sol-gel and other methods.
[0011] Furthermore, the cleaning method for the substrate is selected according to the substrate material, including but not limited to ultraviolet / ozone plasma cleaning, wet chemical cleaning, mechanical grinding and polishing, ultrasonic cleaning, etc., with the aim of thoroughly removing residual impurities and adsorbed organic matter from the substrate surface, which is beneficial to the subsequent self-assembly process.
[0012] Furthermore, the self-assembled molecule described in step 2.1 includes a -NH2 end group and an anchoring group, the anchoring group being selected according to the substrate surface material. For metal surfaces, the anchoring group is -SH or -COOH; for semiconductor surfaces, the anchoring group is -SH, -COOH, or -PO(OH)2; for conductive metal oxide surfaces, the anchoring group is -PO(OH)2, -Si(OR)3, or -COOH.
[0013] Preferably, the self-assembled molecule in step 2.1 may be an aminothiol, an aminobenzylthiophenol, an aminosilane, or an amino-containing carboxylic acid derivative, an amino-containing phosphoric acid derivative, or a mixture thereof.
[0014] Furthermore, the solvent mentioned in step 2.2 is ethanol, water, methanol, or acetone, etc.
[0015] Furthermore, in step 3.1, the pH of the aniline monomer solution is less than 4.
[0016] Furthermore, in step 3.1, the acidic medium is an inorganic acid such as hydrochloric acid, sulfuric acid, or nitric acid, or an organic acid such as tannic acid, phytic acid, tartaric acid, dodecylbenzenesulfonic acid, camphor sulfonic acid, polystyrene sulfonic acid, polyethylene sulfuric acid, naphthalene sulfonic acid, or 2,4-dinitronaphthol-7-sulfonic acid.
[0017] Furthermore, in step 3.1, the acidic medium is selected according to the substrate material to ensure that the doped acid does not have a negative effect on the substrate material, including but not limited to dissolution, swelling, corrosion, etc.
[0018] Furthermore, in step 3.1, the solvent is ethanol, acetone, deionized water, methanol, etc. The solvent is selected according to the substrate material to ensure that the acid and aniline have good solubility, while not having a negative effect on the substrate material, including but not limited to dissolution, swelling, corrosion, etc.
[0019] Furthermore, in step 3.1, the oxidant is ammonium persulfate, potassium dichromate, potassium iodate, hydrogen peroxide, FeCl3, Ce(SO4)2, MnO2, or benzoyl peroxide, etc.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention proposes a method combining self-assembled molecular anchoring and chemical oxidative polymerization. By pre-constructing a self-assembled molecular layer on the substrate surface, the random "homogeneous polymerization" is transformed into controlled "interface-directed growth." The self-assembled molecular layer forms strong covalent or ionic bonds with the substrate, significantly improving interfacial adhesion. This allows the film to remain intact under repeated bending or stretching conditions and maintain its integrity without peeling in strongly polar solvents such as DMF and NMP, exhibiting excellent mechanical and chemical stability. Furthermore, it provides dense nucleation sites for aniline monomers, ensuring the in-situ, uniform, and robust growth of the polyaniline film. The resulting film is uniform, continuous, dense, and free of macroscopic defects, with a thickness deviation within ±5%. The surface roughness (Ra) is significantly reduced. This high uniformity and density ensure consistent electrical properties, improving overall performance and lifespan.
[0021] 2. This invention pretreats the substrate with a self-assembled monolayer, providing a uniform and dense growth starting point for aniline polymerization and effectively guiding heterogeneous growth of the polymerization reaction on the substrate surface. This method not only solves the problem of film uniformity in large-area preparation but also enhances the bonding force between the polyaniline film and the substrate through molecular-level interface design. Furthermore, by controlling the reaction temperature, concentration, and ratio, the polymerization rate and film quality can be effectively regulated. The entire process is carried out at room temperature and pressure, with mild conditions, simple operation, and low cost, making it easy to prepare large-area, high-performance polyaniline films and showing promising application prospects. Attached Figure Description
[0022] Figure 1 This is a scanning electron microscope image of the in-situ growth of a polyaniline film on porous Au / Nylon 66 in Example 1; Figure 2This is a photograph of the in-situ growth of a polyaniline film on porous Au / Nylon 66 in Example 1. Detailed Implementation
[0023] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention and do not limit the scope of the present invention.
