CN116376430B - Anti-icing coating based on oil-based magnetized microneedles, and preparation method and application thereof - Google Patents

Abstract

The application discloses an anti-icing coating based on oil-based magnetized microneedles, and a preparation method and application thereof, wherein the preparation method of the anti-icing coating comprises the following steps: s1: pretreating the surface of the base material to enable the roughness of the surface of the base material to be 2-15 mu m; s2: adding the oil-based nano ferroferric oxide magnetic liquid into diluted resin, and uniformly dispersing to prepare a colloid solution; s3: transferring the colloid solution to the surface of a substrate, and forming a magnetic microneedle array on the surface of the substrate under the action of a magnetic field with the magnetic field strength of 3000-5000 gauss; s4: and (3) curing and forming under the action of a magnetic field with the magnetic field strength of 3000-5000 gauss to obtain the anti-icing coating. The invention can realize the preparation on the surface of a common base material, has extremely low ice adhesion capability and extremely good photo-thermal effect, and further delays the icing time to a great extent.

Description

An anti-icing coating based on oil-based magnetized microneedles and its preparation method and application

Technical field

The invention belongs to the technical field of functional material preparation. Specifically, the invention relates to an anti-icing coating based on oil-based magnetized microneedles and its preparation method and application.

Background technique

From transportation systems to infrastructure to energy systems, icing often causes catastrophic safety issues and huge economic losses. Anti-icing surfaces have a vital impact on human daily life, but it is still difficult to achieve a stable and sturdy surface for low-temperature environments or local low temperatures. Current anti-icing/de-icing strategies mainly include active and passive two directions.

In related technologies, many active anti-icing and de-icing strategies, such as electric or steam heating and melting, de-icing chemicals, mechanical forces, etc., are applied to cold surfaces in sub-zero environments, such as aircraft wings, ship decks, Ice and snow on wind turbine blades, car windows and windshields, winter roads, etc. However, this active de-icing strategy often faces one or more problems such as high cost, low efficiency, large energy consumption, complex design, and environmental pollution.

Passive de-icing mainly includes the following three methods: super-hydrophobic surfaces, liquid-injected smooth surfaces, gel materials, etc. Among them, super-hydrophobic surfaces can capture air and form air pockets at the solid-liquid interface, which can maximize the Reduce the effective contact area between the supercooled droplets and the cold solid substrate to inhibit icing, but at the same time, the defect of this interface is the formation of a high-energy solid-liquid interface, which will promote ice heterogeneity at lower temperatures. Nucleation destroys the air pockets in the structure, resulting in higher ice adhesion strength, and it has the defects of easily damaged microstructure and insufficient stability. Injecting liquid into a smooth surface converts the air pockets into an addable oil film or other low-temperature liquid that is not easy to freeze and is not miscible with water based on the superhydrophobic surface, effectively preventing water from freezing in contact with the material surface. However, due to the injection of liquid The persistence of liquids injected onto smooth surfaces remains a challenge despite migration, evaporation or leakage. Gel materials are used for anti-icing, mainly including hydrogels, ion gels, and organic gels. Hydrogels are mainly made by adding antifreeze additives such as ethylene glycol to the network structure, and by designing the polymer network. The presence of a non-frozen interfacial water lubricating layer on the controlled hydrogel interface further reduces the adhesion of ice on the surface; the organic gel mainly promotes the crack expansion of the interface and ice through modulus imbalance and deformation incompatibility with ice. To achieve surface anti-icing; ion gel uses the lubricating effect of hydrophobic ionic liquid and its low crystallization point to resist icing. However, the gel structures and surfaces of the above three basic configurations all have the disadvantages of poor adhesion to the substrate, low mechanical strength, and are unsustainable.

Contents of the invention

In order to solve the problems in related technologies, the preparation cost of anti-icing surface is high, the preparation process is complex, and the anti-icing performance of most coatings is poor. The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the first aspect of the embodiments of the present invention aims to provide a preparation of an anti-ice coating with an oil-based magnetized microneedle array. method.

The second aspect of the embodiments of the present invention aims to provide an anti-icing coating prepared by the above preparation method.

The third aspect of the embodiment of the present invention aims to provide the application of the above-mentioned anti-icing coating.

The embodiment of the present invention provides a method for preparing an anti-icing coating, which includes the following steps:

S1: Pretreat the surface of the substrate to make the surface roughness of the substrate 2 to 15 μm;

S2: Add the oil-based nano-ferroferrite magnetic liquid into the diluted resin and disperse it evenly to prepare a colloidal solution;

S3: Transfer the colloidal solution to the surface of the substrate, and form a magnetic microneedle array on the surface of the substrate under the action of a magnetic field with a magnetic field strength of 3000 to 5000 Gauss;

S4: Continue to solidify and shape under the action of a magnetic field with a magnetic field strength of 3000 to 5000 Gauss to obtain the anti-icing coating.

In some embodiments, the magnetic microneedles in the magnetic microneedle array are microneedles with a wide bottom and a sharp top, an inclination of 15 to 90°, a length of 200 to 900 μm, and a microneedle density of 300 to 800 needles/microneedle. cm ² .

Preferably, the magnetic microneedles in the magnetic microneedle array are in the shape of an oblique cone, with an inclination of 30° to 60°, and an outer diameter of the bottom of 150 μm to 250 μm.

