CN115521640B

CN115521640B - Atomic oxygen-resistant micro-nano porous coating and preparation method thereof

Info

Publication number: CN115521640B
Application number: CN202210207875.3A
Authority: CN
Inventors: 谷红宇; 唐登航; 章俞之; 吕少波; 张锦麟; 马佳玉; 李昊耕; 宋力昕
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Institute of Ceramics of CAS
Priority date: 2022-03-03
Filing date: 2022-03-03
Publication date: 2023-06-06
Anticipated expiration: 2042-03-03
Also published as: CN115521640A

Abstract

The invention discloses an atomic oxygen antigen micro-nano porous coating and a preparation method thereof. The atomic oxygen antigen micro-nano porous coating comprises the following components: the porous micro-nano structure coating is formed on the surface of the polymer matrix and is formed by bonding nano oxide particles and a silane coupling agent; the silane coupling agent is a silane coupling agent with amino; the polymer matrix is a modified polymer matrix with carboxyl groups. The coating consists of a skeleton consisting of inorganic oxide nano particles, is of a micro-nano structure with nano pores, has obviously improved flexibility, has excellent cracking resistance and has excellent atomic oxygen corrosion resistance; meanwhile, the coating has the characteristic of replaceable nano skeleton composition, can meet the functional requirements of anti-reflection, anti-static and the like of the atomic oxygen prevention coating, has low raw materials and preparation cost, is easy to implement and operate, and can be widely applied to low-orbit spacecrafts influenced by atomic oxygen corrosion in the aerospace field.

Description

Atomic oxygen-resistant micro-nano porous coating and preparation method thereof

Technical Field

The invention relates to an atomic oxygen resistant micro-nano porous coating capable of being functionally designed and a preparation method thereof, which are mainly applied to spacecrafts eroded by atomic oxygen in a low earth orbit space environment, and belong to the technical field of application of aerospace materials.

Background

The polymer material has the characteristics of small density, high strength, good flexibility, easy processing and the like, is an important component part in various fields of medical treatment, electronic information, construction, packaging, aerospace and the like, and has played a great role in various aspects of production, life, scientific research, national defense and the like as an important material closely related to national economy, high and new technology and modern life. For example, polyimide (PI) materials are widely applied to the field of aerospace material application due to the high-strength aromatic heterocyclic structure, excellent high-low temperature alternating stability, mechanical properties, corrosion resistance, irradiation and other properties, and are irreplaceable key materials in heat insulation blankets in spacecraft heat control, solar panels in power supply systems and lightweight structural designs. However, in the space where the low earth orbit is located, atomic oxygen is considered to be the most serious spatial environmental factor for spacecraft threat. The atomic oxygen has stronger oxidizing property, and can oxidize and erode polymers including polyimide, so that the structure and the performance of the polymers are eroded and destroyed to lose effectiveness, and the service life of the low-orbit spacecraft is greatly reduced. The rapid development of space stations, wind-cloud satellites and other low-orbit spacecrafts gradually highlights the importance of atomic oxygen protection technology.

When the low-orbit spacecraft flies in an orbit at a high speed, atomic oxygen with high flux in the space bombards the surface of the spacecraft, the energy of the atomic oxygen can reach 4-5 eV, and polymer materials on the surface are easily oxidized and eroded, so that the atomic oxygen is degraded and disabled. Atomic oxygen protection is generally achieved by introducing inert substances that do not react with atomic oxygen, and isolating the ingress of atomic oxygen. The means for introducing the atomic oxygen inert substance includes direct introduction or indirect reaction with atomic oxygen.

