An ultralubricous microcapsule-based composite coating with temperature-ultraviolet light dual responsiveness and a preparation method thereof

Abstract

The present application belongs to the field of chemical materials, and particularly relates to a kind of temperature-ultraviolet light dual responsive superlubricity microcapsule-based composite coating and a preparation method thereof.The composite coating provided by the present application comprises a microcapsule structure base layer, a hydrophobic modification layer complexed on the microcapsule structure base layer, and a lubricating oil layer complexed on the hydrophobic modification layer;The composition of the microcapsule structure base layer includes temperature-responsive chitosan-Pluronic F127 oil microcapsule and ultraviolet light-responsive chitosan-coumarin oil microcapsule.The coating provided by the present application can controllably release lubricating oil with temperature and ultraviolet light irradiation, thereby maintaining the long-term lubricity of the coating surface, and further making the coating more durable under high temperature and strong ultraviolet light conditions, greatly widening the application prospect of the coating.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials, and particularly relates to a superlubricating microcapsule-based composite coating with dual temperature-ultraviolet light responsiveness and its preparation method. Background Technology

[0002] Superlubricating surfaces with pitcher plant-like structures are a type of solid-liquid composite interface material that has emerged in recent years. By infusing lubricant into a rough substrate with a nano / microstructure, a stable and inert smooth surface is formed. Due to their excellent hydrophobic, self-healing, self-cleaning, and anti-adhesion properties, they have broad application prospects in various fields such as drag reduction, anti-icing, anti-fouling, and corrosion prevention.

[0003] However, the lubricating oils used in coating preparation are mostly carbon compounds, such as perfluoropolyether, silicone oil, and vegetable oil. Their carbon-carbon and carbon-hydrogen bonds have low bond energies. Under high temperature and strong ultraviolet radiation conditions, the lubricating oil is easy to evaporate or degrade, causing the super-lubricated surface to gradually fail, thus severely shortening its service life. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a superlubricating microcapsule-based composite coating with dual temperature-ultraviolet light response and its preparation method. The composite coating provided by this invention can maintain excellent lubrication performance for a long time under high temperature and strong ultraviolet light conditions, overcoming the shortcomings of traditional superlubricating coatings that are prone to failure under harsh environmental conditions.

[0005] This invention provides a superlubricating microcapsule-based composite coating with dual temperature-UV light responsiveness, comprising: a microcapsule structure substrate layer, a hydrophobic modification layer composited on the microcapsule structure substrate layer, and a lubricating oil layer composited on the hydrophobic modification layer; the microcapsule structure substrate layer comprises temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and UV-responsive chitosan-coumarin oil-encapsulated microcapsules.

[0006] Preferably, the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules are prepared by emulsifying, stirring, removing volatile organic solvents, dialysis, and lyophilizing a mixture of chitosan, surfactant, water, lubricating oil, Pluronic F127-dihydroxysuccinimide ester, and volatile organic solvents.

[0007] Preferably, the ratio of chitosan, Pluronic F127-dihydroxysuccinimide ester and lubricating oil is (150-200) mg:(150-200) mg:(0.5-1) mL.

[0008] Preferably, the UV-responsive chitosan-coumarin oil-encapsulated microcapsules are prepared by emulsifying, stirring, removing volatile organic solvents, dialysis, and lyophilizing a mixture of chitosan, surfactant, water, lubricating oil, (7-diethylaminocoumarin-4-methyl)succinimide ester, and volatile organic solvents.

[0009] Preferably, the ratio of chitosan, (7-diethylaminocoumarin-4-methyl)succinimide ester and lubricating oil is (150-200) mg:(150-200) mg:(0.5-1) mL.

[0010] Preferably, the mass ratio of the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules to the UV-responsive chitosan-coumarin oil-encapsulated microcapsules is 1:(0.5-2).

[0011] Preferably, the lubricating oil encapsulated in the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and the UV-responsive chitosan-coumarin oil-encapsulated microcapsules is one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil, and rapeseed oil.

[0012] Preferably, the hydrophobic modification layer comprises one or more of dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltrimethoxysilane and 1H,1H,2H,2H-perfluorodecyltrichlorosilane.

[0013] Preferably, the lubricating oil in the lubricating oil layer is one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil, and rapeseed oil.

[0014] This invention provides a method for preparing a superlubricating microcapsule-based composite coating with temperature-UV dual responsiveness as described in the above-mentioned technical solution, comprising the following steps:

[0015] a) A suspension containing temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and UV-responsive chitosan-coumarin oil-encapsulated microcapsules was coated on the surface of a substrate and dried to form a microcapsule structure substrate layer.

[0016] b) Immerse the substrate treated in step a) into the hydrophobic modification solution, remove and dry it to form a hydrophobic modification layer;

[0017] c) Coating the surface of the hydrophobic modified layer with lubricating oil to form a lubricating oil layer, thereby obtaining a super-lubricating microcapsule-based composite coating with dual temperature-UV light responsiveness.

[0018] Compared with existing technologies, this invention provides a superlubricating microcapsule-based composite coating with dual temperature-UV light responsiveness and its preparation method. The composite coating provided by this invention comprises: a microcapsule structure substrate layer, a hydrophobic modification layer composited on the microcapsule structure substrate layer, and a lubricating oil layer composited on the hydrophobic modification layer; the microcapsule structure substrate layer comprises temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and UV-responsive chitosan-coumarin oil-encapsulated microcapsules. This invention utilizes two types of oil-encapsulated microcapsules with both temperature and UV light responsiveness to construct a rough-structured substrate, hydrophobically modifies the substrate formed by the microcapsules, and finally infuses lubricating oil onto the substrate to obtain a superlubricating coating with dual temperature-UV light responsiveness. In this invention, the temperature-responsive oil-encapsulated microcapsules in the substrate layer are chitosan-Pluronic F127 oil-encapsulated microcapsules. Upon temperature increase, these microcapsules rapidly shrink in size through a sol-gel phase transition, releasing lubricating oil to replenish the lost oil layer on the surface. The UV-responsive oil-encapsulated microcapsules in the substrate layer are chitosan-coumarin oil-encapsulated microcapsules. These microcapsules utilize the pyrolysis properties of coumarin under UV irradiation to rapidly release lubricating oil from the ruptured photoresponsive microcapsules. The coating provided by this invention can controllably release lubricating oil according to changes in temperature and UV irradiation, thereby maintaining the long-term lubricity of the coating surface. This makes the coating more durable under high temperature and strong UV irradiation conditions, greatly broadening the application prospects of the coating. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the preparation process of the superlubricating microcapsule-based composite coating with dual temperature-ultraviolet light response provided by the present invention;

