Preparation method of photo-thermal anti-icing super-hydrophobic coating and super-hydrophobic coating thereof

Abstract

The application discloses a preparation method of a photo-thermal ice-resistant super-hydrophobic coating and the super-hydrophobic coating, and comprises the following steps: heating and vacuumizing polytetrahydrofuran (PTMG) to remove water, so as to obtain PTMG after water removal; heating and vacuumizing hydroxypropyl-terminated polydimethylsiloxane (PDMS-OH) to remove water, so as to obtain PDMS-OH after water removal; mixing the PDMS-OH after water removal and the PTMG after water removal, adding ethyl acetate solvent to stir, adding dicyclohexylmethane diisocyanate (HMDI) and dibutyltin dilaurate (DBTDL) dropwise, pre-polymerizing, adding di(2-hydroxyethyl) disulfide (HEDS) when the reaction reaches equilibrium, and preparing polyurethane after the reaction is completed; mixing ZrN nanoparticles, SiO2-F and the polyurethane to obtain a suspension through ultrasonic treatment; spraying the suspension to obtain a coating, and drying the coating to obtain the photo-thermal ice-resistant super-hydrophobic coating. The coating prepared by the application has excellent ice-resistant performance, and can delay the icing time for up to 1422s at-20 DEG C, and the icing time of a blank control group is 17s, which is better than most of the known ice-resistant super-hydrophobic coatings.

Description

Technical Field

[0001] This invention belongs to the field of anti-icing superhydrophobic coatings, specifically relating to a method for preparing a photothermal anti-icing superhydrophobic coating and the superhydrophobic coating itself. Background Technology

[0002] Icing is a common and unavoidable phenomenon in nature. Excessive ice buildup can hinder the normal operation of aircraft wings, exposed electrical wires, wind turbine blades, and other structures, resulting in significant economic losses. However, traditional anti-icing methods, including mechanical de-icing, heating de-icing, and chemical treatment, suffer from drawbacks such as low efficiency, high energy consumption, and secondary pollution. Therefore, there is an urgent need in this field for an efficient and environmentally friendly solution to solid surface icing.

[0003] In recent decades, researchers have developed a large number of bio-inspired passive anti-icing materials, among which superhydrophobic surfaces are the most common. Superhydrophobic materials can serve as anti-icing materials because their surface micro / nanostructures can trap air layers. These air layers significantly reduce the actual solid-liquid contact area, thus repelling droplets, prolonging freezing time, and reducing ice adhesion strength. Jin et al. prepared superhydrophobic surfaces with ideal anti-icing properties by combining specific structural control with chemical modification. Wang et al. combined PDMS microspheres with ZnO nanofibers to prepare flexible superhydrophobic surfaces with excellent waterproof and anti-icing properties at low temperatures.

[0004] However, in extreme environments such as high humidity and freezing conditions, the anti-icing / de-icing performance will be lost. This is because the rough surface of the micro-nano structure is easily damaged by external forces such as mechanical friction, dynamic impact, peeling, and interlocking structures formed during freezing, resulting in increased ice adhesion and reduced anti-icing time. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a photothermal anti-icing superhydrophobic coating.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a photothermal anti-icing superhydrophobic coating, comprising,

[0009] Polytetrahydrofuran (PTMG) was heated and vacuumed to remove water, resulting in dehydrated PTMG.

[0010] Hydroxypropyl-terminated polydimethylsiloxane PDMS-OH was heated and vacuum dehydrated to obtain dehydrated PDMS-OH.

[0011] The dehydrated PDMS-OH and dehydrated PTMG were mixed, ethyl acetate was added and stirred, and dicyclohexylmethane diisocyanate HMDI and dibutyltin dilaurate DBTDL were added dropwise for prepolymerization. When the reaction reached equilibrium, di(2-hydroxyethyl) disulfide HEDS was added, and the polyurethane was obtained after the reaction was completed.

[0012] ZrN nanoparticles, SiO2-F, polyurethane and ethyl acetate were mixed and ultrasonicated to obtain a suspension.

