Preparation method of environment-responsive shape memory self-repairing smart yin-yang coating

Abstract

The present application relates to a kind of preparation methods of environment response shape memory self-repairing intelligent concordance coating.The preparation method includes the following steps: (1) using spin coating process, preparing polydopamine pretreatment layer on alloy surface;(2) using polyvinyl alcohol static spinning process of wrapping corrosion inhibitor, preparing exogenous nanofiber self-repairing coating on polydopamine pretreatment layer;(3) using ultrasonic assisted polymerization method makes o-phenylphenol and formaldehyde rapid condensation and generates phenol formaldehyde resin microspheres, obtains photo-thermal nanocarbon ball after high-temperature calcination, disperses in shape memory resin, using spin coating process, self-repairing organic composite coating is prepared by spin coating shape memory resin on exogenous nanofiber self-repairing coating outside.The nanofiber of the present application is uniformly dispersed, and the obtained concordance coating is uniform, dense, firmly combined, thickness controllable, has good corrosion resistance, environmental stimulation controllable release performance is good, can satisfy the intelligent self-repairing of multiple working conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of material surface treatment, and particularly relates to a preparation method of an environment-responsive shape memory self-repairing intelligent harmony coating. BACKGROUND

[0002] Traditional protective coatings will inevitably be damaged during use, and since they have single functions and most of the existing surface treatment technologies do not have self-repairing capabilities, corrosion will start from the damaged area of the coating and cause more harmful local corrosion than uniform corrosion.

[0003] Self-repairing coatings refer to intelligent coating systems with the properties of "corrosion induction" and "self-healing", which are an important way to solve the rapid performance degradation of components after the failure of protective layers. After being damaged by external forces or environmental damage, the self-repairing coatings can restore or restore their original corrosion protection function under certain conditions. According to the physicochemical properties and characteristics of self-repairing composite materials, they can be divided into two categories, namely, exogenous self-repairing polymer coatings and intrinsic self-repairing polymer coatings.

[0004] The inorganic nano-containers currently studied and applied more include inorganic nano-containers such as silica nanoparticles, titanium dioxide nanoparticles, polyhydroxy kaolinite, hydrotalcite, zeolite, organic nano-containers such as polymer microcapsules, nanofibers, chitosan, cyclodextrin, and polyelectrolyte self-assembly membranes, and carbon materials such as carbon nanotubes and graphene. The methods based on nano-containers storing corrosion inhibitors in such coatings can repair the corrosion resistance of damaged coatings to some extent. However, overall, the corrosion inhibitors can only inhibit the corrosion reaction for a certain period of time and cannot completely repair the physical shielding effect of the coating. In addition, most of the corrosion inhibitor nano-containers have complex and tedious preparation processes, insufficient repair efficiency, and other problems, which are currently difficult to be applied on a large scale in industrial production. Whether it is an inorganic nano-container or an organic nano-container, due to its specific shape and process limitations, the storage capacity of the corrosion inhibitor is limited, which means that when used for a long time or subjected to a large amount of corrosion medium, the nano-container may fail to provide long-term corrosion protection. Polyvinyl alcohol core-shell nanofibers prepared by electrospinning can effectively improve the problem of limited storage of corrosion inhibitors. Adding coaxial nanofibers loaded with corrosion inhibitors to epoxy coatings can effectively improve the corrosion resistance and scratch self-repairing ability of the coating. However, challenges such as the dispersibility of nanofibers and environmentally stimulated controlled release still need to be addressed.

[0005] The environment-responsive shape memory self-repairing intelligent harmony coating is a new type of intelligent coating that is optimized and improved on the basis of traditional coatings. It can respond immediately to sudden environmental stimuli and the repair effect will change accordingly under the action of different temperatures, pH values, ultraviolet and visible light, etc. It can spontaneously repair various damages and effectively improve the service life of metal products and reduce economic losses.