[0021] Figure 2 This is the synthetic reaction route diagram of Pluronic F127-dihydroxysuccinimide ester provided in Example 1 of the present invention;

[0022] Figure 3 This is a synthetic reaction route diagram of the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules provided in Example 2 of the present invention;

[0023] Figure 4This is a TEM image of the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules provided in Example 2 of the present invention;

[0024] Figure 5 This is a cumulative release curve of lubricating oil in ethanol for temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules at different temperatures, provided in Example 2 of the present invention.

[0025] Figure 6 This is a synthetic reaction route diagram of 7-diethylamino-4-hydroxymethylcoumarin provided in Example 3 of the present invention;

[0026] Figure 7 This is a synthetic reaction route diagram of (7-diethylaminocoumarin-4-methyl)succinimide ester provided in Example 4 of the present invention;

[0027] Figure 8 The synthesis reaction route diagram of the UV-responsive chitosan-coumarin oil-encapsulated microcapsules provided in Example 5 of this invention;

[0028] Figure 9 The photolysis mechanism diagram of the UV-responsive chitosan-coumarin oil-encapsulated microcapsules provided in Example 5 of this invention;

[0029] Figure 10 This is a cumulative release curve of lubricating oil in ethanol for UV-responsive chitosan-coumarin oil-encapsulated microcapsules under both light- and light-free conditions, as provided in Example 5 of this invention.

[0030] Figure 11 This is a diagram showing the water contact angle and sliding angle of the temperature-UV dual-responsive superlubricating microcapsule-based composite coating provided in Embodiment 6 of the present invention after being placed for different times under certain temperature and light conditions. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention provides a superlubricating microcapsule-based composite coating with dual temperature-UV light responsiveness, comprising: a microcapsule structure substrate layer, a hydrophobic modification layer composited on the microcapsule structure substrate layer, and a lubricating oil layer composited on the hydrophobic modification layer; the microcapsule structure substrate layer comprises temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules (Th@CS) and UV-responsive chitosan-coumarin oil-encapsulated microcapsules (Li@CS).

[0033] In the composite coating provided by this invention, the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules in the microcapsule structure substrate layer are prepared by emulsification, stirring reaction, removal of volatile organic solvents, dialysis, and lyophilization of a mixture solution containing chitosan, surfactant, water, lubricating oil, Pluronic F127-dihydroxysuccinimide ester (F127-NHS), and volatile organic solvents. The chitosan preferably has a number-average molecular weight of 100,000 to 1,000,000, more preferably 500,000; the surfactant is preferably a nonionic surfactant, more preferably Tween 80; the lubricating oil is preferably one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil, and rapeseed oil, and the viscosity of the dimethyl silicone oil is preferably 20 to 150 cst; the volatile organic solvent is preferably dichloromethane; the chitosan, Pluronic... The preferred ratio of F127-dihydroxysuccinimide ester to lubricating oil is (150-200) mg:(150-200) mg:(0.5-1) mL, specifically 150 mg:150 mg:0.5 mL; the preferred mass ratio of chitosan to surfactant is (150-200):(600-1000), specifically 150:800; the preferred ratio of chitosan to water is (150-200) mg:(150-200) mL, specifically 150 mg:150 mL; the Pluronic The preferred ratio of F127-dihydroxysuccinimide ester to volatile organic solvent is (150-200) mg:(20-30) mL, specifically 150 mg:25 mL; the pH of the mixture solution is preferably 7.4, which can be adjusted by adding a pH buffer; the preferred method of emulsification is ultrasonic emulsification, the preferred temperature of emulsification is 5-20°C, more preferably 10°C, and the preferred emulsification time is 2-10 min, more preferably 5 min; the preferred temperature of the stirring reaction is 5-20°C, more preferably 10°C, and the preferred stirring reaction time is 12-48 h, more preferably 24 h; the preferred method of removing volatile organic solvent is rotary evaporation; the preferred dialysis is carried out in a phosphate buffer solution with a pH of 7.4, and the preferred dialysis time is 6-24 h, more preferably 12 h.

[0034] In the composite coating provided by this invention, the UV-responsive chitosan-coumarin oil-encapsulated microcapsules in the microcapsule structure substrate layer are prepared by emulsification, stirring reaction, removal of volatile organic solvents, dialysis, and lyophilization of a mixture solution comprising chitosan, surfactant, water, lubricating oil, (7-diethylaminocoumarin-4-methyl)succinimide ester (DEACMS-NHS), and volatile organic solvents. The chitosan preferably has a number-average molecular weight of 100,000 to 1,000,000, more preferably 500,000; the surfactant is preferably a nonionic surfactant, more preferably a Tween surfactant. 80; the lubricating oil is preferably one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil, and rapeseed oil, and the viscosity of the dimethyl silicone oil is preferably 20-150 cst; the volatile organic solvent is preferably dichloromethane; the ratio of chitosan, (7-diethylaminocoumarin-4-methyl)succinimide ester, and lubricating oil is preferably (150-200) mg:(150-200) mg:(0.5-1) mL, specifically 150 mg:150 mg:0.5 mL; the mass ratio of chitosan to surfactant is preferably (150-200):(600-1000), specifically 150:800; the ratio of chitosan to water is preferably (150-200) mg:(150-200) mL, specifically 150 mg:150 mL; the (7- The preferred ratio of diethylaminocoumarin-4-methyl)succinimide ester to volatile organic solvent is (150-200) mg:(20-30) mL, specifically 150 mg:25 mL; the pH of the mixture solution is preferably 7.4, which can be adjusted by adding a pH buffer; the preferred emulsification method is ultrasonic emulsification, the preferred emulsification temperature is 5-20°C, more preferably 10°C, and the preferred emulsification time is 5-20 min, more preferably 10 min; the preferred stirring reaction temperature is 5-20°C, more preferably 10°C, and the preferred stirring reaction time is 12-48 h, more preferably 24 h; the preferred method for removing volatile organic solvent is rotary evaporation; the preferred dialysis is carried out in a phosphate buffer solution with a pH of 7.4, and the preferred dialysis time is 24-72 h, more preferably 48 h.