In some embodiments, the oil-based nanoferric oxide magnetic liquid is prepared by dissolving the ferric oxide nanoparticles in an oily basic solvent, wherein:

In some embodiments, the mass fraction of Fe3O4 nanoparticles is 25% to 40%.

In some embodiments, the particle size of the ferroferric oxide nanoparticles is 20 to 50 nm.

In some embodiments, the oily base solvent is one or more of perfluoropolyether, silicone oil or paraffin oil.

In some embodiments, in the colloidal solution, the volume ratio of the oil-based nanoferroferrite magnetic liquid to the dilute resin is (1-2):1.

In some embodiments, the coating amount of the colloidal solution is 200-350 μl/cm ² . Preferably, the coating amount of the colloidal solution is 200-300 μl/cm ² .

In some embodiments, the diluted resin is prepared by diluting a high-temperature curing resin or a photo-curing resin with a diluting solvent; wherein:

In some embodiments, the high-temperature curing resin is one or more of polydimethylsiloxane, amorphous fluoropolymer, polytetrafluoroethylene, and polychlorotrifluoroethylene; preferably, the The high temperature curing resin is polydimethylsiloxane.

In some embodiments, the photocurable resin is bisphenol A epoxy acrylate or polyurethane acrylate.

In some embodiments, the diluting solvent is one or more of tetrahydrofuran, toluene, methylene chloride, and ethyl acetate.

In some embodiments, the volume ratio of the high-temperature curing resin or the photo-curing resin to the diluting solvent is 1: (0.5-1).

In some embodiments, in step S1, the pretreatment is surface sandblasting or acid etching.

In some embodiments, in step S2, the dispersion is ultrasonic treatment, the frequency of ultrasonic treatment is 20 to 30 kHz, and the time is 6 to 8 hours.

In some embodiments, when diluting the resin in step S2, a high-temperature curing resin is selected, the curing and molding conditions in step S4 are heating and curing at 100 to 120°C for 1 to 2 hours; when a light-curing resin is selected as the diluting resin in step S2, step S4 The conditions for curing and molding in S4 are curing for 1 hour under ultraviolet light with a wavelength of 320 to 400 nm.

In some embodiments, the substrate is selected from metallic materials, non-metallic materials, inorganic materials, organic materials or composite materials.

Embodiments of the present invention also provide an anti-icing coating, which is prepared by the above preparation method.

Embodiments of the present invention also provide applications of the above-mentioned anti-icing coating, which is used in the fields of electric power, transportation, communications or aviation.

In some embodiments, the above-mentioned anti-icing coating is used for anti-icing of heat exchangers, anti-icing of wind turbine blades, anti-icing of vehicles, anti-icing of ships, anti-icing of aircraft surfaces, or anti-icing of power and communication facilities.

The embodiments of the present invention have the following advantages and beneficial effects:

The embodiments of the present invention provide an anti-icing coating for a flexible organogel-based magnetic microneedle array with photothermal effects and a preparation method thereof. The embodiments of the present invention use an "active and passive combination" method to actively, that is, through the photothermal effect of the coating. Natural solar energy is used to heat the coating surface, thereby delaying freezing; passively, the oily ferrofluid prepared by combining resin and oil-based magnetic particles is magnetized by a magnetic field and further cured at high temperature to obtain a water-repellent flexible microneedle array coating. , Low ice adhesion properties. Through the combination of the two, preparation on commonly used substrate surfaces (such as AL, GCr15, stainless steel, glass, silicon wafers, etc.) can be achieved with extremely low ice adhesion and excellent photothermal effects, thus to a large extent. Delay the freezing time.

Description of the drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

Figure 1 is the actual object and characterization diagram of the anti-icing coating prepared in Example 1;

Figure 2 shows the water contact angle of the coating prepared in Example 1 and Example 4;

Figure 3 is a schematic diagram of the ice adhesion strength testing device used in the embodiment of the present invention;

Figure 4 is a physical diagram of the anti-icing coating prepared in Comparative Example 2;

Figure 5 is a physical picture of the anti-icing coating prepared in Comparative Example 3;

Figure 6 is a comparison chart of the anti-ice adhesion strength of the coating of Example 1, the coating of Comparative Example 1, and the mirror aluminum sheet;

Figure 7 is a comparison chart of the anti-ice adhesion strength of the coating and mirror GCr15 sheets in Example 2;

Figure 8 is a comparison chart of the anti-ice adhesion strength of mirror silicon wafers in Example 3;

Figure 9 is a graph of the anti-ice adhesion strength of the coating of Example 4;

Figure 10 is a graph of the anti-ice adhesion strength of the coating of Example 5;

Figure 11 is a graph showing the anti-ice adhesion strength of the coating of Comparative Example 2 and the coating of Comparative Example 3;

Figure 12 is a comparison chart of the ice adhesion strength of the tilted microneedles at different test angles in the coating of Example 1 and the coating of Example 4;

Figure 13 is a comparison chart of the photothermal effect of the substrate with and without anti-icing coating in Example 1;

Figure 14 is a graph showing changes in the anti-ice adhesion strength of the base material with or without anti-ice coating in Example 1 under the photothermal effect;

Figure 15 is a comparison chart of the delayed freezing time of the substrate with and without the anti-icing coating in Example 1.