[0006] In the document with application number "201610956702.6", a "heat-responsive shape memory composite self-repairing coating and its preparation method" is disclosed. Raw materials include an epoxy resin mixture, an epoxy curing agent, and a meltable particle filler. The epoxy resin mixture is composed of an epoxy resin and an epoxy resin diluent, and the molar ratio of the epoxy resin to the epoxy resin diluent is 1:0.2-3. The molar ratio of the epoxy resin mixture to the curing agent is 2:1. The meltable particle filler accounts for 5-20% of the coating mass. The preparation method is to mix and heat the epoxy resin and the epoxy resin diluent, then add the curing agent and ultrasonically stir, then add the meltable particle filler and ultrasonically stir again to obtain a mixed solution. Finally, the obtained mixed solution is uniformly coated on the substrate material and solidified to obtain a shape memory composite coating. The disadvantage of this coating is that it only relies on shape memory effect for repair, and the function is single. In the document with application number "202210236043.4", a "light-heat responsive nanofiber self-repairing coating and its preparation method" is disclosed. The light-heat agent copper hydroxynitrate nanoparticles are loaded on the surface of the nanofiber through self-assembly by electrospinning process to prepare a high-loading nanofiber film. The nanofiber film is added as a filler to the organic resin, and the light-heat responsive self-repairing coating is obtained after curing. When the organic coating is damaged, the light-heat effect of the light-heat agent copper hydroxynitrate nanoparticles loaded on the nanofiber can be excited by light to convert light into heat, realizing the rapid repair of the damaged crack of the organic coating. The disadvantage of this method is that the nanofiber with light-heat response effect is added as a filler to the organic coating, and the uneven dispersion of the nanofiber will affect the performance of the coating, and the coating does not have the function of external aid self-repairing.

[0007] In summary, it is the focus of researchers in the field to develop a coating with uniform, dense, firm bonding, controllable thickness, good corrosion resistance, and intelligent self-repairing under the influence of various environmental factors. SUMMARY

[0008] The purpose of the present application is to provide a preparation method of an environment-responsive shape memory self-repairing intelligent concordant coating to solve the problems of uneven dispersion of nanofiber and poor controllable release performance under environmental stimulation in the prior art.

[0009] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: a preparation method of an environment-responsive shape memory self-repairing intelligent concordant coating, comprising the following steps:

[0010] Step one, a polydopamine pretreatment layer is prepared on the surface of the alloy by spin coating process;

[0011] Step two, using polyvinyl alcohol wrapped corrosion inhibitor electrospinning process, on the polydopamine pretreatment layer prepared exogenous nanofiber self-repairing coating;

[0012] Step three, first, using ultrasonic assisted polymerization method makes the pyrogallol and formaldehyde rapid polycondensation generated phenolic resin microspheres, 500-600℃ high temperature calcination 3~5h get light and heat nanocarbon ball; Then it is dispersed in shape memory resin to get self-repairing organic composite coating; Finally, using spin coating process, it is prepared on the exogenous nanofiber self-repairing coating outside the self-repairing organic composite coating.

[0013] Further, the mass fraction of the above polydopamine pretreatment layer is 5~10; The mass fraction of the exogenous nanofiber self-repairing coating is 40~55; The mass fraction of the self-repairing organic composite coating is 50~55.

[0014] Further, the specific steps of step two include:

[0015] (1) Preparation of electrospinning solution: first, weigh 6~10g polyvinyl alcohol particles into 100~200ml preheated ultrapure water, stand for 5~10min; Then continuously stir for 2~3h at a temperature of 60~80℃ on a magnetic stirrer, with a stirring speed of 500~600rpm; Then add 0.05~0.06g tris(hydroxymethyl)aminomethane and 0.2~0.4g dopamine hydrochloride, respectively, after stirring for 12~24h at 25~40℃, add 0.01~0.08% total mass of repair agent, continue to stir for 2~4h, stand for 20-24h, get electrospinning solution ready for use;

[0016] (2) Preparation of exogenous nanofiber self-repairing coating: place the sample on the receiving screen, place the spinning solution in the syringe, connect the power supply, set the receiving screen distance to 10~20cm, voltage to 10~20.0kV, spinning solution pushing speed to 0.1~0.5mL / h, and receiving time to 1~6h; After electrospinning, place the sample in a vacuum drying oven, heat at a temperature of 60℃~80℃ for 1~2h.

