An anti-icing super-hydrophobic and super-slippery nano-coating material, its preparation method and application

Abstract

The present invention discloses an anti-icing superhydrophobic and super-slippery nano-coating material, its preparation method and application, relating to the technical field of nano-coatings. The anti-icing superhydrophobic and super-slippery nano-coating material provided by the present invention comprises polymer-grafted SiO2 particles, and the particles include a nano-SiO2 core modified by a silane coupling agent, a PAMAM intermediate layer and a perfluoropolyether outer shell. The introduction of PAMAM increases the grafting density of perfluoropolyether on the surface of nano-SiO2. Moreover, the perfluoropolyether not only reduces the surface energy of the coating, but also the end of its molecular chain can move freely to simulate a lubricating effect similar to that of a liquid. Therefore, the coating in the present invention can not only achieve superhydrophobic performance, but also have super-slippery performance. Spraying the coating material of the present invention on the surface of a substrate can obtain an anti-icing superhydrophobic and super-slippery nano-coating, and the coating has excellent adhesion to the substrate.

Description

Technical Field

[0001] The present invention relates to the technical field of nano-coating, and particularly to a nano-coating material with anti-icing, super-hydrophobic and super-slippery properties, a preparation method thereof and an application thereof. Background Art

[0002] Insulators are important components in the power system, which play the roles of isolating voltage and supporting conductors. Under normal working conditions, insulators can effectively prevent conduction between high-voltage live conductors or between a live conductor and the ground, ensuring the stable operation of the system. However, under extreme weather conditions such as freezing rain, icing phenomena such as rime and glaze will appear on the surface of insulators. The ice formed on the surface of insulators often incorporates impurities and contaminants in the air, greatly reducing the electrical insulation performance of the insulators. In severe icing cases, the sheds of the insulators may even be bridged by ice crystals, resulting in a decrease in insulation strength and a shortening of the leakage distance, and further causing frequent ice flashovers, seriously affecting the safety of the power system.

[0003] Hydrophobic modification of the surface of insulator materials can effectively delay the ice formation process on the insulator surface. However, under extreme weather conditions, the droplets on the hydrophobic surface cannot be removed in time after condensing into ice, and these ice surfaces replace the original hydrophobic surface, making subsequent icing still difficult to avoid. Moreover, the construction of a hydrophobic surface usually requires increasing the surface roughness of the material, which may lead to the phenomenon of condensation pinning of tiny droplets in the air on the pores of the insulator material surface under extreme weather conditions. When the supercooling degree is large, these micro-droplets will become the nucleation points for ice crystal growth, greatly increasing the adhesion force between the surface ice and the substrate and making it more difficult to remove.

[0004] In recent years, researchers have proposed a new passive anti-icing technology, namely a super-slippery coating. A super-slippery coating specifically refers to a coating on which external liquids are not wetted and can easily slide off (the sliding angle is extremely small). The root cause lies in the presence of lubricating liquid molecules with a low surface energy, chemically bonded liquid-like molecules, or both on the coating surface. Among them, when there are chemically bonded liquid-like (generally polymers) molecules on the coating surface, one end of the polymer chain segment is fixed on the substrate surface, and the other end is uniformly arranged on the substrate surface in a freely movable manner, thereby simulating a lubricating effect similar to that of a liquid, significantly reducing the adhesion force between external water droplets and the substrate, effectively preventing the adhesion of droplets and accumulated ice on the surface, and not easily showing the pinning phenomenon of droplets and ice crystals.

[0005] Combining two coating mechanisms to construct a superhydrophobic and super-slippery coating can achieve a more long-lasting anti-icing effect, but current research in this area still needs to be deepened. In addition, since most of the insulators used in current power facilities such as substations are made of ceramic and glass materials, their surfaces are smooth and it is difficult to form a strong bond with the coating, especially for superhydrophobic coatings: the surface energy of superhydrophobic materials is low, and the bonding force with the surface of the insulator substrate is even lower, which results in the coating on the insulator surface being prone to peeling and having poor durability, and cannot be used for a long time. Summary of the Invention

[0006] To solve the deficiencies of the prior art, the present invention provides a superhydrophobic and super-slippery anti-icing nano-coating material. Dendritic polymer PAMAM (polyamide-amine) and PFPE (perfluoropolyether) are successively grafted onto silane-coupling-agent-modified nano-SiO2 particles to obtain polymer-grafted SiO2 particles SiO2-PAMAM-PFPE with a core-shell structure. Spraying its dispersion liquid on the surface of the substrate can obtain a superhydrophobic and super-slippery anti-icing nano-coating, and the coating of the present invention has excellent bonding force with the substrate.

[0007] Another object of the present invention is to provide a preparation method of a superhydrophobic and super-slippery anti-icing nano-coating material.