[0035] In the composite coating provided by the present invention, the mass ratio of the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and the UV-responsive chitosan-coumarin oil-encapsulated microcapsules in the microcapsule structure substrate layer is preferably 1:(0.5-2), specifically 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.

[0036] In the composite coating provided by the present invention, the microcapsule structure substrate layer is preferably formed by coating and drying a suspension containing temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and UV-responsive chitosan-coumarin oil-encapsulated microcapsules. The solvent in the suspension is preferably one or more of methanol, ethanol, dimethylformamide (DMF), acetone, and ethyl acetate; the concentration of the suspension is preferably 5–20 mg / mL, specifically 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, 10 mg / mL, 11 mg / mL, 12 mg / mL, 13 mg / mL, 14 mg / mL, 15 mg / mL, 16 mg / mL, 17 mg / mL, 18 mg / mL, 19 mg / mL, or 20 mg / mL; the coating method is preferably spraying; the spraying pressure is preferably 1.1–10 bar; the spraying flow rate is preferably 150–1000 mL / min; the number of coatings is preferably 2–5 times, more preferably 3 times, the coating amount each time is preferably 0.5–2 mL, more preferably 1 mL, and the interval between two adjacent coatings is preferably 0.2–1 h, more preferably 0.5 h.

[0037] In the composite coating provided by the present invention, the hydrophobic modification layer preferably comprises one or more of dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltrimethoxysilane and 1H,1H,2H,2H-perfluorodecyltrichlorosilane.

[0038] In the composite coating provided by this invention, the hydrophobic modification layer is preferably formed by immersing a microcapsule structure substrate layer in a hydrophobic modification solution for a period of time and then removing and drying it. The solute composition of the hydrophobic modification solution has been described previously and will not be repeated here; the solvent of the hydrophobic modification solution is preferably one or more of methanol, ethanol, toluene, n-hexane, n-octane, and n-decane; the concentration of the hydrophobic modification solution is preferably 2–5 wt%, specifically 2 wt%, 3 wt%, 4 wt%, or 5 wt%; the immersion time is preferably 30–60 min, specifically 30 min, 40 min, 50 min, or 60 min.

[0039] In the composite coating provided by the present invention, the lubricating oil in the lubricating oil layer is preferably one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil, and rapeseed oil, and the viscosity of the dimethyl silicone oil is preferably 20-150 cst; the lubricating oil in the lubricating oil layer is preferably the same type as the lubricating oil encapsulated in the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and the ultraviolet light-responsive chitosan-coumarin oil-encapsulated microcapsules.

[0040] In the composite coating provided by the present invention, the lubricating oil layer is preferably formed by applying lubricating oil and then draining it. The coating method is preferably spraying; the spraying pressure is preferably 1.1–10 bar; the spraying flow rate is preferably 150–1000 mL / min; the draining method is preferably vertical placement; and the draining time is preferably 0.5–1 h.

[0041] This invention also provides a method for preparing the superlubricating microcapsule-based composite coating with temperature-UV dual response as described in the above technical solution, such as... Figure 1 As shown, the specific steps include:

[0042] a) A suspension containing temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and UV-responsive chitosan-coumarin oil-encapsulated microcapsules was coated on the surface of a substrate and dried to form a microcapsule structure substrate layer.

[0043] b) Immerse the substrate treated in step a) into the hydrophobic modification solution, remove and dry it to form a hydrophobic modification layer;

[0044] c) Coating the surface of the hydrophobic modified layer with lubricating oil to form a lubricating oil layer, thereby obtaining a super-lubricating microcapsule-based composite coating with dual temperature-UV light responsiveness.

[0045] In the preparation method provided by the present invention, in step a), the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules in the suspension are preferably prepared according to the following steps:

[0046] A volatile organic solution containing lubricating oil and Pluronic F127-dihydroxysuccinimide ester (F127-NHS) was added to an aqueous solution containing chitosan and a surfactant. The mixture was emulsified, stirred, and reacted. The volatile organic solvent was removed, and the mixture was dialyzed and lyophilized to obtain temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules.

[0047] In the above-mentioned preparation steps of temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules provided by the present invention, the lubricating oil in the volatile organic solution is preferably one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil and rapeseed oil, and the viscosity of the dimethyl silicone oil is preferably 20-150 cst.

[0048] In the above-mentioned preparation steps of temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules provided by the present invention, the Pluronic F127-dihydroxysuccinimide ester (F127-NHS) is preferably prepared in a volatile organic solution according to the following steps:

[0049] S1) Pluronic F127, 4-dimethylaminopyridine and organic solvent were mixed, triethylamine was added, and then succinic anhydride was added under a protective atmosphere to carry out the reaction. After the reaction was completed, post-treatment was performed to obtain the intermediate product F127-COOH.

[0050] S2) The F127-COOH, hydroxysuccinimide (NHS) and organic solvent are mixed, and 1-ethyl-3-(3-dimethylaminopropyl)carbonimide hydrochloride (EDC·HCl) is added to react. After the reaction is completed, post-treatment is performed to obtain Pluronic F127-dihydroxysuccinimide ester.

[0051] In the preparation steps of Pluronic F127-dihydroxysuccinimide ester provided by the present invention, in step S1), the mass ratio of Pluronic F127 to 4-dimethylaminopyridine is preferably 12.6 g:(25-30) mg; the organic solvent is preferably 1,4-dioxane; the amount ratio of Pluronic F127 to organic solvent is preferably 12.6 g:(35-40) mL; the amount ratio of Pluronic F127 to triethylamine is preferably 12.6 g:(0.2-0.5) mL; the protective gas is preferably nitrogen; the molar ratio of Pluronic F127 to succinic anhydride is preferably 1:(2.5-3); the reaction temperature is preferably 10-40°C, more preferably 25°C (room temperature); the reaction time is preferably 12-48 h, more preferably 24 h.

