A preservative composite filler, paint, coating and preparation method and application thereof

Abstract

The application discloses a kind of anticorrosive composite fillers, paint, coating and its preparation method and application.The filler is mesoporous flaky silica as carrier, load corrosion inhibitor in its mesoporous structure, and on surface coating pH response release function layer, and further load target functional component.The application further provides the paint prepared from the filler and resin matrix, the coating prepared from the paint and their application in the anticorrosive protection of metal substrate surface.The mesoporous flaky silica in the filler of the application can realize the integration of sheet layer barrier function and corrosion inhibitor load function, pH response release function layer can improve the corrosion inhibitor load stability and improve the interface compatibility of filler and resin matrix, target functional component can impart corresponding target function such as improving the ultraviolet aging resistance of coating and damage early warning capability, etc., and can be applied to the field of long-term anticorrosive protection of metal material surface.

Description

Technical Field

[0001] This invention belongs to the field of metal anti-corrosion coating technology, specifically relating to an anti-corrosion composite filler, a coating prepared from the anti-corrosion coating and a resin matrix, a coating prepared from the coating, the preparation method thereon, and its application. Background Technology

[0003] Metallic materials are widely used in bridges, storage tanks, pipelines, marine engineering equipment, and other engineering structures due to their excellent mechanical properties, machinability, and cost advantages. However, metallic materials are prone to electrochemical corrosion in humid, high-salt, and high-oxygen environments, leading to surface rust, decreased mechanical properties, and in severe cases, shortened equipment lifespan and safety hazards. Therefore, developing efficient and long-lasting steel surface protection technologies is of great significance.

[0004] Existing metal corrosion protection technologies can be broadly categorized into three main types: material-based corrosion protection, electrochemical corrosion protection, and surface protection corrosion protection. Material-based corrosion protection primarily improves the corrosion resistance of the metal itself through alloying, grain refinement, and the addition of corrosion-resistant alloying elements. Its advantages include fundamentally enhancing the intrinsic corrosion resistance of the substrate, long-lasting protection lifespan, and no post-construction maintenance. However, its disadvantages include high alloying element costs, complex smelting and processing techniques, applicability only to specific metal substrates, poor versatility, and inability to perform subsequent corrosion protection modifications on existing metal components. Electrochemical corrosion protection mainly includes sacrificial anode cathodic protection and impressed current cathodic protection. Its advantages include stable corrosion protection, applicability to large continuous components such as buried pipelines and marine steel structures, and the ability to achieve long-term, comprehensive protection. However, its disadvantages include reliance on external power sources or sacrificial anode consumables, the need for periodic replacement of anode materials, high maintenance costs, poor uniformity of protection for complex and irregularly shaped components, and unsuitability for small, precision metal parts.

[0005] Metal surface protection technology is currently the most widely used and adaptable anti-corrosion method. By constructing a protective barrier layer on the surface of the metal substrate, it isolates the corrosive medium from contact with the substrate. It has outstanding advantages such as flexible process, controllable cost, adaptability to various shaped components, and on-site construction. However, existing surface protection technologies still have common technical shortcomings such as insufficient protective stability, poor long-term corrosion resistance, weak adhesion, poor environmental compatibility, and lack of temperature and aging resistance.

[0006] Existing metal surface protection technologies, besides organic anti-corrosion coatings, mainly include three categories: metal plating protection, inorganic passivation / conversion film protection, and ceramic coating protection. Metal plating protection mainly uses electroplating, hot-dip galvanizing, and chemical plating to deposit metal or alloy layers such as zinc, chromium, and nickel on the metal surface. Its advantages are dense and uniform coating, high mechanical strength, and excellent wear resistance and short-term corrosion resistance. Its disadvantages are that electroplating processes cause heavy metal pollution and have high environmental treatment costs, hot-dip galvanizing is prone to component deformation and has high energy consumption, the coating has pores and is prone to electrochemical coupling corrosion, and peeling and flaking are likely to occur after long-term service. Inorganic passivation / conversion film protection relies on chemical oxidation, phosphating, chromate passivation, and other methods to generate passivation layers such as oxide films and phosphating films on the metal surface. Its advantages include thin film thickness, strong adhesion to the substrate, simple construction, and low production cost. Disadvantages include high film porosity, limited barrier performance, suitability only for mildly corrosive environments, poor resistance to acids, alkalis, and damp heat, short protective life, and the highly toxic pollution associated with traditional chromate passivation, which limits its environmental impact. Ceramic coating protection uses inorganic ceramic materials such as oxides and silicates as film-forming substances, offering advantages such as high temperature resistance, strong corrosion resistance, oxidation resistance, and high hardness. Disadvantages include high coating brittleness, poor impact and bending resistance, susceptibility to cracking and peeling due to substrate deformation, high sintering temperatures, stringent processes, poor matching of thermal expansion coefficients between the coating and the metal substrate, and a tendency for interface defects.

[0007] Organic anti-corrosion coatings are widely used for corrosion protection of steel surfaces due to their strong adhesion, good film-forming properties, and excellent resistance to chemical media, making them one of the most widely applied technologies in the field of metal protection. However, traditional organic coatings still have certain limitations during long-term service. On the one hand, the coating resin is prone to defects such as micropores and microcracks during the curing process, allowing corrosive media to gradually penetrate to the metal substrate surface along these defects, thereby weakening the coating's shielding and protective effect. On the other hand, protection modes that rely solely on the barrier properties of the resin matrix itself are difficult to achieve long-term stable protection in complex corrosive environments. This further highlights the technical pain points of existing surface protection systems, such as insufficient protective layer density, numerous corrosive media penetration channels, and poor interfacial bonding stability.

[0008] In existing technologies, conventional two-dimensional sheet-like anti-corrosion fillers can rely on their sheet-like structure to construct physical barrier paths, extending the penetration channels of corrosive media and improving the basic shielding ability of the coating to a certain extent. However, these two-dimensional sheets have inherent structural defects and functional limitations, resulting in significant limitations in comprehensive application and making them difficult to adapt to harsh, complex, and long-term anti-corrosion conditions. Firstly, conventional two-dimensional sheets have limited functionality and poor adaptability, only providing an inert physical barrier effect. They lack dedicated pores and interlayer active sites, and naturally do not possess the structural conditions for efficiently loading and releasing corrosion inhibitors. They can only achieve passive barrier protection and cannot actively passivate and repair areas with micro-defects in the metal. Once micro-cracks develop in the coating and interface peeling occurs, corrosive media can easily and quickly penetrate the gaps between the sheets and erode the substrate, causing the protective system to fail rapidly. Secondly, two-dimensional sheet materials have extremely poor interfacial compatibility and dispersion stability. For example, the original powders such as graphene oxide and conventional inorganic sheets have strong surface inertness, high specific surface area, and significant interfacial van der Waals forces. Direct mixing can easily lead to agglomeration and stacking in the organic resin matrix, resulting in disordered flocculation and clumping. This not only fails to uniformly arrange and construct a continuous and dense labyrinth barrier structure, but also induces a large number of micropores and interfacial defects in situ inside the coating, indirectly forming channels for rapid penetration of corrosive media, which in turn degrades the overall density and mechanical adhesion of the coating. Third, the loading modification process is cumbersome and costly. Currently, to impart corrosion inhibitor loading functionality to conventional two-dimensional sheet materials, the industry relies on a multi-step process involving high-temperature hydrothermal composite, multi-step grafting modification, and exogenous nano-drug doping. This process involves stringent reaction conditions, large amounts of additives and materials, and high production costs for large-scale production. Furthermore, the modification process can easily damage the complete layered morphology of the sheet material, reducing its original shielding effectiveness. The overall process is complex, with poor production controllability, making it difficult to achieve industrial-scale mass production. Fourth, the stability of the service conditions is insufficient. Most two-dimensional sheets have weak weather resistance and aging tolerance. Under long-term outdoor ultraviolet radiation and high-low temperature alternating humid heat cycles, they are prone to layer oxidation distortion, structural embrittlement, and powdering, leading to localized interface debonding and cracking. At the same time, the thermal expansion coefficients of the sheet material, organic resin, and metal matrix are poorly matched, making them prone to interlayer slippage and peeling under stress cycles. This significantly shortens the long-term service life of the anti-corrosion coating and fails to meet the long-term synergistic protection requirements under harsh conditions such as high salt and acid-alkali coupling. In summary, existing two-dimensional sheet-like fillers generally suffer from multiple technical bottlenecks, such as functional fragmentation, poor dispersibility, complex modification, and weak weather resistance. They are difficult to simultaneously meet core requirements such as efficient physical shielding, in-situ corrosion inhibition, and aging resistance for service. The industry urgently needs to develop an integrated composite anti-corrosion filler that natively combines sheet-like barrier structure with multi-level load-bearing porosity, requires no complex modification, and has excellent matrix compatibility.

