Thermal response self-repairing coating with metal antibacterial ions and corrosion inhibitor carried on magnesium alloy surface and preparation method of thermal response self-repairing coating

Abstract

The invention discloses a thermal response self-repairing coating with metal antibacterial ions and a corrosion inhibitor carried on the surface of a magnesium alloy and a preparation method of the thermal response self-repairing coating, and belongs to the technical field of self-repairing coatings. The coating is divided into an upper layer and a lower layer, the upper layer is a polycaprolactone layer containing metal antibacterial ions, and the lower layer is a polycaprolactone layer containing a corrosion inhibitor. The preparation method of the coating comprises the following steps: (1) preparing nano mesoporous silica microspheres; (2) carrying a corrosion inhibitor and metal antibacterial ions in the microspheres; (3) preparing a mixed solution of polycaprolactone and the silicon dioxide microspheres obtained in the step (2); (4) treating the surface of the magnesium alloy matrix; and (5) sequentially spin-coating the solution obtained in the step (2) and the solution obtained in the step (3) onto the surface of the magnesium matrix obtained in the step (4). The preparation route is simple in method and easy and convenient to operate, and the obtained composite coating has the advantages of being good in corrosion resistance, excellent in thermal response self-repairing performance, high in self-repairing repetition rate and capable of stably releasing antibacterial ions for a long time.

Description

Technical Field

[0001] This invention relates to a thermally responsive self-healing coating on a magnesium alloy surface, containing metal antibacterial ions and corrosion inhibitors, and its preparation method, belonging to the field of self-healing coating technology. Background Technology

[0002] Magnesium alloys, due to their excellent biocompatibility, biodegradability, and mechanical properties similar to bone tissue, have shown great potential in the field of biomedical implant materials. However, they also face two major challenges in practical clinical applications: first, the excessively rapid corrosion and degradation rate in physiological environments leads to premature mechanical failure of the implant; second, the risk of postoperative bacterial infection easily leads to complications such as implant failure; and third, during service, they inevitably suffer damage, which is irreparable and accelerates corrosion. Therefore, functional coating modification of magnesium alloy surfaces to control their degradation rate and endow them with highly efficient antibacterial capabilities has become a key research focus and challenge in this field.

[0003] Self-healing coating technology offers a new approach to solving the problem of micro-damage in coatings, and is mainly divided into two categories: exogenous and intrinsic. Exogenous self-healing relies on microcapsules loaded with repair agents, but its repair cycles are limited by capsule capacity, and uneven dispersion can easily lead to incomplete repair. Intrinsic self-healing is based on dynamic covalent bonds (such as the Diels-Alder reaction) or hydrogen bonds to achieve repeated repair, but it suffers from harsh response conditions (requiring high temperature or specific light exposure), low repair efficiency, and insufficient mechanical properties. Among existing technologies, polyether polyol-based polyurethane coatings can achieve self-healing within 48 hours, but there is still a risk of corrosive media penetration after repair; although graphene-reinforced systems can improve repair efficiency, they are rarely used in research on the specific protection of magnesium alloys. In the biomedical field, antibacterial function is one of the core requirements for coatings. Existing antibacterial coatings mainly employ strategies such as silver ion release and chitosan contact killing. For example, silver-containing polyoxometalate and carboxymethyl chitosan composite hydrogels exhibit good antibacterial effects. However, long-term use of silver ions can easily lead to drug resistance, and the compatibility issue between antibacterial agents and self-healing substrates remains unresolved. Meanwhile, medical magnesium alloys require coatings with controllable degradation properties, and existing single-function coatings struggle to balance corrosion resistance, self-healing, and antibacterial performance.

[0004] Polycaprolactone (PCL) is a biodegradable polymer material. However, single PCL coatings suffer from insufficient antibacterial properties, limited mechanical strength, and the potential for accelerated corrosion of the magnesium matrix due to localized acidic microenvironments during degradation. Furthermore, pure PCL coatings exhibit insufficient corrosion resistance. To impart antibacterial properties, conventional methods typically involve directly blending metal ion antibacterial agents (such as silver, copper, and zinc ions) into the polymer matrix. However, this method easily leads to the burst release of antibacterial agents, making long-term antibacterial effects difficult to achieve. High-dose release may also cause cytotoxicity and affect the uniformity and stability of the coating. To improve corrosion resistance, magnesium alloy corrosion inhibitors such as dihydrate and dicalcium phosphate (DCPD), phytic acid, and benzotriazole can be incorporated. However, this method also faces the risk of mutual repulsion between the corrosion inhibitor and PCL, potentially worsening corrosion resistance.

[0005] To address the aforementioned issues, constructing a controllable release functional composite coating is an ideal strategy. Mesoporous silica nanospheres (SiO2) are an excellent drug / ion carrier due to their high specific surface area, ease of functionalization, and good biocompatibility. By embedding broad-spectrum antibacterial agents such as metal ions and magnesium alloy corrosion inhibitors into mesoporous silica nanospheres, direct incompatibility between the antibacterial agents / corrosion inhibitors and polymers can be effectively avoided. Furthermore, the continuous and controllable release of ions can be achieved through the porous structure of the microspheres, thus overcoming the burst release problem and extending the antibacterial period. However, the bonding strength between ordinary mesoporous silica nanospheres and organic materials such as polycaprolactone, as well as magnesium alloys, is particularly insufficient, necessitating enhanced compatibility.

[0006] In coating preparation processes, spin coating offers significant advantages such as ease of operation, uniform film formation, and controllable thickness, making it ideal for preparing thin and dense polymer composite coatings on smooth magnesium alloy surfaces. By uniformly dispersing mesoporous silica nanospheres carrying magnesium alloy corrosion inhibitors and mesoporous silica nanospheres carrying metal antibacterial ions as functional fillers in a PCL matrix and then forming a film using spin coating technology, it is expected to construct a composite protective coating on the magnesium alloy surface that combines physical barrier function with long-lasting intelligent antibacterial / corrosion inhibition. This strategy not only effectively delays the corrosion of the magnesium substrate but also significantly reduces the risk of bacterial infection through the slow release of ions, providing a new technological path for developing next-generation high-performance magnesium alloy implants. Summary of the Invention

[0007] Based on the limitations of existing technologies and coating systems, and considering the significant advantages of spin coating technology, polycaprolactone self-healing materials, corrosion inhibitors, and metal ion antibacterial agents, this invention aims to provide a thermally responsive self-healing / antibacterial / corrosion-resistant composite coating for magnesium alloy surfaces. This coating features simple preparation process, good self-healing effect, high repeatability, excellent corrosion resistance, and stable release of antibacterial ions.

[0008] Meanwhile, this invention provides a method for preparing a thermally responsive self-healing coating on a magnesium alloy surface, which incorporates metal antibacterial ions and corrosion inhibitors. This preparation method is simple and easy to operate, and the resulting composite coating has the characteristics of good corrosion resistance, excellent thermally responsive self-healing performance, high self-healing repeatability, and long-term stable release of antibacterial ions.