[0052] In the preparation steps of Pluronic F127-dihydroxysuccinimide ester provided by the present invention, the post-treatment process in step S1) preferably includes: after the reaction is completed, removing the organic solvent, recrystallizing, and drying to obtain the intermediate product F127-COOH. The method for removing the organic solvent is preferably vacuum distillation; the solvent for recrystallization is preferably diethyl ether.

[0053] In the preparation steps of Pluronic F127-dihydroxysuccinimide ester provided by the present invention, in step S2), the molar ratio of F127-COOH to hydroxysuccinimide is preferably 1:(35-40); the organic solvent is preferably dichloromethane; the amount ratio of F127-COOH to organic solvent is preferably 10g:(100-150)mL, more preferably 10g:120mL; the mass ratio of F127-COOH to 1-ethyl-3-(3-dimethylaminopropyl)carbonimide hydrochloride is preferably 10:(0.8-1), more preferably 10:0.93; the reaction temperature is preferably 5-15℃, more preferably 10℃; and the reaction time is preferably 6-10h.

[0054] In the preparation steps of Pluronic F127-dihydroxysuccinimide ester provided by the present invention, the post-treatment process in step S2) preferably includes: after the reaction is completed, the reaction product is poured into an acidic solution, then extracted with an organic solvent, the organic solvent is removed, the product is purified by silica gel column chromatography, and dried to obtain Pluronic F127-dihydroxysuccinimide ester. The pH value of the acidic solution is preferably 3-5, more preferably 4; the organic solvent is preferably dichloromethane; the method for removing the organic solvent is preferably rotary evaporation; the eluent used for silica gel column chromatography is preferably a mixture of methanol and dichloromethane, and the volume ratio of methanol to dichloromethane is preferably 1:(8-30), more preferably 1:20.

[0055] In the above-mentioned preparation steps of temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules provided by the present invention, the volatile organic solvent in the volatile organic solution is preferably dichloromethane; the ratio of the lubricating oil, Pluronic F127-dihydroxysuccinimide ester and volatile organic solvent is preferably (0.5-1) mL:(150-200) mg:(20-30) mL, specifically 0.5 mL:150 mg:25 mL.

[0056] In the above-mentioned preparation steps of temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules provided by the present invention, the surfactant in the aqueous solution is preferably a nonionic surfactant, more preferably Tween80; the ratio of chitosan, surfactant and water is preferably (150-200) mg:(600-1000) mg:(150-200) mL, specifically 150 mg:800 mg:150 mL; the pH value of the aqueous solution is preferably 7.4, which can be adjusted by adding a pH buffer.

[0057] In the above-mentioned preparation steps of temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules provided by the present invention, the mass ratio of Pluronic F127-dihydroxysuccinimide ester in the volatile organic solution to chitosan in the aqueous solution is preferably 1:(0.5-2), more preferably 1:1.

[0058] In the above-mentioned preparation steps of temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules provided by the present invention, the emulsification method is preferably ultrasonic emulsification, the emulsification temperature is preferably 5-20℃, more preferably 10℃, and the emulsification time is preferably 2-10 min, more preferably 5 min; the stirring reaction temperature is preferably 5-20℃, more preferably 10℃, and the stirring reaction time is preferably 12-48 h, more preferably 24 h; the removal of volatile organic solvents is preferably by rotary evaporation; the dialysis is preferably carried out in a phosphate buffer solution with a pH value preferably 7.4, and the dialysis time is preferably 6-24 h, more preferably 12 h.

[0059] In the preparation method provided by the present invention, in step a), the UV-responsive chitosan-coumarin oil-encapsulated microcapsules in the suspension are preferably prepared according to the following steps:

[0060] A volatile organic solution containing lubricating oil and (7-diethylaminocoumarin-4-methyl)succinimide ester was added to an aqueous solution containing chitosan and a surfactant. The mixture was emulsified, stirred, and reacted. The volatile organic solvent was removed, and the mixture was dialyzed and lyophilized to obtain UV-responsive chitosan-coumarin oil-encapsulated microcapsules.

[0061] In the preparation steps of the above-mentioned UV-responsive chitosan-coumarin oil-encapsulated microcapsules provided by the present invention, the lubricating oil in the volatile organic solution is preferably one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil and rapeseed oil, and the viscosity of the dimethyl silicone oil is preferably 20-150 cst.

[0062] In the preparation steps of the above-mentioned UV-responsive chitosan-coumarin oil-encapsulated microcapsules provided by the present invention, the (7-diethylaminocoumarin-4-methyl)succinimide ester (DEACMS-NHS) is preferably prepared in a volatile organic solution according to the following steps:

[0063] I) SeO2, 7-diethylamino-4-methylcoumarin and organic solvent are mixed and heated under a protective gas atmosphere. After the reaction is completed, post-treatment is performed to obtain 7-diethylamino-4-hydroxymethylcoumarin.

[0064] II) The 7-diethylamino-4-hydroxymethylcoumarin, succinic anhydride, catalyst and organic solvent are mixed and heated to react. After the reaction is completed, post-treatment is performed to obtain (7-diethylaminocoumarin-4-methyl)succinic acid (DEACMS).

[0065] III) The 7-diethylaminocoumarin-4-methyl)succinic acid, 1-ethyl-3-(3-dimethylaminopropyl)carboimide hydrochloride (EDC·HCl), hydroxysuccinimide (NHS) and an organic solvent are mixed and reacted. After the reaction is completed, post-treatment is performed to obtain (7-diethylaminocoumarin-4-methyl)succinimide ester.

[0066] In the preparation steps of (7-diethylaminocoumarin-4-methyl)succinimide ester provided by the present invention, in step I), the molar ratio of SeO2 to 7-diethylamino-4-methylcoumarin is preferably (2-3):1; the organic solvent is preferably dioxane; the ratio of the amount of 7-diethylamino-4-methylcoumarin to the organic solvent is preferably 4.62 g:(100-150) mL; the protective gas is preferably nitrogen; the temperature of the heating reaction is preferably 70-110°C, more preferably 90°C; and the time of the heating reaction is preferably 12-48 h, more preferably 24 h.