[0009] Although there are reports of the use of mesoporous silica in the field of metal corrosion protection technology, for example, CN201711198279.9 focuses on the use of mesoporous silica-loaded corrosion inhibitors for coating modification and discloses a method for preparing a protective coating modified by silica doping. Although this method simplifies the preparation of mesoporous silica-loaded corrosion inhibitors, it has significant shortcomings in metal corrosion protection applications and cannot meet the requirements of long-term and stringent corrosion protection: (1) It does not use two-dimensional sheet-like mesoporous silica, but only mesoporous silica nanoparticles, which cannot form a "maze effect" of sheet stacking. The physical shielding ability is weak, and the corrosive medium can easily penetrate quickly, resulting in limited protection effect; (2) The mesoporous silica is not sealed, and the mesoporous channels are directly exposed. During long-term service, they are easily blocked by corrosive media (such as Cl⁻ and water vapor), and the corrosion inhibitor and the mesoporous channels are only physically adsorbed, with weak bonding force. (3) The surface of mesoporous silica is unmodified and has strong surface inertness. It has poor compatibility with organic resin matrix. Direct mixing can easily cause agglomeration. It cannot be evenly dispersed to form a dense protective structure. It will also generate micropores in the coating, which will form a channel for the corrosive medium to penetrate. (4) It only has a single corrosion inhibition function and does not have anti-aging performance. It requires the addition of anti-aging additives, which leads to complex coating formulation, increased cost, and easy migration and precipitation of additives, affecting the overall protective performance of the coating. (5) The interface bonding between mesoporous silica and metal matrix is ​​not considered. The adhesion between coating and metal matrix is ​​weak. Under long-term working conditions, interface debonding and coating cracking are likely to occur, leading to the failure of the protective system.

[0010] Furthermore, with the increasing complexity of service environments, anti-corrosion coatings not only need to possess excellent corrosion resistance but also need to consider anti-aging properties and damage identification capabilities. Ultraviolet radiation accelerates the aging and degradation of organic coatings, leading to decreased adhesion, cracking, and reduced protective performance. This is a concrete manifestation of the shortcomings in the aging resistance of existing surface protection technologies. On the other hand, traditional anti-corrosion coatings typically lack the ability to visually detect microcracks or localized damage, making it difficult to detect early signs of failure in a timely manner. In summary, existing metal anti-corrosion technologies and surface protection methods all have their inherent defects and cannot meet the long-term anti-corrosion requirements of metal components in harsh corrosive environments such as high salinity in the ocean, acid and alkali conditions in industrial environments, and high temperature and humidity. Therefore, developing an anti-corrosion coating that simultaneously possesses anti-corrosion, anti-aging, and damage early warning functions has significant application value. Summary of the Invention

[0011] To address one or more of the aforementioned technical problems in the prior art, this invention provides a novel method for constructing anti-corrosion coatings. This method utilizes functional fillers to simultaneously achieve sheet shielding and corrosion inhibitor loading, reducing complex composite modification processes and further considering anti-aging and early warning performance, thereby meeting the surface protection requirements of metal materials under long-term service conditions.

[0012] The present invention provides a method for preparing a corrosion-resistant composite filler in a first aspect, the method comprising the following steps: (1) Provide mesoporous lamellar silica; (2) The corrosion inhibitor is loaded into the mesoporous structure of the mesoporous lamellar silica to obtain drug-loaded mesoporous lamellar silica; (3) A pH-sensitive material is used to coat the drug-loaded mesoporous sheet silica to form a pH-responsive release functional layer on the surface of the drug-loaded mesoporous sheet silica; (4) Anchor the target functional component on the surface of the pH-responsive release functional layer to obtain a corrosion-resistant composite filler with the target function.

[0013] In a second aspect, the present invention provides an anti-corrosion composite filler, which is prepared by the preparation method described in the first aspect of the present invention.

[0014] In a third aspect, the present invention provides an anti-corrosion coating, which is prepared using the anti-corrosion composite filler and resin matrix described in the second aspect of the present invention.

[0015] In a fourth aspect, the present invention provides an anti-corrosion coating, wherein the anti-corrosion coating is obtained by applying the anti-corrosion coating described in the second aspect of the present invention, preferably, the anti-corrosion coating is obtained by applying the anti-corrosion coating to the surface of a metal substrate by scraping and curing.

[0016] The present invention provides, in its fifth aspect, the application of the anti-corrosion composite filler described in the second aspect of the present invention, the anti-corrosion coating described in the third aspect of the present invention, or the anti-corrosion coating described in the fourth aspect of the present invention in the anti-corrosion protection of metal substrate surfaces.

[0017] The beneficial effects of this invention are as follows: (1) The present invention uses mesoporous sheet silica as a composite functional filler carrier, and utilizes its sheet structure and mesoporous structure to achieve physical shielding and corrosion inhibitor loading respectively, thereby realizing the integrated construction of sheet barrier function and loading function.

[0018] (2) This invention uses mesoporous sheet-like silica material as a carrier, loads a corrosion inhibitor, and then coats it with a pH-sensitive material. Taking polydopamine as an example, this invention utilizes the self-polymerization reaction of dopamine to form a polydopamine layer, and further anchors the amino-modified target functional component onto the pH-responsive release functional layer through a Michael addition reaction. In the case where the pH-sensitive material is polydopamine, taking zinc oxide quantum dots as an example, when corrosion occurs, the accompanying electrochemical reaction causes a change in the pH value of the corrosion micro-area. Some metal in the anodic area loses electrons to form metal ions, which hydrolyze to form weakly alkaline hydroxides in aqueous solution, causing the pH value of this area to decrease; the polydopamine layer depolymerizes under acidic conditions, releasing the corrosion inhibitor, and the corrosion inhibitor molecules react with Fe 2+ The complexation forms a dense passivation film, which inhibits further corrosion by isolating the metal from the corrosive medium. Furthermore, the Zn released from the dissolution of zinc oxide quantum dots... 2+ OH generated by the reduction of oxygen in the corroded cathode region - Ions combine to form insoluble Zn(OH)2, increasing the thickness of the passivation film and thus prolonging the corrosion inhibition effect.