Detailed ways

The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are intended to explain the present invention, but should not be understood as limiting the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs.

In this article, the term "and/or" is just an association relationship describing related objects, indicating that there can be three relationships, such as A and/or B, which can mean: A exists alone, A and B exist simultaneously, and they exist alone B these three situations.

In this article, the term "a plurality" refers to two or more types (including two types).

Where values are described herein as ranges, it is to be understood that such disclosure includes disclosure of all possible subranges within that range, as well as specific numerical values falling within that range, regardless of whether a specific value is expressly stated. No matter the numerical value or specific subrange.

As used herein, the terms "about" and "around" mean +/-10% of the recited value.

Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

The embodiment of the present invention provides a method for preparing an anti-icing coating, which includes the following steps:

S1: Pretreat the surface of the substrate to make the surface roughness of the substrate 2 to 15 μm;

S2: Add the oil-based nano-ferroferrite magnetic liquid into the diluted resin and disperse it evenly to prepare a colloidal solution;

S3: Transfer the colloidal solution to the surface of the substrate, and form a magnetic microneedle array on the surface of the substrate under the action of a magnetic field with a magnetic field strength of 3000 to 5000 Gauss;

S4: Continue to solidify and form under the influence of a magnetic field with a magnetic field strength of 3000 to 5000 Gauss to obtain an anti-icing coating.

In a specific example, the magnetic field intensity in steps S3 and S4 is the same. Non-limiting examples include: the magnetic field intensity can be 3000 Gauss, 3500 Gauss, 4000 Gauss, 4500 Gauss, 5000 Gauss, etc.

In some embodiments, the magnetic microneedles in the magnetic microneedle array are microneedles that are wide at the bottom and pointed at the top, with an inclination of 15 to 90°, a length of 200 to 900 μm, and a microneedle density of 300 to 800 needles/cm ² . Non-limiting examples: the inclination can be 15°, 30°, 45°, 60°, 90°, etc. The length (average) can be 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, etc.; the microneedle density (average) can be 300/cm ² , 400/cm ² , 450/cm ² , 500 Roots/cm ² , 600 roots/cm ² , 800 roots/cm ² etc.

Preferably, the magnetic microneedles in the magnetic microneedle array are in the shape of an oblique cone, with an inclination of 30 to 60°, and an outer diameter of the bottom of 150 μm to 250 μm.

In some embodiments, the oil-based nanoferric oxide magnetic liquid is prepared by dissolving the ferric oxide nanoparticles in an oily basic solvent, wherein:

In some embodiments, the mass fraction of Fe3O4 nanoparticles is 25% to 40%. Non-limiting examples: the mass fraction can be 25%, 30%, 32%, 35%, 40%, etc.

In some embodiments, the particle size of ferroferric oxide nanoparticles is 20-50 nm. Non-limiting examples: the particle size can be 20nm, 30nm, 35nm, 40nm, 50nm, etc.

In some embodiments, the oily base solvent is one or more of perfluoropolyether, silicone oil, or paraffin oil.

In a specific example, the oil-based nanoferric oxide magnetic liquid is a perfluoropolyether magnetic liquid containing 40 wt.% ferric oxide with an average particle size of 30 nm.

In some embodiments, the volume ratio of the oil-based nanoferroferrite magnetic liquid and the dilute resin in the colloidal solution is (1-2):1. Non-limiting examples: the volume ratio can be 1:1, 1.2:1, 1.4:1, 1.5:1, 2:1, etc.

In some embodiments, the coating amount of the colloidal solution is 200-350 μl/cm ² . Non-limiting examples: the coating amount of the colloidal solution is 200 μl/cm ² , 250 μl/cm ² , 280 μl/cm ² , 300 μl/cm ² , 330 μl/cm ² , 350 μl/cm ² , etc.; preferably, the colloidal solution The coating amount is 200~300μl/cm ² . It should be noted that the colloidal solution must ensure a certain coating amount. If the coating amount is too small, visible microneedles will not be further formed after magnetization by a magnetic field, and will only appear in the shape of extremely small bulges. If the coating amount is too much, the oil-based magnetic microneedles will only be formed in a local area inside after magnetic field magnetization, and the microneedles will be coarse in shape, unevenly distributed and too dispersed. Too much or too little coating is not conducive to the microneedle array exerting its crack propagation promotion effect when ice breaks. In the present invention, the coating amount of the colloidal solution is controlled to be 200-350 μl/cm ² . The uniform magnetic microneedle array can promote the crack expansion when the icicles are separated from the coating, further reducing the adhesion of ice on the surface. And the coating amount of the colloidal solution is 200-300 μl/cm ² for better results.

In some embodiments, the diluted resin is prepared by diluting a high-temperature curing resin or a light-curing resin with a diluting solvent; wherein:

In some embodiments, the high-temperature curing resin is one or more of polydimethylsiloxane, amorphous fluoropolymer, polytetrafluoroethylene, and polychlorotrifluoroethylene; preferably, the high-temperature curing resin is Polydimethylsiloxane.

In some embodiments, the photocurable resin is bisphenol A epoxy acrylate or polyurethane acrylate.

In some embodiments, the diluting solvent is one or more of tetrahydrofuran, toluene, methylene chloride, and ethyl acetate.