[0017] Further, the specific steps in step one include: adding dopamine hydrochloride solid into Tris buffer solution, the pH of the buffer solution is 8.5, stirring to get a dopamine solution with a concentration of 1~2mg / mL; Put the sample on the spin coater, drop the above dopamine solution, the spin coater rotation speed is 500~1000rpm, the rotation time is 2~4h, so that the dopamine is evenly coated on the surface of the sample, stand for 10~12h at room temperature, then wash with ultrapure water, dry with cold air, and reserve for use.

[0018] Further, the preparation of the phenolic resin microspheres in the above-mentioned step three includes: first, 40-50 mL of anhydrous ethanol, 100-150 mL of deionized water and 0.5-0.7 mL of ammonia are measured in a beaker, then 1-1.5 g of o-phenol and 0.5-0.8 g of formaldehyde are added, and after stirring uniformly, it is ultrasonically treated for 10-15 min, the product is separated by centrifugation, washed several times with alcohol, and then the product is vacuum dried at 50-55°C for 10-12 h to obtain the phenolic resin microspheres.

[0019] Further, the dispersion process of the photothermal nanocarbon spheres in the shape memory resin in the above-mentioned step three is that 0.01-0.05 g of nanocarbon spheres is ultrasonically dispersed in DMF solvent for 20-30 min and then added to 100 g of shape memory resin, and mechanically stirred at 80°C for 4-5 h until the photothermal nanocarbon spheres are uniformly dispersed in the resin, ready for use.

[0020] Further, the spin coating process of the self-repairing organic composite coating in the above-mentioned step three is that the sample is placed on the table of the spin coating device, the shape memory resin with dispersed photothermal nanocarbon spheres is added dropwise, the dropwise amount is controlled to be 0.5-1 mL / cm 2 , the spin coating speed is controlled to be in the range of 800-2000 rpm, and after spin coating, the sample is placed in a vacuum drying box and heated at 80-150°C for 2-4 h.

[0021] Further, the types of the repair agent used in the above-mentioned step two (1) include organic corrosion inhibitors or inorganic corrosion inhibitors, the organic corrosion inhibitors include any one of 8-hydroxyquinoline, benzotriazole, 2-mercaptobenzothiazole, tannic acid, and oleic acid, and the inorganic corrosion inhibitors include any one of sodium vanadate, sodium phosphate, sodium stannate, sodium tungstate, and rare earth metal ions.

[0022] Further, the type of the shape memory resin is any one of shape memory epoxy resin, shape memory polyurethane, modified shape memory epoxy resin, or modified shape memory polyurethane.

[0023] Compared with the prior art, the application has the following advantages and beneficial effects:

[0024] 1) In order to improve the bonding force of the nanofiber container to the matrix, the alloy surface is first pretreated with polydopamine to activate the alloy surface, which can effectively improve the bonding force of the matrix to the electrospun coating, then the electrospinning process can effectively improve the loading capacity of the corrosion inhibitor, and the polydopamine is creatively synthesized in situ when preparing the electrospinning solution, which improves the hydrophilicity of polyvinyl alcohol and the corrosion inhibition ability of the repair agent, so that the release of the corrosion inhibitor is more controllable, more intelligent, and more long-acting, and finally the photothermal shape memory resin is used to prepare a shape memory self-repairing organic coating, so that the coating has the ability to repair damage under photothermal stimulation, and can also effectively prevent additional consumption of the corrosion inhibitor due to the rupture of the coating.

[0025] 2) The new environment-responsive shape memory self-repairing intelligent harmony coating prepared by the application has the synergistic effect of a double self-repairing mechanism. On the one hand, the self-help type repair can be realized by using the controllable release of the corrosion inhibitor. On the other hand, the intrinsic self-repairing polymer used in the application has the characteristic of not needing to add a repair agent. The photothermal conversion substance polydopamine is grown in situ in the nanofiber container loaded with the corrosion inhibitor and is spun in situ on the metal surface by electrospinning. The nanofibers are uniformly dispersed. At the same time, the shape memory organic coating is coated on the surface of the nanofiber layer with a void structure. Under the stimulation of infrared radiation, the photothermal conversion is carried out. The dynamic reversible chemical bonds are recombined at the broken damage sites, so that the coating damage site is deformed and restored, and the infinite repair of the same site of the material can be realized, which has higher safety.