[0019] (3) The pH-responsive release functional layer and target functional components on the surface of the filler prepared by the present invention contain active groups. On the one hand, the active groups can enhance the interfacial compatibility between the filler and the resin matrix and improve the degree of crosslinking, thereby improving the overall density of the coating; on the other hand, the plate-like filler forms a "maze effect" structure in the coating, which can effectively extend the diffusion path of the corrosive medium in the coating; furthermore, the active groups such as amino, mercapto or oxygen-containing groups can coordinate with metal ions on the surface of the metal substrate, thereby enhancing the adhesion performance of the coating to the metal substrate and improving the long-term service stability of the coating.

[0020] (4) In the active filler synthesized in the preferred embodiment of the present invention, the surface-anchored target functional component, such as zinc oxide quantum dots, is a wide-bandgap semiconductor inorganic nanomaterial with strong ultraviolet absorption capacity, high transparency, and good resistance to photoaging. Therefore, it can effectively improve the weather resistance and long-term stability of the composite filler. Furthermore, zinc oxide quantum dots exhibit fluorescence quenching characteristics under acidic conditions, which can be used to indicate the occurrence of corrosion processes, thereby endowing the active filler with the dual functions of ultraviolet protection and corrosion early warning. Of course, other functional materials can also be used to endow other target functions. Attached Figure Description

[0021] Figure 1 A transmission electron microscope (TEM) image of the mesoporous lamellar silica prepared in Preparation Example 1 is shown. Wherein, Figure 1 (a) is a transmission electron microscope image of sheet-like mesoporous silica. Figure 1 (b) is Figure 1 (a) is a magnified view of a portion of the image.

[0022] Figure 2 Transmission electron microscopy (TEM) images of the zinc oxide quantum dots and the composite filler (BTA-MSS@PDA-ZnO) supported on benzotriazole corrosion inhibitor prepared in Example 1 are shown. Figure 2 (a) is a transmission electron microscope image of ZnO quantum dots. Figure 2 (b) is a transmission electron microscope image of the composite filler BTA-MSS@PDA-ZnO.

[0023] Figure 3 This study aims to display the electrochemical impedance spectroscopy (EIS) spectra of steel samples with different coatings after immersion for 100 days. Figure 3 (a) is a Nyquist plot. Figure 3 (b) is a Bode plot.

[0024] Figure 4 The image shows the adhesion results of different coatings before and after the UV aging test.

[0025] Figure 5 A schematic diagram illustrating the corrosion inhibition mechanism of the anti-corrosion coating of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] The invention will now be described in detail in accordance with its various aspects.

[0028] First aspect: Preparation method The present invention provides a method for preparing a corrosion-resistant composite filler in a first aspect, the method comprising the following steps: (1) Provide mesoporous sheet silica (MSS); (2) The corrosion inhibitor is loaded into the mesoporous structure of the mesoporous lamellar silica to obtain drug-loaded mesoporous lamellar silica; (3) A pH-sensitive material is used to coat the drug-loaded mesoporous sheet silica to form a pH-responsive release functional layer on the surface of the drug-loaded mesoporous sheet silica; (4) Anchor the target functional component on the surface of the pH-responsive release functional layer to obtain a corrosion-resistant composite filler with the target function.

[0029] Step (1) MSS is required in this step.

[0030] The inventors have discovered that this type of structure of MSS is advantageous in enabling it to simultaneously possess both lamellar barrier function and mesoporous loading function.

[0031] Preferably, the thickness of the MSS is 10 nm to 20 nm (e.g., 15 nm).

[0032] Preferably, the lateral dimension of the MSS is 2 μm to 4 μm (e.g., 3 μm).

[0033] Preferably, the pore size of the MSS is 2nm to 50nm (e.g., 5nm, 8nm, 10nm, 20nm, 30nm or 40nm), more preferably 5nm to 8nm.

[0034] MSS can be prepared by the methods described in this application or other known methods.

[0035] In some implementations, MSS can be prepared using a phase separation method.

[0036] In some preferred embodiments, MSS is prepared by phase separation and then the template agent is removed by calcination to obtain MSS.

[0037] More preferably, the phase separation method uses hexadecyltrimethylammonium bromide (CTAB) (as a template agent), tetraethyl orthosilicate (TEOS), and 3-aminopropyltriethoxysilane (APTES) as raw materials to prepare MSS by phase separation.

[0038] For example, the phase separation method can use an aqueous solution of CTAB as the aqueous phase and a cyclohexane solution of APTES and TEOS as the oil phase. After mechanical emulsification, the micelle-silane oligomer composite particles formed by CTAB, TEOS and APTES are self-assembled at the emulsion interface to form a two-dimensional sheet-like mesoporous silica material.

[0039] In some more specific embodiments, hexadecyl dimethyl ammonium bromide (CTAB) can be dissolved in water, and cyclohexane and ammonia can be added to it. After emulsification by mechanical stirring, a mixture of tetraethyl orthosilicate (TEOS) and 3-aminopropyltriethoxysilane (APTES) can be added dropwise to the reaction system to carry out the reaction. After the reaction is completed, the white product is collected by centrifugation, washed, dried, and calcined to obtain MSS.

[0040] In the above-described method of this invention, the inventors discovered that MSS with more suitable target sheet morphology and mesoporous structure can be prepared by adjusting the amount of hexadecyltrimethylammonium bromide (CTAB) and the volume ratio of tetraethyl orthosilicate to 3-aminopropyltriethoxysilane. Through observation and research, the inventors found that the pore size of the sheet-like silica gradually increases with increasing CTAB content. However, when the pore size is too large, the continuity of the sheet-like structure is disrupted. When the amount of APTES added is low, the resulting silica sheets tend to be curved, making it difficult to maintain good flatness; while when the amount of APTES added is too high, it is prone to self-polymerization, thereby generating rough nanoparticles on the silica surface.

[0041] Preferably, in step (1), the amount of hexadecyltrimethylammonium bromide added is 25 to 400 mg (e.g., 50 mg, 100 mg, 150 mg, 200 mg, 250 mg, 300 mg, 350 mg or 400 mg).

[0042] The volume-to-weight ratio of the tetraethyl orthosilicate to the hexadecyltrimethylammonium bromide is 400:(25-400), for example, 400:50, 400:100, 400:150, 400:200, 400:250, 400:300, 400:350 or 400:400.

[0043] Preferably, the volume ratio of the tetraethyl orthosilicate to 3-aminopropyltriethoxysilane is 400:(150-350), for example, 400:150, 400:200, 400:250, 400:300 or 400:350.

[0044] For example, 50 mg to 400 mg of cetyldimethylammonium bromide (CTAB) can be dissolved in 80 mL of water. The resulting solution is transferred to a round-bottom three-necked flask, and 80 mL of cyclohexane and 200 μL of ammonia are added. The mixture is mechanically emulsified at 400 rpm to 1000 rpm for 2 h. Subsequently, a mixture of 400 μL of tetraethyl orthosilicate (TEOS) and 150 to 350 μL of 3-aminopropyltriethoxysilane (APTES) is added dropwise to the reaction system, and the reaction is carried out at 25 °C for 10 h. After the reaction is completed, the mixture is centrifuged at 8000 rpm for 10 min, and the resulting white product is washed three times with deionized water and dried under vacuum at 60 °C for 24 h. The dried product is then placed in a muffle furnace and calcined at 600 °C for 5 h to obtain MSS.