In some embodiments, the volume ratio of high-temperature curing resin or photo-curing resin to diluting solvent is 1: (0.5-1).

In some embodiments, in step S1, the pretreatment is surface sandblasting or acid etching, so that the roughness of the substrate surface is 2-15 μm. Non-limiting examples include: achieving uniform surface roughness levels of approximately 2 μm, 6 μm, 8 μm, 9 μm, 10 μm, 12 μm, 15 μm, etc.

In some embodiments, in step S2, dispersion is performed by ultrasonic treatment, the frequency of ultrasonic treatment is 20-30 kHz, and the time is 6-8 hours. Non-limiting examples: the frequency of ultrasonic treatment can be 20kHz, 25kHz, 30kHz, etc., and the time can be 6h, 6.5h, 7h, 7.5h, 8h, etc.

In some embodiments, when diluting the resin in step S2, a high-temperature curing resin is selected, the curing and molding conditions in step S4 are heating and curing at 100 to 120°C for 1 to 2 hours; when a light-curing resin is selected as the diluting resin in step S2, step S4 The conditions for curing and molding in S4 are curing for 1 hour under ultraviolet light with a wavelength of 320 to 400 nm.

It can be understood that in step S3, a strong magnet can be used to attract the colloidal solution droplets, and by changing the position of the sample coated with the colloidal solution above the magnet and the distance from the magnet surface, the colloidal solution can be in different directions and The intensity of the magnetic field line position is determined, and magnetic microneedle arrays with different lengths and inclinations are prepared.

In some embodiments, in step S3, the colloidal solution is transferred to the surface of the substrate by spin coating or natural dripping and leveling.

In some embodiments, the substrate is selected from metallic materials, non-metallic materials, inorganic materials, organic materials or composite materials. For example, the base material can be Al wafer, high chromium bearing steel, stainless steel, glass or silicon wafer.

In a second aspect, embodiments of the present invention also provide an anti-icing coating. The anti-icing coating is prepared by the above preparation method.

In a third aspect, embodiments of the present invention also provide applications of the above-mentioned anti-icing coating. The anti-icing coating is used in the fields of electric power, transportation, communications or aviation.

In some embodiments, the anti-icing coating is used for anti-icing heat exchangers, anti-icing wind turbine blades, anti-icing vehicles, anti-icing ships, anti-icing aircraft surfaces, or anti-icing power and communication facilities.

The following are non-limiting examples and comparative examples of the present invention. in:

Perfluoropolyether nano-ferroferrite magnetic liquid: purchased from: Hangzhou Jikang New Materials Co., Ltd.;

Silicone oil type nano-ferroferrite magnetic liquid: purchased from: Hangzhou Jikang New Materials Co., Ltd.;

Polydimethylsiloxane (PDMS) resin: model SYLGARDTM184, purchased from: Dow Corning Company of the United States; includes basic components and curing agent.

AF1601 resin: Model TeflonTM AF1601, purchased from American Chemours Company.

Permanent magnet: high temperature resistant permanent magnet.

In the embodiment of the present invention, an ice adhesion strength testing device is used to test the ice adhesion strength. As shown in Figure 2, the ice adhesion strength test device consists of an ambient temperature control cabinet, a cooling table, (φ1cm*5mm) icing icicle model, a stepping rod and a load cell.

During the test, the cooling table temperature was controlled at -25°C, the ambient temperature control cabinet temperature was set at -10°C, the sample and the frozen icicle mold were placed on the surface of the cooling table, and 1ml of water was added dropwise to the icicle model. ; Leave it for 5 minutes. After the water cools and freezes, adjust the stepper push rod carrying the load cell to the cut surface of the icicle model. The center of the push rod head is 1 to 2 mm away from the cut surface and the height is 1 mm away from the sample surface.

Start the test, control the stepper push rod and load cell to move at a speed of 0.2mm/s until the icicles undergo interface shearing and fracture movement, stop the push rod, and analyze and calculate the force measurement data obtained. During the use The peak value of the instantaneous force at the time of rupture was divided by the ice area of the icicle (area of a φ1cm circle) to obtain ice adhesion strength data.

In the embodiment of the present invention, an experimental xenon lamp is used to simulate sunlight to irradiate the coating sample. Under one sunlight irradiation (that is, the illumination intensity is 96mW/cm ² ), 10cm away from the coating surface, the temperature of the cooling stage (that is, the sample substrate) is At -10°C, use Hikvision infrared thermal imaging camera to measure the surface temperature of the sample to test the photothermal effect of the sample.

In the embodiment of the present invention, a video contact angle measuring instrument and a cooling table are used to test the high delayed icing performance of the obtained coating, and on this basis, the icing delayed performance of the coating under the photothermal effect is tested in combination with xenon lamp irradiation.

Example 1:

A preparation method of anti-icing coating, including the following steps:

The base material is a mirror Al sheet with a size of 1.5cm*1.5cm*1mm, and sandblasting is used to achieve a surface roughness of about 5μm;

Add 3 ml of perfluoropolyether type nano-ferroferrite magnetic liquid (containing 40wt.% ferroferrite nanoparticles with an average particle size of 30 nm) into the mixed liquid of 1 ml of tetrahydrofuran and 1 ml of AF1601 resin, and sonicate for 6 hours. Disperse evenly; obtain colloidal solution;

Drop 600 μl of the obtained colloidal solution onto the surface of the sandblasted aluminum sheet obtained in step (1) to level it naturally, and place the sample above the permanent magnet at a distance of 1cm-1.5cm from the surface of the permanent magnet, with the center of the sample at the permanent magnet. The radius of the magnet is R=1.5cm (the size of the permanent magnet is φ6cm*2cm (radius 3cm), and the magnetic field intensity is 3900 Gauss). After the magnetic field is magnetized, it forms a magnetic microneedle array with an inclination angle of about 45°.