[0024] Example 1 A method for in-situ growth of large-area polyaniline films on a surface specifically includes the following steps: Step 1. Substrate preparation and cleaning; A gold layer with a thickness of 50~300 nm was deposited on porous nylon using electron beam evaporation. The resulting Au / Nylon substrate was then treated with ozone plasma for 15 minutes to thoroughly clean the surface. Step 2. Preparation of self-assembled molecular layers; 2.1 Add p-aminothiophenol to ethanol to prepare a self-assembled molecule solution with a concentration of 2 mmol / L; 2.2 The cleaned substrate was immersed in a self-assembly molecular solution and carried out a self-assembly reaction for 18 hours under light-protected conditions. After the reaction was completed, the substrate was removed and rinsed with ethanol to remove physically adsorbed molecules, resulting in a functionalized substrate with amino functional groups on its surface. Step 3. Preparation of polyaniline film; 3.1 Add aniline and sulfuric acid to deionized water to prepare an aniline monomer solution with an aniline concentration of 0.1 mol / L and an acid concentration of 1 mol / L; Ammonium persulfate was added to deionized water to prepare an aqueous solution of ammonium persulfate (APS) with a concentration of 1 mol / L, which was then used as an oxidant. 3.2 The functionalized substrate treated in step 2 was placed in an aniline monomer solution in an ice-water bath at 0-5℃. Under magnetic stirring, a pre-cooled ammonium persulfate solution at 0-5℃ was slowly added dropwise to the aniline monomer solution. The ammonium persulfate and aniline in the added ammonium persulfate solution were equimolar. After the addition was completed within 30 min, the reaction was continued to be stirred for 4 hours. After the reaction was completed, the substrate was removed and washed with ethanol and deionized water in sequence to remove loosely adsorbed polyaniline particles. Finally, it was air-dried at room temperature to obtain a uniform and dense emerald green polyaniline film on the substrate surface.
[0025] Example 2 A method for in-situ growth of large-area polyaniline films on a surface specifically includes the following steps: Step 1. Substrate preparation and cleaning; ITO with a thickness of 50~300 nm was deposited on blank glass as a substrate by magnetron sputtering. The ITO glass was ultrasonically cleaned in acetone, ethanol and deionized water for 15 minutes each, dried with nitrogen, and then treated with ozone plasma for 30 minutes to thoroughly clean the surface. Step 2. Preparation of self-assembled molecular layers; 2.1 Add p-3-aminopropyltriethoxysilane (APTES) to ethanol to prepare a self-assembled molecular solution with a concentration of 8 mmol / L; 2.2 The cleaned ITO glass was immersed in a self-assembly molecular solution and carried out a self-assembly reaction for 18 hours under light-protected conditions. After the reaction was completed, the substrate was removed and rinsed with ethanol, and then heat-treated at 100°C for 10 minutes to stabilize the silane layer, thus obtaining a functionalized ITO substrate. Step 3. Preparation of polyaniline film; 3.1 Aniline and camphor sulfonic acid were added to deionized water to prepare an aniline monomer solution with a concentration of 0.1 mol / L and an acid concentration of 1 mol / L; Ammonium persulfate was added to deionized water to prepare an aqueous solution of ammonium persulfate (APS) with a concentration of 1 mol / L, which was then used as an oxidant. 3.2 The functionalized ITO substrate treated in step 2 was placed in an aniline monomer solution in an ice-water bath at 0-5℃. Under magnetic stirring, a pre-cooled ammonium persulfate solution at 0-5℃ was slowly added dropwise to the aniline monomer solution. The ammonium persulfate and aniline in the added ammonium persulfate solution were equimolar. After the addition was completed within 30 min, the reaction was continued to be stirred for 4 hours. After the reaction was completed, the substrate was removed and washed with ethanol and deionized water in sequence to remove loosely adsorbed polyaniline particles. Finally, it was air-dried at room temperature to obtain a uniform and dense emerald green polyaniline film on the surface of the ITO substrate.
[0026] Example 3 A method for in-situ growth of large-area polyaniline films on a surface specifically includes the following steps: Step 1. Substrate preparation and cleaning; A 50-300 nm thick gold layer was deposited on the surface of a PET film using a thermal evaporation deposition method. The resulting Au / PET substrate was then treated with ozone plasma for 30 minutes to thoroughly clean the surface. Step 2. Preparation of self-assembled molecular layers; 2.1 Add p-aminothiophenol to ethanol to prepare a self-assembled molecule solution with a concentration of 2 mmol / L; 2.2 The cleaned substrate was immersed in a self-assembly molecular solution and carried out a self-assembly reaction for 18 hours under light-protected conditions. After the reaction was completed, the substrate was removed and rinsed with ethanol to remove physically adsorbed molecules, resulting in a functionalized substrate with amino functional groups on its surface. Step 3. Preparation of polyaniline film; 3.1 Add aniline and dodecylbenzenesulfonic acid (DBSA) to deionized water to prepare an aniline monomer solution with a concentration of 0.1 mol / L and an acid concentration of 1 mol / L; Ammonium persulfate was added to deionized water to prepare an aqueous solution of ammonium persulfate (APS) with a concentration of 1 mol / L, which was then used as an oxidant. 3.2 The functionalized substrate treated in step 2 was placed in an aniline monomer solution in an ice-water bath at 0-5℃. Under magnetic stirring, a pre-cooled ammonium persulfate solution at 0-5℃ was slowly added dropwise to the aniline monomer solution. The ammonium persulfate and aniline in the added ammonium persulfate solution were equimolar. After the addition was completed within 30 min, the reaction was continued to be stirred for 4 hours. After the reaction was completed, the substrate was removed and washed with ethanol and deionized water in sequence to remove loosely adsorbed polyaniline particles. Finally, it was air-dried at room temperature to obtain a uniform and dense emerald green polyaniline film on the surface of the flexible PET / Au substrate. The film did not show obvious peeling when bent.