[0026] 3) The environment-responsive shape memory self-repairing intelligent harmony coating formed by the application is composed of three different coatings. The surface is uniform, dense, firmly combined, and the thickness is controllable. The coating has good corrosion resistance and can meet the intelligent self-repairing of various working conditions. The intelligent self-repairing can be realized under the influence of various environmental factors. The environmental stimulation has good controllable release performance. The coating is suitable for various alloy materials such as aluminum, magnesium, titanium alloy light alloy, non-ferrous metal alloy, black alloy and composite materials.

[0027] 4) The process of the application is simple, easy to operate, stable, high in processing efficiency, low in material cost, and easy to realize large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The self-repairing principle of the shape memory self-repairing composite coating prepared by the application;

[0029] Figure 2 The macroscopic morphology of the self-repairing composite coating prepared by the application;

[0030] Figure 3 The microscopic morphology of the self-repairing composite coating prepared by the application;

[0031] Figure 4 The self-repairing process at different temperatures;

[0032] Figure 5 The self-repairing process of cracks with different widths at 80 DEG C;

[0033] Figure 6 The response of the repair rate of the self-repairing coating to different environmental factors;

[0034] Figure 7 The influence of the innovative use of dopamine pretreatment in the application on the polarization curve of the photothermal response shape memory self-repairing coating. DETAILED DESCRIPTION

[0035] The technical solutions of the present application are further described in detail below in combination with examples, but the protection scope of the present application is not limited thereto.

[0036] Example 1

[0037] Referring to Figure 1 An environment-responsive shape memory self-repairing intelligent harmonious coating comprises the following components in mass parts:

[0038] A polydopamine pretreatment layer 5 parts;

[0039] An exogenous nanofiber self-repairing coating 40 parts;

[0040] A shape memory self-repairing organic composite coating with photothermal effect 55 parts.

[0041] Sample pretreatment: The sample is polished with sandpaper, then cleaned with acetone, alcohol or deionized water, and dried with cold air for standby.

[0042] Step 1, place the sample after surface treatment in a dopamine hydrochloride solution to obtain a polydopamine pretreatment layer, the specific steps are as follows:

[0043] Dopamine hydrochloride solid is added to 200ml Tris buffer, the buffer pH is 8.5, to obtain a dopamine solution with a concentration of 1mg / mL; the sample is placed on a spin coater, the dopamine solution is added dropwise, the spin coater rotates at a speed of 500rpm, and the rotation time is 2h, so that the dopamine is uniformly coated on the surface of the sample, and after standing at room temperature for 10h, it is cleaned with ultrapure water and dried with cold air for standby.

[0044] Step 2, based on the polydopamine pretreatment layer of step 1, polyvinyl alcohol spinning solution mixed with a repairing agent is spun onto the surface of the sample by electrospinning process to prepare an exogenous nanofiber self-repairing coating, the specific steps are as follows:

[0045] (1) Preparation of electrospinning solution: 6g of polyvinyl alcohol particles is added to 100ml of ultrapure water preheated, and left to stand for 5min to allow the polyvinyl alcohol particles to swell fully. Place the conical flask on a magnetic stirrer and continuously stir at 60℃ for 2h at a stirring speed of 500rpm. After the polyvinyl alcohol is fully dissolved, add 0.05g of tris(hydroxymethyl) aminomethane and 0.2g of dopamine hydrochloride, respectively. After stirring at 25℃ for 12h, add 0.01% of the total mass of the repairing agent, which is tannic acid, and continue to stir for 2-4h, and stand for 24h for standby;

[0046] (2) Preparation of electrospinning nanofiber self-repairing coating: place the sample on the receiving screen, place the spinning solution in the syringe, turn on the power, set the receiving screen distance to 10 cm, voltage to 10 kV, spinning solution pushing speed to 0.1 mL / h, and receiving time to 1 h; after electrospinning, place the sample in a vacuum drying oven to volatilize the solvent, temperature 60 ℃, heating time 1 h.