Place the magnet and sample as a whole on a high-temperature heating stage, heat to 100°C and hold for 2 hours, and then air-cool for 10 hours to obtain an anti-icing coating. The anti-icing coated magnetic microneedle array finally prepared in Example 1 has a tilt angle of about 45°, an average length of about 500 μm, and an average microneedle density of about 400 needles/cm ² .

Example 2:

A preparation method of anti-icing coating, including the following steps:

The base material is a mirror GCr15 sheet with a size of 1.5cm*1.5cm*1mm, and acid etching is used to achieve a surface roughness of about 10μm;

Add 3 ml of silicone oil type nano-ferroferrite magnetic liquid (containing 40wt.% ferroferrite nanoparticles with an average particle size of 30 nm) into a mixed liquid of 1 ml of toluene and 1 ml of PDMS resin (polydimethylsiloxane) , and ultrasonicated for 6 hours to disperse evenly; a colloidal solution was obtained;

Drop 600 μl of the obtained colloidal solution onto the sandblasted GCr15 surface obtained in step (1) to level it naturally, and place the sample above the permanent magnet at a distance of 1cm-1.5cm from the surface of the permanent magnet, with the center of the sample located on the permanent magnet. At the radius R=1cm (the permanent magnet size is φ6cm*2cm, the magnetic field intensity is 3900 Gauss), after the magnetic field is magnetized, it forms a magnetic microneedle array with an inclination angle of about 60°.

Place the magnet and sample as a whole on a high-temperature heating stage, heat to 100°C and hold for 2 hours, and then air-cool for 10 hours to obtain an anti-icing coating. The anti-icing coated magnetic microneedle array finally prepared in Example 2 has a tilt angle of about 60°, an average length of about 500 μm, and an average microneedle density of about 500/cm ² .

Example 3:

A preparation method of anti-icing coating, including the following steps:

The base material is a silicon wafer with a size of 1.5cm*1.5cm*0.5mm, and sandblasting is used to achieve a surface roughness of about 2μm;

Add 2 ml of perfluoropolyether nano-ferroferrite magnetic liquid (containing 40wt.% ferroferrite nanoparticles with an average particle size of 30 nm) to 1 ml of tetrahydrofuran and 1 ml of PDMS resin (polydimethylsiloxane). into the mixed liquid, and ultrasonicate for 6 hours to disperse evenly; a colloidal solution is obtained;

Drop 600 μl of the obtained colloidal solution onto the surface of the sandblasted silicon wafer obtained in step (1) to level it naturally, and place the sample above the permanent magnet at a distance of 1cm-1.5cm from the surface of the permanent magnet, with the center of the sample at the permanent magnet. The radius of the magnet is R=1.5cm (the size of the permanent magnet is φ6cm*2cm, and the magnetic field intensity is 3900 Gauss). After the magnetic field is magnetized, it forms a magnetic microneedle array with an inclination angle of about 45°.

Place the magnet and sample as a whole on a high-temperature heating stage, heat to 90°C and hold for 2 hours, and then air-cool for 10 hours to obtain an anti-icing coating. The anti-icing coated magnetic microneedle array finally prepared in Example 3 has a tilt angle of about 45°, an average length of about 500 μm, and an average microneedle density of about 400 needles/cm ² .

Example 4

A preparation method of anti-icing coating, including the following steps:

The base material is a mirror Al sheet with a size of 1.5cm*1.5cm*1mm, and sandblasting is used to achieve a surface roughness of about 5μm;

Add 3 ml of perfluoropolyether type nano-ferric oxide magnetic liquid (containing 40wt.% ferric oxide nanoparticles with an average particle size of 30 nm) into the mixed liquid of 1 ml of tetrahydrofuran and 1 ml of AF1601 resin, and sonicate for 6 hours. Disperse evenly; obtain colloidal solution;

Drop 750 μl of the obtained colloidal solution onto the surface of the sandblasted aluminum sheet obtained in step (1) to level it naturally, and place the sample above the permanent magnet at a distance of 1cm-1.5cm from the surface of the permanent magnet, with the center of the sample at the permanent magnet. The radius R of the magnet is 1.5cm (the size of the permanent magnet is φ6cm*2cm (radius 3cm), and the magnetic field intensity is 3900 Gauss). After the magnetic field is magnetized, it forms a magnetic microneedle array with a uniform tilt angle of about 45°. The microneedle phase It is thicker than in Example 1, and the distribution is slightly dispersed.

Place the magnet and sample as a whole on a high-temperature heating stage, heat to 100°C and hold for 2 hours, and then air-cool for 10 hours to obtain an anti-icing coating. The anti-icing coated magnetic microneedle array finally prepared in Example 4 has a tilt angle of about 45°, an average length of about 600 μm, and an average microneedle density of about 300 needles/cm ² .

