Multidimensional composite light-heat hydrophobic anti-icing coating and preparation method thereof

Abstract

This invention discloses a multi-dimensional composite photothermal hydrophobic anti-icing coating and its preparation method. The coating comprises a flexible hydrophobic matrix and a photothermal material uniformly dispersed within the flexible hydrophobic matrix; the flexible hydrophobic matrix is ​​a polydimethylsiloxane (PDMS) matrix; the photothermal material is a ternary composite photothermal material comprising titanium nitride (TiN), carbon nanotubes (CNTs), and MXene, with a silanized surface; wherein the mass ratio of TiN, CNTs, and MXene is (0.5–2):(0.5–2):(0.5–1). This coating enhances photothermal performance through broad-spectrum light absorption and a highly efficient thermally conductive network. Simultaneously, based on multi-scale effects, surface roughening results in a robust hydrophobic surface, integrating efficient photothermal de-icing and passive hydrophobic anti-icing functions, and exhibiting excellent durability. The preparation method includes material modification, composite coating preparation, coating, and curing steps; the process is simple and easily scalable.

Description

Technical Field

[0001] This invention belongs to the field of functional composite materials and surface engineering technology, specifically relating to a multi-dimensional composite photothermal hydrophobic anti-icing coating and its preparation method. Background Technology

[0002] In frigid environments, icing on the surfaces of power facilities, such as transmission lines, towers, and fittings, can lead to serious functional failures and safety accidents. Traditional anti-icing technologies, such as thermal de-icing, consume enormous amounts of energy, chemical de-icing agents cause environmental pollution, and mechanical de-icing is inefficient and easily damages the substrate.

[0003] In recent years, photothermal anti-icing technology has attracted widespread attention due to its ability to directly utilize solar energy, a clean energy source. Its principle involves using photothermal materials in the coating to convert absorbed light energy into heat energy, raising the surface temperature above freezing point and thus achieving active de-icing. Simultaneously, the hydrophobic surface effectively slows down the icing process and significantly reduces the adhesion strength between the ice layer and the substrate, making the ice layer easier to detach under wind or its own weight, achieving passive anti-icing. Combining the photothermal effect with hydrophobic properties is considered an ideal strategy for achieving efficient and energy-saving anti-icing.

[0004] However, existing photothermal hydrophobic composite coating technologies still face many challenges in practical applications: 1. Limitations of Photothermal Materials: Single photothermal materials (such as graphene and carbon black) suffer from narrow solar light absorption spectra and limited photothermal conversion efficiency. Some high-performance materials, such as precious metal nanoparticles (gold and silver), are expensive and have poor stability, making them difficult to apply in practice.

[0005] 2. Material compatibility and stability issues: Many high-efficiency photothermal materials (such as MXene and carbon nanotubes) have hydrophilic surfaces, which have poor compatibility with commonly used hydrophobic polymer matrices (such as PDMS). During mixing and curing, they are prone to agglomeration or migration to the coating surface, forming hydrophilic points. These hydrophilic points become preferential sites for ice nucleation, severely weakening the overall hydrophobicity and anti-icing performance of the coating.

[0006] 3. Insufficient functional synergy: The composite of single-dimensional components cannot form an efficient thermally conductive network, which is not conducive to the efficient transfer of photogenerated heat to the icing-coating interface and the performance of ice melting. At the same time, single-dimensional particles are not enough to induce sufficient surface roughening effect to improve hydrophobicity and the delayed icing effect is weak. In addition, simple physical blending is difficult to achieve efficient synergy between photothermal and hydrophobic functions. If the photothermal material is unevenly distributed or not firmly bonded to the substrate, it will not only affect the photothermal efficiency, but also the mechanical durability of the coating will be poor, which cannot meet the requirements of long-term outdoor use.

[0007] Therefore, it is of great significance to develop a composite anti-icing coating with high photothermal conversion efficiency, excellent hydrophobic properties, good multi-component compatibility, good environmental stability, and simple preparation process. Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, this invention provides a multi-dimensional composite photothermal hydrophobic anti-icing coating and its preparation method, which can achieve a perfect combination of efficient photothermal conversion and robust hydrophobicity, has the dual functions of active de-icing and passive anti-icing, and has strong durability.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a multi-dimensional composite photothermal hydrophobic anti-icing coating. This coating is applied to the surface of a metal substrate and comprises a flexible hydrophobic matrix and a photothermal material uniformly dispersed within the flexible hydrophobic matrix; The flexible hydrophobic matrix is ​​a polydimethylsiloxane (PDMS) matrix. The photothermal material is a ternary composite photothermal material comprising titanium nitride (TiN), carbon nanotubes (CNTs), and MXene, with a surface modified by silanization; wherein the mass ratio of TiN, CNTs, and MXene is (0.5-2):(0.5-2):(0.5-1). Preferably, the mass ratio of TiN, CNTs, and MXene is 1:1:0.5.