[0027] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for in-situ growth of a large-area polyaniline film, characterized in that, Includes the following steps: Substrate preparation and cleaning; Based on the substrate material, anchoring groups that are chemically bonded to the substrate surface and end groups that polymerize with aniline are selected as self-assembly molecules to form a self-assembly molecular layer on the substrate. A solution of aniline monomer and an oxidant solution were prepared, and in-situ polymerization was completed to obtain a large-area polyaniline film.
2. A method for in-situ growth of a large-area polyaniline film, characterized by comprising the following steps: Step 1. Substrate preparation and cleaning; Step 2. Preparation of self-assembled molecular layers; 2.1 Based on the substrate material, select anchoring groups that simultaneously have chemical bonds with the substrate surface and end groups that polymerize with aniline as self-assembled molecules; 2.2 The self-assembled molecules were added to a solvent to prepare a self-assembled molecule solution with a concentration of 2-10 mmol / L; 2.3 The cleaned substrate was immersed in a self-assembly molecular solution and carried out a self-assembly reaction under light-protected conditions. After the reaction was completed, it was removed and rinsed to obtain the functionalized substrate. Step 3. Preparation of polyaniline film; 3.1 Aniline and an acidic medium were added to a solvent to prepare an aniline monomer solution with an aniline concentration of 0.01~0.1 mol / L and an acid concentration of 0.1~1 mol / L; An oxidant solution with a concentration of 0.1 ~ 1 mol / L is prepared by adding the oxidant to the solvent. 3.2 The functionalized substrate after step 2 is immersed in an aniline monomer solution. Under stirring conditions, an oxidant solution is added dropwise to the aniline monomer solution. The oxidant in the added oxidant solution is equimolar with aniline. After the addition is complete, continue stirring to react; after the reaction is complete, remove the substrate to obtain a large-area polyaniline film grown in situ.
3. The method for in-situ growth of large-area polyaniline films according to claim 1 or 2, characterized in that, The substrate is one of metal, conductive metal oxide, or semiconductor.
4. The method for in-situ growth of large-area polyaniline films according to claim 1 or 2, characterized in that, The substrate is a composite substrate formed by preparing metal, transparent conductive metal oxide, or semiconductor on the surface of a non-conductive metal oxide or polymer film through physical vapor deposition, chemical vapor deposition, or sol-gel method.
5. The method for in-situ growth of large-area polyaniline films according to claim 3, characterized in that, The metals are Au, Ag, and Pt; the conductive metal oxides are ITO, FTO, and AZO; and the semiconductors are Si, Ge, and GaAs.
6. The method for in-situ growth of large-area polyaniline films according to claim 4, characterized in that, Non-conductive metal oxides are Al2O3, TiO2, and CuO; polymer films are PVDF, Nylon, and PET films; metals are Au, Ag, and Pt; conductive metal oxides are ITO, FTO, and AZO; and semiconductors are Si, Ge, and GaAs.
7. The method for in-situ growth of large-area polyaniline films according to claim 1 or 2, characterized in that, The self-assembled molecule includes an -NH2 end group and an anchoring group; for metal surfaces, the anchoring group is -SH or -COOH; for semiconductor surfaces, the anchoring group is -SH, -COOH, or -PO(OH)2; for conductive metal oxide surfaces, the anchoring group is -PO(OH)2, -Si(OR)3, or -COOH.
8. The method for in-situ growth of large-area polyaniline films according to claim 1 or 2, characterized in that, The self-assembled molecule is one or more of aminothiols, aminobenzylthiophenols, aminosilanes, amino-containing carboxylic acid derivatives, and amino-containing phosphoric acid derivatives.
9. The method for in-situ growth of large-area polyaniline films according to claim 2, characterized in that, The solvent in step 2.2 is ethanol, water, methanol or acetone, and the solvent in step 3.1 is ethanol, acetone, deionized water or methanol.
10. The method for in-situ growth of large-area polyaniline films according to claim 2, characterized in that, In step 3.1, the oxidant is ammonium persulfate, potassium dichromate, potassium iodate, hydrogen peroxide, FeCl3, Ce(SO4)2, MnO2 or benzoyl peroxide.