[0045] In some alternative embodiments, the phase separation method can still be used to prepare sheet-like mesoporous silica. The difference is that, based on the phase separation method described above, toluene can be used instead of cyclohexane as the oil phase, and the amount of silicon source can be appropriately increased. Since this method is similar to the aforementioned phase separation method in terms of the mechanism of oil-water interface-induced assembly, the resulting MSS usually still has similar two-dimensional sheet structure and mesoporous characteristics.

[0046] In some more specific embodiments, CTAB can be dissolved in water, and the pH of the solution can be adjusted to approximately 10 using concentrated ammonia. TEOS and APTES are separately dispersed in toluene to form the oil phase. The aqueous and oil phases are mixed and homogenized to emulsify, allowing the resulting emulsion system to react. After the reaction is complete, the emulsion is washed and filtered, and the resulting white precipitate is collected. This precipitate is then washed with, for example, ethanol and water, filtered, dried, and calcined to obtain MSS.

[0047] For example, 20–100 mg of CTAB can be dissolved in 50 g of distilled water at 60 °C, and the pH of the solution can be adjusted to approximately 10 using concentrated ammonia. Separately, 1.45 g of TEOS and 0.3–0.5 g of APTES are added to 30 g of toluene and ultrasonically dispersed to form the oil phase. The aqueous and oil phases are then mixed and sheared and emulsified using a high-speed homogenizer at 8000 rpm for 5 min to obtain an emulsion system. This emulsion system is then transferred to a three-necked flask and reacted at 35 °C for 12 h. After the reaction, the emulsion is washed with ethanol and filtered, and the resulting white precipitate is collected. This precipitate is then washed and filtered repeatedly with ethanol and distilled water, and vacuum dried at 60 °C for 24 h. The dried product is then placed in a muffle furnace and calcined at 600 °C for 5 h to obtain MSS.

[0048] It should be noted that in the above method where toluene replaces cyclohexane as the oil phase, the plate-like structure is mainly formed at the oil-water interface. Due to the instability of the interface structure during its formation and breakage, the resulting product may exhibit a certain degree of morphological diversity.

[0049] In some alternative embodiments, MSS can be prepared using template-induced self-assembly or a soft template method. In other embodiments, the sheet-like mesoporous silica can be prepared using a template-induced self-assembly method. This method typically uses surfactants or block copolymers such as CTAB, sodium dodecyl sulfate (SDS), or polyethylene oxide-propylene oxide-ethylene oxide triblock copolymer (P123) as soft templates. By constructing a confined self-assembly system and controlling the concentration of the silicon source, the pH of the system, and the type of co-solvent, the MSS can be prepared in a controllable manner.

[0050] Compared with phase separation methods, MSS prepared by template-induced self-assembly or soft template methods usually have more uniform and regular morphology, and relatively small lateral dimensions, which can be about 100~500nm (e.g. 200nm, 300nm or 400nm), and the thickness is usually about 80~110nm.

[0051] Compared to phase separation methods using toluene as the oil phase, this invention uses cyclohexane as the oil phase and incorporates a mechanical emulsification process, resulting in better process stability and facilitating the control of the structural continuity and morphological integrity of the obtained MSS. Compared to template-induced self-assembly methods, this invention has relatively lower requirements for system conditions and is simpler to operate. It also facilitates the formation of suitable mesoporous structures while simultaneously creating two-dimensional lamellar structures, enabling the resulting material to possess both lamellar barrier properties and mesoporous drug-carrying capabilities. Furthermore, the prepared MSS has a high aspect ratio, allowing for the construction of more complex barrier network structures within the coating, thereby extending the transport path of corrosive media and enhancing the shielding and protective effect of the coating. Therefore, it is more suitable as a functional filler carrier in anti-corrosion coatings.

[0052] Step (2) In this step, the corrosion inhibitor is loaded into the mesoporous structure of the MSS to obtain the drug-loaded MSS.

[0053] Preferably, the corrosion inhibitor is an organic corrosion inhibitor. More preferably, the corrosion inhibitor is one or more selected from benzotriazole (BTA), tannic acid, 8-hydroxyquinoline, and 2-mercaptobenzothiazole.

[0054] Preferably, in this step, the corrosion inhibitor is loaded into the mesoporous structure of the MSS using a vacuum impregnation method.

[0055] In this application, the drug-loaded MSS can be represented as drug-MSS. Taking benzotriazole (BTA) as an example, the drug-loaded MSS can be denoted as BTA-MSS.

[0056] Step (3) In this step, a pH-sensitive material is used to coat the drug-loaded mesoporous sheet silica to form a pH-responsive release functional layer on the surface of the drug-loaded MSS.

[0057] Preferably, the pH-sensitive material is selected from polydopamine (PDA), chitosan (CS), and polyethyleneimine (PEI). These materials can form a pH-responsive release functional layer on the surface of the drug-loaded MSS and provide more active sites for the subsequent surface immobilization of target functional components. For example, PDA can provide phenolic hydroxyl groups, quinone groups, amino groups, and π-π sites, and has adhesion, coordination, addition, and stacking properties, making it highly versatile. For example, CS is mainly composed of primary amino and hydroxyl groups, has good biocompatibility, and is suitable for the immobilization of biomolecules or drugs. For example, PEI has a high density of primary amines, secondary amines, and / or tertiary amines, strong positive charge, and numerous amino sites, making it suitable for electrostatic loading and extensive grafting modification.

[0058] More preferably, the substance is polydopamine, so that a polydopamine layer can be formed after a dopamine self-polymerization reaction.

[0059] More preferably, the self-polymerization reaction is carried out in a Tris-HCl buffer solution with a pH of 8.0 to 9.0 (e.g., pH 8.5) for a reaction time of 6 to 24 hours (e.g., 6 hours, 12 hours, or 24 hours).

[0060] Preferably, the dopamine is in the form of dopamine hydrochloride (DA·HCl), and the dosage can be, for example, from 50 mg to 200 mg (e.g., 50 mg, 100 mg, 150 mg or 200 mg).

[0061] Taking DA and BTA-MSS as examples, 40 mg of the drug-loaded MSS obtained in step (2), such as BTA-MSS, can be weighed and dispersed in 20 mL of Tris-HCl buffer solution (50 mmol·L⁻¹). -1 The mixture was stirred magnetically for 10 min at pH 8.5. Separately, 100 mg of DA·HCl was dispersed in 20 mL of Tris-HCl buffer solution. The two dispersions were mixed and stirred at 25 °C for 12 h. After the reaction was complete, the sample was collected by centrifugation at 10000 rpm and washed repeatedly with deionized water until the pH of the supernatant was close to neutral. The supernatant was then freeze-dried to obtain BTA-MSS@PDA.

[0062] Taking BTA-MSS@PDA as an example, in these embodiments, the PDA layer of the prepared BTA-MSS@PDA can be completely coated on the surface of BTA-MSS, thereby effectively inhibiting the early release of BTA and providing more active sites for the subsequent surface immobilization of target functional components.

[0063] Besides PDA, other materials that can form a pH-responsive release functional layer on the MSS surface through chemical bonding and / or interfacial interactions can also be considered as alternative materials, such as CS or PEI.

[0064] The inventors have discovered that the aforementioned polymer material can be used to construct a surface responsive layer, but its resistance to ultraviolet aging is generally inferior to that of a PDA.