[0010] Furthermore, the surface silanization modification employs a silane coupling agent; the silane coupling agent is 3-aminopropyltriethoxysilane KH-550 or 3-methacryloyloxypropyltrimethoxysilane KH-570.

[0011] Furthermore, the ternary composite photothermal material has a mass fraction of 0.5%-3% in the PDMS matrix; the metal matrix is ​​aluminum alloy or steel.

[0012] Secondly, this invention provides a method for preparing the aforementioned multi-dimensional composite photothermal hydrophobic anti-icing coating. The method includes the following steps: S1. Prepare a ternary composite material powder with a surface modified by silanization; the ternary composite material powder includes titanium nitride (TiN), carbon nanotubes (CNT), and MXene; wherein the mass ratio of TiN, CNT, and MXene is (0.5-2):(0.5-2):(0.5-1). S2. The ternary composite material powder is added to polydimethylsiloxane PDMS, and the ternary composite material powder is uniformly dispersed in PDMS by stirring and ultrasonic treatment. Then, a curing agent is added for curing to obtain a composite coating. S3. Apply the composite coating onto the metal substrate to form the multidimensional composite photothermal hydrophobic anti-icing coating.

[0013] Further, step S1 includes: S11. Weigh TiN nanoparticles, CNTs and MXene nanosheets according to the mass ratio, disperse them in anhydrous ethanol and sonicate them to obtain corresponding dispersions with a concentration of 0.5-2 mg / mL. S12. Mix the three dispersions, and add an ethanol solution of silane coupling agent dropwise to the mixed dispersions under magnetic stirring to obtain a mixed system; wherein, the total amount of silane coupling agent added is 5%-15% of the total mass of the photothermal material; S13. After refluxing the mixture at 50-70℃ for 4-8 hours, collect the reactants by centrifugation, wash with ethanol, and then vacuum dry at 60-80℃ for 6-12 hours to obtain the modified composite powder.

[0014] Further, in step S11, the ultrasonic treatment power is 300-500W and the time is 30-60 minutes; in step S13, the centrifugation collection speed is 8000-12000rpm and the time is 10 minutes.

[0015] Further, step S2 includes: S21. Add the modified composite powder to PDMS at a mass fraction of 0.5%-3%, stir with a mechanical stirrer, and then use a probe-type ultrasonic instrument to alternately disperse the powder with ultrasound until the ternary composite powder is uniformly dispersed in PDMS until no visible agglomerates are found, thus obtaining the PDMS base polymer; wherein, the stirring speed during the initial stirring is lower than the stirring speed of the mechanical stirrer. S22. Add curing agent to PDMS base polymer and stir mechanically again until the mixture is uniform to obtain composite coating; wherein the mass ratio of PDMS base polymer to curing agent is 10:1.

[0016] Further, in step S21, the mechanical stirrer rotates at 1000-2000 rpm for 30 minutes; the probe-type ultrasonic instrument has a power of 200-400W and operates in a periodic intermittent manner for a total time of 5-10 minutes; in step S22, after adding the curing agent, the mechanical stirrer rotates at 500-800 rpm for 10-15 minutes.

[0017] Further, step S3 includes: S31. Grind, polish and ultrasonically clean the metal substrate, and dry it with nitrogen gas; S32. Apply the composite coating to the surface of the metal substrate using a dip coating method, a scraping method, or a spraying method to form a wet film; S33. Let the metal substrate coated with wet film stand at room temperature for 10-30 minutes, then pre-cur at 70℃~90℃ for 1 hour, and then heat to 100-120℃ to continue curing for 1-2 hours.

[0018] Further, in step S32, the spraying method includes: diluting the composite coating with n-hexane or petroleum ether to a viscosity of 20-50 cP, and uniformly spraying 2-4 layers at a distance of 15-25 cm from the metal substrate using a spray gun under a pressure of 0.2-0.4 MPa, with an interval of 30-60 seconds between each layer; the lifting method includes: vertically immersing the metal substrate in the composite coating for 30-60 seconds, and then uniformly lifting it at a constant speed of 50-200 mm / min; the scraping method includes: using a coater with a preset thickness of 100-300 μm.