[0067] In the preparation steps of (7-diethylaminocoumarin-4-methyl)succinimide ester provided by the present invention, in step I), the post-treatment process preferably includes: after the reaction is completed, the reaction product is filtered, the obtained filter residue is dissolved in a solvent, then a reducing agent is added to the solution, the reaction is neutralized with acid after a period of time, then the solvent is removed, the solid residue is dissolved a second time and then extracted, the extract is purified by column chromatography to obtain 7-diethylamino-4-hydroxymethylcoumarin. The solvent for dissolving the filter residue is preferably a mixed solution of tetrahydrofuran and ethanol, with a volume ratio of tetrahydrofuran to ethanol preferably 1:(0.5-2), more preferably 1:1; the ratio of the solvent for dissolving the filter residue to 7-diethylamino-4-methylcoumarin is preferably (100-200) mL:4.62 g; the reducing agent is preferably NaBH4; the mass ratio of the reducing agent to 7-diethylamino-4-methylcoumarin is preferably (1-1.5):4.62, more preferably 1.3:4.62; the reaction temperature is preferably 10-40℃, more preferably 25℃ (room temperature); the reaction time is preferably 2-6 h, more preferably 4 h; the acid is preferably dilute hydrochloric acid, with a concentration preferably 0.5-2 mol / L, more preferably 1 mol / L. / L; the solvent removal is preferably carried out under vacuum; the solvent used for the secondary dissolution is preferably dichloromethane; the preferred ratio of dichloromethane to 7-diethylamino-4-methylcoumarin is (50-80) mL:4.62 g; the extraction solution used for extraction is K2CO3 solution, the concentration of which is preferably 0.2-1 mol / L, more preferably 0.5 mol / L; the number of extractions is preferably 2-5 times, more preferably 3 times; the eluent used for column purification is preferably a mixed solution of petroleum ether and ethyl acetate, the preferred volume ratio of which is (1-5):1, more preferably 2:1; the preferred ratio of the eluent to 7-diethylamino-4-methylcoumarin is (150-250) mL:4.62 g.

[0068] In the preparation steps of (7-diethylaminocoumarin-4-methyl)succinimide ester provided by the present invention, in step II), the molar ratio of 7-diethylamino-4-hydroxymethylcoumarin to succinic anhydride is preferably 2:(3-6), more preferably 2:4; the catalyst is preferably 4-dimethylaminopyridine; the molar ratio of 7-diethylamino-4-hydroxymethylcoumarin to the catalyst is preferably 2:(0.5-1.5), more preferably 2:1; the organic solvent is preferably chloroform; the ratio of 7-diethylamino-4-hydroxymethylcoumarin to the organic solvent is preferably 2.47 g:(100-150) mL; the temperature of the heating reaction is preferably 40-70°C, more preferably 55°C; and the time of the heating reaction is preferably 12-48 h, more preferably 24 h.

[0069] In the preparation steps of (7-diethylaminocoumarin-4-methyl)succinimide ester provided by the present invention, in step II), the post-treatment process preferably includes: after the reaction, removing the organic solvent, washing, extracting, washing again, acidifying, and drying to obtain (7-diethylaminocoumarin-4-methyl)succinic acid. The method for removing the organic solvent is preferably vacuum evaporation; the washing agent for the first washing is preferably a dilute hydrochloric acid solution, the concentration of which is preferably 0.5–2 mol / L, more preferably 1 mol / L, and the ratio of the washing agent to 7-diethylamino-4-hydroxymethylcoumarin is preferably (20–50) mL: 2.47 g; the extractant used for the extraction is preferably a saturated NaHCO3 solution, and the ratio of the extractant to 7-diethylamino-4-hydroxymethylcoumarin is preferably (50–70) mL: 2.47 g. The washing agent used for the second washing is preferably diethyl ether, and the ratio of the washing agent to 7-diethylamino-4-hydroxymethylcoumarin is preferably (50-100) mL:2.47 g; the acidification reagent is preferably dilute hydrochloric acid, and the pH value of the acidified solution is preferably 4-6, more preferably 5; the drying method is preferably vacuum drying, the drying temperature is preferably 30-50℃, more preferably 40℃, and the drying time is preferably 12-48 h, more preferably 24 h.

[0070] In the preparation steps of (7-diethylaminocoumarin-4-methyl)succinimide ester provided by the present invention, in step III), the molar ratio of (7-diethylaminocoumarin-4-methyl)succinic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbonimide hydrochloride and hydroxysuccinimide is preferably 1:(0.5-2):(0.5-2), more preferably 1:1:1; the organic solvent is preferably dimethyl sulfoxide (DMSO); the ratio of the organic solvent to (7-diethylaminocoumarin-4-methyl)succinic acid is preferably (50-150) mL:5 mmol, more preferably 75 mL:5 mmol; the temperature of the mixing reaction is preferably 10-40°C, more preferably 25°C (room temperature); the time of the mixing reaction is preferably 0.5-2 h, more preferably 1 h.

[0071] In the preparation steps of (7-diethylaminocoumarin-4-methyl)succinimide ester provided by the present invention, in step III), the post-treatment process preferably includes: removing the organic solvent after the reaction is completed. The method for removing the organic solvent is preferably vacuum distillation.

[0072] In the preparation steps of the above-mentioned UV-responsive chitosan-coumarin oil-encapsulated microcapsules provided by the present invention, the volatile organic solvent in the volatile organic solution is preferably dichloromethane; the ratio of the amount of lubricating oil, (7-diethylaminocoumarin-4-methyl)succinimide ester and volatile organic solvent is preferably (0.5-1) mL:(150-200) mg:(20-30) mL, specifically 0.5 mL:150 mg:25 mL.