[0013] A suspension is sprayed to obtain a coating, which is then dried to obtain a photothermal anti-icing superhydrophobic coating.

[0014] As a preferred embodiment of the preparation method described in this invention, the polytetrahydrofuran (PTMG) is heated and vacuum-evacuated to remove water, wherein the heating temperature is 100–120°C and the vacuum-evacuation time is 2–3 hours.

[0015] As a preferred embodiment of the preparation method described in this invention, the hydroxypropyl-terminated polydimethylsiloxane PDMS-OH is heated and vacuum-dehydrated, wherein the heating temperature is 110-120°C and the vacuum dehydration time is 2-3 hours.

[0016] In a preferred embodiment of the preparation method described in this invention, the following components are included by mass: PDMS-OH is 1-20 parts, PTMG is 18-20 parts, dicyclohexylmethane diisocyanate (HMDI) is 6-9 parts, dibutyltin dilaurate (DBTDL) is 0.01-0.06 parts, di(2-hydroxyethyl) disulfide (HEDS) is 2-4 parts, and ethyl acetate is 140-180 parts.

[0017] In a preferred embodiment of the preparation method described in this invention, the prepolymerization reaction is carried out at a temperature of 60°C for 3 hours; the polyurethane is obtained after the reaction is completed at a temperature of 60°C for 8 hours.

[0018] As a preferred embodiment of the preparation method described in this invention, the SiO2-F is prepared by a method comprising:

[0019] Anhydrous ethanol, ammonia, deionized water and 1H,1H,2H,2H-perfluorodecyltriethoxysilane were added to SiO2 and the mixture was stirred vigorously to disperse it.

[0020] The product suspension was obtained by reacting at 30–40℃ for 20–24 hours.

[0021] The suspension was centrifuged at 10,000 rpm for 10 minutes, washed 2-3 times with ethanol, and then dried in a vacuum oven to obtain the product.

[0022] In a preferred embodiment of the preparation method described in this invention, the ratio of SiO2, anhydrous ethanol, ammonia, deionized water and 1H,1H,2H,2H-perfluorodecyltriethoxysilane is 2-4g: 100-180mL: 4-8mL: 10-20mL: 1-2mL.

[0023] In a preferred embodiment of the preparation method described in this invention, ZrN nanoparticles, SiO2-F, polyurethane, and ethyl acetate are mixed, wherein, based on the mass parts of the raw materials, the ZrN nanoparticles are 0.07 to 0.7 parts, the SiO2-F is 0.5 to 0.8 parts, the polyurethane is 1 to 2 parts, and the ethyl acetate is 15 to 18 parts.

[0024] As a preferred embodiment of the preparation method described in this invention, the step of spraying the suspension to obtain the coating includes,

[0025] Use a spray gun with a nozzle diameter of 0.3mm to repeatedly spray the suspension 3 to 5 times, with a spraying distance of 10cm and a spraying temperature of 25℃.

[0026] The obtained coating was then placed in a forced-air drying oven and heated at 80°C for 1 hour to obtain the coating.

[0027] Another objective of this invention is to overcome the shortcomings of the prior art and provide a photothermal anti-icing superhydrophobic coating with a thickness of 150–200 μm.

[0028] Beneficial effects of this invention:

[0029] (1) The coating prepared by the present invention has excellent anti-icing properties. It can delay the freezing time by up to 1422s at -20℃, while the freezing time of the blank control group is 17s, which is better than most known anti-icing superhydrophobic coatings.

[0030] (2) With the addition of zirconium nitride nanoparticles in the process of this invention, the coating can be heated to 61°C under 1 unit of sunlight irradiation, and has excellent photothermal de-icing performance; the contact angle of the coating can reach 160.6° and the roll-off angle is as low as 0.7°, which has excellent superhydrophobic properties; the coating can maintain superhydrophobicity under 30 3M strong adhesive tape peeling tests, 350g sand impact and 6L water droplet erosion, and has high durability; the ice adhesion of the coating of this invention can reach 51.9Kpa.