[0008] Another object of the present invention is to provide a preparation method of a superhydrophobic and super-slippery anti-icing nano-coating.

[0009] The above objects of the present invention are achieved by the following technical solutions:

[0010] A superhydrophobic and super-slippery anti-icing nano-coating material includes a core, an intermediate layer and a shell from the inside out. The core includes silane-coupling-agent-modified nano-SiO2 particles, the intermediate layer includes polyamide-amine, and the shell includes acyl chloride-modified perfluoropolyether.

[0011] The anti-icing superhydrophobic and super-slippery nanocoating material provided by the present invention (which can be represented by SiO2-PAMAM-PFPE) grafts a dendritic polymer PAMAM (polyamide-amine) on the surface of nano-SiO2 particles first, providing a large number of active sites for the grafting of acyl chloride-modified PFPE (perfluoropolyether). As a result, the acyl chloride-modified PFPE can be grafted onto the surface of nano-SiO2 particles to form a shell through the nucleophilic addition reaction between acyl chloride and amine. Moreover, these active sites provided by PAMAM are distributed in a dendritic manner, avoiding the influence of steric hindrance and other effects on the subsequent grafting density of PFPE. Therefore, a high-density grafting of PFPE can be achieved on the surface of SiO2-PAMAM. The grafting of PFPE can reduce the surface energy, and the material in the present invention can form a rough structure through the accumulation of nanoparticles after being coated on the substrate surface. The combination of the two factors of low surface energy and rough texture can endow the coating formed by the present invention with superhydrophobicity. However, compared with conventional superhydrophobic surfaces, the simultaneous introduction of PAMAM and PFPE into nano-SiO2 particles in the present invention can enable the free movement of the ends of PFPE (the PFPE molecular chain has high flexibility), thereby simulating a liquid-like lubricating effect, making the contact between the coating surface and water change from a micro-nano level solid-liquid contact to a molecular level liquid-liquid contact, reducing the adhesion resistance of the droplet rolling on the coating surface. Therefore, the coating in the present invention can possess super-slippery performance, reducing the friction coefficient of external droplets on the coating surface, effectively slowing down the nucleation and growth of ice crystals on the coating surface, and also preventing the pinning effect of ice crystals from affecting the anti-icing performance of the coating. At the same time, the contact between the outermost PFPE of the material in the present invention and the substrate is similar to a solid-liquid contact. Even though the surface energy of the material in the present invention is reduced, the solid-liquid contact mode can reduce the number of air gaps between the coating material and the substrate. Therefore, the coating material in the present invention can still form a good bond with the substrate even though the surface energy is reduced. All in all, the coating provided by the present invention has excellent adhesion to the substrate while possessing high hydrophobicity and super-slippery performance.

[0012] Preferably, the silane coupling agent includes an amino silane coupling agent.

[0013] The surface of nano-SiO2 particles contains hydroxyl groups. After reacting with an amino silane coupling agent, amino groups can be grafted onto the surface. On this basis, a dendritic polymer PAMAM intermediate layer can be formed on the surface of nano-SiO2 particles through chemical bonding.

[0014] In a specific embodiment of the present invention, the amino silane coupling agent includes 3-aminopropyltriethoxysilane.

[0015] More preferably, the nano-SiO2 particles modified by the silane coupling agent are prepared by reacting nano-SiO2 particles with a silane coupling agent in a mass ratio of (50~80):35, and the temperature of the reaction is 50~100 °C.

[0016] In a specific embodiment of the present invention, the reaction is carried out in a solution.

[0017] More specifically, the solution includes toluene. More specifically, the mass ratio of the toluene to the nano-SiO2 particles is (350~450):65.

[0018] More specifically, the reaction time is 1~3 h.

[0019] More specifically, the reaction is carried out under oscillating conditions.

[0020] More specifically, the reaction further includes a drying step. More specifically, the drying temperature is 50~60 °C.

[0021] Preferably, the particle size of the nano-SiO2 particles is 10~60 nm.

[0022] More preferably, the particle size of the nano-SiO2 particles is 20~50 nm.

[0023] Preferably, the thickness of the intermediate layer is 200~500 nm.

[0024] Preferably, the thickness of the outer shell is 60~300 nm.

[0025] More preferably, the thickness of the outer shell is 150~300 nm.

[0026] It should be noted that the test method for the particle size and thickness in the present invention is as follows: perform a cross-section SEM test on the material, observe the particle size of the inner core, the thickness of the intermediate layer and the outer shell for 10 samples in sequence and calculate their arithmetic mean values, and take the approximate integer as the final value.

[0027] Preferably, the polyamide-amine is prepared by reacting methyl acrylate with ethylenediamine in a mass ratio of (15~40):(300~800), and the temperature of the reaction is 20~30 °C.