[0065] In the embodiments, the inventors also prepared BTA-MSS@CS as a comparison and compared its UV aging resistance with that of BTA-MSS@PDA, verifying that PDA does indeed have an advantage in improving the UV aging resistance of composite fillers.

[0066] Step (4) In this step, the target functional component is anchored on the surface of the pH-responsive release functional layer to obtain a corrosion-resistant composite filler with the target function.

[0067] The enhanced target function imparted to the anti-corrosion composite filler by the target functional component is selected from one or more of the following: UV aging resistance, corrosion warning, shielding, thermal conductivity, antibacterial properties, flame retardancy, and charring ability. In this invention, the "enhancement" of the target function includes both the enhancement of the target function from none to its present state and the enhancement of the target function after anchoring the target functional component, relative to the target function already possessed without the target functional component.

[0068] Preferably, the target functional component is selected from one or more of quantum dot materials (e.g., zinc oxide quantum dots (ZnO QDs), graphene oxide quantum dots, or carbon quantum dots), metal nanoparticles (e.g., silver nanoparticles), metal oxide nanoparticles (e.g., Fe(OH)3 nanoparticles), inorganic flame retardant components, and carbon-based nanomaterials.

[0069] Preferably, the quantum dot material is ZnO QDs, graphene oxide quantum dots, or carbon quantum dots. In this case, the target functional component is preferably an amino-modified quantum dot material. More preferably, the target functional component is amino-modified ZnO QDs.

[0070] More preferably, the particle size of the target functional component is 3 nm to 5 nm.

[0071] Preferably, when the target functional component has an amino-modified target functional component, the target functional component can be anchored via a Michael addition reaction.

[0072] More preferably, when the target functional component is an amino-modified ZnO QDs, the target functional component is prepared by a sol-gel method.

[0073] Taking ZnO QDs as an example, in this invention, the pH-responsive release functional layer, namely the polydopamine layer, can function as a pH-responsive release valve, and the ZnO QDs can provide resistance to ultraviolet aging and early warning of corrosion. When the packing is in a corrosive environment, the peeling and release of the core material (i.e., corrosion inhibitor) by the polydopamine layer plays a role, and the fluorescence quenching phenomenon caused by the dissolution of quantum dots provides early warning of corrosion.

[0074] In this step, in addition to ZnO QDs, other target functional components can be immobilized on the surface of pH-responsive release functional layers, such as polydopamine layers. These target functional components can be selected from metal nanoparticles, metal oxide nanoparticles, inorganic flame retardant components, carbon-based nanomaterials, and other quantum dot materials, such as silver nanoparticles, titanium dioxide, Fe(OH)3 nanoparticles, CDs (carbon dots) or carbon nanotubes, graphene oxide quantum dots, and carbon quantum dots. The introduction of these target functional components can respectively endow the composite filler with additional functions such as enhanced shielding (e.g., provided by carbon nanotubes) or thermal conductivity (e.g., provided by carbon nanotubes). For example, silver nanoparticles can more effectively impart antibacterial properties to the material, while the hybrid structure formed by Fe(OH)3 nanoparticles and, for example, polydopamine can more effectively improve the flame retardancy and char formation ability of the material.

[0075] Second aspect: Corrosion-resistant composite filler In a second aspect, the present invention provides an anti-corrosion composite filler, which is prepared by the preparation method described in the first aspect of the present invention.

[0076] The anti-corrosion composite filler provided by this invention can possess the functions of anti-corrosion, self-warning (or other functions), and anti-UV aging (or other functions). The functional composite filler uses MSS as a carrier and a corrosion inhibitor as the loaded active material. The pH-responsive release functional layer of the functional composite filler can act as a pH-responsive release valve. The target functional component, such as ZnO QDs, can have anti-UV aging properties and provide early warning of corrosion. In this case, the resulting anti-corrosion composite filler is an anti-aging self-warning anti-corrosion coating. When the anti-corrosion composite filler is in a corrosive environment, the exfoliation of the polydopamine layer releases the core material, which then functions, and the fluorescence quenching phenomenon caused by quantum dot dissolution provides early warning of corrosion.

[0077] Third aspect: Anti-corrosion coatings In a third aspect, the present invention provides an anti-corrosion coating, which is prepared using the anti-corrosion composite filler and resin matrix described in the second aspect of the present invention.

[0078] In preparing the coating, the composite functional filler described in the second aspect of the present invention can be added to the resin matrix, and after dispersion, coating and curing, an anti-corrosion coating is obtained.

[0079] Preferably, the resin matrix is ​​selected from one of epoxy resin, polyurethane resin, vinyl resin and acrylic resin.

[0080] In the coating, appropriate curing agents (polyetheramines, polyamines, imidazoles, isocyanates, peroxides, etc.) can be added according to the selected resin matrix. The curing agents and their dosage can be determined by those skilled in the art within their own capabilities.

[0081] Preferably, the amount of the anti-corrosion composite filler is 0.25% to 1.25% based on the weight of the resin matrix, for example, 0.50%, 0.75% or 1.00%, more preferably 0.75%.

[0082] As described above, the anti-corrosion composite filler of the present invention can possess anti-corrosion, self-warning, and anti-UV aging functions, i.e., it can be an anti-aging self-warning anti-corrosion composite filler. In this case, the anti-corrosion coating of the present invention is an anti-aging self-warning anti-corrosion coating with corresponding functions (of course, depending on the target functional components used, the self-warning and / or anti-UV aging functions may be replaced by other target functions or further superimposed). Like the anti-corrosion composite filler used in the present invention, the anti-corrosion coating also uses MSS as a carrier and loads a corrosion inhibitor (e.g., BTA). Taking the pH-responsive release functional layer as a polydopamine layer as an example, ZnO QDs can be anchored on its surface to impart anti-UV aging and early corrosion warning functions. By introducing the composite filler into the coating system (taking epoxy resin E51 as an example, its curing agent can be polyetheramine D2000 and D400), the barrier ability of the coating against corrosive media can be improved, and its weather resistance, anti-corrosion properties, and early corrosion self-warning ability can be enhanced.

[0083] Fourth aspect: Anti-corrosion coating In a fourth aspect, the present invention provides an anti-corrosion coating, wherein the anti-corrosion coating is obtained by applying the anti-corrosion coating described in the second aspect of the present invention, preferably, the anti-corrosion coating is obtained by applying the anti-corrosion coating to the surface of a metal substrate by scraping or spraying and then curing it.

[0084] Taking polydopamine as the pH-sensitive material and zinc oxide quantum dots as the target functional component as an example, the corrosion inhibition mechanism of the anti-corrosion coating is as follows: Figure 5 As shown. The filler forms a passivation film through the labyrinth effect, response release function, and anti-UV aging function, thereby blocking the corrosive medium of the anti-corrosion coating and ultimately achieving the effects of anti-corrosion, anti-aging, and corrosion early warning. In other words, in this case, the present invention... The anti-corrosion coating is an anti-aging, self-warning anti-corrosion coating.

[0085] Fifth aspect: Application The present invention provides, in its fifth aspect, the application of the anti-corrosion composite filler described in the second aspect of the present invention, the anti-corrosion coating described in the third aspect of the present invention, or the anti-corrosion coating described in the fourth aspect of the present invention in the anti-corrosion protection of metal substrate surfaces. Example

[0086] The embodiments of the present invention will be described in detail below with reference to the examples. These examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified, specific implementation conditions in the examples should be followed according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without specified manufacturers are all commercially available conventional products.