[0047] Step three, prepare shape memory intrinsic self-repairing organic composite coating with photothermal effect on the sample surface by spin coating process, the specific steps are as follows:

[0048] (1) Prepare phenolic resin microspheres by ultrasonic assisted polymerization method, first measure 40 mL of anhydrous ethanol, 100 mL of deionized water and 0.5 mL of ammonia in a beaker, then add 1 g of o-phenol and 0.5 g of formaldehyde, stir uniformly, then ultrasonic treatment for 10 min, stop ultrasonic treatment after a large amount of yellow insoluble substance is generated, separate the product by centrifugation, wash with alcohol for 3 times, then vacuum dry the product at 50 ℃ for 10 h to obtain phenolic resin microspheres.

[0049] (2) Place the microspheres in a tube furnace with N2 at 500 ℃ for 3 h, and naturally cool to obtain the final product, photothermal nanocarbon spheres.

[0050] (3) Take 0.01 g of nanocarbon spheres, ultrasonic dispersion in DMF solvent for 30 min, then add to 100 g of shape memory resin, mechanical stirring at 80 ℃ for 4 h, until the photothermal nanocarbon spheres are uniformly dispersed in the resin, then collect the product for use.

[0051] (4) Place the sample on the spin coating device table, drop the shape memory resin with dispersed photothermal nanocarbon spheres, control the drop amount to be 1 mL / cm 2 , control the spin coating speed in the range of 800-2000 rpm, after spin coating, place the sample in a vacuum drying oven, heat at 80 ℃ for 2 h.

[0052] Example two, an environment responsive shape memory self-repairing intelligent concordant coating, by mass fraction, comprising the following components:

[0053] Polydopamine pretreatment layer 8 parts;

[0054] Exogenous nanofiber self-repairing coating 42 parts;

[0055] Shape memory self-repairing organic composite coating with photothermal effect 50 parts.

[0056] Sample pretreatment: polish the sample with sandpaper; then wash with acetone, alcohol or deionized water, and dry with cold air.

[0057] Step one, the sample after surface treatment is placed in a dopamine hydrochloride solution to obtain a polydopamine pretreatment layer, the specific steps are as follows:

[0058] Dopamine hydrochloride solid is added to 250ml Tris buffer, the buffer pH is 8.5, and a dopamine solution with a concentration of 1.5mg / mL is obtained; the sample is placed on a spin coater, and the dopamine solution is added dropwise, the spin coater rotates at a speed of 1000rpm, and the rotation time is 4h, so that the dopamine is uniformly coated on the surface of the sample, and after standing at room temperature for 10h, it is washed with ultrapure water and dried with cold air.

[0059] Step two, based on the polydopamine pretreatment layer of step one, polyvinyl alcohol spinning solution mixed with repair agent is spun onto the surface of the sample by electrospinning process to prepare an external aid type nanofiber self-repairing coating, the specific steps are as follows:

[0060] (1) Preparation of electrospinning solution: 6-10g of polyvinyl alcohol particles is added to 100ml of preheated ultrapure water, and the mixture is allowed to stand for 10min to allow the polyvinyl alcohol particles to swell fully. The conical flask is placed on a magnetic stirrer and stirred at 60℃ for 3h at a speed of 600rpm. After the polyvinyl alcohol is fully dissolved, 0.05g of tris(hydroxymethyl) aminomethane and 0.4g of dopamine hydrochloride are added, and the mixture is stirred at 40℃ for 24h. Then, 0.05% of the total mass of repair agent, which is benzotriazole, is added, and the mixture is stirred for another 2h. After standing for 24h, the solution is ready for use.