[0028] More preferably, the polyamide-amine is prepared by reacting methyl acrylate with ethylenediamine in a mass ratio of (25~40):(500~600).

[0029] By reacting methyl acrylate and ethylenediamine, dendritic PAMAM polyamide-amine can be constructed. Among them, the "branches" of the dendritic polymer are mainly ethylenediamine structures, and methyl acrylate can be regarded as the "nodes" for forming new branches. Controlling the ratio of the two compounds within the above range can obtain dendritic PAMAM with a more suitable structure, which can not only ensure hydrophobicity (too many "branches" of PAMAM may lead to a decrease in hydrophobicity), but also improve the grafting density of PFPE modified by subsequent acyl chlorination as much as possible.

[0030] More preferably, the mass ratio of the silane coupling agent-modified nano-SiO2 particles to methyl acrylate is 60:(15 - 40).

[0031] More preferably, the mass ratio of the silane coupling agent-modified nano-SiO2 particles to methyl acrylate is 60:(25 - 40).

[0032] After controlling the ratio of methyl acrylate and ethylenediamine, the structure of dendritic PAMAM remains basically unchanged. On this basis, adjusting the mass ratio of methyl acrylate to the silane coupling agent-modified nano-SiO2 particles is beneficial to obtaining PAMAM with a more suitable grafting amount, and thus obtaining better performance. Too much grafting amount of PAMAM is also likely to lead to a decrease in the hydrophobicity of the coating.

[0033] More preferably, the average molecular weight of the acyl chloride-modified perfluoropolyether is 1000 - 4000.

[0034] More preferably, the mass ratio of the silane coupling agent-modified nano-SiO2 particles to the acyl chloride-modified perfluoropolyether is (80 - 95):(5 - 20).

[0035] More preferably, the mass ratio of the silane coupling agent-modified nano-SiO2 particles to the acyl chloride-modified perfluoropolyether is (85 - 90):(10 - 15).

[0036] The present invention also protects a preparation method of the above anti-icing super-hydrophobic and super-slippery nano-coating material, which includes the following steps:

[0037] S1. Mix the silane coupling agent-modified nano-SiO2 particles and methyl acrylate, react at 40 - 80 °C to obtain SiO2-MA, add ethylenediamine and continue to react at 20 - 30 °C, and obtain SiO2-PAMAM after the reaction;

[0038] S2. Mix the SiO2-PAMAM obtained in step S1 with the acyl chloride-modified perfluoropolyether, carry out a grafting reaction at 60 - 100 °C, and the anti-icing super-hydrophobic and super-slippery nano-coating material can be obtained after the reaction.

[0039] In a specific embodiment of the present invention, the reaction time at 40 - 80 °C in step S1 is 3 - 5 h.

[0040] In a specific embodiment of the present invention, the reaction at 40 - 80 °C in step S1 is carried out in an inert atmosphere. More specifically, the inert atmosphere is a nitrogen atmosphere.

[0041] In a specific embodiment of the present invention, the reaction at 40 - 80 °C in step S1 is carried out in a solution, and the solution includes methanol. More specifically, the volume of the methanol is 450 - 500 mL.

[0042] In a specific embodiment of the present invention, the reaction at 40 - 80 °C in step S1 is carried out under oscillating conditions.

[0043] In a specific embodiment of the present invention, after the reaction at 40 - 80 °C in step S1 to obtain SiO2 - MA, it further includes a step of drying SiO2 - MA.

[0044] In a specific embodiment of the present invention, the time for continuing the reaction by adding ethylenediamine in step S1 is 10 - 14 h.

[0045] In a specific embodiment of the present invention, the reaction of continuing to add ethylenediamine in step S1 is carried out in a solution, and the solution includes methanol. More specifically, the volume of the methanol is 350 - 450 mL.

[0046] In a specific embodiment of the present invention, the reaction of continuing to add ethylenediamine in step S1 is carried out under oscillating conditions.

[0047] In a specific embodiment of the present invention, after the reaction of continuing to add ethylenediamine in step S1 to obtain SiO2 - PAMAM, it further includes a step of drying SiO2 - PAMAM.

[0048] In a specific embodiment of the present invention, the preparation method of the acyl - chlorinated modified perfluoropolyether in step S2 includes the following steps:

[0049] Mix an excessive amount of SOCl2 with the perfluoropolyether with terminal carboxyl groups, and react at 40 - 60 °C for 1 - 2 h to acyl - chlorinate the terminal carboxyl groups of the perfluoropolyether with terminal carboxyl groups, thereby obtaining the acyl - chlorinated modified perfluoropolyether.

[0050] More specifically, after the reaction at 40 - 60 °C, it further includes a step of raising the temperature to 80 - 100 °C and continuing the reaction for 5 - 15 min.