Example 5

A preparation method of anti-icing coating, including the following steps:

The base material is a mirror Al sheet with a size of 1.5cm*1.5cm*1mm, and sandblasting is used to achieve a surface roughness of about 5μm;

Add 3 ml of perfluoropolyether type nano-ferroferrite magnetic liquid (containing 40wt.% ferroferrite nanoparticles with an average particle size of 30 nm) into the mixed liquid of 1 ml of tetrahydrofuran and 1 ml of AF1601 resin, and sonicate for 6 hours. Disperse evenly; obtain colloidal solution;

Drop 600 μl of the obtained colloidal solution onto the surface of the sandblasted aluminum sheet obtained in step (1) to level it naturally, and place the sample above the permanent magnet at a distance of 1cm-1.5cm from the surface of the permanent magnet, with the center of the sample at the permanent magnet. The radius of the magnet is R=0cm (the size of the permanent magnet is φ6cm*2cm (radius 3cm), and the magnetic field intensity is 3900 Gauss). After the magnetic field is magnetized, it forms a magnetic microneedle array with an inclination angle of about 90° (that is, perpendicular to the base). .

Place the magnet and sample as a whole on a high-temperature heating stage, heat to 100°C and hold for 2 hours, and then air-cool for 10 hours to obtain an anti-icing coating. The tilt angle of the anti-icing coated magnetic microneedle array finally prepared in Example 5 is about 90°, the average length is about 300 μm, and the average microneedle density is about 500 needles/cm ² .

Comparative example 1

A preparation method of anti-icing coating, including the following steps:

The base material is a mirror Al sheet with a size of 1.5cm*1.5cm*1mm, and sandblasting is used to achieve a surface roughness of about 5μm;

Add 3 ml of perfluoropolyether type nano-ferroferrite magnetic liquid (containing 40wt.% ferroferrite nanoparticles with an average particle size of 30 nm) into the mixed liquid of 1 ml of tetrahydrofuran and 1 ml of AF1601 resin, and sonicate for 6 hours. Disperse evenly; obtain colloidal solution;

Drop 600 μl of the obtained colloidal solution onto the surface of the sandblasted aluminum sheet obtained in step (1), let it level naturally, and then place it on a high-temperature heating stage, heat to 100°C and keep for 2 hours, and then air-cool for 10 hours to obtain the unformed Sample of magnetic microneedle array.

Comparative example 2

A preparation method of anti-icing coating, including the following steps:

The base material is a mirror Al sheet with a size of 1.5cm*1.5cm*1mm, and sandblasting is used to achieve a surface roughness of about 5μm;

Add 3 ml of perfluoropolyether type nano-ferroferrite magnetic liquid (containing 40wt.% ferroferrite nanoparticles with an average particle size of 30 nm) into the mixed liquid of 1 ml of tetrahydrofuran and 1 ml of AF1601 resin, and sonicate for 6 hours. Disperse evenly; obtain colloidal solution;

Drop 100 μl of the obtained colloidal solution onto the surface of the sandblasted aluminum sheet obtained in step (1), and place the sample above the permanent magnet at a height of 1cm-1.5cm from the surface and a radius R=1.5cm (the size of the permanent magnet is φ6cm* 2cm (radius 3cm), magnetic field intensity is 3900 Gauss), but due to the small amount of colloidal solution added and the insufficient content of perfluoropolyether nanoferroferrite magnetic liquid in it, visible microneedles were not formed after magnetization by the magnetic field. , only showing a very small bulging shape. As shown in Figure 4.

Place the magnet and sample as a whole on a high-temperature heating stage, heat to 100°C and hold for 2 hours, and then air-cool for 10 hours to obtain an anti-icing coating.

Comparative example 3

A preparation method of anti-icing coating, including the following steps:

The base material is a mirror Al sheet with a size of 1.5cm*1.5cm*1mm, and sandblasting is used to achieve a surface roughness of about 5μm;

Add 3 ml of perfluoropolyether type nano-ferroferrite magnetic liquid (containing 40wt.% ferroferrite nanoparticles with an average particle size of 30 nm) into the mixed liquid of 1 ml of tetrahydrofuran and 1 ml of AF1601 resin, and sonicate for 6 hours. Disperse evenly; obtain colloidal solution;

Drop 1000 μl of the obtained colloidal solution onto the surface of the sandblasted aluminum sheet obtained in step (1), and place the sample above the permanent magnet at a height of 1cm-1.5cm from the surface and a radius R=1.5cm (the size of the permanent magnet is φ6cm* 2cm (radius 3cm), magnetic field intensity is 3900 Gauss). After the magnetic field is magnetized, it forms magnetic microneedles with an inclination angle of about 45° in a local area of the interior. However, the microneedles are coarse in shape, unevenly distributed and too scattered. As shown in Figure 5.

Place the magnet and sample as a whole on a high-temperature heating stage, heat to 100°C and hold for 2 hours, and then air-cool for 10 hours to obtain an anti-icing coating.