[0019] The beneficial effects of this invention are that, compared with the prior art, 1. Highly Efficient Photothermal-Hydrophobic Synergistic Anti-Icing Capability: Through the plasmon effect of zero-dimensional TiN, the lattice vibrational heat of one-dimensional CNTs, and the free carrier absorption of two-dimensional MXene, a multi-mechanism photothermal synergy is achieved. The TiN / CNT / MXene ternary composite system realizes complementary spectral absorption and synergistic photothermal mechanisms, exhibiting photothermal conversion efficiency far exceeding that of single materials, achieving broadband and efficient photothermal conversion. Simultaneously, surface silanization modification solves the compatibility problem between the photothermal material and the PDMS matrix, giving the coating a robust hydrophobic surface that effectively prevents water droplet wetting and ice nucleation. The multi-scale effects of zero-dimensional TiN, one-dimensional CNTs, and two-dimensional MXene can, on the one hand, induce uneven shrinkage during the crosslinking of PDMS prepolymer, triggering a surface wrinkling and roughening effect, improving surface hydrophobicity and delaying icing capability; on the other hand, it can construct a highly efficient thermally conductive multi-scale network structure within the coating, achieving efficient transfer of photogenerated heat to the icing-coating interface. Under light, the enhanced photothermal effect generates heat and optimized thermal conductivity promotes heat transfer, which can accelerate the melting of the ice interface, forming a water-lubricated layer that makes the ice adhesion strength extremely low and easy to remove under slight external force.

[0020] 2. Excellent durability and environmental stability: Surface modification of the photothermal material using a silane coupling agent not only solves the compatibility issue with the PDMS matrix and avoids hydrophilic point defects, but also enhances interfacial adhesion, improving the coating's mechanical wear resistance and erosion resistance. In particular, the introduction of TiN and CNTs significantly improves the overall oxidation resistance of the composite coating, effectively inhibiting MXene degradation and enabling the coating to have a long service life in harsh outdoor environments.

[0021] 3. Simple preparation process and easy to scale up: The raw materials used in this invention are relatively inexpensive, the preparation process does not require complex equipment, and coating processes such as dip coating, scraping coating and spraying are mature and suitable for preparation on large or complex shaped substrates, with good industrialization prospects. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the microstructure of the multi-dimensional composite photothermal hydrophobic anti-icing coating of the present invention; Figure 2 This is a flowchart of the preparation method of the multi-dimensional composite photothermal hydrophobic anti-icing coating of the present invention.

[0023] Figures 3(a) and 3(b) show the surface morphology of PDMS-based coatings containing only TiN and ternary TiN-MXene-CNT, respectively. Figure 4(a) and Figure 4(b) show the contact angles of PDMS-based coatings containing only TiN and ternary TiN-MXene-CNT, respectively. Figures 5(a) and 5(b) are comparisons of the photothermal effects of PDMS base coatings containing only TiN and those containing ternary TiN-MXene-CNT, respectively.

[0024] Figure labeling: 1 is titanium nitride (TiN); 2 is carbon nanotube (CNT); 3 is Mxene; 4 is PDMS matrix; 5 is metal matrix. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.

[0026] It should be noted that in this invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0027] According to a first aspect of the present invention, a multi-dimensional composite photothermal hydrophobic anti-icing coating is provided.

[0028] like Figure 1In one embodiment, the multidimensional composite photothermal hydrophobic anti-icing coating is applied to the surface of a metal substrate 5 and comprises: a flexible hydrophobic matrix and a photothermal material uniformly dispersed in the flexible hydrophobic matrix. The flexible hydrophobic matrix is ​​a polydimethylsiloxane (PDMS) matrix 4. The photothermal material is a ternary composite photothermal material comprising titanium nitride (TiN) 1, carbon nanotubes (CNT) 2, and MXene 3 with a silanized surface; wherein the mass ratio of TiN 1, CNT 2, and MXene 3 is (0.5-2):(0.5-2):(0.5-1). More preferably, the mass ratio of TiN, CNT, and MXene is 1:1:0.5.

[0029] PDMS is a linear organosilicon polymer whose molecular backbone consists of alternating silicon-oxygen bonds (Si-O-Si) and methyl (-CH3) side chains. Due to the hydrophobicity of methyl groups and the flexibility of siloxane chains, PDMS has extremely low surface energy (approximately 20-22 mN / m), making it an ideal matrix material for constructing hydrophobic surfaces. Simultaneously, PDMS exhibits good flexibility, weather resistance, and chemical stability, enabling it to adapt to the deformation requirements of outdoor power facilities (such as transmission lines, towers, and fittings) under temperature variations and mechanical vibrations.