[0087] Preparation Example 1: Preparation of Lamellar Mesoporous Silica Using Cyclohexane as Oil 200 mg of cetyldimethylammonium bromide (CTAB) was dissolved in 80 mL of water. The resulting solution was transferred to a round-bottom three-necked flask, and 80 mL of cyclohexane and 200 μL of ammonia were added. The mixture was mechanically emulsified at 700 rpm for 2 h. Subsequently, a mixture of 400 μL of tetraethyl orthosilicate (TEOS) and 250 μL of aptase was added dropwise to the reaction system, and the reaction was carried out at 25 °C for 10 h. After the reaction was completed, the mixture was centrifuged at 8000 rpm for 10 min. The resulting white product was washed three times with deionized water and dried under vacuum at 60 °C for 24 h. The dried product was then placed in a muffle furnace and calcined at 600 °C for 5 h to obtain MSS.

[0088] Preparation Example 2: Preparation of plate-like mesoporous silica using toluene as an oil In this preparation example, the sheet-like mesoporous silica is still prepared using the phase separation method. The difference lies in that toluene is used instead of cyclohexane as the oil phase, and the amount of silicon source is appropriately increased. Since this method is similar to the aforementioned phase separation method in terms of the mechanism of oil-water interface-induced assembly, the resulting sheet-like mesoporous silica still has similar two-dimensional sheet structure and mesoporous characteristics. The specific preparation steps are as follows: 50 mg (20–100 mg) of CTAB was dissolved in 50 g of distilled water at 60 °C, and the pH of the solution was adjusted to approximately 10 using concentrated ammonia. Separately, 1.45 g of TEOS and 0.5 g (0.3–0.5 g) of APTES were added to 30 g of toluene and ultrasonically dispersed to obtain the oil phase. The aqueous and oil phases were then mixed and sheared and emulsified using a high-speed homogenizer at 8000 rpm for 5 min to obtain an emulsion system. This emulsion system was transferred to a three-necked flask and reacted at 35 °C for 12 h. After the reaction, the emulsion was washed with ethanol and filtered. The resulting white precipitate was collected, washed with ethanol and water respectively, filtered, and then vacuum dried at 60 °C for 24 h. The dried product was placed in a muffle furnace and calcined at 600 °C for 5 h to obtain MSS. It is worth noting that in this method, the lamellar structure is mainly formed at the oil-water interface. Due to the instability of the interface structure during its formation and rupture, the resulting product will exhibit a certain degree of morphological diversity.

[0089] Under the conditions of Preparation Examples 1 and 2, the prepared sheet-like silica has a suitable mesoporous structure (e.g., Figure 1 Studies have found that as the amount of CTAB added increases, the pore size of the sheet-like silica gradually increases, but when the pore size is too large, the continuity of the sheet-like structure is disrupted. When the amount of APTES added is low, the resulting silica sheets tend to be curved and difficult to maintain good flatness; while when the amount of APTES added is too high, it is prone to self-polymerization, resulting in the formation of rough nanoparticles on the silica surface. On the other hand, when the stirring speed is low, the size of the resulting sheet-like silica is larger; when the stirring speed is too high, the continuity of the sheet-like structure deteriorates.

[0090] Preparation Example 3: Preparation of Spherical Mesoporous Silica (MSN) To investigate the effect of filler morphology on coating performance, the inventors also prepared zero-dimensional spherical mesoporous silica (MSN) as a comparative example. The preparation process was as follows: 0.063 g of NaOH was dissolved in 110 mL of deionized water and heated to 80 °C. Subsequently, 0.225 g of CTAB was added to the solution under magnetic stirring, and stirring continued until completely dissolved. The resulting solution was transferred to a three-necked flask and stirred continuously at 80 °C and 300 rpm. Then, a 25 wt.% solution of TEOS in anhydrous ethanol (prepared by dissolving 1.25 g of TEOS in 3.75 g of anhydrous ethanol) was added dropwise, and the reaction continued for 2 h after the addition was complete. After the reaction was complete, the white product was collected by filtration, washed three times with deionized water, and dried under vacuum at 60 °C for 24 h. The dried product was placed in a muffle furnace and calcined at 600 °C for 5 h to obtain spherical mesoporous silica (MSN).

[0091] Preparation Example 4: Preparation of BTA-MSS 0.10 g of MSS was weighed and ultrasonically dispersed in a saturated BTA ethanol solution. The mixture was then transferred to a vacuum drying oven, and a vacuum of 0.08 MPa was maintained for 30 min to allow the air trapped in the mesoporous channels of the sheet-like silica to escape completely. Air was then introduced to restore atmospheric pressure, and the pressure rise was used to force the solution into the mesoporous structure to complete the impregnation. This process was repeated three times. The product was collected by centrifugation and washed three times with deionized water to remove residual BTA from the surface. Finally, the sample was dried at 60 °C for 12 h to obtain BTA-MSS.

[0092] Preparation Example 5: Preparation of BTA-MSS@PDA Weigh 40 mg of BTA-MSS and disperse it in 20 mL of Tris-HCl buffer solution (50 mmol·L⁻¹). -1 The BTA-MSS dispersion was obtained by magnetic stirring in a solution of pH 8.5 for 10 min. Separately, 80 mg of dopamine hydrochloride (DA·HCl) was dispersed in 20 mL of Tris-HCl buffer to obtain a DA dispersion. The two dispersions were mixed and stirred at 25 °C for 12 h. After the reaction was complete, the sample was collected by centrifugation at 10000 rpm and washed repeatedly with deionized water until the supernatant reached neutral pH. The supernatant was then freeze-dried to obtain BTA-MSS@PDA.

[0093] Preparation Example 6: Preparation of BTA-MSS@CS The inventors further prepared BTA-MSS@CS as a comparative example and compared its UV aging resistance with that of BTA-MSS@PDA to verify the advantages of PDA in improving the UV aging resistance of composite fillers. The specific preparation steps are as follows: The preparation of MSS and the loading of BTA were the same as in the preparation example above, and CS was coated on the MSS surface using the glutaraldehyde crosslinking method.

[0094] First, 5.1 g of sodium acetate and 20 mL of acetic acid were mixed and dissolved in water to prepare a 250 mL buffer solution with a pH of 3.6. 400 mg of BTA-MSS, prepared using the same method as in Preparation Example 1, was placed in a beaker, and 120 mL of the above buffer solution was added. The mixture was sonicated for 15 min to ensure thorough dispersion. Then, 20 mL of a 0.025 mol / L sodium dodecylbenzenesulfonate solution was added to the beaker as a surfactant. After stirring for 1 hour, 6 mL of a 1 wt% chitosan-acetic acid solution was added. After reacting at room temperature for 4 hours, 6 mL of glutaraldehyde was added as a crosslinking agent. After continuing the reaction for another 4 hours, the product was centrifuged, washed three times each with deionized water and ethanol, and finally dried under vacuum at 60°C to obtain BTA-MSS@CS.

[0095] Preparation Example 7: Preparation of amino-modified ZnO QDs Weigh 2.6 g of Zn(CH3COO)2 and add it to 75 mL of anhydrous ethanol. Stir magnetically at 80 °C until completely dissolved. Cool the system to 50 °C and add 10 mL of 1.75 mol·L⁻¹ KOH ethanol solution dropwise, continuing the reaction for 1 h. Then, add a mixed solution containing 200 μL of 3-aminopropyltriethoxysilane (APTES) and 2 mL of deionized water to the reaction system, and continue the reaction for 30 min. After the reaction is complete, collect the product by centrifugation at 10000 rpm to obtain amino-modified ZnO QDs. Wash with anhydrous ethanol and then disperse in anhydrous ethanol to store as a dispersion for later use.