[0031] (3) The coating preparation method of the present invention is simple, efficient and low cost. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0033] Figure 1 This is an infrared diffraction peak diagram of polyurethane in an embodiment of the present invention;

[0034] Figure 2 This is a contact angle diagram of the polyurethane body material in an embodiment of the present invention;

[0035] Figure 3 This is a stress-strain curve of the polyurethane bulk material in an embodiment of the present invention;

[0036] Figure 4 The infrared image of fluorinated nano-SiO2 in the embodiment of the present invention;

[0037] Figure 5 The diagram shows the contact angle and roll-off angle of different superhydrophobic coatings prepared in the embodiments of the present invention;

[0038] Figure 6 These are surface SEM images of different coatings in the embodiments of the present invention;

[0039] Figure 7 The above are photothermal temperature rise curves of different coatings in the embodiments of the present invention;

[0040] Figure 8 This is a temperature change diagram of the superhydrophobic photothermal coating under repeated heating and cooling cycles in an embodiment of the present invention;

[0041] Figure 9 These are photographs of water droplets freezing on different coatings in embodiments of the present invention;

[0042] Figure 10 This is a diagram showing the freezing time of water droplets on different coatings in an embodiment of the present invention;

[0043] Figure 11 This is a diagram showing the ice adhesion force of different coatings in an embodiment of the present invention;

[0044] Figure 12 The diagram shows the durability test results in this embodiment of the invention, where a is the gravel impact test, b is the water droplet impact test, and c is the tape peeling test. Detailed Implementation

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0046] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0047] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0048] This invention designs and synthesizes a hydrophobic and tough polyurethane, blends it with fluorinated modified nano-silica and zirconium nitride nanoparticles to obtain a superhydrophobic coating, and sprays it to form a photothermal anti-icing superhydrophobic coating.

[0049] The present invention firstly synthesizes hydrophobic polyurethane. HMDI is selected as the hard segment, and hydroxypropyl-terminated PDMMS and PTMG are used as mixed soft segments to prepolymerize polyurethane. Furthermore, HEDS is selected as a chain extender to endow the polyurethane with self-healing properties. The Si-O and SS bonds in infrared spectroscopy indicate the successful synthesis of polyurethane.

[0050] The hydrophobic properties of the synthesized polyurethane were tested, and it was found that with the addition of PDMS, the CA of the polyurethane initially increased and then remained unchanged. The stress-strain curve analysis of the polyurethane showed that its mechanical properties gradually deteriorated with the addition of PDMS. Therefore, PU-10 was selected as the polyurethane base, with a contact angle as high as 108.5°, a fracture stress of up to 35 MPa, and a fracture elongation of up to 880%, which is superior to most polyurethanes.

[0051] Next, the nano-silica was fluorinated to reduce its surface energy and improve the hydrophobic properties of the coating. The absorption peak at 1200 nm indicates that the cf bond was successfully incorporated, and the silica was successfully fluorinated.

[0052] Photothermal coatings were prepared with different proportions of nanoparticles, where zrn20 represents 20% of the total nanoparticle content.

[0053] To investigate the superhydrophobic properties of the prepared coating, the contact angle was measured. It was found that the contact angle of the coating gradually decreased with the increase of ZrN content. The contact angle of Zrn0-50 was above 165 degrees, which met the superhydrophobic requirements, while the contact angle of Zrn70 was only 130 degrees.

[0054] In this embodiment of the invention, polytetramethylene ether glycol (PTMG 2000) was purchased from Invista.

[0055] Dicyclohexylmethane diisocyanate (HMDI), dibutyltin dilaurate (DBTDL), and ethyl acetate were purchased from Shanghai Mailin Biochemical Co., Ltd.

[0056] Bis(2-hydroxyethyl) disulfide (HEDS) was purchased from Alfa Esha Chemical Co., Ltd.; hydroxypropyl-terminated dimethylsiloxane (Si-OH, Mn=2000) was purchased from Jiande Polymer New Materials Co., Ltd.

[0057] SiO2 nanoparticles (20nm) were purchased from Jiangsu New Material Technology Co., Ltd.; nano ZrN particles (30nm) were purchased from Beijing Zhongke Yinuo New Material Technology Co., Ltd.; other raw materials were all commercially available products.