[0073] In the preparation steps of the above-mentioned UV-responsive chitosan-coumarin oil-encapsulated microcapsules provided by the present invention, the surfactant in the aqueous solution is preferably a nonionic surfactant, more preferably Tween 80; the ratio of chitosan, surfactant and water is preferably (150-200) mg:(600-1000) mg:(150-200) mL, specifically 150 mg:800 mg:150 mL; the pH value of the aqueous solution is preferably 7.4, which can be adjusted by adding a pH buffer.

[0074] In the preparation steps of the above-mentioned UV-responsive chitosan-coumarin oil-encapsulated microcapsules provided by the present invention, the mass ratio of (7-diethylaminocoumarin-4-methyl)succinimide ester in the volatile organic solution to chitosan in the aqueous solution is preferably 1:(0.5-2), more preferably 1:1.

[0075] In the preparation steps of the above-mentioned UV-responsive chitosan-coumarin oil-encapsulated microcapsules provided by the present invention, the emulsification method is preferably ultrasonic emulsification, the emulsification temperature is preferably 5-20℃, more preferably 10℃, and the emulsification time is preferably 5-20 min, more preferably 10 min; the stirring reaction temperature is preferably 5-20℃, more preferably 10℃, and the stirring reaction time is preferably 12-48 h, more preferably 24 h; the removal of volatile organic solvents is preferably by rotary evaporation; the dialysis is preferably carried out in a phosphate buffer solution with a pH value preferably 7.4, and the dialysis time is preferably 24-72 h, more preferably 48 h.

[0076] In the preparation method provided by the present invention, in step a), the mass ratio of the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and the UV-responsive chitosan-coumarin oil-encapsulated microcapsules in the suspension is preferably 1:(0.5-2), specifically 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.

[0077] In the preparation method provided by the present invention, in step a), the solvent in the suspension emulsion is preferably one or more of methanol, ethanol, dimethylformamide (DMF), acetone and ethyl acetate.

[0078] In the preparation method provided by the present invention, in step a), the concentration of the suspension is preferably 5 to 20 mg / mL, specifically 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, 10 mg / mL, 11 mg / mL, 12 mg / mL, 13 mg / mL, 14 mg / mL, 15 mg / mL, 16 mg / mL, 17 mg / mL, 18 mg / mL, 19 mg / mL or 20 mg / mL.

[0079] In the preparation method provided by the present invention, in step a), the substrate includes, but is not limited to, metal, ceramic, plastic or glass, which is preferably cleaned before being coated with the suspension.

[0080] In the preparation method provided by the present invention, in step a), the coating method is preferably spraying; the spraying pressure is preferably 1.1 to 10 bar; the spraying flow rate is preferably 150 to 1000 mL / min; the number of coatings is preferably 2 to 5 times, more preferably 3 times; the coating amount each time is preferably 0.5 to 2 mL, more preferably 1 mL; and the interval between two adjacent coatings is preferably 0.2 to 1 h, more preferably 0.5 h.

[0081] In the preparation method provided by the present invention, in step a), the drying temperature is preferably 10-40°C, more preferably 25°C (room temperature).

[0082] In the preparation method provided by the present invention, in step b), the solute component of the hydrophobic modified solution is preferably one or more of dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltrimethoxysilane and 1H,1H,2H,2H-perfluorodecyltrichlorosilane.

[0083] In the preparation method provided by the present invention, in step b), the solvent of the hydrophobic modified solution is preferably one or more of methanol, ethanol, toluene, n-hexane, n-octane and n-decane.

[0084] In the preparation method provided by the present invention, in step b), the concentration of the hydrophobic modified solution is preferably 2 to 5 wt%, specifically 2 wt%, 3 wt%, 4 wt%, or 5 wt%.

[0085] In the preparation method provided by the present invention, in step b), the immersion time is preferably 30 to 60 minutes, specifically 30 minutes, 40 minutes, 50 minutes or 60 minutes.

[0086] In the preparation method provided by the present invention, in step b), the drying temperature is preferably 10-40°C, more preferably 25°C (room temperature).

[0087] In the preparation method provided by the present invention, in step c), the lubricating oil is preferably one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil, and rapeseed oil, and the viscosity of the dimethyl silicone oil is preferably 20-150 cSt; the lubricating oil is preferably the same type as the lubricating oil encapsulated in the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and the ultraviolet light-responsive chitosan-coumarin oil-encapsulated microcapsules.

[0088] In the preparation method provided by the present invention, in step c), the coating method is preferably spraying; the spraying pressure is preferably 1.1 to 10 bar; the spraying flow rate is preferably 150 to 1000 mL / min; the draining method is preferably vertical placement; and the draining time is preferably 0.5 to 1 h.

[0089] The technical solution provided by this invention utilizes two types of oil-encapsulated microcapsules with temperature and UV light responsiveness to construct a rough-structured substrate. The substrate formed by the microcapsules is then hydrophobically modified, and finally, lubricating oil is infused onto the substrate, resulting in a super-lubricating coating with dual temperature and UV light responsiveness. In this invention, the temperature-responsive oil-encapsulated microcapsules in the substrate layer are chitosan-Pluronic F127 oil-encapsulated microcapsules, which rapidly shrink in size and release lubricating oil to replenish the oil layer lost on the surface through a sol-gel phase transition when the temperature rises. The UV-responsive oil-encapsulated microcapsules in the substrate layer are chitosan-coumarin oil-encapsulated microcapsules, which utilize the pyrolysis characteristics of coumarin under UV irradiation to rapidly release lubricating oil from the ruptured photoresponsive microcapsules. The coating provided by this invention can controllably release lubricating oil according to changes in temperature and UV irradiation, thereby maintaining the long-term lubricity of the coating surface and making the coating more durable under high temperature and strong UV irradiation conditions, greatly broadening the application prospects of the coating.

[0090] For clarity, the following examples will be used to provide a detailed description.

[0091] Example 1

[0092] according to Figure 2 The reaction route shown synthesizes Pluronic F127-dihydroxysuccinimide ester (F127-NHS), and the specific process includes:

[0093] 12.6 g of nonionic surfactant Pluronic F127 and 25 mg of 4-dimethylaminopyridine were dissolved in 35 mL of 1,4-dioxane, and 0.3 mL of triethylamine was added and stirred until homogeneous. Then, 300 mg of succinic anhydride was added under N2 protection, and the mixture was stirred and reacted at room temperature for 24 hours. After removing the organic solvent 1,4-dioxane by distillation under vacuum, the product was dissolved in diethyl ether, filtered, and then recrystallized after cooling. The precipitate was dried overnight to obtain product F127-COOH.