[0009] Meanwhile, this invention provides the application of a thermally responsive self-healing coating on a magnesium alloy surface, incorporating metal antibacterial ions and corrosion inhibitors, in biomedical implant materials.

[0010] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a nanoporous silica microsphere with high capacity loading, good dispersibility, optimized surface hydrophilic / hydrophobic properties, and excellent compatibility with polycaprolactone.

[0011] In a second aspect, the present invention provides a thermally responsive self-healing / antibacterial / corrosion-resistant composite coating for magnesium alloy surfaces.

[0012] Optionally, the thickness of the composite coating is 15-25 μm; Preferably, the main body of the composite coating is composed of polycaprolactone, and the composite coating is divided into upper and lower layers. The upper layer (i.e., the layer near the surface) is a polycaprolactone layer containing metal antibacterial ions, and the lower layer (i.e., the layer near the magnesium alloy substrate) is a polycaprolactone layer containing corrosion inhibitors. A third aspect of the present invention provides a method for preparing a thermally responsive self-healing / antibacterial / corrosion-resistant composite coating on a magnesium alloy surface, comprising the following steps: S1. Preparation of mesoporous silica nanospheres (MSNs) with high capacity carrying capacity, good dispersibility, and optimized surface hydrophilic / hydrophobic properties, comprising the following steps: (1) Dissolve surfactant A (main surfactant), surfactant B (short-chain alcohol co-surfactant to adjust sphericity) and auxiliary nonionic surfactant C (to adjust mesoporous structure and expand mesoporous pore size) in alkaline solution A in a certain proportion, heat and stir, then add a small amount of neutral inorganic salt dropwise, and always keep the temperature constant and stir to form a transparent micelle solution. (2) Dissolve the silicon source in a mixed solution of ethanol and water, add a small amount of alkaline solution B, and heat and stir. (3) Slowly add the solution obtained in (2) to the micelle solution obtained in (1) and heat and stir. (4) Heating and ultrasonically stirring the solution obtained in (3); (5) Slowly add acidic solution A to the solution obtained in (4) to adjust the pH; (6) Filter the solution obtained in (5), and dialyze the filtrate to obtain dialysate; (7) Add a small amount of surface modifier (to improve surface hydrophilic / hydrophobic properties) to the dialysate obtained in (6), heat and stir, and then dialyze again; (8) The dialysate obtained in (7) was freeze-dried to obtain nano-mesoporous silica microspheres (MSNs) with large capacity, good dispersibility and optimized surface hydrophilic / hydrophobic properties. S2. The steps of loading the corrosion inhibitor into the nanoporous silica microspheres obtained in S1 include: (1) The nanoporous silica microspheres obtained in S1 were placed in a mixed solution of ethanol and acidic solution B, and refluxed at high temperature. After filtration, they were washed with deionized water until neutral and then dried under vacuum. (2) Dissolve the nano-mesoporous silica microspheres and corrosion inhibitor obtained in (1) in alkaline solution C in a certain proportion, heat and stir, then add a small amount of auxiliary shaking agent and shake at room temperature; (3) The solution obtained in (2) was centrifuged, filtered, washed with deionized water, and vacuum dried to obtain nano-mesoporous silica microspheres loaded with corrosion inhibitor. S3. The steps of incorporating metal antibacterial ions into the nanoporous silica microspheres obtained in S1 include: (1) The nanoporous silica microspheres obtained in S1 were placed in a mixed solution of ethanol and acidic solution C, and refluxed at high temperature. After filtration, they were washed with deionized water until neutral and then dried under vacuum. (2) Dissolve the nano-mesoporous silica microspheres obtained in (1) and the antibacterial ion salt in alkaline solution D in a certain proportion, heat and stir, then add a small amount of auxiliary shaking agent and shake at room temperature; (3) The solution obtained in (2) was centrifuged, filtered, washed with deionized water, and vacuum dried to obtain nano-mesoporous silica microspheres carrying metal antibacterial ions. S4. Dissolve a portion of the organic particles in an organic solvent, divide it into two portions, and add the silica microspheres obtained in S2 and S3 to each portion. Heat and stir. S5. The magnesium alloy substrate is subjected to pre-grinding, polishing, ultrasonic cleaning, alkaline heat treatment and pickling in sequence, and finally air-dried. S6. Spin-coat the mixed solution obtained in S4 onto the magnesium alloy substrate, and after drying, an organic composite coating containing antibacterial ions and corrosion inhibitors is obtained.