[0058] Example 1

[0059] This embodiment provides a method for preparing polyurethane:

[0060] (1) Prepare the raw materials:

[0061] PDMS-OH (hydroxypropyl-terminated polydimethylsiloxane), PTMG (polytetrahydrofuran), HMDI (dicyclohexylmethane diisocyanate), HEDS (di(2-hydroxyethyl) disulfide), DBTDL (dibutyltin dilaurate), ethyl acetate;

[0062] The raw materials and their proportions are shown in Table 1.

[0063] Table 1

[0064]

[0065]

[0066] (2) Preparation process:

[0067] First, heat the PTMG to 120℃ and remove water under vacuum for 2 hours;

[0068] PDMS-OH was heated to 110℃ and vacuum dehydrated for 2 hours;

[0069] After dehydration, PDMS-OH and PTMG were mixed and then added to ethyl acetate solvent with stirring. HMDI and catalyst DBTDL were added dropwise, and prepolymerization was carried out at 60°C for 3 hours. The isocyanate content was titrated, and HEDS was slowly added when the reaction reached equilibrium. The reaction was carried out at 60°C for 8 hours to complete the preparation of polyurethane.

[0070] (3) Product characterization:

[0071] The infrared results of the prepared polyurethane are shown in the figure. Figure 1 .

[0072] from Figure 1 It can be seen that 2260cm -1 The disappearance of the NCO peak and 510 cm -1 Absorption peak at the SS bond, 640 cm⁻¹ -1 The appearance of the CS bond absorption peak indicates that the polyurethane was successfully prepared.

[0073] The contact angle of the polyurethane substrate (1 ml of polyurethane solution was dropped onto a 2*2 cm square glass slide, and the solvent evaporated to form a polyurethane substrate film) is shown in the figure. Figure 2 ,from Figure 2 It can be seen that as the content of PDMS-OH increases, the contact angle of polyurethane increases from 89.5° (hydrophilic state) to 108.5° (hydrophobic state), and the hydrophobic angle of polyurethane increases slowly after the content of PDMS-OH increases to 10%.

[0074] (4) Stress-strain curve of polyurethane:

[0075] Test conditions for polyurethane stress-strain curves (polyurethane processed into 2 / 20 dumbbell shape according to national standards), tensile testing speed of 200 mm / min using an Instronic tensile testing machine, polyurethane stress-strain curves are available in [reference needed]. Figure 3 As can be seen, with the increase of PDMS-OH content, the tensile stress and tensile strain of the material are reduced to varying degrees. PU-10 has both good hydrophobic properties and excellent mechanical properties.

[0076] Example 2

[0077] This embodiment provides a method for preparing a photothermal superhydrophobic coating, the main steps of which are:

[0078] (1) Prepare raw materials: PU (polyurethane PU-10 prepared in Example 1), SiO2-F, ZrN (30nm);

[0079] The preparation process of SiO2-F is as follows: 180ml of anhydrous ethanol, 8ml of ammonia water, 20ml of deionized water and 2ml of PFDTES (1H,1H,2H,2H-perfluorodecyltriethoxysilane) are added to 4g of SiO2 and the mixture is stirred vigorously to disperse.

[0080] The product suspension was obtained by reacting at 40℃ for 24 hours.

[0081] The suspension was then centrifuged at 10,000 rpm for 10 min, washed three times with ethanol, and then placed in a vacuum oven at 60°C for 24 h to obtain the product.

[0082] See the infrared image of fluorinated nano-silica. Figure 4 ,from Figure 4 It can be seen from this that 1200cm -1 The absorption peak at that point indicates the insertion of the CF bond, indicating successful fluorination.

[0083] The specific formulation of the photothermal superhydrophobic coating is shown in Table 2.

[0084] Table 2

[0085] sample PU(g) <![CDATA[SiO2-F(g)]]> ZrN(g) Ethyl acetate (g) <![CDATA[SiO2]]> 1.83 0.70 0 17.47 <![CDATA[ZrN@SiO2]]> 1.83 0.56 0.14 17.47 ZrN 1.83 0 0.70 17.47

[0086] (2) Specific preparation method of photothermal superhydrophobic coating:

[0087] ZrN nanoparticles, SiO2-F, PU and ethyl acetate were mixed in different proportions as recorded in Table 2 and sonicated for 12 h to obtain a suspension.