[0061] (2) Preparation of electrospinning nanofiber self-repairing coating: The sample is placed on a receiving screen, the spinning solution is placed in a syringe, the power is turned on, the receiving screen distance is set to 15cm, the voltage is set to 15kV, the spinning solution pushing speed is set to 0.4mL / h, and the receiving time is set to 4h. After electrospinning, the sample is placed in a vacuum drying oven to evaporate the solvent, the temperature is set to 60℃, and the heating time is set to 1h.

[0062] Step three, shape memory polyurethane is prepared on the surface of the sample by spin coating process to prepare a shape memory intrinsic type self-repairing organic composite coating with photothermal effect, the specific steps are as follows:

[0063] (3) Phenolic resin microspheres are prepared by ultrasonic assisted polymerization method. First, 40mL of anhydrous ethanol, 100mL of deionized water and 0.7mL of ammonia water are measured in a beaker, then 1.5g of o-phenol and 0.7g of formaldehyde are added, and the mixture is stirred uniformly and ultrasonically treated for 10min. After a large amount of yellow insoluble substance is generated, the ultrasonic treatment is stopped, the product is separated by centrifugation, washed with alcohol for 3 times, and then dried in a vacuum oven at 50℃ for 12h to obtain phenolic resin microspheres.

[0064] (2) The microspheres were placed in a tube furnace with N2 and calcined at 500°C for 3 hours, and then naturally cooled to obtain the final product, photothermal carbon nanospheres.

[0065] (3) Take 0.05g of carbon nanospheres and ultrasonically disperse them in DMF solvent for 30min. Then add them to 100g of shape memory resin and mechanically stir at 80℃ for 5h until the photothermal carbon nanospheres are uniformly dispersed in the resin. Then collect the product for later use.

[0066] (4) Place the sample on the spin coating stage and dropwise add shape memory resin containing dispersed photothermal carbon nanospheres, controlling the dropwise addition rate to 1 mL / cm³. 2 Control the spin coating speed within the range of 800 to 2000 rpm. After spin coating, place the sample in a vacuum drying oven and heat at 80°C for 4 hours.

[0067] Example 3: An environmentally responsive shape memory self-healing smart synergistic coating, comprising the following components by mass parts:

[0068] 10 portions of polydopamine pretreatment layer;

[0069] 45 copies of nanofiber container external self-healing coating;

[0070] Forty-five samples of shape memory intrinsic self-healing organic composite coatings with photothermal effect were obtained.

[0071] Sample pretreatment: Polish the sample with sandpaper; then clean it with acetone, alcohol or deionized water, and dry it with cold air for later use.

[0072] Step 1: Place the surface-treated sample in a hydrochloric acid-dopamine solution to obtain a polydopamine pretreatment layer. The specific steps are as follows:

[0073] Polish the sample with sandpaper; then clean it with acetone, alcohol, or deionized water, and dry it with cold air for later use. Add solid dopamine hydrochloride to 300 ml of Tris buffer (pH 8.5) to obtain a dopamine solution with a concentration of 2 mg / mL. Place the sample on a spin coater, add the above dopamine solution dropwise, and spin coat the sample at 1000 rpm for 4 hours to ensure uniform coating of dopamine on the sample surface. After standing at room temperature for 12 hours, clean it with ultrapure water and dry it with cold air for later use.

[0074] Step two: Based on the polydopamine pretreatment layer from step one, the polyvinyl alcohol spinning solution mixed with the repair agent is spun onto the sample surface using an electrospinning process to prepare an externally supported nanofiber self-healing coating. The specific steps are as follows:

[0075] (1) Preparation of electrospinning solution: 8 g of polyvinyl alcohol particles was added to 100 ml of preheated ultrapure water, and was left for 10 min to allow the polyvinyl alcohol particles to swell fully. A conical flask was placed on a magnetic stirrer, and was continuously stirred at 80°C for 3 h at a stirring speed of 500 rpm. After the polyvinyl alcohol was fully dissolved, 0.05 g of tris-hydroxymethyl aminomethane and 0.4 g of dopamine hydrochloride were added, respectively. After stirring at 25°C for 12 h, 0.08% of a repairing agent by total mass was added, and the stirring was continued for 4 h. The repairing agent was sodium stannate. After standing for 20 h, the sample was ready for use.