[0051] The purpose of the above - mentioned temperature - raising and continuing the reaction is to remove the unreacted SOCl2.

[0052] In a specific embodiment of the present invention, the grafting reaction in step S2 is carried out under water bath and reflux conditions.

[0053] In a specific embodiment of the present invention, the time of the grafting reaction in step S2 is 22 to 26 h.

[0054] In a specific embodiment of the present invention, after obtaining the anti-icing superhydrophobic and super-slippery nano-coating material in step S2, the steps of suction filtration and drying are further included. More specifically, the drying is carried out at 50 to 70 °C for 22 to 26 h.

[0055] The present invention also protects a preparation method of an anti-icing superhydrophobic and super-slippery nano-coating, which includes the following steps:

[0056] Spray the dispersion liquid of the anti-icing superhydrophobic and super-slippery nano-coating material on the surface of the substrate and cure it, then an anti-icing superhydrophobic and super-slippery nano-coating can be formed on the surface of the substrate.

[0057] In a specific embodiment of the present invention, the substrate can be glass.

[0058] In a specific embodiment of the present invention, the dispersion liquid of the anti-icing superhydrophobic and super-slippery nano-coating material includes the anti-icing superhydrophobic and super-slippery nano-coating material SiO2-PAMAM-PFPE and a solvent, and the solvent includes butyl acetate, ethanol and FEVE-type fluorocarbon resin. More specifically, the mass ratio of butyl acetate, ethanol and FEVE-type fluorocarbon resin is (600 to 1000):(300 to 500):50. More specifically, the mass ratio of the solvent to SiO2-PAMAM-PFPE is (950 to 1550):(60 to 100).

[0059] In a specific embodiment of the present invention, the preparation method of the dispersion liquid includes the following steps: mix SiO2-PAMAM-PFPE with the solvent, stir for 30 min and ultrasonically disperse for 10 min.

[0060] Preferably, before the spraying, the step of plasma activation of the substrate surface is further included.

[0061] More preferably, the plasma activation is carried out using a plasma gas, and the gas includes at least two of oxygen, nitrogen and argon.

[0062] More preferably, the plasma activation is: after ionizing with a voltage of 300 W to 1000 W to obtain a plasma gas, carry out the activation.

[0063] More preferably, when the plasma activation is carried out, the gas flow rate is 5 to 100 sccm, and the plasma activation time is 5 to 30 min.

[0064] In a specific embodiment of the present invention, before the plasma activation, a step of cleaning the substrate is further included.

[0065] More specifically, the cleaning includes the following steps: wetting the surface of the substrate with water to soften the dirt and reduce friction, gently scrubbing the surface of the substrate with a soft brush or sponge to remove the dirt, performing overall cleaning of the substrate with a high-pressure water gun, and blowing dry the surface of the substrate with gas after the cleaning to complete the cleaning process. More specifically, the pressure of the high-pressure water gun is controlled at 500 - 1000 bar.

[0066] In a specific embodiment of the present invention, after spraying the dispersion liquid of the anti-icing super-hydrophobic and super-slippery nano-coating material on the surface of the substrate, the curing is heat curing. More specifically, the heat curing includes the following steps:

[0067] Spraying a solution containing a photothermal material on the surface of the film, and after the photothermal material is cured, covering the film on the surface of the substrate sprayed with the anti-icing super-hydrophobic and super-slippery nano-coating material and performing light irradiation, so that the coating material can be cured to form an anti-icing super-hydrophobic and super-slippery nano-coating.

[0068] More specifically, the film includes at least one of polyethylene terephthalate (PET), polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), polypropylene (PP), polystyrene (PS), or polyvinyl chloride (PVC).

[0069] More specifically, the photothermal material includes at least one of carbon black, carbon nanotubes, and graphene.

[0070] More specifically, the solution containing the photothermal material further includes a resin crosslinking agent.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] The anti-icing super-hydrophobic and super-slippery nano-coating prepared by the present invention has super-hydrophobic and super-slippery properties, with a static water contact angle as high as over 143° and a rolling angle as low as below 8°. It can effectively prevent water droplets from adsorbing and staying on the surface of the coating. Therefore, it can be applied to the anti-icing of the surface of insulators. After 8 hours of testing under freezing rain conditions, no icicles appear on the surface of the insulators coated with the coating of the present invention. At the same time, the nano-coating provided by the present invention has excellent adhesion to the substrate. Description of the Drawings

[0073] Figure 1 The photo of the water droplet contact angle on the glass surface for insulators after plasma activation.

[0074] Figure 2 The photo of the water droplet contact angle on the glass surface for insulators after coating with the anti-icing super-hydrophobic and super-slippery nano-coating in Example 1 of the present invention.