[0013] In step S1(1), optionally, the surfactant A is selected from hexadecyltrimethylammonium bromide or polyoxyethylene sorbitan monooleate, the surfactant B is selected from ethanol, propanol, butanol or n-pentanol, the alkaline solution A is selected from potassium hydroxide solution or sodium hydroxide solution, and the neutral inorganic salt is selected from sodium chloride, potassium chloride, sodium sulfate or potassium sulfate. In step S1(1), preferably, the surfactant C is selected as F127-triblock copolymer; In step S1(1), optionally, the mass ratio of surfactant A, surfactant B and surfactant C is (10.7-15):1:(3.3-4); In step S1(1), optionally, the pH of the alkaline solution A is 11-12; In step S1(1), optionally, the concentrations of surfactant A, surfactant B and surfactant C in the alkaline solution are 0.01-0.05 mol / L; In step S1(1), optionally, the concentration of the neutral inorganic salt in the mixed solution is 0.02-0.06 mol / L; In step S1(1), optionally, the stirring method is magnetic heating stirring, the heating temperature is 75-85 ℃, the stirring speed is 300-500 rpm, and the stirring time is 1-2 h; In step S1(2), the silicon source is selected from tetraethyl orthosilicate, methyl orthosilicate or 3-aminopropyltriethoxysilane, and the alkaline solution B is selected from ammonia water, sodium bicarbonate solution or sodium acetate solution. In step S1(2), optionally, the volume ratio of the silicon source, ethanol and water is 1:(1.75-2.25):(0.45-0.55); In step S1(2), optionally, the pH of the alkaline solution B is 7.5-8.5; In step S1(2), optionally, the stirring method is magnetic heating stirring, the heating temperature is 35-45℃, the stirring speed is 150-200 rpm, and the stirring time is 0.5-1 h; In step S1(3), optionally, the stirring method is magnetic heating stirring, the heating temperature is 55-65℃, the stirring speed is 200-300 rpm, and the stirring time is 1-2 h; In step S1(4), optionally, the stirring method is magnetic heating stirring, the heating temperature is 85-95℃, the stirring speed is 300-500 rpm, and the stirring time is 6-8 h; In step S1(4), optionally, the ultrasonic frequency is 20-40 kHz; In step S1(5), optionally, the acidic solution A is selected from hydrochloric acid and sulfuric acid solutions; In step S1(5), optionally, the concentration of the acidic solution A is 0.1-0.2 mol / L; In step S1(5), optionally, the pH is adjusted to 7.5-8.5; In step S1(6), optionally, the molecular weight cutoff of the dialysis is 1500-2500 Da, the dialysis solution is deionized water, and the dialysis time is 12-48 h; In step S1(6), preferably, the dialysate is replaced every 6 hours; In step S1(7), optionally, the surface modifier is selected from aminopropyltriethoxysilane, 3-mercaptopropyltriethoxysilane or vinyltris(β-methoxyethoxy)silane; In step S1(7), optionally, the mass ratio of the dialysate to the surface modifier is (10-20):1; In step S1(7), optionally, the stirring method is magnetic heating stirring, the heating temperature is 55-65℃, the stirring speed is 200-300 rpm, and the stirring time is 1-2 h; In step S1(7), optionally, the molecular weight cutoff of the dialysis is 1500-2500 Da, the dialysis solution is deionized water, and the dialysis time is 12-18 h; In step S1(7), preferably, the dialysate is replaced every 6 hours; In step S1(8), optionally, the freeze-drying temperature is -65 to -45°C, and the vacuum degree is <10. 2 Pa; In step S2(1), optionally, the acidic solution B is selected from hydrochloric acid or sulfuric acid; In step S2(1), optionally, the concentration of the acidic solution B is 0.1-0.2 mol / L; In step S2(1), optionally, the volume ratio of the ethanol to the acidic solution B is (10-20):1, and the mass ratio of the nanoporous silica microspheres to the mixed solution is (7-9):20. In step S2(1), optionally, the reflux extraction temperature is 55-65 ℃ and the time is 6-8 h; In step S2(1), optionally, the vacuum drying temperature is 55-65 ℃ and the vacuum degree is <10. 2 The Pa time is 12-15 h; In step S2(2), optionally, the corrosion inhibitor is selected from phytic acid, dicalcium phosphate dihydrate or benzotriazole, the alkaline solution C is selected from ammonia water, sodium bicarbonate solution or sodium acetate solution, and the auxiliary vibration agent is selected from polyvinylpyrrolidone. In step S2(2), optionally, the pH of the alkaline solution C is 8-10; In step S2(2), optionally, the mass ratio of the nano-silica microspheres, corrosion inhibitor and auxiliary oscillator is 10∶(2-3)∶0.01; In step S2(2), optionally, the heating and stirring temperature is 35-45 ℃, the stirring speed is 100-200 rpm, and the time is 2-3 h; In step S2(2), optionally, the oscillation speed is 90-120 rpm and the time is 18-24 h; In step S2(3), optionally, the centrifugation speed is 8000-10000 rpm and the time is 10-15 min; In step S2(3), optionally, the number of washing cycles is 3-5, the drying temperature is 80-100 ℃, and the vacuum degree is <10. 2 Pa, time is 8-12 h.

[0014] In step S3, except for the following two steps, the parameters of the remaining steps are the same as those in S2; In step S3(2), optionally, the antibacterial ionic salt is selected from one or more of silver nitrate, copper nitrate, zinc nitrate, silver acetate, copper acetate, zinc acetate, copper sulfate, zinc sulfate, copper chloride, and zinc chloride. In step S3(2), preferably, the antibacterial ionic salt is not simultaneously selected from silver salts, chloride salts, and sulfates; In step S4, preferably, the organic particles are polycaprolactone and the organic solvent is dichloromethane. In step S4, optionally, the mass fraction of polycaprolactone in the composite organic solution is 8-12%, the mass fraction of the nanoporous silica microspheres carrying metal antibacterial ions is 4-6%, and the mass fraction of the nanoporous silica microspheres carrying corrosion inhibitors is 4-6%. In step S5, preferably, the pre-grinding sequence is to use sandpaper of 80 mesh, 320 mesh, 600 mesh, 1000 mesh, 1500 mesh and 2000 mesh in sequence, the ultrasonic cleaning sequence is to perform ultrasonic cleaning in acetone, anhydrous ethanol and deionized water in sequence, the alkaline heat treatment solution is sodium hydroxide solution, and the acid washing solution is oxalic acid solution. In step S5, optionally, the ultrasonic cleaning time is 10-15 min each time, the concentration of the alkaline heat treatment solution is 1-5 mol / L, the alkaline heat treatment temperature is 60-80 ℃, the alkaline heat treatment time is 10-15 min, the concentration of the acid washing solution is 0.01-0.02 mol / L, and the acid washing time is 30-120 s; In step S6, preferably, the spin coating sequence is as follows: first spin coating a mixed solution containing a corrosion inhibitor, and then spin coating a mixed solution containing metal antibacterial ions; In step S6, preferably, the volume of the solution in a single spin coating is 200 μL. In step S6, optionally, the number of spin coatings of the mixed solution containing the corrosion inhibitor is 10-15 times, and the number of spin coatings of the mixed solution containing metal antibacterial ions is 10-15 times. In step S6, optionally, the spin coating method is divided into two steps: the first step has a rotation speed of 500-1000 rpm and a time of 10-15 s, and the second step has a rotation speed of 2000-2500 rpm and a time of 30-45 s. In step S6, optionally, the drying temperature is 50-55 ℃ and the drying time is 2-4 h.

[0015] Application of a thermally responsive self-healing coating on a magnesium alloy surface, incorporating metal antibacterial ions and corrosion inhibitors, in biomedical implant materials.

[0016] The beneficial effects of this invention are: The thermally responsive self-healing / antibacterial / corrosion-resistant coating of this invention can not only provide effective corrosion protection for magnesium and its alloys in simulated physiological environments, but also rapidly repair minor damage to the magnesium alloy substrate during service in a magnetothermal environment. Furthermore, it can release metal antibacterial ions stably over a long period of time, thus exerting an antibacterial effect. Attached Figure Description

[0017] Figure 1 The Ag-coated surface on pure magnesium prepared in Example 1 of this invention + / Cu 2+ Photographs of thermally responsive self-healing coatings containing antibacterial ions and phytic acid corrosion inhibitors; Figure 2 The Ag-coated surface on pure magnesium prepared in Example 1 of this invention + / Cu 2+ Microscopic images of a thermally responsive self-healing coating of antibacterial ions and phytic acid corrosion inhibitor undergoing thermal self-healing upon heating in a magnetothermal coil after being artificially scratched. Figure 3 The Cu-coated surface of AZ31 magnesium alloy prepared in Example 2 of this invention 2+ / Zn2+ SEM images of cross-sections of thermally responsive self-healing coatings with antibacterial ions and calcium hydrogen phosphate dihydrate corrosion inhibitor; Figure 4 These are SEM images of microspheres without any material obtained in Comparative Example 1 and Example 1 of the present invention. (a) is Comparative Example 1, and (b) is Example 1. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Example 1

[0019] This embodiment prepares a method for mounting Ag on a pure magnesium surface. + / Cu 2+ The steps for creating a thermally responsive self-healing coating using antibacterial ions and phytic acid corrosion inhibitors are as follows: S1. Preparation of nanoporous silica microspheres (MSNs): (1) Dissolve 0.2 g of sodium hydroxide in 360 mL of deionized water at 80 °C. Add 0.75 g of hexadecyltrimethylammonium bromide, 0.05 g of ethanol, 0.20 g of F127-triblock copolymer and 0.45 g of sodium chloride (0.45 g of sodium chloride was dissolved in 5 mL of deionized water and then added dropwise) to the solution. Stir magnetically at 300 rpm for 2 h at 80 °C.