[0076] (2) Preparation of electrospinning nanofiber self-repairing coating: The sample was placed on a receiving screen, and the spinning solution was placed in a syringe. The power was turned on, and the receiving screen distance was set to 20 cm, the voltage was set to 20.0 kV, the spinning solution pushing speed was set to 0.5 mL / h, and the receiving time was set to 6 h. After the electrospinning was completed, the sample was placed in a vacuum drying oven, and the solvent was volatilized. The temperature was 60°C, and the heating time was 2 h.

[0077] Step three, based on step two, a shape memory polyurethane was prepared on the surface of the sample by a spin coating process to prepare a shape memory intrinsic self-repairing organic composite coating with photothermal effect. The specific steps are as follows:

[0078] (1) Phenolic resin microspheres were prepared by ultrasonic assisted polymerization. 50 mL of anhydrous ethanol, 150 mL of deionized water and 0.5 mL of ammonia were first measured in a beaker, then 1.5 g of o-phenol and 0.6 g of formaldehyde were added, and after stirring uniformly, it was ultrasonically treated for 15 min. After a large amount of yellow insoluble substance was generated, the ultrasonic treatment was stopped, and the product was separated by centrifugation, washed with alcohol for 3 times, and then the product was vacuum dried at 55°C for 13 h to obtain phenolic resin microspheres.

[0079] (2) The microspheres were placed in a tube furnace with N2 at 500°C for 5 h, and the final product, photothermal nanocarbon spheres, was obtained by natural cooling.

[0080] (3) 0.02 g of nanocarbon spheres was ultrasonically dispersed in DMF solvent for 30 min, and then was added to 100 g of shape memory resin. The mixture was mechanically stirred at 80°C for 5 h until the photothermal nanocarbon spheres were uniformly dispersed in the resin, and then the product was collected for standby.

[0081] (4) The sample was placed on the spin coating device table, and the shape memory resin with dispersed photothermal nanocarbon spheres was added dropwise. The dropwise amount was controlled to be 1 mL / cm 2 , and the spin coating speed was controlled to be in the range of 800-2000 rpm. After the spin coating was completed, the sample was placed in a vacuum drying oven, and was heated at 150°C for 4 h.

[0082] Example 1 is the best embodiment.

[0083] ReferenceFigure 2 , Figure 3 It can be seen that the prepared self-repairing coating is uniform and smooth in macro and micro views.

[0084] Referring to Figure 4 It can be seen that the prepared self-repairing coating has different repair effects at different repair temperatures, and the repair effect is obvious under heating at 80℃.

[0085] Referring to Figure 5 It can be seen that the prepared self-repairing coating has good self-repairing performance under different scratch widths.

[0086] Referring to Figure 6 It can be seen that the prepared self-repairing coating has good environmental stimulation self-repairing effect under the stimulation of infrared light.

[0087] Referring to Figure 7 It can be seen that the self-repairing coating prepared by dopamine pretreatment has the best corrosion resistance.