[0096] Preparation Example 8: Preparation of Anti-aging Self-early Warning Corrosion-preventing Composite Filler (BTA-MSS@PDA-ZnO) ZnO QDs are anchored to the surface of BTA-MSS@PDA via Michael addition reaction, and the reaction mechanism is shown in Equation 1. Specifically, the quinone conjugated double bond active sites on the PDA surface undergo Michael addition reaction with the primary or secondary amine groups on the amino-modified ZnO QDs surface to form a covalent bond, thereby achieving stable anchoring of ZnO QDs on the PDA surface.

[0097] Formula 1 The specific steps are as follows: Weigh 25 mg of BTA-MSS@PDA and disperse it in 70 mL of Tris-HCl buffer solution. Add 25 mg of dried ZnO QDs separated from the dispersion and stir at 40 °C for 12 h. After the reaction is complete, centrifuge to collect the product, wash it three times with deionized water, and freeze-dry it to obtain the filler product BTA-MSS@PDA-ZnO.

[0098] Preparation Example 9: Preparation of Corrosion-Resistant Composite Filler (BTA-MSS@CS) The preparation was carried out in essentially the same manner as in Preparation Example 8, except that an equal amount of BTA-MSS@CS prepared in the above preparation example was used instead of BTA-MSS@PDA to obtain the filler product BTA-MSS@CS.

[0099] Preparation Example 10: Preparation of Corrosion-Resistant Composite Filler (BTA-MSN@PDA-ZnO) The preparation method was basically the same as that used for BTA-MSS, BTA-MSS@PDA, and BTA-MSS@PDA-ZnO. For example, the prepared MSN was further subjected to BTA impregnation, PDA coating, and ZnO loading in the same way as the mesoporous silica, so as to compare the application effects of different morphologies of mesoporous silica in anti-corrosion coatings. The difference was that MSN was used instead of MSS. Thus, BTA-MSN, BTA-MSN@PDA, and BTA-MSN@PDA-ZnO were prepared in sequence.

[0100] Example 1: Preparation of BTA-MSS@PDA-ZnO composite anti-corrosion coating Step 1: Select Q235 carbon steel plate as the substrate. The chemical composition of Q235 steel is: S: 0.045%, P: 0.045%, C: 0.20%, Cu: 0.30%, Si: 0.35%, Mn: 1.40%, with the balance being Fe. Before coating, the steel substrate is mechanically polished sequentially with 600-grit and 800-grit sandpaper until a bright metal surface is obtained. It is then rinsed sequentially with deionized water and ethanol, and dried at 60°C for later use.

[0101] Step 2: Add BTA-MSS@PDA-ZnO filler to E-51 epoxy resin at a mass fraction of 0.75 wt.%, using ethyl acetate as a diluent, and ultrasonically disperse until uniform. Then, compound the epoxy resin E-51 with curing agents D-400 and D-2000 at a molar ratio of 10:9:1 to obtain the BTA-MSS@PDA-ZnO coating.

[0102] Step 3: Apply the prepared BTA-MSS@PDA-ZnO coating evenly to the surface of the Q235 steel prepared in the above steps by spraying, and cure at 80℃ for 10h to obtain a steel sample with BTA-MSS@PDA-ZnO coating (coating thickness is 90±5μm).

[0103] Examples 2 to 11: Preparation of other anti-corrosion coatings Step 1: Prepare the steel using the same method as in Step 1 of Example 1.

[0104] Step 2: Prepare coatings using the same method as in Step 2 of Example 1, except that the BTA-MSS@PDA-ZnO filler in Example 1 is replaced with materials from the same source as those used in the above preparation examples, or with ZnO QDs, MSS, BTA-MSS, BTA-MSS@PDA, MSN, BTA-MSN, BTA-MSN@PDA, BTA-MSN@PDA-ZnO, and BTA-MSS@CS prepared in the above preparation examples. The corresponding coatings are prepared using the same method and are respectively denoted as ZnO / EP, MSS / EP, BTA-MSS / EP, BTA-MSS@PDA / EP, MSN / EP, BTA-MSN / EP, BTA-MSN@PDA / EP, BTA-MSN@PDA-ZnO / EP, and BTA-MSS@CS / EP coatings.

[0105] Step 3: Prepare the coating in the same manner as in Step 3 of Example 1, and prepare a control coating (EP) with pure epoxy resin without any fillers to obtain steel samples with the corresponding coating (coating thickness of 90±5μm).

[0106] Test Example 1: Electrochemical Impedance Spectroscopy (EIS) Test According to ASTM G3-2014, electrochemical workstation testing was used. Specifically, the steel samples with anti-corrosion coatings prepared in Examples 1 to 11 were immersed in a 3.5 wt.% NaCl aqueous solution for 100 days, and then the low-frequency impedance value (|Z|) was measured. 0.01Hz To evaluate the corrosion resistance of the coating.

[0107] The test results of the control group EP, ZnO / EP, MSS / EP, BTA-MSS / EP, and BTA-MSS@PDA / EP will be plotted. Figure 3 (a) is a Nyquist plot. Figure 3 (b) is a Bode plot. For example... Figure 3 As shown, after immersion in a 3.5 wt.% NaCl solution for 100 days, the impedance value of the BTA-MSS@PDA-ZnO / EP coating remained at 7.71 × 10⁻⁶. 9 Ω·cm 2 It exhibits excellent corrosion protection performance. This is mainly attributed to the fact that the lamellar mesoporous structure of MSS can construct relatively tortuous diffusion channels in the resin (such as epoxy resin) matrix, prolonging the diffusion of water, oxygen, and Cl. -This reduces the transport path of corrosive media, thereby decreasing their migration rate to the metal / coating interface and improving the coating's shielding performance. Simultaneously, the amino active groups on the PDA layer and ZnO QDs surface can react with resin systems (e.g., epoxy systems) or form strong interfacial interactions, helping to improve the dispersion and interfacial bonding of fillers in the matrix, thus increasing the coating's density. Furthermore, these amino active sites can coordinate with iron ions on the metal surface, enhancing coating adhesion and reducing the risk of interfacial failure. In addition, ZnO QDs have absorption and scattering effects on ultraviolet light, which can mitigate the aging damage caused by ultraviolet radiation to the resin matrix (e.g., epoxy matrix), thereby improving the long-term stability of the coating.

[0108] As shown in Table 1, the anti-corrosion performance of other anti-corrosion coatings prepared in other comparative examples, such as MSN / EP, BTA-MSN / EP, BTA-MSN@PDA / EP, and BTA-MSN@PDA-ZnO / EP, gradually increases with the degree of filler surface modification. It is noteworthy that, under the corresponding modification conditions, the impedance values ​​of the spherical mesoporous silica-based composite coatings are all lower than those of the corresponding lamellar mesoporous silica-based composite coatings; that is, the impedance values ​​of MSN / EP, BTA-MSN / EP, BTA-MSN@PDA / EP, and BTA-MSN@PDA-ZnO / EP are lower than those of MSS / EP, BTA-MSS / EP, BTA-MSS@PDA / EP, and BTA-MSS@PDA-ZnO / EP, respectively. This result indicates that the filler morphology has a significant impact on the anti-corrosion performance of the coating. Compared to spherical MSN, MSS-based active fillers not only help improve the density of the coating, but also, due to their larger aspect ratio, can create a more tortuous diffusion path for corrosive media in the coating, thus forming a more significant "maze effect". This more effectively delays the penetration of corrosive media into the metal substrate surface, thereby improving the anti-corrosion performance of the coating.