[0020] (2) Dissolve 3.75 g of tetraethyl orthosilicate in a mixed solution of 5 mL of ethanol and 3 mL of deionized water, then add 0.05 mL of ammonia water with pH 8, and magnetically stir at 150 rpm for 30 min at 35 ℃.

[0021] (3) Add the solution in (2) dropwise into the micelles in (1) using a constant pressure separatory funnel, and stir magnetically at 300 rpm for 2 h at 60 ℃.

[0022] (4) The solution obtained in (3) was heated to 85 °C and magnetically stirred at 300 rpm for 6 h in an ultrasonic environment of 20 kHz.

[0023] (5) Add 0.1 mol / L hydrochloric acid dropwise to the solution in (4) to adjust the pH to 8.0.

[0024] (6) The solution obtained in (5) was filtered. After filtration, it was dialyzed using a dialysis bag with a molecular weight cutoff of 2000 Da for 48 h. The dialysate was deionized water and was replaced every 6 h.

[0025] (7) Add 0.25 g of aminopropyltriethoxysilane to the dialysate obtained in (6), and stir magnetically at 300 rpm for 2 h at 60 ℃. Dialyze again using a dialysis bag with a molecular weight cutoff of 2000 Da for 18 h. The dialysate is deionized water and is replaced every 6 h.

[0026] (8) Cooling and drying were carried out at -55 °C and under a vacuum of 10 Pa to obtain 1.15 g of nanoporous silica microspheres (MSNs) with large capacity, good dispersibility and optimized surface hydrophilic / hydrophobic properties.

[0027] S2. The corrosion inhibitor is incorporated into the nanoporous silica microspheres obtained in S1: (01) The MSNs obtained in S1 were placed in a mixture of 3.2 mL ethanol and 0.35 mL 0.1 mol / L hydrochloric acid solution and extracted by reflux at 60 °C for 6 h. Then, they were dried at 60 °C under a vacuum of 10 Pa for 12 h.

[0028] (02) The product obtained in (01) and 0.30 g of phytic acid were placed in 5 g of ammonia water with pH 8. The mixture was magnetically stirred at 100 rpm for 2 h at 35 ℃. After cooling to room temperature, 0.02 g of polyvinylpyrrolidone was added and the mixture was shaken at 90 rpm for 24 h.

[0029] (03) The solution obtained in (02) is centrifuged at 8000 rpm for 15 min, filtered and washed 5 times, and dried at 80 ℃ for 8 hours to obtain nano-mesoporous silica microspheres loaded with calcium hydrogen phosphate dihydrate corrosion inhibitor.

[0030] S3. Incorporating metal antibacterial ions into the nanoporous silica microspheres obtained in S1: (001) Prepare another sample of nanoporous silica microspheres according to S1. Place the MSNs obtained in S1 in a mixed solution of 3.2 mL ethanol and 0.35 mL 0.1 mol / L hydrochloric acid solution and reflux extract at 60 °C for 6 h. Then dry at 60 °C and in a vacuum environment of 10 Pa for 12 h.

[0031] (002) The product obtained in (001) and 0.15 g silver nitrate and 0.15 g copper nitrate were placed in 5 g ammonia water with pH 8. The mixture was magnetically stirred at 100 rpm for 2 h at 35 ℃. After cooling to room temperature, 0.02 g polyvinylpyrrolidone was added and the mixture was shaken at 90 rpm for 24 h.

[0032] (003) The solution obtained in (002) is centrifuged at 8000 rpm for 15 min, filtered, washed 5 times, and dried at 80 ℃ for 8 hours to obtain the Ag-loaded solution. + / Cu 2+ Nanoporous silica microspheres with antibacterial ions.

[0033] S4. Dissolve 2.0 g of polycaprolactone particles and 1.0 g of nanoporous silica microspheres loaded with corrosion inhibitor obtained in S2 in 23 g of dichloromethane at room temperature and stir magnetically for 1 h.

[0034] Separately, 2.0 g of polycaprolactone particles and 1.0 g of nanoporous silica microspheres carrying metal antibacterial ions obtained in S3 were dissolved in 23 g of dichloromethane at room temperature and magnetically stirred for 1 h.

[0035] S5. The magnesium alloy substrate is subjected to pre-grinding, polishing, ultrasonic cleaning, alkaline heat treatment, and pickling in sequence, and finally air-dried. Pure magnesium discs with a diameter of 15 mm and a thickness of 5 mm were prepared using wire cutting technology. They were then polished sequentially with sandpaper of 80 grit, 320 grit, 600 grit, 1000 grit, 1500 grit, and 2000 grit. After polishing, the discs were ultrasonically cleaned for 10 min each in acetone, anhydrous ethanol, and deionized water. The cleaned discs were then placed in a 2 mol / L sodium hydroxide solution at 60 ℃ for alkali heat treatment for 15 min. Subsequently, the discs were placed in a 0.015 mol / L oxalic acid solution at room temperature for acid washing for 60 s. Finally, the discs were dried with a stream of cold air.

[0036] S6. Spin-coat the mixed solution obtained in S4 onto the magnesium alloy substrate, and after drying, an organic composite coating containing antibacterial ions and corrosion inhibitors is obtained. The spin-coating sequence is as follows: first spin-coat the mixed solution containing the corrosion inhibitor, and then spin-coat the mixed solution containing the metal antibacterial ions.

[0037] Specifically, using a pipette, a mixed organic solution containing corrosion inhibitors obtained in S4 was dropped onto the surface of a pure magnesium disc, with each drop containing 200 μL. A spin coater was then started to spin coat at 500 rpm for 10 s, followed by a change to 2000 rpm for 30 s, repeating this process 10 times. Next, a mixed organic solution containing metal antibacterial ions obtained in S4 was dropped onto the surface of the pure magnesium disc, with each drop containing 200 μL. The spin coater was then started to spin coat at 500 rpm for 10 s, followed by a change to 2000 rpm for 30 s, repeating this process 10 times. Finally, the spin-coated sample was placed in a drying oven at 55 ℃ for 2 h to obtain Ag-coated pure magnesium. + / Cu 2+ A heat-responsive self-healing coating with antibacterial ions and phytic acid corrosion inhibitors, with an average thickness of about 15 μm, is colorless and transparent.