[0030] In this embodiment, three materials of different dimensions—titanium nitride (TiN) nanoparticles (zero-dimensional), carbon nanotubes (CNTs, one-dimensional), and MXene nanosheets (two-dimensional)—are used. Through composition and structural optimization design, a three-dimensional network structure is formed in which "zero-dimensional TiN is attached to two-dimensional MXene, and one-dimensional CNTs are interspersed as thermally conductive bridges." This structure can achieve spectral complementarity, thermally conductive network optimization, and superposition of multiple mechanisms of thermal conversion, exhibiting a synergistic photothermal enhancement effect, specifically reflected in the following aspects: 1. Complementary Spectral Absorption: TiN exhibits localized surface plasmon resonance, efficiently absorbing visible light (approximately 450-700 nm); MXene, through free carrier vibrations, is particularly adept at absorbing near-infrared light (700-2500 nm); CNTs, through the vibrations (phonons) of the carbon atom lattice, absorb a broad spectrum including near-infrared light (ultraviolet to far-infrared). When these three are combined, the coating's absorption spectrum covers the main energy distribution range of the solar spectrum from 300-2500 nm, resulting in a significantly higher solar spectral utilization rate than single or binary combinations.

[0031] 2. Construction of a Three-Dimensional Thermally Conductive Network: Two-dimensional MXene sheets possess high in-plane thermal conductivity (up to several hundred W / (m·K)), but exhibit significant interlayer thermal resistance. One-dimensional CNTs, acting as "thermal bridges," are interspersed between MXene sheets, connecting zero-dimensional TiN particles to form a continuous three-dimensional thermally conductive network. This network enables the heat generated by photothermal conversion to be rapidly transferred to the entire coating surface, preventing localized overheating and improving de-icing efficiency. Simultaneously, experimental results show that the multi-dimensional effects of zero-dimensional TiN, one-dimensional CNTs, and two-dimensional MXene can induce uneven shrinkage during the crosslinking of PDMS prepolymer, resulting in surface wrinkling structures, increasing surface contact angle and hydrophobicity, and effectively delaying surface icing.

[0032] 3. Superposition of multiple thermal conversion mechanisms: TiN mainly relies on plasmon nonradiative relaxation for heat generation; MXene mainly relies on the Joule heating effect of free charge carriers; CNT mainly relies on lattice vibration (phonon) for heat generation. The superposition of these three different physical mechanisms produces a synergistic enhancement effect of "1+1+1>3". Under the same light intensity, the steady-state temperature rise of the ternary composite coating is significantly higher than that of the binary system.

[0033] 4. Optimization and Control of Mass Ratio: The mass ratio of the three components is a key parameter determining the strength of the synergistic effect. After systematic optimization, the mass ratio range was determined to be (0.5-2):(0.5-2):(0.5-1), preferably 1:1:0.5. Under this ratio: the absorption spectrum of each component is optimally complementary, with an average absorption rate of over 90% in the 300-2500 nm range; the thermal conductivity network connectivity is optimal because CNTs are sufficient to bridge MXene sheets, TiN fills the gaps, and thermal resistance is minimized; the surface roughness is also suitable, with the filler forming a uniform micro-nano rough structure in PDMS, achieving superhydrophobicity (contact angle >150°, roll-off angle <10°) and low ice adhesion. If the proportion of a certain component is too low, the absorption in the corresponding spectral segment will be insufficient, the thermal conductivity path will be broken, or the surface roughness will be insufficient; if the proportion is too high, it may cause absorption redundancy, filler agglomeration, or exposure of hydrophilic points. Therefore, this mass ratio range allows the coating to have both active de-icing and passive anti-icing effects, and it also has strong durability.

[0034] As can be seen, the TiN / CNT / MXene ternary composite system and the optimization of the mass ratio achieve complementary spectral absorption and synergistic photothermal mechanism, exhibiting a photothermal conversion efficiency far exceeding that of single materials, realizing broadband and efficient photothermal conversion (see Example 1, Comparative Example 1 and Comparative Example 2 for details).

[0035] Furthermore, the ternary composite photothermal material is surface-silanized to solve the compatibility problem between the photothermal material and the PDMS matrix.

[0036] Specifically, the surfaces of TiN, CNT, and MXene are typically rich in hydrophilic functional groups such as hydroxyl (-OH) and carboxyl (-COOH). When directly blended with a hydrophobic PDMS matrix, due to interfacial energy differences, the ternary composite photothermal materials tend to migrate to the coating surface or aggregate, forming micron-sized aggregates. These hydrophilic aggregates, once exposed to the coating surface, disrupt the hydrophobic state and pin water droplets, becoming preferential sites for ice nucleation and leading to the failure of anti-icing performance. In contrast, photothermal materials modified with silanization transform from hydrophilic to hydrophobic, enabling uniform dispersion within the PDMS matrix and avoiding hydrophilic defects.

[0037] Therefore, this embodiment can effectively achieve the dual effects of "active photothermal de-icing" and "passive hydrophobic anti-icing" by using a TiN / CNT / MXene ternary composite photothermal material uniformly dispersed in PDMS and with a surface modified by silanization.