Figure 1 is a physical picture and a cross-sectional representation of the oil-based magnetic fluid microneedle array coating prepared in Example 1 of the present invention; Figure 2 is a water contact angle diagram of the coating in Example 1 and Example 4; it can be seen from Figure 1 : Add the optimal proportion and amount of oil-based magnetic liquid, and the prepared coating has obvious morphological characteristics of a tilted microneedle array, and it can be seen from Figure 2 that after the oil-based magnetic liquid and resin are mixed and solidified to form the microneedle array, The coating has a water contact angle of 100° to 120°, which is related to the synergistic effect of a thin oil film precipitating on the surface of the oil-based magnetic liquid after solidification and low surface energy resin, which also determines the low ice adhesion of the coating. A major reason for the characteristics.

Figure 4 is a physical picture of the coating prepared in Comparative Example 2. It can be seen from Figure 4 that due to the small amount of colloidal solution added and the insufficient content of perfluoropolyether nanometer ferroferrite magnetic liquid in it, the magnetic field cannot be further magnetized. Visible microneedles are formed, showing only a very small bulging shape.

Figure 5 is a physical picture of the coating prepared in Comparative Example 3. It can be seen from Figure 5 that after the magnetic field is magnetized, magnetic microneedles with an inclination angle of about 45° are formed in the internal local area. However, the microneedles are coarse in shape and unevenly distributed. Uniform and too scattered.

Figures 6 to 8 show the changes in the anti-ice adhesion strength of the substrate with or without anti-ice coating in Examples 1 to 3 and Comparative Example 1; it can be seen that the oil-based magnetic microneedle array coating prepared by the present invention has Compared with the untreated substrate surface, the ice adhesion strength has a greater decrease, and the decreases are all above 95%; the ice adhesion strength of the coating prepared on the Al surface in Example 1 is 17KPa, and in Example 2 The ice adhesion strengths of the coatings prepared on GCr15 wafers and on silicon wafers in Example 3 were both less than 20KPa, showing good anti-icing properties. This is mainly attributed to: 1) The low freezing point of the oil film precipitated on the coating surface causes the icicles formed on the surface to easily detach from the oil film surface. 2) The uniform magnetic microneedle array can promote the crack expansion when the icicles are separated from the coating, further reducing the adhesion of ice on the surface. In addition, Comparative Example 1 is a control sample without applying a magnetic field and without forming a magnetic microneedle array, and the ice adhesion strength on its surface is relatively high.

Figure 9 shows a relatively uniform magnetic microneedle array coating with a relatively large amount of colloidal solution prepared by the present invention in Example 4. The microneedles on the surface of the coating are relatively thick and dispersed, and its ice adhesion strength is about 33KPa. , compared with the untreated substrate surface, the ice adhesion strength decreased by more than 93%, and the ice adhesion strength increased compared with Example 1.

Figure 10 shows the magnetic microneedle coating prepared by placing the sample with colloidal solution in the center of the magnet in Example 5. Due to the particularity of the position, the prepared microneedle array is perpendicular to the substrate surface, and the ice adhesion strength is 52Kpa. left and right, the ice adhesion strength is higher.

Figure 11 shows the ice adhesion strength of the coating in Comparative Example 2 (ice adhesion strength is 104KPa) and Comparative Example 3 (ice adhesion strength is 130KPa). It can be seen from the comparison that the coatings prepared in the embodiments of the present invention have uniform oil The ice adhesion strength of the base magnetic microneedle array is much lower than that of Comparative Examples 2-3. This is mainly due to the fact that an appropriate amount of colloidal solution needs to be added to form the oil-based magnetic microneedle array. When the amount of colloidal solution is too small, the content of the oil-based nanoferroferrite magnetic liquid is insufficient, and the visible magnetic liquid cannot be further formed after magnetization. Microneedles only appear in the shape of tiny bulges. When too much colloidal solution is added, oil-based magnetic microneedles are only formed in local areas inside after magnetic field magnetization, and the microneedles are coarse in shape, unevenly distributed, and too dispersed. Both situations are not conducive to the microneedle array exerting its crack propagation promotion effect on ice rupture, thereby making the ice adhesion strength higher.

Figure 12 shows the ice adhesion strength of the oil-based magnetic microneedle arrays prepared in Example 1 and Example 4 in different test directions. The results can be seen that whether it is the uniform and fine oil-based magnetic microneedle formed in Example 1, or For the relatively thick magnetic microneedle array formed in Example 4, the ice adhesion strength tested in the counter-microneedle tilt direction is relatively low, while the ice adhesion strength tested in the microneedle tilt direction is relatively high. This is Since the oil-based magnetic microneedle array is flexible, when the icicle is pushed against the tilt direction of the microneedle, the tip of the oil-based magnetic microneedle deforms first due to force, and the deformation range is larger, which is more likely to cause and promote cracks between the ice and the surface. Expansion, that is, it is easier to push ice away from the surface, and the ice adhesion strength is lower; when pushed along the inclined direction, the wide bottom of the oil-based magnetic microneedle is stressed first, and it is not easy to deform or has a small degree of deformation. It is necessary to increase the lateral pushing force to achieve the emergence and expansion of cracks between the ice and the surface, which will lead to greater ice adhesion strength. At the same time, it can also be seen that the uniform and fine oil-based magnetic microneedle array in Example 1 has better anti-ice adhesion performance.

Figure 13 is a comparison of the photothermal effects of the substrate with and without anti-icing coating in Example 1; it can be seen from Figure 13 that the measured surface temperature of the sample is 15°C higher than that of the ordinary Al sheet.