[0088] Use a spray gun with a nozzle diameter of 0.3mm to spray repeatedly 5 times, with a spraying distance of 10cm and a spraying temperature of 25℃;

[0089] The obtained coating was then placed in a forced-air drying oven and heated at 80°C for 1 hour to obtain a coating (thickness of 200 μm).

[0090] (3) Coating contact angle test

[0091] Contact angle test method: Using a Krüss DSA 100 contact angle meter, at a suitable temperature, add 5 μL of deionized water to the periphery and center of the prepared sample respectively, and take the average value as the contact angle.

[0092] Roll-off angle test method: At a suitable temperature, drop 8 μL of deionized water onto the sample, slowly move the tilting slide, and the angle at which the water droplet begins to roll off is the roll-off angle. Take the average value of 5 measurements.

[0093] The measurement results are shown below. Figure 5 It can be seen that for a pure SiO2 coating, the contact angle is 165.4°; however, from... Figure 6 It can be seen that there are many nanoparticles aggregated on its surface, which is not conducive to large-scale industrial production. Therefore, ZrN nanoparticles are added for regulation.

[0094] For the SiO2@ZrN coating, the contact angle is 160.6°. SEM images show that the nanoparticle cluster size is reduced and the distribution is more uniform. At higher magnification, higher porosity and micro / nano-level micropores can be observed. Its suitable multi-level micro / nano structure makes it an ideal superhydrophobic coating for further performance studies. The contact angle of the pure ZrN coating is only 111°, and the surface tends to be flat, not exhibiting superhydrophobic properties. For SiO2-F, the coating surface shows large aggregation of nanoparticles and a multi-level micro / nano structure, which is the reason for the coating's superhydrophobicity. With the addition of ZrN, the aggregation of surface nanoparticles weakens, but a micro / nano structure still exists. For pure ZrN, the surface tends to be flat, and there is no multi-level micro / nano structure; the coating does not have superhydrophobic properties.

[0095] Example 3

[0096] Coating photothermal temperature rise test

[0097] Coating photothermal heating test conditions:

[0098] The samples were irradiated with a xenon lamp (PE300L-3A) commonly used as a solar simulator to evaluate photothermal performance; the intensity of simulated sunlight was measured by a solar power meter (CEL-FZ-A); and the surface temperature of the samples was recorded using a digital thermometer.

[0099] Infrared images were captured using a portable FT-IR (Hikvision H10) infrared thermal imager.

[0100] from Figure 7 As can be seen, for a pure glass sheet without any treatment, the equilibrium temperature after 150s is about 28℃; for a coating with only SiO2 added, the equilibrium temperature can reach 36℃; for SiO2@ZrN and ZrN coating, the equilibrium temperatures are 60.9℃ and 61.1℃, respectively. This shows that adding a small amount of ZrN nanoparticles can exhibit good photothermal conversion ability, implying the important role of ZrN nanoparticles in photothermal heating.

[0101] The coating repeated heating and cooling cycle experiment was achieved by simulating a 10-minute sunlight exposure followed by a 10-minute cooling cycle. Figure 8 As can be seen, the heating curves of the coating surface are quite similar, and the final equilibrium temperature of the coating is also stable. Therefore, SiO2@ZrN has a stable photothermal conversion capability.

[0102] Example 4

[0103] (1) Coating anti-icing time test

[0104] Coating anti-icing time test conditions: Icing test was conducted on a cold stage.

[0105] The surface temperature was set to -20°C, and a water droplet (5 μL) was dropped onto the coating surface using a pipette. The freezing time of the water droplet was measured to evaluate its anti-freezing behavior. The freezing time was defined as the time it takes for the water droplet to change from the liquid phase to the solid phase.