[0038] Application of a thermally responsive self-healing coating on a magnesium alloy surface, incorporating metal antibacterial ions and corrosion inhibitors, in biomedical implant materials.

[0039] like Figure 1 As shown, the obtained pure magnesium surface is coated with Ag + / Cu 2+ The heat-responsive self-healing coating of antibacterial ions and phytic acid corrosion inhibitors is colorless and transparent.

[0040] like Figure 2 As shown, Ag is loaded onto the obtained pure magnesium surface. + / Cu 2+ The thermally responsive self-healing coating of antibacterial ions and phytic acid corrosion inhibitor is placed in a magnetothermal coil. The sample is heated by the inherent eddy current effect of metal in alternating current. The surface temperature of the sample can reach above 60 ℃ in about 60-80 s. The fluidity of polycaprolactone increases, and the pre-existing cracks are self-healed. Example 2

[0041] This embodiment describes the preparation of a Cu-coated substrate on the surface of AZ31 magnesium alloy. 2+ / Zn 2+ The thermally responsive self-healing coating of antibacterial ions and calcium hydrogen phosphate dihydrate corrosion inhibitor is constructed using the following steps: S1. Preparation of mesoporous silica nanospheres (MSNs) with large capacity, good dispersibility, and optimized surface hydrophilic / hydrophobic properties: (1) Dissolve 0.2 g potassium hydroxide in 360 mL of deionized water at 80 °C. Add 0.8 g polyoxyethylene sorbitan monooleate, 0.075 g propanol, 0.25 g F127-triblock copolymer and 0.40 g sodium sulfate to the solution. Stir magnetically at 500 rpm for 1 h at 75 °C. (2) Dissolve 4.0 g methyl orthosilicate in a mixture of 5 mL ethanol and 3 mL deionized water. Add 0.05 mL sodium bicarbonate at pH 7.5. Stir magnetically at 200 rpm for 60 min at 45 °C. (3) Add the solution from (2) dropwise to the micelles from (1) using a constant pressure separatory funnel. Stir magnetically at 200 rpm for 1 h at 55 °C. (4) Heat to 95 °C and stir magnetically at 500 rpm in an ultrasonic environment at 40 kHz. (5) Add 0.2 mol / L sulfuric acid dropwise to the solution in (3) and adjust the pH to 7.5; (6) After filtration, dialyze with a dialysis bag with a molecular weight cutoff of 1500 Da for 12 hours. The dialysate is deionized water and is replaced every 6 hours; (7) Add 0.25 g of 3-mercaptopropyltriethoxysilane to the dialysate and stir magnetically at 200 rpm for 1 hour at 55°C. Then dialyze again with a dialysis bag with a molecular weight cutoff of 1500 Da for 12 hours. The dialysate is deionized water and is replaced every 6 hours; (8) Cool and dry at -65°C and a vacuum of 100 Pa to obtain 1.18 g of nano-mesoporous silica microspheres (MSNs) with large capacity, good dispersibility and optimized surface hydrophilic / hydrophobic properties. S2, (1) The MSNs obtained in S1 were placed in a mixed solution of 3.2 mL ethanol and 0.35 mL 0.2 mol / L sulfuric acid solution and refluxed at 55 °C for 8 h. Then, they were dried at 55 °C under a vacuum of 100 Pa for 15 h. (2) The product obtained in (1) and 0.35 g of dicalcium phosphate dihydrate were placed in a 5 g sodium bicarbonate solution with a pH of 8.0. The mixture was magnetically stirred at 200 rpm for 3 h at 45 °C. After cooling to room temperature, 0.02 g of polyvinylpyrrolidone was added and the mixture was shaken at 120 rpm for 18 h. (3) The mixture was centrifuged at 10000 rpm for 15 min, filtered, washed 3 times, and dried at 100 °C for 12 h to obtain nanoporous silica microspheres loaded with dicalcium phosphate dihydrate corrosion inhibitor. S3, (1) Prepare another sample of nanoporous silica microspheres according to S1. Place the MSNs obtained in S1 in a mixed solution of 3.2 mL ethanol and 0.35 mL 0.2 mol / L sulfuric acid solution, and reflux extract at 60 °C for 6 h. Then dry at 60 °C under vacuum of 10 Pa for 12 h. (2) Place the product obtained in (1) and 0.20 g zinc sulfate and 0.25 g copper sulfate in 5 g ammonia water with pH 8.5. Stir magnetically at 100 rpm for 2 h at 35 °C. After cooling to room temperature, add 0.02 g polyvinylpyrrolidone and shake at 90 rpm for 24 h. (3) Centrifuge at 8000 rpm for 15 min, filter and wash 5 times. Dry at 80 °C for 8 h to obtain Cu-loaded microspheres. 2+ / Zn 2+ Antibacterial ion nanoporous silica microspheres; S4. Dissolve 1.6 g of polycaprolactone particles and 1.0 g of the mesoporous silica microspheres obtained in S2 in 18.4 g of dichloromethane at room temperature and stir magnetically for 1 h; Separately, dissolve 1.6 g of polycaprolactone particles and 1.0 g of the mesoporous silica microspheres obtained in S3 in 18.4 g of dichloromethane at room temperature and stir magnetically for 1 h. S5. ZK60 magnesium alloy discs with a diameter of 20 mm and a thickness of 5 mm were prepared using wire cutting technology. They were polished sequentially with 80-grit, 320-grit, 600-grit, 1000-grit, 1500-grit, and 2000-grit sandpaper. After polishing, they were ultrasonically cleaned for 15 min in acetone, anhydrous ethanol, and deionized water, respectively. Then, the cleaned sample was placed in a sodium hydroxide solution with a concentration of 1 mol / L at 80 ℃ for alkaline heat treatment for 10 min. Subsequently, the sample was placed in an oxalic acid solution with a concentration of 0.01 mol / L at room temperature for acid washing for 30 s. Finally, it was dried with a stream of cold air.

[0042] S6. Using a pipette, drop 200 μL of the mixed organic solution containing corrosion inhibitor obtained in S4 onto the surface of a ZK60 magnesium alloy disc. Then, start a spin coater and spin coat at 1000 rpm for 15 s, then change the speed to 2500 rpm for 45 s, repeating this operation 15 times. Next, using a pipette, drop 200 μL of the mixed organic solution containing metal antibacterial ions obtained in S2 onto the surface of a pure magnesium disc. Then, start a spin coater and spin coat at 1000 rpm for 15 s, then change the speed to 2500 rpm for 45 s, repeating this operation 15 times. Finally, place the spin-coated sample in a drying oven at 50 ℃ for 4 h to obtain Cu coated on the surface of the ZK60 magnesium alloy disc. 2+ / Zn 2+ Thermally responsive self-healing coating with antibacterial ions and calcium hydrogen phosphate dihydrate corrosion inhibitor.