Figure 14 shows the ice adhesion strength of the oil-based magnetic microneedle array coating in Example 1 after being irradiated with a xenon lamp to simulate "sunlight" for 2 minutes. The ice adhesion strength on the surface is further reduced to about 7KPa. Combined with Figure 13, it can be analyzed that under the action of photothermal effect, the surface temperature of the coating gradually increases, and the ice combined with the surface gradually turns into local water molecules, and then gradually expands into a water film, which further exhibits lower ice adhesion during testing. strength.

Figure 15 is a comparison of the delayed freezing time of the substrate with and without the anti-icing coating in Example 1. The high delayed freezing performance of the obtained coating was tested using a video contact angle measuring instrument and a cooling table, and based on this, combined with the xenon lamp irradiation test The freezing delay performance of the coating under the action of photothermal effect can be seen from Figure 15. The freezing time of the substrate with the anti-icing coating in Example 1 of the present invention is extended to about 62 times that of the sandblasted aluminum sheet.

As used herein, the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean specific features, structures, materials, or features described in connection with the embodiment or example. Features are included in at least one embodiment or example of the invention. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification unless they are inconsistent with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above-mentioned embodiments are illustrative and should not be construed as limitations of the present invention. Those of ordinary skill in the art can make modifications to the above-mentioned embodiments within the scope of the present invention. The embodiments are subject to changes, modifications, substitutions and variations.

Claims (11)

1. A method for preparing an anti-icing coating, characterized in that it includes the following steps: S1: Pretreat the surface of the substrate to make the surface roughness of the substrate 2 to 15 μm; S2: Add the oil-based nano-ferroferrite magnetic liquid into the diluted resin and disperse it evenly to prepare a colloidal solution; S3: Transfer the colloidal solution to the surface of the substrate, and form a magnetic microneedle array on the surface of the substrate under the action of a magnetic field with a magnetic field strength of 3000 to 5000 Gauss; S4: Continue to solidify and shape under the action of a magnetic field with a magnetic field strength of 3000 to 5000 Gauss to obtain the anti-icing coating; The oil-based nano-ferroferric oxide magnetic liquid is prepared by dissolving the ferroferric oxide nanoparticles in an oily basic solvent; The particle size of the ferric oxide nanoparticles is 20 to 50 nm; The oily base solvent is one or more of perfluoropolyether, silicone oil or paraffin oil; In the colloidal solution, the volume ratio of the oil-based nanoferroferrite magnetic liquid and the dilute resin is (1-2):1; The coating amount of the colloidal solution is 200-350 μL/cm ² ; The diluted resin is prepared by diluting high-temperature curing resin or light-curing resin with a diluting solvent; wherein: The high-temperature curing resin is one or more of polydimethylsiloxane, amorphous fluoropolymer, polytetrafluoroethylene, and polychlorotrifluoroethylene; The photocurable resin is bisphenol A epoxy acrylate or polyurethane acrylate; The diluting solvent is one or more of tetrahydrofuran, toluene, methylene chloride, and ethyl acetate; The volume ratio of the high-temperature curing resin or the light-curing resin to the diluting solvent is 1: (0.5-1). 2. The method for preparing an anti-icing coating according to claim 1, characterized in that the magnetic microneedles in the magnetic microneedle array are microneedles with a wide bottom and a sharp top, with an inclination of 15 to 90° and a length of The microneedle density is 200-900 μm, and the microneedle density is 300-800 needles/cm ² . 3. The preparation method of anti-icing coating according to claim 1, characterized in that, The mass fraction of the ferric oxide nanoparticles is 25-40%. 4. The preparation method of anti-icing coating according to claim 1, characterized in that, The coating amount of the colloidal solution is 200-300 μL/cm ² . 5. The method for preparing an anti-icing coating according to claim 1, wherein the high-temperature curing resin is polydimethylsiloxane. 6. The preparation method of anti-icing coating according to claim 1, characterized in that, In step S1, the pretreatment is surface sandblasting or acid etching; And/or, in step S2, the dispersion is ultrasonic treatment, the frequency of ultrasonic treatment is 20 to 30 kHz, and the time is 6 to 8 hours. 7. The preparation method of an anti-icing coating according to claim 5, characterized in that when the diluting resin selects a high-temperature curing resin in step S2, the conditions for curing and molding in step S4 are heating and curing at 100-120°C for 1 ~2h; when diluting the resin in step S2 and selecting a light-curing resin, the conditions for curing and molding in step S4 are curing under ultraviolet light with a wavelength of 320-400 nm for 1 hour. 8. The preparation method of the anti-icing coating according to claim 1, characterized in that the magnetic microneedles in the magnetic microneedle array are in the shape of an oblique cone, with an inclination of 30 to 60°, and a bottom outer diameter of 150 μm to 150 μm. 250μm. 9. An anti-icing coating, characterized in that the anti-icing coating is prepared by the preparation method according to any one of claims 1 to 8. 10. The application of an anti-icing coating according to claim 9, characterized in that the anti-icing coating is used in the fields of electric power, transportation, communication or aviation. 11. The application of an anti-icing coating according to claim 10, characterized in that it is used for anti-icing of heat exchangers, anti-icing of wind turbine blades, anti-icing of vehicles, anti-icing of ships, anti-icing of aircraft surfaces, or Ice protection for power and communication facilities.