The existing atomic oxygen protection technology can be divided into a matrix modification technology and a surface layer protection technology according to the part where the atomic oxygen inert substance is introduced. The method for modifying the whole matrix is disclosed in patent (104356413A) for preparing an anti-proton oxygen polyimide hybrid film containing octa-cage silsesquioxane structure, which is characterized in that diamine POSS is introduced into a polyimide molecular main chain by adopting a copolycondensation method, and finally the polyimide film containing octa-cage silsesquioxane is obtained. The introduction of the modifying group needs to change the monomer of the corresponding polyimide, so as to achieve the aim of introducing the modifying group on the main side chain and the side chain of the polymer after polymerization, but the mechanical property of the polyimide matrix is reduced. Under the action of bending and heat stress, the polyimide modified matrix is easy to peel and crack, the compactness is easy to damage, and the protection performance is poor. In order to not change the original excellent performance of the polyimide matrix, protection is another protection strategy on the surface of the matrix, and extensive research and application are obtained. Surface protection mainly consists of two main categories, surface modification and coating protection. Both the surface modification layer and the organic coating generally have the characteristics of high bonding strength with the substrate and excellent flexibility, but have the risk of being difficult to meet the special requirements of certain application parts, such as increasing the transmittance, preventing static electricity, shielding ultraviolet, and reducing the flexibility and bonding strength with the substrate after being subjected to the action of atomic oxygen. The inorganic anti-atomic oxygen coating can realize the appointed additional functions by selecting corresponding materials, such as silicon dioxide and indium tin oxide coating can respectively realize the additional functions of anti-reflection, anti-static and ultraviolet shielding; meanwhile, the inorganic coating is easier to realize more excellent atomic oxygen resisting performance. However, the inorganic coating has the problems of poor flexibility and weak binding force, and is easy to peel and crack under the action of bending stress, thermal stress and the like, so that the anti-atomic oxygen performance of the inorganic coating is obviously reduced, and the application of the inorganic coating is greatly limited. Therefore, if the problem that the inorganic coating is easy to peel and crack can be solved, the inorganic coating has the same excellent flexibility and bonding strength with a matrix as the organic coating and the modified layer, and the excellent AO (oxygen-free) resistance and mechanical property can be obtained, so that the requirements of long service life, light weight, high reliability and easy implementation of the atomic oxygen resistance protective coating in the aerospace field can be met. Therefore, the silicon dioxide anti-atomic oxygen coating with the micro-nano porous structure solves the problem that a compact silicon dioxide coating is easy to fall off and crack, and has important significance and practical requirements.

Disclosure of Invention

Aiming at the defects existing in the prior art, different from the thought of pursuing densification by general physical isolation, based on the characteristic that AO high activity tends to adsorb bond, the invention creatively provides an antigen oxygen micro-nano porous coating capable of being functionally designed and a preparation method thereof based on a novel strategy of regulating and controlling an atomic oxygen resistant coating micro-nano structure, which is different from the thought of improving the density of an inorganic coating to improve the AO resistance. The coating has relatively excellent atomic oxygen resistance, good flexibility and spalling resistance; the composition of the coated nano-oxide spheres is replaceable so as to realize different functionalization; raw materials and preparation cost are low; easy to implement and operate. In the patent, the aperture of the atomic oxygen resistant micro-nano porous coating is adjusted by controlling the particle size of the powder, and the porosity of the coating is adjusted by controlling the particle size of the powder and the addition amount of the crosslinking agent.

The invention adopts the technical proposal for solving the problems that:

in one aspect, the present invention provides an atomic oxygen resistant micro-nano porous coating, comprising: the porous micro-nano structure coating is formed on the surface of the polymer matrix and consists of nano oxide particles; the polymer matrix is a modified polymer matrix with carboxyl groups. Preferably, the atomic oxygen micro-nano porous coating comprises: the porous micro-nano structure coating is formed on the surface of the polymer matrix and is formed by bonding nano oxide particles and a silane coupling agent; the silane coupling agent is a silane coupling agent with amino; the polymer matrix is a modified polymer matrix with carboxyl; and, the silane coupling agent reacts with the polymer matrix to form a bonding layer. For example, the thickness of the bonding layer is 0 to 1000nm, preferably 20nm to 1000nm.

In the invention, the acting force between the porous micro-nano structure coating layer formed by bonding nano oxide particles and the silane coupling agent and the modified polymer matrix with carboxyl is mainly from the bonding of the silane coupling agent with amino and the modified matrix with carboxyl. The antigen atomic oxygen micro-nano porous coating material which can be functionally designed is suitable for being directly coated on a substrate to be used as an atomic oxygen resistant coating or being coated on the surfaces of other atomic oxygen resistant materials to be used as a functional layer.

Preferably, the nano oxide particles comprise at least one of silicon dioxide, indium tin oxide and zinc oxide; the nano oxide particles are spherical nano particles or quasi-spherical nano particles, and the particle size is 7 nm-30 nm.