[0075] Figure 3 The icing condition of the insulator sample with the anti-icing superhydrophobic and super-slippery nano-coating of the present invention on its surface (left) under simulated freezing rain conditions and its comparison photo with the untreated insulator (right). Detailed implementation manners

[0076] The present invention will be further described below in conjunction with the detailed implementation manners, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw material reagents used in the embodiments of the present invention are conventionally purchased raw material reagents. Among them, the raw material information used in each embodiment and the comparative example is as follows:

[0077] Carboxyl-terminated perfluoropolyether: Carboxyl-terminated PFPE, CAS No.: 51798-33-5, purchased from Fuzhou Taipuda New Materials Co., Ltd., with an average molecular weight of 2000.

[0078] Example 1

[0079] A preparation method of an anti-icing superhydrophobic and super-slippery nano-coating material, comprising the following steps:

[0080] S1. In a nitrogen atmosphere, 60 g of nano-SiO2 particles modified with a silane coupling agent and 31 mL (29.6 g) of methyl acrylate are mixed and added to a flask containing 480 mL of methanol solvent, and oscillated at 60 °C for 4 hours to fully react and then dried to obtain SiO2-MA. Mix SiO2-MA and 600 mL (539.4 g) of ethylenediamine, add them to 400 mL of methanol solvent at 25 °C and oscillate for reaction for 12 h, and dry the reaction product to obtain SiO2-PAMAM;

[0081] S2. Mix 6.67 g of perfluoropolyether modified by acyl chlorination with the SiO2-PAMAM obtained in step S1 (the mass ratio of the nano-SiO2 particles modified with the silane coupling agent to the perfluoropolyether modified by acyl chlorination in S1 is 90:10), and reflux in a water bath at 80 °C for 24 h for grafting reaction. After the reaction, filter the obtained suspension and dry it at 60 °C for 24 h to obtain the anti-icing superhydrophobic and super-slippery nano-coating material SiO2-PAMAM-PFPE;

[0082] The preparation method of the nano-SiO2 particles modified with the silane coupling agent described in step S1 comprises the following steps: Mix 65 g of nano-SiO2 particles with a particle size of 20 nm and 35 mL (33.11 g) of the silane coupling agent 3-aminopropyltriethoxysilane, oscillate and react in 400 mL of toluene solvent at 75 °C for 2 h, and dry the product at 55 °C to obtain the nano-SiO2 particles modified with the silane coupling agent, and the particle size of the particles remains basically unchanged before and after modification;

[0083] The preparation method of the acyl chloride-modified PFPE described in step S2 includes the following steps:

[0084] Mix an excess of SOCl2 with 60 g of perfluoropolyether with terminal carboxyl groups, react at 50 °C for 1.5 h, then raise the temperature to 90 °C and continue for 10 min to remove the unreacted SOCl2, obtaining the acyl chloride-modified perfluoropolyether.

[0085] The anti-icing superhydrophobic and super-slippery nano-coating material prepared in this example includes a core, an intermediate layer, and a shell from the inside out. The core includes nano-SiO2 particles with a particle size of 20 nm modified by a silane coupling agent. The intermediate layer includes a dendritic polymer polyamidoamine with a thickness of ~300 nm. The shell includes the acyl chloride-modified perfluoropolyether with a thickness of ~200 nm.

[0086] Example 2

[0087] A preparation method of an anti-icing superhydrophobic and super-slippery nano-coating material, which is only different from Example 1 in that:

[0088] The nano-SiO2 particles modified by the silane coupling agent described in step S1 are prepared by reacting nano-SiO2 particles with a particle size of 10 nm and an equal mass of the silane coupling agent.

[0089] The anti-icing superhydrophobic and super-slippery nano-coating material prepared in this example includes a core, an intermediate layer, and a shell from the inside out. The core includes nano-SiO2 particles with a particle size of 10 nm modified by a silane coupling agent. The intermediate layer includes a dendritic polymer polyamidoamine with a thickness of ~320 nm. The shell includes the acyl chloride-modified perfluoropolyether with a thickness of ~190 nm.

[0090] Example 3

[0091] A preparation method of an anti-icing superhydrophobic and super-slippery nano-coating material, which is only different from Example 1 in that:

[0092] The nano-SiO2 particles modified by the silane coupling agent described in step S1 are prepared by reacting nano-SiO2 particles with a particle size of 60 nm and an equal mass of the silane coupling agent.

[0093] The anti-icing superhydrophobic and super-slippery nano-coating material prepared in this example includes a core, an intermediate layer, and a shell from the inside out. The core includes nano-SiO2 particles with a particle size of 60 nm modified by a silane coupling agent. The intermediate layer includes a dendritic polymer polyamidoamine with a thickness of ~260 nm. The shell includes the acyl chloride-modified perfluoropolyether with a thickness of ~200 nm.