[0106] The results of the coating anti-icing time test are shown below. Figure 9 , Figure 10 As can be seen from the figure, for an unmodified glass slide, the water droplet will freeze completely after 17 seconds.

[0107] When water droplets come into contact with the ZrN coating, the hydrophobicity of the coating and the thermal insulation properties of the polyurethane itself can effectively extend the freezing time to 331s. For the superhydrophobic coatings SiO2 and SiO2@ZrN, due to the lower surface energy and the rugged micro-nano hierarchical structure, the solid-liquid contact area is significantly reduced, and the trapped air layer can also effectively reduce heat transfer, thus greatly improving the coating's ability to delay freezing.

[0108] However, the two coatings exhibit significantly different anti-icing properties. SiO2@ZrN delays the icing time by 1422 s, more than twice that of SiO2 (631 s). This is likely due to the smaller nanoscale agglomerates and more uniform agglomeration distribution on the SiO2@ZrN surface, which creates a higher energy barrier for heterogeneous nucleation, thus greatly extending the icing time. The introduction of ZrN nanoparticles and SiO2-F demonstrates a synergistic anti-icing effect.

[0109] (2) Coating ice adhesion test

[0110] The test conditions for coating ice adhesion and the test method for surface ice adhesion are as follows:

[0111] Fix the test sample on the cold stage surface, apply vacuum grease to the bottom of the cuvette, and then place the cuvette on the surface of the test sample. Pour deionized water into the cuvette.

[0112] The cold stage was cooled to -15°C using a cryogenic coolant circulation pump and maintained for 5 hours to allow the water column on the surface of the test sample to freeze completely.

[0113] Push the cuvette parallel to the surface with a force gauge until the ice block moves. Record the maximum force (Fm) required for the ice column to slide off the coating surface to assess the ice adhesion strength.

[0114] τ ice =(Fm) / A ice , where τ ice For ice adhesion strength, A ice This represents the base area of ​​the icicle. Repeat the experiment five or more times and take the average value.

[0115] The results of the coating ice adhesion test are shown below. Figure 11 For pure glass sheets, the ice adhesion force reaches 225.5 kPa, the ice adhesion force of coatings with only ZrN is 133.7 kPa, the ice adhesion force of coatings with only SiO2-F is 31.8 kPa, and the ice adhesion force of SiO2@ZrN is as low as 69.3 kPa.

[0116] Example 5

[0117] (1) Coating durability test:

[0118] Test conditions for coating durability testing: The coating's robustness is tested using a sand impact test, in which a continuous stream of sand particles falls from a height of 30 cm and impacts the surface of a sample tilted at 45°.

[0119] The coating's CA was then tested.

[0120] (2) The stability of the coating was further studied by simulating the impact of artificial raindrops. In the simulated artificial raindrop impact test, a continuous stream of water fell from a height of 30 cm and impacted the surface of the sample at an angle of 45°. Then the CA of the coating was tested.

[0121] (3) Actual tape peel test

[0122] Peel test was performed using 3MVHB 5952 tape:

[0123] Pressure was applied to the coating using a 1kg weight;

[0124] The hydrophobicity of the tape was measured by rolling it evenly 20 times with weights and then peeling it off.

[0125] See coating durability test results Figure 12 Among them, a is the gravel impact test, b is the water droplet impact test, and c is the tape peel test. It can be seen that, thanks to the excellent mechanical properties of the polyurethane substrate, the coating can remain superhydrophobic under 30 3M strong tape peel tests, 350g gravel impact, and 6L water droplet erosion, indicating that it has high durability.

[0126] Comparative Example 1

[0127] The reported icing time results on the photothermal superhydrophobic coatings are shown in Table 3.

[0128] Table 3 shows the reported icing times on photothermal superhydrophobic coatings.

[0129]

[0130] As can be seen from Table 3, the SiO2@ZrN coating can delay the freezing time of a 5 μL water droplet by up to 1422 s at -20 °C, which is better than most known photothermal superhydrophobic coatings.