[0038] Preferably, the surface silanization modification employs a silane coupling agent; the silane coupling agent is 3-aminopropyltriethoxysilane (KH-550) or 3-methacryloyloxypropyltrimethoxysilane (KH-570). Silane coupling agents are a class of compounds with bifunctional groups, generally having the formula R-Si(OR')3, where OR' is a hydrolyzable group (such as ethoxy or methoxy), and R is an organic functional group (such as amino or methacryloyloxy). During the modification process, the ethoxy / methoxy groups of the silane coupling agent hydrolyze to generate silanol bonds (Si-OH), which undergo a condensation reaction with the hydroxyl groups on the surface of the ternary composite photothermal material to form covalent bonds; at the other end, organic functional groups (such as -NH2, -C(CH3)=CH2) are introduced. These organic functional groups have good compatibility with the PDMS molecular chain and can participate in the cross-linking reaction of PDMS to achieve chemical bonding. This significantly enhances the interfacial bonding between the photothermal material and the PDMS matrix, improving the mechanical durability of the coating.

[0039] Preferably, the ternary composite photothermal material has a mass fraction of 0.5%-3% in the PDMS matrix. This is because, according to experimental data, a mass fraction below 0.5% results in weak photothermal effect, insufficient hydrophobic roughness, and difficulty for ice to slide off; a mass fraction above 3% leads to poor matrix encapsulation, brittle and easily damaged coating, and filler agglomeration, resulting in decreased photothermal efficiency.

[0040] Preferably, the metal substrate is aluminum alloy or steel. Aluminum alloy and steel are the most commonly used materials in the power industry, and they require high coating adhesion. The coating of the present invention is perfectly suited to the coating requirements of aluminum alloy and steel, not only providing waterproofing and ice protection but also offering a physical barrier to delay corrosion.

[0041] According to a second aspect of the present invention, a method for preparing a multi-dimensional composite photothermal hydrophobic anti-icing coating is provided.

[0042] like Figure 2 In one embodiment, the preparation method includes the following steps: S1. Prepare a ternary composite material powder with a surface modified by silanization; the ternary composite material powder includes titanium nitride (TiN), carbon nanotubes (CNT), and MXene; wherein the mass ratio of TiN, CNT, and MXene is (0.5-2):(0.5-2):(0.5-1).

[0043] Specifically, the steps include: S11. Weigh TiN nanoparticles, CNTs and MXene nanosheets according to the mass ratio, disperse them in anhydrous ethanol and sonicate them to obtain corresponding dispersions with a concentration of 0.5-2 mg / mL.

[0044] Preferably, the ultrasonic treatment has a power of 300-500W and a duration of 30-60 minutes.

[0045] S12. Mix the three dispersions, and add an ethanol solution of silane coupling agent dropwise to the mixed dispersions under magnetic stirring to obtain a mixed system; wherein, the total amount of silane coupling agent added is 5%-15% of the total mass of the photothermal material.

[0046] Preferably, the volume fraction of the silane coupling agent in the ethanol solution is 1%-5%; the preferred silane coupling agent is 3-aminopropyltriethoxysilane (KH-550) or 3-methacryloyloxypropyltrimethoxysilane (KH-570).

[0047] S13. After refluxing the mixture at 50-70℃ for 4-8 hours, collect the reactants by centrifugation, wash with ethanol, and then vacuum dry at 60-80℃ for 6-12 hours to obtain the modified composite powder.

[0048] During the reaction, the silanol generated by the hydrolysis of the silane coupling agent undergoes condensation with the hydroxyl groups on the filler surface to achieve covalent grafting, thereby significantly enhancing the compatibility of the photothermal material with PDMS, preventing hydrophilic electrical exposure, and significantly improving the interfacial bonding force between the photothermal material and the PDMS matrix, greatly increasing the mechanical durability of the coating.

[0049] Preferably, the centrifugation collection is carried out at a speed of 8000-12000 rpm for 10 minutes.

[0050] When washing with ethanol, it is preferable to wash with anhydrous ethanol three or more times to remove unreacted coupling agent.

[0051] S2. The ternary composite material powder is added to polydimethylsiloxane PDMS, and the powder is uniformly dispersed in PDMS by stirring and ultrasonic treatment. Then, a curing agent is added for curing to obtain a composite coating.

[0052] Specifically, the steps include: S21. Add the modified composite powder to PDMS at a mass fraction of 0.5%-3%, stir with a mechanical stirrer, and then use a probe-type ultrasonic instrument to alternately disperse the powder with ultrasound until the ternary composite powder is uniformly dispersed in PDMS until there are no visible agglomerates, thus obtaining the PDMS base polymer; wherein, the stirring speed during the initial stirring is lower than the stirring speed of the mechanical stirrer.