[0094] Example 4

[0095] A preparation method of an anti-icing super-hydrophobic and super-slippery nano-coating material, which is only different from Example 1 in that:

[0096] The added amount of methyl acrylate in step S1 is 40 mL (38.2 g), and the added amount of ethylenediamine is 800 mL (719.2 g).

[0097] The anti-icing super-hydrophobic and super-slippery nano-coating material prepared in this example includes a core, an intermediate layer and a shell from the inside out. The core includes nano-SiO2 particles with a particle size of 20 nm modified by a silane coupling agent. The intermediate layer includes a dendritic polymer polyamide-amine with a thickness of ~420 nm, and the shell includes perfluoropolyether modified by acyl chloride with a thickness of ~140 nm.

[0098] Example 5

[0099] A preparation method of an anti-icing super-hydrophobic and super-slippery nano-coating material, which is only different from Example 1 in that:

[0100] The added amount of methyl acrylate in step S1 is 20 mL (19.1 g), and the added amount of ethylenediamine is 400 mL (359.6 g).

[0101] The anti-icing super-hydrophobic and super-slippery nano-coating material prepared in this example includes a core, an intermediate layer and a shell from the inside out. The core includes nano-SiO2 particles with a particle size of 20 nm modified by a silane coupling agent. The intermediate layer includes a dendritic polymer polyamide-amine with a thickness of ~350 nm, and the shell includes perfluoropolyether modified by acyl chloride with a thickness of ~180 nm.

[0102] Example 6

[0103] A preparation method of an anti-icing super-hydrophobic and super-slippery nano-coating material, which is only different from Example 1 in that:

[0104] The mass of perfluoropolyether modified by acyl chloride added in step S2 is 15 g (the mass ratio of nano-SiO2 particles modified by silane coupling agent to perfluoropolyether modified by acyl chloride in S1 is 80:20).

[0105] The anti-icing super-hydrophobic and super-slippery nano-coating material prepared in this example includes a core, an intermediate layer and a shell from the inside out. The core includes nano-SiO2 particles with a particle size of 20 nm modified by a silane coupling agent. The intermediate layer includes a dendritic polymer polyamide-amine with a thickness of ~300 nm, and the shell includes perfluoropolyether modified by acyl chloride with a thickness of ~260 nm.

[0106] Example 7

[0107] A preparation method of an anti-icing super-hydrophobic and super-slippery nano-coating material, which is only different from Example 1 in that:

[0108] In step S2, the mass of the perfluoropolyether modified by acyl chloride added is 3.16 g (the mass ratio of the nano-SiO2 particles modified by silane coupling agent to the perfluoropolyether modified by acyl chloride in S1 is 95:5).

[0109] The anti-icing super-hydrophobic and super-slippery nano-coating material prepared in this example includes a core, an intermediate layer and a shell from the inside out. The core includes nano-SiO2 particles with a particle size of 20 nm modified by silane coupling agent. The intermediate layer includes dendritic polymer polyamidoamine with a thickness of ~300 nm. The shell includes perfluoropolyether modified by acyl chloride with a thickness of ~60 nm.

[0110] Comparative Example 1

[0111] A preparation method of a nano-coating material, which is only different from Example 1 in that:

[0112] Do not perform the PAMAM grafting in step S1; that is, directly react the nano-SiO2 particles modified by silane coupling agent with the perfluoropolyether modified by acyl chloride.

[0113] The nano-coating material prepared in this comparative example includes a core and a shell from the inside out. The core includes nano-SiO2 particles with a particle size of 20 nm modified by silane coupling agent. The shell includes perfluoropolyether modified by acyl chloride with a thickness of ~450 nm.

[0114] Comparative Example 2

[0115] A preparation method of a nano-coating material, which is only different from Example 1 in that:

[0116] Do not perform the PEFE grafting in step S2; that is, end the reaction after obtaining SiO2-PAMAM in step S1.

[0117] The nano-coating material prepared in this comparative example includes a core and a shell from the inside out. The core includes nano-SiO2 particles with a particle size of 20 nm modified by silane coupling agent. The shell includes dendritic polymer polyamidoamine with a thickness of ~300 nm.

[0118] Comparative Example 3

[0119] A preparation method of a nano-coating material, which is only different from Example 1 in that:

[0120] In step S2, replace the perfluoropolyether modified by acyl chloride with an equal mass of FEP (perfluoroethylene-propylene) modified by acyl chloride.

[0121] The nano - coating material prepared in this comparative example includes a core, an intermediate layer, and a shell from the inside out. The core includes nano - SiO₂ particles with a particle size of 20 nm modified by a silane coupling agent. The intermediate layer includes a dendritic polymer polyamide - amine with a thickness of about 300 nm. The shell includes FEP modified by acyl chloride with a thickness of about 200 nm.