[0109] Table 1. Corrosion resistance of the coated samples in each comparative example

[0110] |Z| 0.01Hz Measured under normal conditions (25℃, 3.5wt% NaCl aqueous solution) for 100 days; NT indicates not detected. "-ZnO" when referring to fillers, coatings, and coatings indicates the presence of ZnO QDs, consistent throughout the text.

[0111] Test Example 2: Adhesion Test The procedure was performed according to GB / T 5210-2006. The coating to be tested was applied to four Sa2.5 grade sandblasted steel plates, and the coating thickness after curing was approximately 90 μm. A two-component adhesive was used to bond a 20 mm diameter spindle to the coating surface. After curing for 24 hours, the spindle was pulled out at a loading rate of 1 MPa / s perpendicular to the coating surface until the coating separated from the steel plate.

[0112] like Figure 4 As shown, pull-out tests of different composite coatings before UV aging revealed that the doping of composite fillers improved coating adhesion to varying degrees. Among them, compared to MSS / EP and BTA-MSS / EP, the introduction of amino-modified ZnO QDs and polydopamine-modified fillers resulted in a more significant improvement in coating adhesion. This is presumably because these fillers have abundant amino active sites on their surface, which can participate in the curing process of epoxy resin, increasing crosslinking density and enhancing coating compactness. They can also coordinate with iron ions on the Q235 steel substrate surface, thereby strengthening the interfacial bonding between the coating and the substrate, further improving coating adhesion.

[0113] Test Example 3: UV Aging Resistance Test The aging process was conducted in a UVA aging chamber according to GB / T 14522-2008 standard. The irradiance used was 0.77 W / m². 2 The samples were irradiated with a fluorescent lamp at 340 nm. Steel samples with the corresponding anti-corrosion coating prepared according to the above method underwent a 7-day aging test. Then, the adhesion before and after aging was compared using the pull-out test described above to evaluate the barrier performance of the coating.

[0114] like Figure 4As shown, after 7 days of UV aging, the adhesion of the BTA-MSS@PDA / EP and BTA-MSS@PDA-ZnO / EP composite coatings was higher than that of other composite coatings, indicating that the introduction of the PDA layer and ZnO quantum dots is beneficial to improving the UV aging resistance of the coatings. The strength loss of the pure EP coating was approximately 55%, the largest among all samples. Among them, ZnO / EP, BTA-MSS@PDA / EP, and BTA-MSS@PDA-ZnO / EP all had an adhesion retention rate of over 80% after the aging test, indicating that ZnO quantum dots and PDA can, to a certain extent, slow down the aging damage of epoxy groups caused by UV irradiation, thereby maintaining the stability of the coating structure. Furthermore, the test results of the BTA-MSS@CS doped system show that the abundant polar groups such as hydroxyl and amino groups on the CS surface also help to improve its dispersibility in the coating and enhance the density of the coating. However, after UV aging, its adhesion retention rate is significantly lower than that of BTA-MSS@PDA / EP, indicating that CS can be used as a candidate material for the response release valve layer, but it is not as good as PDA in improving the coating's resistance to UV aging.

[0115] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0116] Finally, it should be noted that: the above description details the microcapsules with self-healing, anti-corrosion, and self-early warning functions, their preparation methods, and their applications disclosed in the embodiments of the present invention. Specific examples have been used to illustrate the implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a corrosion-resistant composite filler, characterized in that, The preparation method includes the following steps: (1) Provide mesoporous lamellar silica; (2) The corrosion inhibitor is loaded into the mesoporous structure of the mesoporous lamellar silica to obtain drug-loaded mesoporous lamellar silica; (3) A pH-sensitive material is used to coat the drug-loaded mesoporous sheet silica to form a pH-responsive release functional layer on the surface of the drug-loaded mesoporous sheet silica; (4) Anchor the target functional component on the surface of the pH-responsive release functional layer to obtain a corrosion-resistant composite filler with the target function.

2. The preparation method according to claim 1, characterized in that: The thickness of the mesoporous sheet-like silica is 10 nm to 20 nm; The mesoporous lamellar silica has a lateral dimension of 2 μm to 4 μm; and / or The mesoporous sheet-like silica has a pore size of 2 nm to 50 nm, preferably 5 nm to 8 nm.

3. The preparation method according to claim 1, characterized in that: The corrosion inhibitor is an organic corrosion inhibitor, preferably one or more selected from benzotriazole, tannic acid, 8-hydroxyquinoline, and 2-mercaptobenzothiazole; The pH-sensitive material is selected from one of polydopamine, chitosan, and polyethyleneimine; and / or The target functional component imparts enhanced target functions to the anti-corrosion composite filler, selected from one or more of the following: UV aging resistance, corrosion warning, shielding, thermal conductivity, antibacterial properties, and flame retardancy; preferably, the target functional component is selected from one or more of the following: quantum dot materials, metal nanoparticles, metal oxide nanoparticles, inorganic flame retardant components, and carbon-based nanomaterials.

4. The preparation method according to claim 1, characterized in that: In step (1), plate-like silica is prepared by phase separation method, and mesoporous plate-like silica is obtained after calcination to remove the template agent; In step (2), the corrosion inhibitor is loaded into the mesoporous structure of the mesoporous lamellar silica using a vacuum impregnation method; In step (4), the pH-sensitive material is polydopamine, the target functional component is amino-modified, and the target functional component is anchored by a Michael addition reaction.

5. The preparation method according to claim 4, characterized in that: In step (1), the sheet-like silica is prepared using hexadecyltrimethylammonium bromide as a template agent and tetraethyl orthosilicate and 3-aminopropyltriethoxysilane as raw materials; Preferably, in step (1), the amount of hexadecyltrimethylammonium bromide added is 25-400 mg; the volume weight ratio of tetraethyl orthosilicate to hexadecyltrimethylammonium bromide is 400:(25-400); and the volume ratio of tetraethyl orthosilicate to 3-aminopropyltriethoxysilane is 400:(150-350).

6. The preparation method according to claim 4, characterized in that: The pH-sensitive material is polydopamine, and the polydopamine forms a polydopamine layer through a dopamine self-polymerization reaction. Preferably, the self-polymerization reaction is carried out in a Tris-HCl buffer solution with a pH of 8.0 to 9.0 for a reaction time of 6 to 24 hours.

7. A corrosion-resistant composite filler, characterized in that, The anti-corrosion composite filler is prepared by the preparation method according to any one of claims 1 to 6.

8. An anti-corrosion coating, characterized in that, The anti-corrosion coating is prepared using the anti-corrosion composite filler and resin matrix as described in claim 7; Preferably, the resin matrix is ​​selected from one of epoxy resin, polyurethane resin, vinyl resin and acrylic resin; More preferably, the amount of the anti-corrosion composite filler is 0.25% to 1.25% based on the weight of the resin matrix.

9. An anti-corrosion coating, characterized in that, The anti-corrosion coating is prepared by applying the anti-corrosion coating according to claim 8.

10. The application of the anti-corrosion composite filler of claim 7, the anti-corrosion coating of claim 8, or the anti-corrosion coating of claim 9 in the anti-corrosion protection of metal substrate surfaces.

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