Preferably, the silane coupling agent is at least one selected from 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, N-aminoethyl-3-aminopropyl triethoxysilane, and 3-aminopropyl methyldiethoxysilane, preferably 3-aminopropyl triethoxysilane.

Preferably, the ratio of the nano-oxide particles to the silane coupling agent is (25-150) mg: (0-10) mu L. Preferably, the ratio of the nano-oxide particles to the silane coupling agent is 50mg: (0-10) mu L, preferably the content of the silane coupling agent is not 0. More preferably, the ratio of the nano-oxide particles to the silane coupling agent is 50mg: (1-10) mu L.

Preferably, the surface of the nano oxide particles is subjected to alkylation treatment; the surface modifier used in the alkylation treatment is at least one selected from hexamethyldisilazane, chlorosilane and 3-aminopropyl triethoxysilane; preferably, the ratio of the nano-oxide particles to the surface modifier is (25-150) mg: (10-100) mu L.

Preferably, the modified polymer matrix with carboxyl is prepared from an imide ring-or/and ester group-containing polymer through alkali/acid two-step treatment; more preferably, the imide ring-containing or/and ester group-containing polymer is polyimide, polyester, or polyethylene terephthalate; the alkali/acid two-step treatment comprises: the polymer matrix is firstly reacted and modified in alkali solution for 0.5 to 3 hours at room temperature, and then reacted and modified in acid solution for 0.5 to 3 hours; preferably, the alkali solution is sodium hydroxide solution with the concentration of 0.5-2 mol/L, and the acid solution is acetic acid solution with the concentration of 0.5-2 mol/L.

On the other hand, the invention also provides a preparation method of the atomic oxygen antigen micro-nano porous coating, which comprises the following steps:

(1) Mixing nano oxide particles with a solvent, adding a surface modifier, performing ultrasonic treatment and stirring treatment to complete alkylation treatment, and obtaining nano oxide particle dispersion liquid;

(2) Adding a silane coupling agent into the nano oxide particle dispersion liquid to obtain a mixed solution;

(3) And (3) coating the mixed solution on the surface of the modified polymer matrix with carboxyl to form a wet film, and performing heat treatment in an air atmosphere to obtain the atomic oxygen resistant micro-nano porous coating.

Preferably, the solvent is at least one selected from water, alcohol and ketone; the ketone is ketone solvent containing ketone carbonyl, preferably at least one of acetone, butanone, methyl isobutyl ketone and cyclohexanone.

Preferably, the frequency of the ultrasonic treatment is more than 30kHz and the time is more than 1h; the rotation speed of the stirring treatment is 200-400 rpm, and the time is 2-22 hours; the total time of ultrasonic treatment and stirring treatment=total alkylation time is 4-24 hours, and 12 hours is preferable.

Preferably, the coating method comprises the following steps: one of spin coating, drip coating, spray coating, knife coating, dip-coating; the number of the coating is 3 to 9, preferably 6.

Preferably, the temperature of the heat treatment is one temperature value or gradient temperature formed by more than two temperature values within 80-250 ℃, and the total treatment time is 3-12 hours.

The beneficial effects are that:

(1) The antigen sub-oxygen micro-nano porous coating which can be functionally designed has excellent antigen sub-oxygen performance due to the fact that the main framework of the coating is an inorganic oxide nano material;

(2) Unlike available dense inorganic coating with easy peeling and cracking, the coating material has obviously raised flexibility and high bonding strength and excellent peeling preventing performance, and has obviously raised flexibility and capacity of preventing cracking during cold-hot alternation and bending, and the coating is combined with polyimide substrate via the modifying layer;

(3) The composition of the coated nanoparticles can be replaced to achieve functional designability; the coating is suitable for being directly coated on a substrate to be used as an atomic oxygen resistant coating or being coated on the surfaces of other atomic oxygen resistant coatings to be used as a functional layer;

(4) The raw materials and the preparation cost of the coating are low, the requirements on equipment are low, the process is simple and the operation is convenient.