[0043] like Figure 3 As shown, the obtained ZK60 magnesium alloy surface is coated with Cu 2+ / Zn 2+ The average thickness of the thermally responsive self-healing coating containing antibacterial ions and calcium hydrogen phosphate dihydrate corrosion inhibitor is approximately 20 μm.

[0044] Application of a thermally responsive self-healing coating on a magnesium alloy surface, incorporating metal antibacterial ions and corrosion inhibitors, in biomedical implant materials. Example 3

[0045] This embodiment describes the preparation of a Zn-coated surface on an AZ31 magnesium alloy. 2+ The thermally responsive self-healing coating with antibacterial ions and phytic acid corrosion inhibitors is constructed using the following steps: S1、(1) Dissolve 0.2 g sodium hydroxide in 360 mL of deionized water at 80 °C, add 0.8 g polyoxyethylene sorbitan monooleate, 0.075 g ethanol, 0.25 g F127-triblock copolymer and 0.45 g sodium chloride to the solution, and stir magnetically at 300 rpm for 2 h at 85 °C; (2) Dissolve 4.0 g 3-aminopropyltriethoxysilane in a mixed solution of 5 mL ethanol and 3 mL deionized water, and add 0.05 mL of ammonia water with pH 8.5, and stir magnetically at 150 rpm for 30 min at 35 °C; (3) Add the solution in (2) dropwise to the micelles in (1) using a constant pressure separatory funnel, and stir magnetically at 300 rpm for 2 h at 60 °C; (4) Raise the temperature to 85 °C. (3) Stir magnetically at 300 rpm for 6 h in an ultrasonic environment at 20 kHz; (5) Add 0.15 mol / L sulfuric acid dropwise to the solution in (3) to adjust the pH to 8.5; (6) After filtration, dialyze using a dialysis bag with a molecular weight cutoff of 2500 Da for 48 h, using deionized water as the dialysate, and change it every 6 h; (7) Add 0.25 g of 3-mercaptopropyltriethoxysilane to the dialysate, stir magnetically at 300 rpm for 2 h at 65 ℃, and dialyze again using a dialysis bag with a molecular weight cutoff of 2500 Da for 18 h, using deionized water as the dialysate, and change it every 6 h; (8) Cool and dry at -45 ℃ and a vacuum of 10 Pa to obtain 1.03 g. High-capacity, well-dispersible, and optimized surface hydrophilic / hydrophobic properties of nanoporous silica microspheres (MSNs); S2, (1) The MSNs obtained in S1 were placed in a mixed solution of 3.2 mL ethanol and 0.35 mL 0.15 mol / L sulfuric acid solution and extracted by reflux at 65 °C for 6 h. Then, they were dried at 65 °C under a vacuum of 10 Pa for 12 h. (2) The product obtained in (1) and 0.35 g phytic acid were placed in 5 g ammonia water with pH 10 and magnetically stirred at 100 rpm for 2 h at 35 °C. After cooling to room temperature, 0.02 g polyvinylpyrrolidone was added and shaken at 90 rpm for 24 h. (3) The mixture was centrifuged at 8000 rpm for 15 min, filtered, washed 5 times, and dried at 80 °C for 8 h to obtain nano-mesoporous silica microspheres loaded with phytic acid corrosion inhibitor. S3, (1) Prepare another sample of nanoporous silica microspheres according to S1. Place the MSNs obtained in S1 in a mixed solution of 3.2 mL ethanol and 0.35 mL 0.15 mol / L sulfuric acid solution and reflux extract at 60 °C for 6 h. Then dry at 60 °C and vacuum at 10 Pa for 12 h. (2) Place the product obtained in (1) and 0.50 g zinc chloride in 5 g ammonia water with pH 8.5. Stir magnetically at 100 rpm for 2 h at 35 °C. After cooling to room temperature, add 0.02 g polyvinylpyrrolidone and shake at 90 rpm for 24 h. (3) Centrifuge at 8000 rpm for 15 min, filter and wash 5 times. Dry at 80 °C for 8 h to obtain Zn-loaded microspheres. 2+ Antibacterial ion nanoporous silica microspheres; S4. Dissolve 1.6 g of polycaprolactone particles and 1.0 g of the mesoporous silica microspheres obtained in S2 in 18.4 g of dichloromethane at room temperature and stir magnetically for 1 h; Separately, dissolve 1.6 g of polycaprolactone particles and 1.0 g of the mesoporous silica microspheres obtained in S3 in 18.4 g of dichloromethane at room temperature and stir magnetically for 1 h. S5. AZ31 magnesium alloy discs with a diameter of 20 mm and a thickness of 5 mm were prepared using wire cutting technology. They were then polished sequentially with 80-grit, 320-grit, 600-grit, 1000-grit, 1500-grit, and 2000-grit sandpaper. After polishing, the discs were ultrasonically cleaned for 10 min each in acetone, anhydrous ethanol, and deionized water. The cleaned discs were then placed in a 5 mol / L sodium hydroxide solution at 60 ℃ for alkali heat treatment for 15 min. Subsequently, the discs were placed in a 0.02 mol / L oxalic acid solution at room temperature for acid washing for 120 s. Finally, the discs were dried with a stream of cold air.

[0046] S6. Using a pipette, drop 200 μL of the mixed organic solution containing corrosion inhibitor obtained in S4 onto the surface of an AZ31 magnesium alloy disc. Then, start a spin coater and spin coat at 500 rpm for 10 s, then change the speed to 2000 rpm for 30 s, repeating this operation 10 times. Next, using a pipette, drop 200 μL of the mixed organic solution containing metal antibacterial ions obtained in S2 onto the surface of a pure magnesium disc. Then, start a spin coater and spin coat at 500 rpm for 10 s, then change the speed to 2000 rpm for 30 s, repeating this operation 15 times. Finally, place the spin-coated sample in a drying oven at 55 ℃ for 4 h to obtain Zn coated on the surface of the AZ31 magnesium alloy. 2+ A thermally responsive self-healing coating with antibacterial ions and phytic acid corrosion inhibitors, with an average coating thickness of approximately 25 μm.

[0047] Application of a thermally responsive self-healing coating on a magnesium alloy surface, incorporating metal antibacterial ions and corrosion inhibitors, in biomedical implant materials. Example 4

[0048] The only difference between this embodiment and Embodiment 1 is that: In S2, phytic acid is replaced with alkaline calcium hydrogen phosphate dihydrate, that is, the acidic corrosion inhibitor is replaced with an alkaline corrosion inhibitor.

[0049] Comparative Example 1

[0050] The only difference between this comparative example and Example 1 is that: In S1, the auxiliary nonionic surfactant B in (1) is removed, that is, the sphericity improvement of the nanoporous silica microspheres is removed; In S1, the auxiliary nonionic surfactant C in (1) is removed, that is, the expansion treatment of the nanoporous silica microspheres is removed.