[0053] Preferably, manual stirring can be performed using a stirring rod before stirring with a mechanical stirrer. Alternatively, if a stirring rod is unavailable, low-speed stirring can be performed first, followed by high-speed stirring with a mechanical stirrer. The preferred high-speed stirring speed is 1000-2000 rpm, and the stirring time is 30 minutes. Alternatively, high-speed stirring can be performed directly with a mechanical stirrer. The probe-type ultrasonic instrument has a power of 200-400W and operates in a periodic intermittent mode for a total time of 5-10 minutes. This periodic intermittent operation can be set, for example, to a mode of 2 seconds of operation followed by a 3-second interval.

[0054] S22. Add curing agent to PDMS base polymer and stir mechanically again until the mixture is uniform to obtain composite coating; wherein the mass ratio of PDMS base polymer to curing agent is 10:1.

[0055] Preferably, after adding the curing agent, the mechanical stirring speed is 500-800 rpm, and the stirring time is 10-15 minutes.

[0056] S3. Apply the composite coating onto the metal substrate to form the multidimensional composite photothermal hydrophobic anti-icing coating.

[0057] Specifically, the steps include: S31. Grind, polish and ultrasonically clean the metal substrate, and dry it with nitrogen.

[0058] The metal matrix can be, for example, an aluminum alloy or steel.

[0059] Ultrasonic cleaning is preferably performed by ultrasonically cleaning the ground and polished metal substrate in acetone and anhydrous ethanol for 15 minutes each.

[0060] Step S31 can effectively remove oil and impurities from the surface of the metal substrate.

[0061] S32. Apply the composite coating to the surface of the metal substrate using a dip coating method, a scraping method, or a spraying method to form a wet film.

[0062] The spraying method includes: diluting the composite coating with n-hexane or petroleum ether to a viscosity of 20-50 cP, and uniformly spraying 2-4 layers at a distance of 15-25 cm from the metal substrate using a spray gun under a pressure of 0.2-0.4 MPa, with an interval of 30-60 seconds between each layer.

[0063] The lifting method includes: vertically immersing the metal substrate in the composite coating for 30-60 seconds, and then lifting it at a constant speed of 50-200 mm / min.

[0064] The scraping method includes: fixing the metal substrate horizontally, and using a coater with a preset thickness of 100-300 μm to scrape the coating onto the surface.

[0065] S33. Let the metal substrate coated with wet film stand at room temperature for 10-30 minutes, then pre-cur at 70℃~90℃ for 1 hour, and then heat to 100-120℃ to continue curing for 1-2 hours.

[0066] Among these methods, allowing the coating to stand at room temperature can help smooth the surface and release some air bubbles.

[0067] Pre-curing and further curing can be carried out in an oven. Pre-curing allows the coating to initially take shape and remove air bubbles, while further curing allows PDMS to fully cross-link, forming a tough, smooth, and firmly bonded hydrophobic photothermal composite coating to the metal substrate.

[0068] The effects of the present invention will be better illustrated below through Example 1 and Comparative Examples 1 and 2.

[0069] Example 1 This embodiment provides a preferred embodiment of the preparation method of a multi-dimensional composite photothermal hydrophobic anti-icing coating of the present invention, comprising the following steps: S1. Surface silanization modification of ternary composite photothermal materials: Weigh 50 mg of TiN nanoparticles with a particle size of approximately 20 nm, 50 mg of multi-walled carbon nanotubes with a diameter of 10-20 nm and a length of 1-5 μm, and 25 mg of monolayer or few-layer Ti3C2T xMXene nanosheets were dispersed separately in 50 mL of anhydrous ethanol and sonicated at 400 W for 40 minutes to obtain dispersions. The three dispersions were mixed, and 5 mL of an ethanol solution containing 5% KH-550 (v / v) was slowly added under magnetic stirring to obtain a mixed system. The mixed system was refluxed at 60 °C for 6 hours. After the reaction, the precipitate was collected by centrifugation at 12000 rpm for 10 minutes, washed three times with ethanol, and vacuum dried at 70 °C for 10 hours to obtain the modified composite powder.

[0070] S2. Preparation of composite coating: Take 2g of the above modified powder (accounting for 2% of the total mass of PDMS) and add it to 98g of Dow Corning 184 PDMS. First, stir with a mechanical stirrer at 1500rpm for 30min, then use a probe-type ultrasonic instrument at 300W power, with a working mode of 2s on and 3s off, for a total ultrasonic time of 8min. Then add 9.8g of curing agent and stir at 600rpm for 12min to obtain a uniform composite coating.