Drawings

FIG. 1 is an electron micrograph of the surface of an atomic oxygen resistant silica micro-nano porous coating of example 1, wherein the micro-nano structure of the coating is formed by arranging spherical or nearly spherical nano particles after the coating is formed, agglomerates of the multi-particles have certain nanoscale mesoporous pores inside, and larger macroporous pores are formed among the agglomerates;

FIG. 2 is an EDS plot of the surface of an atomic oxygen resistant silica micro-nano porous coating of example 1, which coating is seen to contain three elements, carbon, nitrogen, oxygen and silicon, wherein the silicon element is 10.08at%;

FIG. 3 is a photograph of a glass of the atomic oxygen resistant silica micro-nano porous coating of example 1 after a bending test, wherein the photograph shows that the coating has excellent flexibility and bonding strength with a substrate without peeling and cracking after repeated bending for 180 degrees and 500 times on a cylinder with the diameter of 2 mm;

FIG. 4 is a photograph of a photo of the atomic oxygen resistant silica micro-nano porous coating in example 1 after a cold and hot cycle test, wherein the photograph shows that the coating has no peeling and cracking after being respectively cycled for 100 times in a cold and hot environment with the temperature of +/-100 ℃, and has excellent thermal stress resistance;

FIG. 5 is a photograph of a glass of the atomic oxygen resistant silica micro-nano porous coating of example 1 after the adhesion is tested by a cross-cut method, and the cut part of the obtained coating is completely smooth without any grid delamination, the adhesion is the highest grade 0, and the bonding strength of the coating and the matrix is high;

FIG. 6 is a graph showing the Transmittance curve (wherein the abscissa represents Wavelength/nm and the ordinate represents Transmittance transmissibility/%); from the graph, the silicon dioxide micro-nano porous coating with atomic oxygen resistance has an anti-reflection function within the range of 700-1000 nm, and the maximum anti-reflection is 4.99%;

FIG. 7 is a photo-mirror comparison of the atomic oxygen resistant silica micro-nano porous coating in example 1 before and after the ground atomic oxygen simulation test, and it can be known from the photo-mirror comparison that the morphology of the coating is not damaged obviously after atomic oxygen erosion, no spalling and cracking phenomenon occurs, and the stability of the atomic oxygen effect is strong;

FIG. 8 is a photograph of a mirror of the atomic oxygen resistant silica micro-nano porous coating of example 2 after the adhesion was tested by a cross-cut method, and it is known from the figure that the cut intersections of the resulting coating have small pieces of peeling off, and the adhesion is 1 grade;

FIG. 9 is a photomicrograph of the atomic oxygen resistant silica micro-nano porous coating of example 3, from which it is seen that the resulting coating has poor uniformity, discontinuities and cracks. The pictures show that the nano silicon dioxide without surface modification has poor film forming property, and the surface modification step is indispensable;

FIG. 10 is a photograph of a mirror of an atomic oxygen resistant silica micro-nano porous coating of example 6, from which it is seen that 30nm silica produces a coating with poor uniformity and uncovered micro-domains;

FIG. 11 is a photograph of a mirror of an atomic oxygen resistant silica micro-nano porous coating of example 7, from which it is seen that the coating prepared from 50nm silica has poor uniformity and an uncovered micro-region is present;

FIG. 12 is a photograph of an atomic oxygen test of a silica micro-nano porous coating with atomic oxygen in example 9, wherein the coating has obvious cracks after the atomic oxygen test, and a small excess of APTES can cause the cracks of the coating;

FIG. 13 is a photograph of an atomic oxygen test of a silica micro-nano porous coating of example 10, wherein the coating has obvious cracks after the atomic oxygen test, and the more excessive APTES can also cause the cracks of the coating;

FIG. 14 is a graph showing that the ITO micro-nano porous coating with atomic oxygen resistance in example 11 has no obvious cracks and has uniform and smooth surface;

FIG. 15 is a schematic structural diagram of a functionalized design of an atomic oxygen resistant micro-nano porous coating according to the present invention, wherein it is known that the coating can be directly coated on a substrate to be used as an atomic oxygen protective coating or coated on the surface of other atomic oxygen resistant coatings to be used as a functional layer. The coating is internally formed by a skeleton consisting of inorganic oxide nano particles, and micro-nano structures of nano-scale pores are arranged among the particle skeleton; preferably, the coating and the substrate are connected through a bonding layer (or modified bonding layer), and the bonding strength is high.

Detailed Description

The invention is further illustrated by the following embodiments, which are to be understood as merely illustrative of the invention and not limiting thereof.