[0131] This invention combines passive anti-icing with active photothermal de-icing to develop a photothermal anti-icing material for outdoor use. Under sunlight, the coating heats up, and as the ice begins to melt, a thin water film forms beneath it, significantly reducing the ice's adhesion strength and allowing it to detach under gravity or gentle natural wind. Therefore, it greatly reduces the damage to the micro / nano hierarchical structure during repeated icing / de-icing cycles, thus extending its service life.

[0132] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for preparing a photothermal anti-icing superhydrophobic coating, characterized in that: include, Polytetrahydrofuran (PTMG) was heated and vacuumed to remove water, resulting in dehydrated PTMG. Hydroxypropyl-terminated polydimethylsiloxane PDMS-OH was heated and vacuum dehydrated to obtain dehydrated PDMS-OH; The dehydrated PDMS-OH and dehydrated PTMG were mixed, ethyl acetate was added and stirred, and dicyclohexylmethane diisocyanate HMDI and dibutyltin dilaurate DBTDL were added dropwise for prepolymerization. When the reaction reached equilibrium, di(2-hydroxyethyl) disulfide HEDS was added, and the polyurethane was obtained after the reaction was completed. ZrN nanoparticles, fluorinated modified nano-silica SiO2-F, polyurethane, and ethyl acetate were mixed and ultrasonically mixed to obtain a suspension. The ZrN nanoparticles comprised 0.07–0.7 parts by mass, the SiO2-F comprised 0.5–0.8 parts by mass, the polyurethane comprised 1–2 parts by mass, and the ethyl acetate comprised 15–18 parts by mass. A coating is obtained by spraying the suspension and drying it to obtain a photothermal anti-icing superhydrophobic coating.

2. The preparation method according to claim 1, characterized in that: The process involves heating polytetrahydrofuran (PTMG) to remove water under vacuum, wherein the temperature is raised to 100-120°C and the vacuum removal time is 2-3 hours.

3. The preparation method according to claim 1 or 2, characterized in that: The process involves heating and vacuum dehydrating the hydroxypropyl-terminated polydimethylsiloxane PDMS-OH, wherein the temperature is raised to 110-120°C and the vacuum dehydration time is 2-3 hours.

4. The preparation method according to claim 1, characterized in that: Based on the mass fractions of the raw materials, the PDMS-OH is 1-20 parts, the PTMG is 18-20 parts, the dicyclohexylmethane diisocyanate (HMDI) is 6-9 parts, the dibutyltin dilaurate (DBTDL) is 0.01-0.06 parts, the di(2-hydroxyethyl) disulfide (HEDS) is 2-4 parts, and the ethyl acetate is 140-180 parts.

5. The preparation method according to claim 1 or 4, characterized in that: The prepolymerization reaction is carried out at a temperature of 60°C for 3 hours; the reaction is completed to obtain polyurethane, wherein the reaction temperature is 60°C and the reaction time is 8 hours.

6. The preparation method according to claim 1, characterized in that: The SiO2-F is prepared by the following methods: Anhydrous ethanol, ammonia, deionized water and 1H,1H,2H,2H-perfluorodecyltriethoxysilane were added to SiO2 and dispersed by vigorous stirring. The product suspension was obtained by reacting at 30-40℃ for 20-24 hours. The suspension was centrifuged at 10,000 rpm for 10 min, washed 2-3 times with ethanol, and then dried in a vacuum oven to obtain the product.

7. The preparation method according to claim 6, characterized in that: The ratio of SiO2, anhydrous ethanol, ammonia, deionized water and 1H,1H,2H,2H-perfluorodecyltriethoxysilane is 2~4g:100~180mL:4~8mL:10~20mL:1~2mL.

8. The preparation method according to claim 1, characterized in that: The process of spraying a suspension to obtain a coating includes, Use a spray gun with a nozzle diameter of 0.3mm to repeatedly spray the suspension 3 to 5 times, with a spraying distance of 10cm and a spraying temperature of 25℃. The obtained coating was then placed in a forced-air drying oven and heated at 80°C for 1 hour to obtain the coating.

9. The photothermal anti-icing superhydrophobic coating prepared by any one of claims 1 to 8, characterized in that: The thickness of the photothermal anti-icing superhydrophobic coating is 150~200μm.

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