[0071] S3. Coating Preparation: A 5cm × 5cm aluminum alloy plate was used as the metal substrate. The plate was polished, ultrasonically cleaned in acetone and anhydrous ethanol for 15 minutes each, and then dried with nitrogen. Using a pull-out method, the metal substrate was pulled out of the coating at a speed of 100mm / min and allowed to level at room temperature for 20 minutes. Then, the sample was placed in an oven and cured at 80℃ for 1 hour, followed by curing at 100℃ for 1.5 hours. The sample was then cooled to room temperature in the oven to obtain the coated sample.

[0072] The experimental results of the surface morphology, contact angle, and photothermal effect of the coating prepared in Example 1 are shown in Figures 3(b), 4(b), and 5(b), respectively. Figure 3(b) shows that the coating surface of Example 1 exhibits a wrinkled structure, which may be due to uneven shrinkage induced during the crosslinking of the PDMS prepolymer by the multidimensional effects of zero-dimensional TiN, one-dimensional CNT, and two-dimensional MXene. Figure 4(b) shows that the surface water contact angle (CA) of the coating is 129.4°. This wrinkled surface structure and large contact angle indicate that the coating of Example 1 has good hydrophobicity. Figure 5(b) shows that the highest temperature reached by the coating surface of Example 1 under this illumination condition is 62.2℃, representing that the coating has a good photothermal effect. Furthermore, abrasion resistance tests were conducted on the coating, and the results show that it has excellent mechanical abrasion resistance and erosion resistance.

[0073] Comparative Example 1 Comparative Example 1 also relates to a method for preparing a multidimensional composite photothermal hydrophobic anti-icing coating. The method steps of Comparative Example 1 are largely the same as those of Example 1, but the surface silanization modification process of the ternary composite photothermal material in step S1 of Example 1 is omitted. Instead, an unmodified TiN / CNT / MXene mixture (i.e., 50 mg of TiN nanoparticles with a particle size of about 20 nm, 50 mg of multi-walled carbon nanotubes with a diameter of 10-20 nm and a length of 1-5 μm, and 25 mg of monolayer or few-layer Ti3C2T) is directly applied. x A mixture of MXene nanosheets was directly compounded with PDMS.

[0074] Related experimental results show that nanoparticle aggregation and protrusions are visible on the coating surface, the water contact angle is lower than that of Example 1, and the hydrophobicity is lower than that of Example 1. The photothermal heating performance is slightly lower than that of Example 1, but the ice adhesion strength is significantly increased, and the coating performance deteriorates significantly after the wear resistance test.

[0075] Comparative Example 2 The steps are the same as in Example 1, but the photothermal material uses only an equal mass (i.e., 2% of the total mass of PDMS) of TiN, without MXene and CNT.

[0076] The experimental results of the surface morphology, contact angle, and photothermal effect of the coating prepared in Comparative Example 2 are shown in Figures 3(a), 4(a), and 5(a), respectively. Figure 3(a) shows that the surface roughness of the coating in Comparative Example 2 is relatively low. Figure 4(a) shows that the water contact angle CA of the coating surface in Comparative Example 2 is 114.5°. Both the low roughness and the small contact angle indicate that the hydrophobic effect of the coating in Comparative Example 2 is relatively weak. Figure 5(a) shows that the highest temperature reached by the coating surface of Comparative Example 2 under this illumination condition is 46.1℃, which is significantly lower than that of Example 1, indicating a poorer photothermal effect.

[0077] Through Example 1 and the two comparative examples, it can be found that the overall performance of the coating prepared by the present invention is significantly better than that of the comparative examples, which proves the effectiveness and necessity of ternary composite and its optimized ratio.

[0078] In summary, the coating of this invention, through composition and structural design, forms a three-dimensional network in which "zero-dimensional (TiN) adheres to two-dimensional (MXene), with one-dimensional (CNT) interspersed as thermally conductive bridges." Zero-dimensional TiN exhibits plasmon resonance, enabling efficient absorption of visible light; two-dimensional MXene generates heat through free carrier vibrations, particularly adept at absorbing ultraviolet light; and one-dimensional CNTs generate heat through the vibration of the carbon atom lattice (phonons), absorbing a broad spectrum including near-infrared light. This structure achieves spectral complementarity (broad spectrum absorption from ultraviolet to near-infrared) and mechanistic complementarity (plasmon resonance, electrothermal effect, lattice heat), resulting in a synergistic photothermal enhancement effect. It achieves a perfect combination of efficient photothermal conversion and robust hydrophobicity, possessing both active de-icing and passive anti-icing capabilities, and exhibiting strong durability.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A multi-dimensional composite photothermal hydrophobic anti-icing coating, applied to the surface of a metal substrate, characterized in that: The coating comprises a flexible hydrophobic matrix and a photothermal material uniformly dispersed in the flexible hydrophobic matrix; The flexible hydrophobic matrix is ​​a polydimethylsiloxane (PDMS) matrix. The photothermal material is a ternary composite photothermal material comprising titanium nitride (TiN), carbon nanotubes (CNT), and MXene, with the surface modified by silanization; wherein the mass ratio of TiN, CNT, and MXene is (0.5-2):(0.5-2):(0.5-1).