[0094] 10 g of the obtained product (F127-COOH) and 0.38 g of hydroxysuccinimide (NHS) were dissolved in 120 mL of dichloromethane at 10 °C. Then, 0.93 g of 1-ethyl-3-(3-dimethylaminopropyl)carbonimide hydrochloride (EDC·HCl) was added, and the mixture was stirred at 10 °C for 6 h. After that, the mixture was poured into deionized water at pH 4.0, extracted with dichloromethane, and rotary evaporated to obtain a yellow oil. The product was then purified on a silica gel column using a methanol / dichloromethane mixture with a volume ratio of 1:20. After solvent evaporation, a white solid Pluronic F127-dihydroxysuccinimide ester (F127-NHS) was obtained.

[0095] Example 2

[0096] according to Figure 3 The reaction route shown synthesizes temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules (Th@CS), and the specific process includes:

[0097] 150 mg of chitosan (number average molecular weight 500,000) and 800 mg of nonionic surfactant Tween 80 were dissolved in 150 mL of phosphate buffer solution at pH 7.4. 0.5 mL of perfluoropolyether Krytox oil and 150 mg of Pluronic F127-dihydroxysuccinimide ester (F127-NHS) prepared in Example 1 were dissolved in 25 mL of dichloromethane and added to the above-mentioned chitosan and Tween 80 mixture. The mixture was ultrasonically emulsified at 10 °C for 5 minutes, stirred for 24 hours, and then the dichloromethane was removed by rotary evaporation. After dialyzing in phosphate buffer solution (pH 7.4) for 12 hours, the mixture was lyophilized to obtain temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules (Th@CS).

[0098] The Th@CS prepared in this embodiment was observed by transmission electron microscopy (TEM), and the results were as follows: Figure 4 As shown, Figure 4These are TEM images of the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules provided in Example 2 of this invention. Image A was tested at 15°C, and Image B was tested at 65°C. The scale bar is 2 μm. Figure 4 It can be seen that the size of temperature-responsive chitosan-PluronicF127 oil-encapsulated microcapsules decreases significantly with increasing temperature.

[0099] The Th@CS prepared in this embodiment was placed in ethanol, and the release of lubricating oil at different temperatures (15℃, 45℃, 65℃) was detected. The results are as follows. Figure 5 As shown, Figure 5 This is a cumulative lubricant release curve in ethanol for temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules at different temperatures, as provided in Example 2 of this invention. Figure 5 It can be seen that the higher the temperature, the more lubricating oil is released from the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules.

[0100] Example 3

[0101] according to Figure 6 The reaction route shown synthesizes 7-diethylamino-4-hydroxymethylcoumarin. The specific process includes:

[0102] 4.44 g of oxidant SeO2 was added to 100 mL of dioxane solution containing 4.62 g of 7-diethylamino-4-methylcoumarin. The mixture was then stirred at 90 °C under nitrogen protection for 24 hours. The reaction mixture was then filtered, and the resulting dark brown residue was dissolved in 100 mL of a 1:1 mixture of tetrahydrofuran and ethanol. 1.3 g of reducing agent NaBH4 was slowly added, and the mixture was stirred at room temperature for 4 hours. The mixture was then neutralized with 1 M HCl, and the solvent was removed under vacuum. The residue was diluted with 50 mL of CH2Cl2 and extracted three times with 0.5 M K2CO3 solution. The organic extract was purified by a 2:1 mixture of petroleum ether and ethyl acetate to obtain a reddish-brown solid, 7-diethylamino-4-hydroxymethylcoumarin.

[0103] Example 4

[0104] according to Figure 7 The reaction route shown synthesizes (7-diethylaminocoumarin-4-methyl)succinimide ester (DEACMS-NHS), and the specific process includes:

[0105] 2.47 g of 7-diethylamino-4-hydroxymethylcoumarin, 2 g of succinic anhydride, and 0.61 g of catalyst 4-dimethylaminopyridine were dissolved in 100 mL of CHCl3. The reaction mixture was then refluxed and stirred at 55 °C for 24 hours. After removing CHCl3 by vacuum evaporation, the residual mixture was washed three times with 20 mL of 1 M HCl solution, then extracted with 50 mL of saturated NaHCO3 solution. The alkaline aqueous phase was washed with 50 mL of diethyl ether and acidified to pH 5.0 with 1 M HCl. The precipitate in the diethyl ether was then vacuum dried at 40 °C for 24 hours to obtain a yellow solid (7-diethylaminocoumarin-4-methyl)succinic acid (DEACMS).

[0106] 5 mmol DEACMS, 5 mmol EDC·HCl and 5 mmol NHS were added sequentially to 75 mL DMSO. After stirring at room temperature for 1 hour, the solvent was removed by vacuum distillation to obtain solid (7-diethylaminocoumarin-4-methyl)succinimide ester (DEACMS-NHS).

[0107] Example 5

[0108] according to Figure 8 The reaction route shown synthesizes UV-responsive chitosan-coumarin oil-encapsulated microcapsules (Li@CS), and the specific process includes:

[0109] 0.5 mL of perfluoropolyether Krytox oil and 150 mg of DEACMS-NHS prepared in Example 4 were dissolved in 25 mL of dichloromethane, and then added dropwise to 150 mL of phosphate buffer solution with pH = 7.4 containing 150 mg chitosan (CS) and 800 mg of nonionic surfactant Tween 80. The mixture was ultrasonically emulsified at 10 °C for 10 min, stirred for 24 h, and then the dichloromethane was removed by rotary evaporation. The resulting mixture was dialyzed in phosphate buffer solution with pH = 7.4 for 48 h and lyophilized to obtain UV-responsive chitosan-coumarin oil-encapsulated microcapsules (Li@CS).