In the present disclosure, the atomic oxygen resistant micro-nano porous coating is composed of a skeleton composed of inorganic oxide nanoparticles and a silane coupling agent, is a micro-nano structure with nanopores, has significantly improved flexibility, excellent anti-cracking performance, and has excellent atomic oxygen resistant erosion performance. Meanwhile, the coating has the characteristic of replaceable nano skeleton composition, can meet the functional requirements of anti-reflection, anti-static and the like of the atomic oxygen prevention coating, has low raw materials and preparation cost, is easy to implement and operate, and can be widely applied to low-orbit spacecrafts influenced by atomic oxygen corrosion in the aerospace field.

In alternative embodiments, the diameter of the nano-oxide may be in the range of 7 to 50nm diameter, spherical or spheroidal nanoparticles of one or more diameters. The nano-oxides have replaceability so as to realize different functionalization, and the nano-powder is oxide and doped powder taking the oxide as a matrix, including but not limited to: silicon dioxide, indium tin oxide, zinc oxide, and the like.

In an alternative embodiment, the silane coupling agent is primarily an amino hydrocarbyl silane having an amino group, is one or a mixture of more of 3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane, N-aminoethyl-3-aminopropyl triethoxy silane and 3-aminopropyl methyl diethoxy silane according to any proportion. Preferably the aminoalkylsilane is 3-aminopropyl triethoxysilane.

In an alternative embodiment, the polymer matrix is a polymer containing imide rings, ester groups, and the like such as polyimide, polyester, and the like, which can generate carboxyl groups on the surface after two-step liquid phase treatment of alkali/acid, including but not limited to: polyimide, polyethylene terephthalate, and the like.

In an alternative embodiment, the thickness of the atomic oxygen micro-nano porous coating is no more than 1 μm.

In one embodiment of the present invention, the nano-oxide powder is dispersed in a suitable solvent to obtain a dispersion liquid having good dispersion. Adding a certain amount of amino alkyl silane as a cross-linking agent into the dispersion liquid, coating the mixture on the surface of a polymer matrix modified by alkali/acid or other coating to form a wet film, and finally performing heat treatment in an air atmosphere to obtain the anti-atomic oxygen micro-nano porous coating capable of being functionally designed.

The preparation method of the anti-proton oxygen micro-nano porous coating which can be functionally designed is exemplified by spherical silicon dioxide with the particle size of 15nm, hexamethyldisilazane, acetone, 3-aminopropyl triethoxysilane and polyimide film modified by alkali acid which are respectively used as oxide nano powder, a surface modifier, a solvent, a cross-linking agent and a polymer matrix.

The oxide nano powder is dispersed in a proper dispersion solvent, and the surface modifier is added and then the surface of the powder is modified by ultrasonic and stirring, so that the nano powder dispersion liquid with good dispersion can be obtained. Wherein, the ratio of the oxide nano powder to the dispersion solvent is 5-30 mg/mL, and the mass concentration is preferably 10mg/mL. The ratio of the surface modifier to the solvent is 2 to 20. Mu.L/mL, preferably 10. Mu.L/mL. The ultrasound process should be conducted at a frequency of greater than 30kHz for a period of greater than 1 hour. Each time for 1 hour at 60kHz, a total of 2 times is preferred. Specifically, the preparation of a well-dispersed silica ketone solution comprises: 25 to 150mg (e.g., 50 mg) of 15nm silica powder was stirred into 5mL of acetone. 10 to 100. Mu.L (e.g., 50. Mu.L) of hexamethyldisilazane is then added. After 1 hour of ultrasonic dispersion at room temperature of 60kHz, stirring is carried out at 300rpm for 12 hours, then ultrasonic treatment is carried out for 1 hour, and finally, a good silica ketone solution can be dispersed.

Adding a certain amount of amino alkyl silane as a cross-linking agent into the oxide nano powder dispersion liquid, coating the mixture on the surface of a polymer matrix modified by alkali/acid or other atomic oxygen resistant coatings to form a wet film, and finally performing heat treatment in an air atmosphere to obtain the atomic oxygen resistant micro-nano porous coating capable of being functionally designed. The ratio of the amount of the crosslinking agent amino hydrocarbyl silane to the solvent may be 0 to 2. Mu.L/mL, preferably 1. Mu.L/mL. According to the scheme, the method for modifying the matrix polymer by the alkali/acid two steps comprises the steps of placing the matrix in a 1mol/L sodium hydroxide solution for modification for 1h, and repeatedly cleaning with deionized water and absolute ethyl alcohol to remove residual alkali liquor; then placing the mixture in 1mol/L acetic acid solution for modification for 1h, and repeatedly cleaning the mixture by using deionized water and absolute ethyl alcohol after the modification is finished so as to remove residual acid liquor. And finally drying in air for standby.