2. The multi-dimensional composite photothermal hydrophobic anti-icing coating according to claim 1, characterized in that: The surface silanization modification employs a silane coupling agent; the silane coupling agent is 3-aminopropyltriethoxysilane KH-550 or 3-methacryloyloxypropyltrimethoxysilane KH-570.

3. The multi-dimensional composite photothermal hydrophobic anti-icing coating according to claim 1, characterized in that: The ternary composite photothermal material has a mass fraction of 0.5%-3% in the PDMS matrix; the metal matrix is ​​aluminum alloy or steel.

4. A method for preparing a multi-dimensional composite photothermal hydrophobic anti-icing coating as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Prepare a ternary composite material powder with a surface modified by silanization; the ternary composite material powder includes titanium nitride (TiN), carbon nanotubes (CNT), and MXene; wherein the mass ratio of TiN, CNT, and MXene is (0.5-2):(0.5-2):(0.5-1). S2. The ternary composite material powder is added to polydimethylsiloxane PDMS, and the ternary composite material powder is uniformly dispersed in PDMS by stirring and ultrasonic treatment. Then, a curing agent is added for curing to obtain a composite coating. S3. Apply the composite coating onto the metal substrate to form the multidimensional composite photothermal hydrophobic anti-icing coating.

5. The preparation method according to claim 4, characterized in that, Step S1 includes: S11. Weigh TiN nanoparticles, CNTs and MXene nanosheets according to the mass ratio, disperse them in anhydrous ethanol and sonicate them to obtain corresponding dispersions with a concentration of 0.5-2 mg / mL. S12. Mix the three dispersions, and add an ethanol solution of silane coupling agent dropwise to the mixed dispersions under magnetic stirring to obtain a mixed system; wherein, the total amount of silane coupling agent added is 5%-15% of the total mass of the photothermal material; S13. After refluxing the mixture at 50-70℃ for 4-8 hours, collect the reactants by centrifugation, wash with ethanol, and then vacuum dry at 60-80℃ for 6-12 hours to obtain the modified composite powder.

6. The preparation method according to claim 5, characterized in that, In step S11, the ultrasonic treatment power is 300-500W and the time is 30-60 minutes; in step S13, the centrifugation collection speed is 8000-12000rpm and the time is 10 minutes.

7. The preparation method according to claim 4, characterized in that, Step S2 includes: S21. Add the modified composite powder to PDMS at a mass fraction of 0.5%-3%, stir with a mechanical stirrer, and then use a probe-type ultrasonic instrument to alternately disperse the powder with ultrasound until the ternary composite powder is uniformly dispersed in PDMS until no visible agglomerates are found, thus obtaining the PDMS base polymer; wherein, the stirring speed during the initial stirring is lower than the stirring speed of the mechanical stirrer. S22. Add curing agent to PDMS base polymer and stir mechanically again until the mixture is uniform to obtain composite coating; wherein the mass ratio of PDMS base polymer to curing agent is 10:

1.

8. The preparation method according to claim 7, characterized in that, In step S21, the mechanical stirrer rotates at 1000-2000 rpm for 30 minutes; the probe-type ultrasonic instrument has a power of 200-400W and operates in a periodic intermittent manner for a total time of 5-10 minutes; in step S22, after adding the curing agent, the mechanical stirrer rotates at 500-800 rpm for 10-15 minutes.

9. The preparation method according to claim 4, characterized in that, Step S3 includes: S31. Grind, polish and ultrasonically clean the metal substrate, and dry it with nitrogen gas; S32. Apply the composite coating to the surface of the metal substrate using a dip coating method, a scraping method, or a spraying method to form a wet film; S33. Let the metal substrate coated with wet film stand at room temperature for 10-30 minutes, then pre-cur at 70℃~90℃ for 1 hour, and then heat to 100-120℃ to continue curing for 1-2 hours.

10. The method according to claim 9, characterized in that: In step S32, the spraying method includes: diluting the composite coating with n-hexane or petroleum ether to a viscosity of 20-50 cP, and uniformly spraying 2-4 layers at a distance of 15-25 cm from the metal substrate using a spray gun under a pressure of 0.2-0.4 MPa, with an interval of 30-60 seconds between each layer; the lifting method includes: vertically immersing the metal substrate in the composite coating for 30-60 seconds, and then uniformly lifting it at a constant speed of 50-200 mm / min; the scraping method includes: using a coater with a preset thickness of 100-300 μm.

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