[0051] Figure 4 Comparing the SEM images of the unloaded mesoporous silica microspheres obtained in Comparative Example 1(a) and Example 1(b), it can be found that the microspheres obtained in Example 1 have good sphericity, larger diameter and pore size, and better dispersibility. The diameter and pore size of the microspheres obtained in Example 1 and Comparative Example 1 are shown in Table 1 below.

[0052] Table 1. Microsphere diameter and pore size obtained in Example 1 and Comparative Example 1

[0053] Comparative Example 2 The only difference between this comparative example and Example 1 is that: In S1, (6) and (7) are cancelled, that is, the modification of the surface hydrophilic / hydrophobic properties of the nanoporous silica microspheres is cancelled.

[0054] Comparative Example 3

[0055] The only difference between this comparative example and Example 1 is that: In S1(1), 0.70 g of cetyltrimethylammonium bromide, 0.05 g of ethanol, and 0.15 g of F127-triblock copolymer are added, i.e., the mass ratio of surfactant A, surfactant B and surfactant C is 14:1:3.

[0056] Comparative Example 4

[0057] The only difference between this comparative example and Example 1 is that: In S1(1), 0.80 g of cetyltrimethylammonium bromide, 0.05 g of ethanol, and 0.25 g of F127-triblock copolymer are added, i.e., the mass ratio of surfactant A, surfactant B and surfactant C is 16:1:5.

[0058] The above-mentioned embodiments and comparative examples were subjected to in vitro simulated immersion tests and antibacterial performance tests. The samples were immersed in HBSS at a constant temperature of 37 ℃, and the hydrogen gas released from the samples was collected at regular intervals. The amount of hydrogen released was used to evaluate the corrosion resistance. The antibacterial performance of the samples at different times was tested, as shown in Tables 2, 3 and 4 below.

[0059] Table 2. HBSS components used in the hydrogen evolution immersion test of this invention.

[0060] Table 3. Hydrogen evolution amount in in vitro simulated immersion tests of the embodiments and comparative examples of the present invention.

[0061] Table 3 shows that Examples 1, 2, 3, and 4 exhibit excellent corrosion resistance. Comparative Example 1, due to the small pore volume of the microspheres and the low content of corrosion inhibitor, shows slightly insufficient corrosion resistance. Comparative Example 2, due to the poor compatibility between the microspheres and polycaprolactone, suffers from pores created by the heterogeneous structure, which impairs the coating's corrosion resistance. Comparative Examples 3 and 4 show slightly insufficient corrosion resistance due to either a higher or lower mass ratio of surfactant A, surfactant B, and surfactant C.

[0062] Table 4. Antibacterial rates (E. coli) of the embodiments and comparative examples of the present invention after different soaking times.

[0063] Table 4 shows that Examples 1, 2, 3, and 4 all exhibit excellent antibacterial properties, while Comparative Examples 2, 3, and 4 show significantly reduced antibacterial properties. This demonstrates that the specific surfactant ratio and hydrophobic modification of this invention not only improves the compatibility of the nanoporous silica microspheres but also enhances the antibacterial ability of the coating. Comparative Example 1, with its small microsphere pore volume and low antibacterial ion content, shows insufficient antibacterial performance. It should be noted that the release of metal antibacterial ions is related to environmental pH; acidic environments promote the release of metal antibacterial ions. Therefore, the antibacterial rates of Examples 2 and 4 are slightly lower than those of Examples 1 and 3. It can be concluded that in this invention, acidic corrosion inhibitors are more suitable for the application of metal antibacterial ions.

[0064] It should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all the features of the foregoingly disclosed embodiments. Therefore, the claims, following the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0065] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the invention is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A type of nanoporous silica microsphere, characterized in that, Includes the following steps: Step 1: Dissolve surfactant A, surfactant B and auxiliary nonionic surfactant C in alkaline solution A at a mass ratio of (10.7-15):1:(3.3-4), heat and stir, then add neutral inorganic salt dropwise while maintaining constant temperature and stirring to form a transparent micelle solution. Step 2: Dissolve the silicon source in a mixed solution of ethanol and water, add alkaline solution B, and heat and stir. Step 3: Add the solution obtained in Step 2 dropwise to the micelle solution obtained in Step 1, and heat and stir. Step four: Heating and ultrasonically stirring the solution obtained in step three; Step 5: Add acidic solution A to the solution obtained in step 4 to adjust the pH. Step six: Filter the solution obtained in step five, and dialyze the filtrate to obtain dialysate; Step 7: Add a surface modifier to the dialysate obtained in Step 6, heat and stir, and then dialyze again; Step 8: Freeze-dry the dialysate obtained in Step 7 to obtain the final product.

2. The nanoporous silica microspheres according to claim 1, characterized in that, In step one, Surfactant A is selected from hexadecyltrimethylammonium bromide or polyoxyethylene sorbitan monooleate; Surfactant B is selected from ethanol, propanol, butanol, or n-pentanol; Surfactant C is selected as F127-triblock copolymer; Alkaline solution A is selected from potassium hydroxide solution or sodium hydroxide solution; the pH of alkaline solution A is 11-12, and the concentrations of surfactant A, surfactant B and surfactant C in alkaline solution A are 0.01-0.05 mol / L; The heating and stirring are performed using magnetic heating, with a heating temperature of 75-85 ℃, a stirring speed of 300-500 rpm, and a stirring time of 1-2 hours. Neutral inorganic salts are selected from sodium chloride, potassium chloride, sodium sulfate, or potassium sulfate.

3. The nanoporous silica microspheres according to claim 1, characterized in that, In step two, The silicon source is selected from tetraethyl orthosilicate, methyl orthosilicate, or 3-aminopropyltriethoxysilane; Alkaline solution B is selected from ammonia water, sodium bicarbonate solution, or sodium acetate solution; The volume ratio of silicon source, ethanol and water is 1:(1.75-2.25):(0.45-0.55); The pH of alkaline solution B is 7.5-8.5; The stirring method is magnetic heating, the heating temperature is 35-45℃, the stirring speed is 150-200 rpm, and the stirring time is 0.5-1 h.

4. The nanoporous silica microspheres according to claim 1, characterized in that, In step three, the stirring method is magnetic heating stirring, the heating temperature is 55-65℃, the stirring speed is 200-300 rpm, and the stirring time is 1-2 hours; In step four, the stirring method is magnetic heating stirring, the heating temperature is 85-95℃, the stirring speed is 300-500 rpm, and the stirring time is 6-8 h; the ultrasonic frequency is 20-40 kHz. In step five, acidic solution A is selected from hydrochloric acid or sulfuric acid solution; the concentration of acidic solution A is 0.1-0.2 mol / L; the pH is adjusted to 7.5-8.5; In step six, the molecular weight cutoff for dialysis is 1500-2500 Da, the dialysate is deionized water, and the dialysis time is 12-48 hours; the dialysate is changed every 6 hours. In step eight, the freeze-drying temperature is -65°C to -45°C, and the vacuum degree is <10. 2 Pa.