Specifically, 0 to 10. Mu.L (e.g., 5. Mu.L) of 3-aminopropyl triethoxysilane is added to the well-dispersed silica ketone solution. After stirring for 10min, 4 drops of the solution were added dropwise each time and spin-coated on a polyimide film substrate modified with 20X 20mm alkali acid at a rotation speed of 1000rpm for 12s, for a total of 6 times, followed by heat treatment in an air atmosphere at 80, 110, 150℃for 1h, 3h, respectively. Finally, the antigen sub-oxygen micro-nano porous coating with the functional design can be obtained. The coating method may be any one of a spin coating method, a drop coating method, a spray coating method, a blade coating method, and a dip-coating method.

The method of the invention has the advantages that: the commercial nano oxide powder (such as silicon dioxide) is adopted as the raw material, the variety and granularity of the raw material can be selected in a wide range, and the price is low; by modifying the surface of nano oxide (such as silicon dioxide), the dispersibility is greatly improved, so that the film is uniform and no obvious agglomeration occurs. The use of the silane coupling agent with amino hydrocarbon not only increases the bonding between nano particles, so that the flexibility of the coating is obviously improved, but also generates firm bonding between the coating and the surface of the polyimide after surface modification, and obviously improves the adhesive force of the coating. The invention is based on a novel strategy for regulating and controlling the micro-nano structure of the atomic oxygen resistant coating, and the related coating consists of a skeleton consisting of inorganic oxide nano particles, is a micro-nano structure with nano pores, has obviously improved flexibility, excellent cracking resistance and excellent atomic oxygen resistance; meanwhile, the coating has the characteristic of replaceable nano skeleton composition, can meet the functional requirements of anti-reflection, anti-static and the like of the atomic oxygen prevention coating, has low raw materials and preparation cost, is easy to implement and operate, and can be widely applied to low-orbit spacecrafts influenced by atomic oxygen corrosion in the aerospace field.

And (3) testing: the atomic oxygen corrosion resistance of the sample is characterized by adopting ground atomic oxygen simulation test equipment, and the mass loss is measured by using a precision balance; adopting space cold and hot circulation simulation test equipment to represent the thermal stress cracking resistance of the sample; testing bending stress cracking resistance of a sample by adopting a QTY-10A bending tester; the bonding strength between the coating and the substrate is characterized by adopting a hundred-blade dicing method test, specifically, 3M610 adhesive tape is used for sticking and observing after dicing; the surface topography of the sample was observed using a scanning electron microscope.

The present invention will be further illustrated by the following examples. It is also to be understood that the following examples are given solely for the purpose of illustration and are not to be construed as limitations upon the scope of the invention, since numerous insubstantial modifications and variations will now occur to those skilled in the art in light of the foregoing disclosure. The specific process parameters and the like described below are also merely examples of suitable ranges, i.e., one skilled in the art can make a suitable selection from the description herein and are not intended to be limited to the specific values described below.

Example 1

According to the technical scheme of the invention, the atomic oxygen resistant micro-nano porous coating material is prepared, when the nano oxide is silicon dioxide, the coating system takes acetone as a solvent, wherein the concentration of the silicon dioxide, the surface modifier hexamethyldisilazane and the 3-aminopropyl triethoxysilane is respectively 10mg/mL, 10 mu L/mL and 1 mu L/mL. 50mg of 15nm silica powder was stirred into 5mL of acetone. Subsequently 50. Mu.L of hexamethyldisilazane was added with stirring for surface modification. The mixed solution is ultrasonically dispersed for 1h at 25 ℃ at 60kHz, then stirred for 12h at 300rpm, and then is further ultrasonically treated for 1h, so that a well-dispersed silicon dioxide acetone solution can be obtained. To this solution was added 5. Mu.L of 3-aminopropyl triethoxysilane. After stirring for 10min, 4 drops of the solution were added dropwise at each time, spin-coated for 12s on a polyimide film substrate modified with 20X 20mm alkali acid at a rotation speed of 1000rpm, and then subjected to heat treatment for 1h, 1h and 3h respectively in an air atmosphere at 80, 110 and 150 ℃. Finally, the antigen sub-oxygen micro-nano porous coating with functional design can be obtained.