[0088] The above examples only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method for preparing an environmentally responsive shape memory self-healing smart Janus coating, characterized in that, The method comprises the following steps: Step one, using spin coating process, preparing polydopamine pretreatment layer on the surface of the alloy; Step two, using polyvinyl alcohol static spinning process wrapped with corrosion inhibitor, preparing exogenous nanofiber self-repairing coating on the polydopamine pretreatment layer; Step three, first, using ultrasonic assisted polymerization method to make pyrogallol and formaldehyde quickly condensate to generate phenolic resin microspheres, and then calcining at 500-600℃ for 3-5h to obtain photo-thermal nanocarbon spheres; then dispersing the photo-thermal nanocarbon spheres in shape memory resin to obtain a self-repairing organic composite coating; finally, using spin coating process, spin coating the self-repairing organic composite coating outside the exogenous nanofiber self-repairing coating; the mass fraction of the polydopamine pretreatment layer is 5-10; the mass fraction of the exogenous nanofiber self-repairing coating is 40-55; and the mass fraction of the self-repairing organic composite coating is 50-55; The specific steps of step two comprise: (1) preparation of electrostatic spinning liquid: first, 6-10g of polyvinyl alcohol particles are added into 100-200ml of preheated ultrapure water, and then placed for 5-10min; then, continuously stirring is carried out at a temperature of 60-80℃ for 2-3h on a magnetic stirrer, and the stirring speed is 500-600rpm; then, 0.05-0.06g of tris(hydroxymethyl)aminomethane and 0.2-0.4g of dopamine hydrochloride are added, respectively, and after stirring for 12-24h at 25-40℃, 0.01-0.08% of a total mass of repair agent is added, and the stirring is continuously carried out for 2-4h, and then placed for 20-24h to obtain the electrostatic spinning liquid for standby use; (2) preparation of exogenous nanofiber self-repairing coating: the sample is placed on a receiving screen, the spinning liquid is placed in a syringe, the power is turned on, the receiving screen distance is set to 10-20cm, the voltage is set to 10-20.0kV, the spinning liquid pushing speed is set to 0.1-0.5mL / h, and the receiving time is set to 1-6h; after the electrostatic spinning is completed, the sample is placed in a vacuum drying oven, the temperature is set to 60-80℃, and the heating time is set to 1-2h; The specific steps of step one comprise: dopamine hydrochloride solid is added into Tris buffer solution, the pH of the buffer solution is 8.5, and stirring is carried out to obtain a dopamine solution with a concentration of 1-2mg / mL; the sample is placed on a spin coater, the dopamine solution is added dropwise, the spin coater rotation speed is 500-1000rpm, and the rotation time is 2-4h, so that the dopamine is uniformly coated on the surface of the sample, and after being placed at room temperature for 10-12h, the sample is cleaned with ultrapure water, dried by cold air, and standby use.

2. The method for preparing an environmentally responsive shape memory self-healing intelligent synergistic coating according to claim 1, characterized in that, The preparation of the phenolic resin microspheres in step three comprises: first, 40-50mL of anhydrous ethanol, 100-150mL of deionized water and 0.5-0.7mL of ammonia water are measured in a beaker, then 1-1.5g of pyrogallol and 0.5-0.8g of formaldehyde are added, the mixture is stirred uniformly, and then ultrasonic treatment is carried out for 10-15min, the product is separated by centrifugation, washed with alcohol for several times, and then vacuum dried at 50-55℃ for 10-12h to obtain the phenolic resin microspheres.

3. The method of claim 2, wherein the method further comprises the step of: The dispersion process of the photo-thermal nanocarbon ball in the shape memory resin in the third step is that 0.01-0.05 g of the nanocarbon ball is ultrasonically dispersed in DMF solvent for 20-30 min, and then added into 100 g of the shape memory resin, and mechanically stirred at 80°C for 4-5 h until the photo-thermal nanocarbon ball is uniformly dispersed in the resin, and then prepared.

4. The method of claim 3, wherein the method further comprises the step of: The spin coating process of the self-repairing organic composite coating in step three is to place the sample on the spin coating device table, drop the shape memory resin dispersed with photothermal carbon nanospheres, control the drop amount to be 0.5-1 mL / cm 2 , control the spin coating speed in the range of 800-2000 rpm, and after spin coating, place the sample in a vacuum drying box and heat at 80-150 DEG C for 2-4 h.

5. The method of claim 4, wherein the method further comprises the step of: The repair agent used in the second step (1) includes any one of an organic corrosion inhibitor or an inorganic corrosion inhibitor, the organic corrosion inhibitor includes any one of 8-hydroxyquinoline, benzotriazole, 2-mercaptobenzothiazole, tannic acid, and oleic acid, and the inorganic corrosion inhibitor includes any one of sodium vanadate, sodium phosphate, sodium stannate, sodium tungstate, and rare earth metal ions.

6. The method of claim 5, wherein the method further comprises the step of: The shape memory resin is any one of a shape memory epoxy resin and a shape memory polyurethane.

7. The method of claim 6, wherein the method further comprises the step of: The shape memory resin is a modified shape memory epoxy resin or a modified shape memory polyurethane.

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