[0110] The UV-responsive chitosan-coumarin oil-encapsulated microcapsules prepared in this embodiment undergo photolysis under UV irradiation. The photolysis mechanism is as follows: Figure 9 As shown, Figure 9 The photolysis mechanism diagram of the UV-responsive chitosan-coumarin oil-encapsulated microcapsules provided in Example 5 of this invention.

[0111] The Li@CS prepared in this embodiment was placed in ethanol, and the results were measured under ultraviolet light irradiation (wavelength 365 nm, light intensity 5 mW / cm²). 2 The results of lubricant release under light-free conditions are as follows: Figure 10 As shown, Figure 10 This is a cumulative release curve of lubricating oil in ethanol from UV-responsive chitosan-coumarin oil-encapsulated microcapsules under both light- and light-free conditions, as provided in Example 5 of this invention. Figure 10 It can be seen that with the increase of light exposure time, the amount of lubricating oil released first increases rapidly and then tends to stabilize, and the amount of lubricating oil released under light conditions is significantly greater than that under dark conditions.

[0112] Example 6

[0113] Preparation of temperature-UV dual-responsive superlubricating microcapsule-based composite coating:

[0114] The Th@CS prepared in Example 2 and the Li@CS prepared in Example 5 were dispersed in ethanol at a mass ratio of 1:1 to prepare a microcapsule solution with a concentration of 10 mg / mL. The solution was then uniformly sprayed onto a glass substrate that had been ultrasonically cleaned with acetone, ethanol, and water for 10 min. The solution was sprayed three times, with 1 mL of solution used each time and a spraying interval of 0.5 h.

[0115] Then, the substrate that has undergone the above treatment is immersed in a toluene solution of 1H,1H,2H,2H-perfluorooctyltrimethoxysilane with a mass concentration of 2 wt% for 60 min, and then dried at room temperature.

[0116] Finally, after spraying perfluoropolyether Krytox oil onto the substrate surface that has undergone the above treatment, and placing it vertically for 1 hour to remove excess oil, a temperature-UV dual-responsive superlubricating microcapsule-based composite coating is obtained.

[0117] At 65℃, wavelength 365nm, and light intensity 5mW / cm² 2 Under ultraviolet light irradiation, the water contact angle (CA) and sliding angle (SA) of the temperature-UV dual-response superlubricating microcapsule-based composite coating prepared in this embodiment were tested after being placed for different times. The results are as follows: Figure 11 As shown, Figure 11 This is a diagram showing the water contact angle and sliding angle of the temperature-UV dual-response superlubricating microcapsule-based composite coating provided in Embodiment 6 of the present invention after being placed under certain temperature and light conditions for different times. Figure 11 It can be seen that the coating has good stability under high temperature and long-term light exposure conditions, and the water contact angle and sliding angle remain basically unchanged.

[0118] 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 superlubricating microcapsule-based composite coating with dual temperature-UV light responsiveness, characterized in that, include: The microcapsule structure base layer, the hydrophobic modification layer composited on the microcapsule structure base layer, and the lubricating oil layer composited on the hydrophobic modification layer; the components of the microcapsule structure base layer include temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and UV-responsive chitosan-coumarin oil-encapsulated microcapsules.

2. The superlubricating microcapsule-based composite coating according to claim 1, characterized in that, The temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules are prepared by emulsifying, stirring, removing volatile organic solvents, dialysis, and lyophilizing a mixture of chitosan, surfactant, water, lubricating oil, Pluronic F127-dihydroxysuccinimide ester, and volatile organic solvents.

3. The superlubricating microcapsule-based composite coating according to claim 2, characterized in that, The ratio of chitosan, Pluronic F127-dihydroxysuccinimide ester and lubricating oil is (150-200) mg:(150-200) mg:(0.5-1) mL.

4. The superlubricating microcapsule-based composite coating according to claim 1, characterized in that, The UV-responsive chitosan-coumarin oil-encapsulated microcapsules are prepared by emulsifying, stirring, removing volatile organic solvents, dialysis, and lyophilizing a mixture of chitosan, surfactant, water, lubricating oil, (7-diethylaminocoumarin-4-methyl)succinimide ester, and volatile organic solvents.

5. The superlubricating microcapsule-based composite coating according to claim 4, characterized in that, The ratio of chitosan, (7-diethylaminocoumarin-4-methyl)succinimide ester and lubricating oil is (150-200) mg:(150-200) mg:(0.5-1) mL.

6. The superlubricating microcapsule-based composite coating according to claim 1, characterized in that, The mass ratio of the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules to the UV-responsive chitosan-coumarin oil-encapsulated microcapsules is 1:(0.5-2).

7. The superlubricating microcapsule-based composite coating according to claim 1, characterized in that, The lubricating oil encapsulated in the temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and the UV-responsive chitosan-coumarin oil-encapsulated microcapsules is one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil, and rapeseed oil.

8. The superlubricating microcapsule-based composite coating according to claim 1, characterized in that, The hydrophobic modification layer comprises one or more of the following: dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, 1H,1H,2H,2H-perfluorooctyltrimethoxysilane, and 1H,1H,2H,2H-perfluorodecyltrichlorosilane.

9. The superlubricating microcapsule-based composite coating according to claim 1, characterized in that, The lubricating oil in the lubricating oil layer is one or more of dimethyl silicone oil, perfluoropolyether Krytox oil, palm oil, olive oil, almond oil, and rapeseed oil.

10. A method for preparing a superlubricating microcapsule-based composite coating with temperature-UV dual responsiveness as described in any one of claims 1 to 9, characterized in that, Includes the following steps: a) A suspension containing temperature-responsive chitosan-Pluronic F127 oil-encapsulated microcapsules and UV-responsive chitosan-coumarin oil-encapsulated microcapsules was coated on the surface of a substrate and dried to form a microcapsule structure substrate layer. b) Immerse the substrate treated in step a) into the hydrophobic modification solution, remove and dry it to form a hydrophobic modification layer; c) Coating the surface of the hydrophobic modified layer with lubricating oil to form a lubricating oil layer, thereby obtaining a super-lubricating microcapsule-based composite coating with dual temperature-UV light responsiveness.

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