Under the system with the concentration of 3-aminopropyl triethoxysilane being 1 mu L/mL, the accumulated dosage is 5.22 multiplied by 10 ²¹ atoms/cm ² After the ground atomic oxygen simulation test of (2), the mass loss per unit area of the PI sample protected by the porous silica coating is 0.15mg/cm ² . Through 500 times

After the cylinder is bent or subjected to 100 times of +/-100 ℃ cold and hot cycle test, the appearance structure is not obviously damaged, and the situation of peeling and cracking is avoided. The coating adhesion grades measured by the cross-hatch method are all the highest grade 0, the cutting part is completely smooth, and no grid layering exists; the transmittance is increased within the range of 700-1000 nm, and the maximum anti-reflection is 4.99%.

Example 2

The preparation process of the atomic oxygen resistant micro-nano porous coating in the present example 2 is different from that of the example 1 only in that: no 3-aminopropyl triethoxysilane was added. In this example, the binding force of the coating without the addition of 3-aminopropyl triethoxysilane to the substrate was reduced and the cross-hatch rating was reduced to level 1.

Example 3

The preparation process of the atomic oxygen resistant micro-nano porous coating in this example 3 is different from that of example 1 only in that: no surface modifier hexamethyldisilazane was added. The coating in this example was poor in uniformity, discontinuous and cracked. As shown in fig. 9, the nano silica without surface modification is poor in film forming property, and the surface modification step is indispensable.

Example 4

The preparation process of the atomic oxygen resistant micro-nano porous coating in this example 4 is different from that of example 1 only in that: siO (SiO) ₂ The particle size was 7nm.

Example 5

The preparation process of the atomic oxygen resistant micro-nano porous coating in this example 5 is different from that of example 1 only in that: siO (SiO) ₂ The particle size was 20nm.

Example 6

The preparation process of the atomic oxygen resistant micro-nano porous coating in this example 6 is different from that of example 1 only in that: siO (SiO) ₂ The particle size was 30nm. As shown in FIG. 10, 30nm silica produced coatings with poor uniformity and uncovered micro-domains.

Example 7

The preparation process of the atomic oxygen resistant micro-nano porous coating in this example 7 is different from that of example 1 only in that: siO (SiO) ₂ The particle size was 50nm. As shown in FIG. 11, 30nm silica produced coatings with poor uniformity and uncovered micro-domains.

Example 8

The preparation process of the atomic oxygen resistant micro-nano porous coating in this example 8 is different from that of example 1 only in that: APTES was added in an amount of 10. Mu.L.

Example 9

The preparation process of the atomic oxygen antigen micro-nano porous coating in this example 9 is described with reference to example 1, and only the difference is that: APTES was added in an amount of 15. Mu.L. As shown in fig. 12, after atomic oxygen testing, the coating developed significant cracks, indicating that a small excess of APTES resulted in the coating cracking.

Example 10

The preparation process of the atomic oxygen resistant micro-nano porous coating in this example 10 is different from that of example 1 only in that: APTES was added in an amount of 50. Mu.L. As shown in fig. 13, after atomic oxygen testing, the coating developed significant cracks, indicating that a greater excess of APTES also resulted in the development of cracks in the coating.

Example 11

The preparation process of the atomic oxygen resistant micro-nano porous coating in this example 11 is different from that of example 1 only in that: the alternative nano powder is Indium Tin Oxide (ITO), APTES and hexamethyldisilazane are not added, the solvent is water, and the matrix is polyimide material coated with atomic oxygen protection layer. As shown in FIG. 14, the prepared ITO functional layer has no obvious cracks, and the surface is uniform and smooth. The ITO functional layer has the same excellent adhesive force and flexibility as the silicon dioxide coating, and simultaneously endows the material with antistatic function, and the sheet resistance is 80kΩ/≡s, so that the aerospace application requirement is met.