[0122] Comparative Example 4

[0123] A preparation method of a nano - coating material, which is only different from Example 1 in that:

[0124] In step S1, nano - SiO₂ particles modified by a silane coupling agent are not added, and methyl acrylate is directly reacted with ethylenediamine to form PAMAM.

[0125] The nano - coating material prepared in this comparative example includes a core and a shell from the inside out. The core includes a dendritic polymer polyamide - amine with a thickness of about 320 nm. The shell includes perfluoropolyether modified by acyl chloride with a thickness of about 210 nm.

[0126] Performance test: Next, the coating materials obtained in the examples and comparative examples are respectively sprayed on the glass surface and the insulator surface for insulators. After forming the coating, their basic performance and anti - icing performance are tested. The test schemes and the obtained effects are shown in Effect Examples 1 and 2.

[0127] Effect Example 1: Basic performance test of the coating

[0128] Preparation of the coating: The coating materials obtained in Examples 1 - 7 and Comparative Examples 1 - 4 are dispersed in a solvent composed of 800 g of butyl acetate, 400 g of ethanol, and 50 g of FEVE - type fluorocarbon resin. After stirring for 30 min, ultrasonic dispersion is carried out for 10 min to obtain a dispersion liquid. After spraying it on the surface of the substrate (glass for insulators) and curing, a super - hydrophobic and super - slippery anti - icing nano - coating can be obtained. The spraying amount is about 50 mg / cm 2 ; The surface of the substrate is cleaned and plasma - activated before spraying. Specifically: The surface of the substrate is wetted with deionized water, the surface is cleaned with a soft brush, and then washed again with a high - pressure water gun with a pressure of 500 bar. After washing, it is dried with an air gun for 5 min. Then, the surface of the washed and dried substrate is activated by an atmospheric plasma generator, introducing oxygen and argon with a flow rate of 50 sccm each, inputting a plasma power of 500 W, and uniformly treating the substrate surface for 20 min; The curing is as follows: Carbon black and a resin cross - linker are coated on the surface of a PET film. After curing, the film is wrapped around the substrate surface sprayed with the coating material and placed in natural sunlight for 4 h to heat - cure the coating.

[0129] Hydrophobicity and lubricity test of the coating: The hydrophobicity and lubricity of the coating were tested using a contact angle measuring instrument, represented by the static water contact angle and the sliding angle respectively. The adhesion between the coating film and the substrate was evaluated with reference to the cross-cut tape test standard of ISO 2409, ranging from 0 to 5 levels, with level 0 being the highest.

[0130] The specific performance test data are shown in Table 1 below:

[0131] Table 1 Hydrophobicity and lubricity test data of the coatings in the examples and comparative examples

[0132]

[0133] As can be seen from Table 1 above, the anti-icing superhydrophobic and super-slippery nano-coating prepared by the present invention has superhydrophobic properties, with a static water contact angle as high as over 143° and a rolling angle as low as below 8°, indicating excellent sliding performance and the ability to prevent water droplets from adsorbing and staying on the coating surface.

[0134] Among them, according to the data of Examples 1 to 3, it can be seen that using nano-SiO2 particles with a particle size in the more preferred range of 20 to 50 nm in the present invention to construct the superhydrophobic and super-slippery coating in the present invention (Example 1) can achieve better superhydrophobic and super-slippery properties. This may be because, compared with larger-sized nano-particles, SiO2 particles with a size of 20 to 50 nm can make the coating have a higher surface roughness; while compared with smaller-sized nano-particles, particles with a size of 20 to 50 nm can make the coating have a more appropriate grafting ratio of PAMAM and PFPE.

[0135] According to the data of Examples 1, 4 to 5, it can be seen that the grafting amount of PAMAM on the surface of nano-SiO2 particles has an important influence on the contact angle and sliding angle of the coating (the ratio of methyl acrylate to ethylenediamine remains unchanged in Examples 1, 4 to 5, and the structure of PAMAM remains basically unchanged). When the grafting amount of PFPE remains unchanged and the grafting amount of PAMAM is higher (Example 4), since PAMAM itself is hydrophilic, it will lead to a decrease in the hydrophobicity of the coating; but a decrease in the grafting amount of PAMAM (Example 5) will affect the grafting amount of PFPE, so it will also lead to a decrease in the hydrophobicity of the coating.

[0136] According to the data of Examples 1, 6 to 7, it can be seen that the grafting amount of PFPE on the surface of nano-particles also has an important influence on the contact angle and sliding angle of the coating. When the grafting amount of PFPE is too high (Example 6), it may lead to a decrease in the activity space of the flexible chain of PFPE, so the hydrophobic and lubricating properties decrease; while when the grafting amount of PFPE is too low (Example 7), it has a greater impact on the contact angle and sliding angle of the coating.