5. The nanoporous silica microspheres according to claim 1, characterized in that, In step seven, the surface modifier is selected from aminopropyltriethoxysilane, 3-mercaptopropyltriethoxysilane or vinyltris(β-methoxyethoxy)silane; the mass ratio of dialysate to surface modifier is (10-20):1; The stirring method is magnetic heating stirring, the heating temperature is 55-65℃, the stirring speed is 200-300 rpm, and the stirring time is 1-2 hours; The molecular weight cutoff for dialysis is 1500-2500 Da, the dialysate is deionized water, and the dialysis time is 12-18 h. The dialysis fluid should be changed every 6 hours.

6. A method for preparing a thermally responsive self-healing coating on a magnesium alloy surface, comprising metal antibacterial ions and a corrosion inhibitor, characterized in that, Includes the following steps: S01, the corrosion inhibitor is incorporated into the nanoporous silica microspheres according to any one of claims 1 to 5; S02, the metal antibacterial ions are incorporated into the nanoporous silica microspheres according to any one of claims 1 to 5; SO3 is obtained by dissolving organic particles in an organic solvent, dividing the solution into two portions, and adding each portion to a mixed solution obtained from SO1 and SO2, and then heating and stirring. S04, the magnesium alloy substrate is subjected to pre-grinding, polishing, ultrasonic cleaning, alkaline heat treatment and pickling in sequence, and finally air drying; S05, spin-coat the mixed solution obtained in S03 onto the magnesium alloy substrate. The spin-coating sequence is as follows: first spin-coat the mixed solution containing corrosion inhibitor, then spin-coat the mixed solution containing metal antibacterial ions. After drying, a thermally responsive self-healing coating with metal antibacterial ions and corrosion inhibitor on the magnesium alloy surface is obtained.

7. The preparation method according to claim 5, characterized in that, Step S01 includes: S011, place the nano-mesoporous silica microspheres in a mixed solution of ethanol and acidic solution B, reflux extract at high temperature, filter, wash with deionized water until neutral, and vacuum dry; S012, dissolve the nanoporous silica microspheres obtained in S011 and the corrosion inhibitor in alkaline solution C in a certain proportion, heat and stir, then add the auxiliary shaking agent and shake at room temperature; S013, the solution obtained in S012 is centrifuged, filtered, washed with deionized water, and vacuum dried to obtain nanoporous silica microspheres loaded with corrosion inhibitor. Step S02 includes: S021, place nanoporous silica microspheres in a mixed solution of ethanol and acidic solution C, reflux extract at high temperature, filter, wash with deionized water until neutral, and vacuum dry; S022, dissolve the nanoporous silica microspheres obtained in S021 and the antibacterial ionic salt in alkaline solution D in a certain proportion, heat and stir, then add an auxiliary shaking agent and shake at room temperature; S023, the solution obtained in S022 is centrifuged, filtered, washed with deionized water, and vacuum dried to obtain nanoporous silica microspheres carrying metal antibacterial ions. In SO3, the organic particles are polycaprolactone, and the organic solvent is dichloromethane; in the mixed solution, the mass fraction of polycaprolactone is 8-12%, the mass fraction of nanoporous silica microspheres carrying metal antibacterial ions is 4-6%, and the mass fraction of nanoporous silica microspheres carrying corrosion inhibitors is 4-6%.

8. The preparation method according to claim 7, characterized in that, In S011, acidic solution B is selected from hydrochloric acid or sulfuric acid; the concentration of acidic solution B is 0.1-0.2 mol / L; the volume ratio of ethanol to acidic solution B is (10-20):1, and the mass ratio of nanoporous silica microspheres to the mixed solution of ethanol and acidic solution B is (7-9):20; the reflux extraction temperature is 55-65 ℃, and the time is 6-8 h; the vacuum drying temperature is 55-65 ℃, and the vacuum degree is <10. 2 Pa, time is 12-15 h; In S012, the corrosion inhibitor is selected from phytic acid, calcium hydrogen phosphate dihydrate, or benzotriazole; the alkaline solution C is selected from ammonia, sodium bicarbonate solution, or sodium acetate solution; the auxiliary shaking agent is polyvinylpyrrolidone; the pH of the alkaline solution C is 8-10; the mass ratio of nano-silica microspheres, corrosion inhibitor, and auxiliary shaking agent is 10:(2-3):0.01; the heating and stirring temperature is 35-45 ℃, the stirring speed is 100-200 rpm, and the time is 2-3 h; the shaking speed is 90-120 rpm, and the time is 18-24 h. In S013, the centrifugation speed is 8000-10000 rpm, the time is 10-15 min; the washing number is 3-5 times, the drying temperature is 80-100 ℃, and the vacuum degree is <10. 2 Pa, time is 8-12 h; In S021, acidic solution C is selected from hydrochloric acid or sulfuric acid; the concentration of acidic solution C is 0.1-0.2 mol / L; the volume ratio of ethanol to acidic solution C is (10-20):1, and the mass ratio of nanoporous silica microspheres to the mixed solution of ethanol and acidic solution C is (7-9):20; the reflux extraction temperature is 55-65 ℃, and the time is 6-8 h; the vacuum drying temperature is 55-65 ℃, and the vacuum degree is <10. 2 Pa, time is 12-15 h; In S022, the antibacterial ionic salt is selected from one or more of silver nitrate, copper nitrate, zinc nitrate, silver acetate, copper acetate, zinc acetate, copper sulfate, zinc sulfate, copper chloride, and zinc chloride; the auxiliary shaking agent is polyvinylpyrrolidone; the pH of the alkaline solution D is 8-10; the mass ratio of nano-silica microspheres, antibacterial ionic salt, and auxiliary shaking agent is 10:(2-3):0.01; the heating and stirring temperature is 35-45 ℃, the stirring speed is 100-200 rpm, and the time is 2-3 h; the shaking speed is 90-120 rpm, and the time is 18-24 h. In S023, the centrifugation speed is 8000-10000 rpm, the time is 10-15 min; the washing number is 3-5 times, the drying temperature is 80-100 ℃, and the vacuum degree is <10. 2 Pa, time is 8-12 h.

9. A thermally responsive self-healing coating on a magnesium alloy surface, containing metal antibacterial ions and a corrosion inhibitor, obtained by the preparation method according to claim 6, characterized in that... The coating thickness is 15-25 μm; the coating consists of two layers, the upper layer is a polycaprolactone layer containing metal antibacterial ions, and the lower layer is a polycaprolactone layer containing corrosion inhibitors.

10. The application of the thermally responsive self-healing coating on a magnesium alloy surface, containing metal antibacterial ions and corrosion inhibitors, as described in claim 9, in biomedical implant materials.

Images