The present invention can be realized by the respective raw materials listed in the present invention, and the upper and lower limits and interval values of the respective raw materials, and the upper and lower limits and interval values of the process parameters, and examples are not shown here. The data of the listed examples are shown in Table 1:

finally, what is necessary here is: the above embodiments are only for further detailed description of the technical solutions of the present invention, and should not be construed as limiting the scope of the present invention, and some insubstantial modifications and adjustments made by those skilled in the art from the above description of the present invention are all within the scope of the present invention.

Claims

1. The preparation method of the atomic oxygen antigen micro-nano porous coating is characterized by comprising the following steps of:

(1) Mixing nano oxide particles with a solvent, adding a surface modifier, performing ultrasonic treatment and stirring treatment to complete alkylation treatment, and obtaining nano oxide particle dispersion liquid; the nano oxide particles are spherical nano particles or quasi-spherical nano particles, and the particle size is 7 nm-20 nm;

(2) Adding a silane coupling agent into the nano oxide particle dispersion liquid to obtain a mixed solution; the ratio of the nano oxide particles to the silane coupling agent is (25-150) mg: (0 to 10 and not 0) μL;

(3) Coating the mixed solution on the surface of a modified polymer matrix with carboxyl to form a wet film, and performing heat treatment in an air atmosphere to obtain an atomic oxygen resistant micro-nano porous coating;

the atomic oxygen resisting micro-nano porous coating is a porous micro-nano structure coating formed on the surface of a polymer matrix and formed by bonding nano oxide particles and a silane coupling agent, wherein the silane coupling agent is a silane coupling agent with amino groups; and the silane coupling agent reacts with the polymer matrix to form a bonding layer; the surfaces of the nano oxide particles are subjected to alkylation treatment; the surface modifier used in the alkylation treatment is selected from hexamethyldisilazane;

the polymer matrix is a modified polymer matrix with carboxyl, and the modified polymer matrix with carboxyl is prepared from an imide ring-containing or/and ester group-containing polymer through alkali/acid two-step treatment, wherein the imide ring-containing or/and ester group-containing polymer is polyimide, polyester or polyethylene terephthalate.

2. The method of claim 1, wherein the nano-oxide particles comprise at least one of silica, indium tin oxide, and zinc oxide.

3. The method of claim 1, wherein the bonding layer has a thickness of no more than 1000nm.

4. A method of producing according to claim 3, wherein the thickness of the bonding layer is 20nm to 1000nm.

5. The method according to claim 1, wherein the silane coupling agent is at least one selected from the group consisting of 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, N-aminoethyl-3-aminopropyl triethoxysilane, and 3-aminopropyl methyldiethoxysilane.

6. The method of any one of claims 1-5, wherein the ratio of the nano-oxide particles to the surface modifier is (25-150) mg: (10-100) mu L.

7. The method of any one of claims 1-5, wherein the alkali/acid two-step treatment comprises: the polymer matrix is firstly reacted and modified in alkali solution for 0.5 to 3 hours at room temperature, and then reacted and modified in acid solution for 0.5 to 3 hours.

8. The method according to claim 7, wherein the alkali solution is sodium hydroxide solution having a concentration of 0.5 to 2mol/L, and the acid solution is acetic acid solution having a concentration of 0.5 to 2 mol/L.

9. The method according to claim 1, wherein the solvent is at least one selected from the group consisting of water, alcohol, and ketone; the ketone is ketone solvent containing ketone carbonyl;

the frequency of the ultrasonic treatment is more than 30kHz, and the time is more than 1h; the rotation speed of the stirring treatment is 200-400 rpm, and the time is 2-22 hours; the total time of the ultrasonic treatment and the stirring treatment=total alkylation time is 4 to 24 hours.

10. The method according to claim 9, wherein the ketone is at least one of acetone, butanone, methyl isobutyl ketone, and cyclohexanone.

11. The method of claim 1, wherein the coating comprises: one of spin coating, drip coating, spray coating, knife coating, dip-coating; the number of the coating is 3 to 9.

12. The method of claim 11, wherein the number of applications is 6.

13. The method according to claim 1, wherein the heat treatment is performed at a temperature of 80 to 250 ℃ or at a gradient temperature formed by two or more temperature values, and the total treatment time is 3 to 12 hours.