[0137] As can be seen from Comparative Examples 1-2, in the coating provided by the present invention, to achieve superhydrophobic and super-slippery properties, two polymers, PAMAM and PFPE, must be grafted; according to Comparative Example 3, when the highly flexible PFPE is replaced with FEP, the surface still has a relatively high contact angle and hydrophobicity. However, since FEP does not have the high flexibility of PFPE and the lubricating effect similar to that of a liquid, the coating does not have super-slippery characteristics, resulting in a significant increase in the water droplet sliding angle of the coating. At the same time, the grafting of FEP will lead to a decrease in the surface energy of the particles, and further lead to a decrease in the bonding force between the coating and the substrate.

[0138] According to Comparative Example 4, PAMAM-PFPE was directly sprayed on the surface of the substrate. Due to the lack of nano-SiO2 particles, a rough texture could not be formed on the surface of the substrate, so its contact angle was not higher than 120°. However, due to the grafting of a high-density of highly flexible PFPE chains on the substrate under the action of PAMAM, the coating still had certain super-slippery characteristics and showed a relatively low water droplet sliding angle.

[0139] Effect Example 2: Anti-icing performance test of the coating

[0140] The untreated insulator (only the cleaning step was performed) and the insulator coated with the anti-icing superhydrophobic and super-slippery nano-coating in Example 1 of the present invention were jointly placed in a simulated freezing rain environment (-10 °C, continuously spraying water at ~4 °C) for anti-icing performance testing. After spraying for 0.5 h, it was kept warm for 1.5 h, and this was taken as one cycle. After 4 cycles, the icing situation on the surface of the insulator was observed.

[0141] The specific performance test situation is as Figure 3 shown: The untreated insulator (right) on the surface had thick ice, while the treated insulator (left) had no icing situation because water droplets could not nucleate and freeze on its surface due to the high hydrophobicity and super-slipperiness of the surface.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A nano - coating material with anti - icing, super - hydrophobic and super - slippery properties, characterized in that, From the inside out, it includes a core, an intermediate layer and a shell. The core includes nano-SiO2 particles modified with a silane coupling agent, the intermediate layer includes polyamide-amine, and the shell includes perfluoropolyether modified by acyl chloride; The silane coupling agent includes an amino silane coupling agent; The preparation method of the anti-icing superhydrophobic and super-slippery nano-coating material includes the following steps: S1. Mix the nano-SiO2 particles modified with a silane coupling agent with methyl acrylate, react at 40-80 °C to obtain SiO2-MA, add ethylenediamine and continue to react at 20-30 °C, and obtain SiO2-PAMAM after the reaction; S2. Mix the SiO2-PAMAM obtained in step S1 with the perfluoropolyether modified by acyl chloride, carry out a grafting reaction at 60-100 °C, and the anti-icing superhydrophobic and super-slippery nano-coating material can be obtained after the reaction.

2. The anti-icing super-hydrophobic and super-slippery nano-coating material according to claim 1, wherein The nano-SiO2 particles modified with a silane coupling agent are prepared by reacting nano-SiO2 particles with a silane coupling agent in a mass ratio of (50-80):35, and the reaction temperature is 50-100 °C.

3. The anti-icing superhydrophobic and super-slippery nano-coating material according to claim 1, wherein It includes at least one of the following (a)-(c): (a) The particle size of the nano-SiO2 particles is 10-60 nm; (b) The thickness of the intermediate layer is 200-500 nm; (c) The thickness of the shell is 60-300 nm.

4. The anti-icing superhydrophobic and super-slippery nano-coating material according to claim 3, characterized in that, The polyamide-amine is prepared by reacting methyl acrylate with ethylenediamine in a mass ratio of (15-40):(300-800), and the reaction temperature is 20-30 °C.

5. The anti-icing super-hydrophobic and super-slippery nano-coating material according to claim 4, characterized in that, The mass ratio of the nano-SiO2 particles modified with a silane coupling agent to methyl acrylate is 60:(15-40).

6. The anti-icing super-hydrophobic and super-slippery nano-coating material according to claim 3, wherein The average molecular weight of the perfluoropolyether modified by acyl chloride is 1000-400.

7. The anti-icing super-hydrophobic and super-slippery nano-coating material according to claim 6, wherein The mass ratio of the nano-SiO2 particles modified with a silane coupling agent to the perfluoropolyether modified by acyl chloride is (80-95):(5-20).

8. A preparation method of an anti-icing super-hydrophobic and super-slippery nano-coating, characterized in that, It includes the following steps: Spray the dispersion of the anti-icing superhydrophobic and super-slippery nano-coating material according to any one of claims 1-7 on the surface of the substrate and cure it, and an anti-icing superhydrophobic and super-slippery nano-coating can be formed on the surface of the substrate.

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