A fan blade low-ice adhesion super-hydrophobic ice-repellent functional layer and a preparation method thereof
By constructing a stress-responsive functional layer, the micro-stress generated by ice crystal growth is used to trigger the release of lubricating medium, which solves the problem of superhydrophobic coating failure in high humidity freezing rain environment and achieves the effect of low ice adhesion and multiple cycles of wind turbine blades.
Patent Information
- Application Number
- CN202610629109.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-09
- Publication Date
- 2026-06-05
AI Technical Summary
Existing superhydrophobic coatings fail in high-humidity freezing rain environments, leading to increased adhesion between the ice layer and the blades, making it difficult for the ice to detach on its own under blade vibration or centrifugal force, thus affecting the normal operation of the wind turbine blades.
A stress-responsive functional layer is constructed using a flexible polymer matrix and nanocontainers. Through micron-scale papillary arrays and fluorination treatment, the micro-stress generated by ice crystal growth triggers the release of lubricating medium, forming a dynamic molecular lubricating layer and reducing the adhesion strength of the ice layer.
In high-humidity freezing rain environments, the functional layer can maintain low ice adhesion performance, extend the protection cycle, adapt to complex climatic conditions, and has the ability to be recycled multiple times, avoiding microstructure damage.
Smart Images
Figure CN122146163A_ABST
Abstract
Description
Technical Field
[0001] This disclosure belongs to the field of wind turbine blade coating preparation technology, specifically relating to a low-ice-adhesion superhydrophobic ice-repellent functional layer for wind turbine blades and its preparation method. Background Technology
[0002] Wind turbine blade icing is one of the key technical challenges hindering the operation of wind farms in high-altitude and cold regions. When wind turbine blades encounter low-temperature clouds, freezing rain, or wet snow during winter operation, supercooled water droplets freeze rapidly upon impact with the blade surface, forming different types of ice layers. Among these, the "smooth ice" formed under freezing rain conditions is dense, transparent, and adheres tightly to the blade surface. Even if the adhesion strength is relatively low, it can still disrupt the original aerodynamic shape of the blade, leading to reduced power generation and increased unit vibration. Research both domestically and internationally has focused on two main areas to address this problem: active de-icing technology and passive anti-icing coatings.
[0003] Superhydrophobic coatings are currently a research hotspot in the field of passive anti-icing. A superhydrophobic coating is a functional coating with a water contact angle greater than 150° and a roll-off angle less than 10°. It is typically achieved by constructing micron- or nano-scale rough structures combined with low surface energy materials. The working principle of these coatings is to utilize the surface microstructure to trap air, forming an air cushion layer that reduces the actual contact area between water and the solid surface. This allows supercooled water droplets to easily roll off before freezing, or to exhibit low ice adhesion strength after freezing due to the small contact area. However, superhydrophobic coatings face specific environmental challenges in practical wind farm applications.
[0004] Wind farms in the mountainous areas of Southwest China often experience high humidity and fluctuating temperatures near freezing points during winter, with frequent freezing rain. Under these conditions, traditional superhydrophobic coatings have inherent limitations. High humidity causes water vapor to condense within the coating's microstructure, filling the micron- or nano-scale rough structures with liquid water or tiny ice crystals, thus disrupting the crucial air cushion layer. This process causes the coating surface to transition from a Cassillo state to a Wenzel state—from a state where droplets are suspended on top of the microstructure to a state where droplets wet and fill the gaps between the microstructures. This results in a significant decrease in surface hydrophobicity, and the ice layer eventually forms a strong mechanical interlocking structure with the coating. At this point, the superhydrophobic coating loses its low ice adhesion properties, and the ice layer is difficult to detach under blade vibration or centrifugal force. Summary of the Invention
[0005] This disclosure aims to at least solve one of the technical problems existing in the prior art, and to provide a low-ice adhesion superhydrophobic ice-repellent functional layer for wind turbine blades and its preparation method.
[0006] One aspect of this disclosure provides a method for preparing a low-ice-adhesion superhydrophobic ice-repellent functional layer for wind turbine blades, the method comprising: Provide wind turbine blade substrates and pre-treat their surfaces; An adhesive transition layer is coated onto the pretreated substrate surface and then cured. Prepare a stress-responsive functional slurry, the functional slurry comprising a flexible polymer matrix and a nanocontainer uniformly dispersed in the flexible polymer matrix and encapsulated with a low surface energy lubricating medium; The functional slurry is coated onto the surface of the cured substrate bonding transition layer, and a micron-scale papillary array is constructed on the surface of the functional slurry by a template imprinting process. The functional slurry is then cured to form a functional layer body with a micron-scale papillary array. Remove the template and fluorinate the surface of the functional layer body.
[0007] Optionally, the preparation of the stress-responsive functional slurry includes: Hollow mesoporous silica nanocontainers encapsulated with low molecular weight polydimethylsiloxane were prepared as nanocontainers. A flexible polysiloxane elastomer prepolymer with a glass transition temperature below -50℃ was prepared as a flexible polymer matrix; The nanocontainer and thickener are added to the flexible polysiloxane elastomer prepolymer and then ground and dispersed evenly to obtain the functional slurry.
[0008] Optionally, the preparation of hollow mesoporous silica nanocontainers encapsulated with low molecular weight polydimethylsiloxane includes: Hollow mesoporous silica nanoparticles are placed in a vacuum reactor, and low molecular weight polydimethylsiloxane is dropped in under vacuum conditions, so that the polydimethylsiloxane fills the channels of the mesoporous silica. After filling, tetraethyl orthosilicate is used to carry out an in-situ sol-gel reaction on the surface of the nanoparticles to form a coating layer to seal the pore openings; After separation, washing, and drying, hollow mesoporous silica nanocontainers encapsulated with low molecular weight polydimethylsiloxane were obtained; wherein, The hollow mesoporous silica nanoparticles have an average pore size of 4-6 nm and a particle size of 150-250 nm; the low molecular weight polydimethylsiloxane has a viscosity of 45-55 cSt.
[0009] Optionally, the preparation of the flexible polysiloxane elastomer prepolymer with a glass transition temperature below -50°C includes: Using hydroxyl-terminated polydimethylsiloxane as raw material, a crosslinking agent and a catalyst are added, and the mixture is stirred and reacted at 75-85℃ for 2.5-3.5 hours under nitrogen protection to obtain a prepolymer.
[0010] Optionally, the hydroxyl-terminated polydimethylsiloxane has a molecular weight of 20,000, the crosslinking agent is methyltriethoxysilane, and the catalyst is dibutyltin dilaurate.
[0011] Optionally, the mass ratio of the nanocontainer to the flexible polysiloxane elastomer prepolymer is 5-15:100; The thickener is fumed silica.
[0012] Optionally, the template imprinting process includes: Prepare soft templates with micron-scale cavities or protrusions; After the functional slurry is coated onto the adhesive transition layer surface of the substrate, the soft template is immediately attached to the surface of the functional slurry and a uniform pressure of 0.02 to 0.05 MPa is applied. The substrate with the template is placed in a vacuum oven with a vacuum degree of less than -0.08 MPa gauge pressure and cured at 60°C for 8 hours to allow the functional slurry to crosslink and solidify, and to replicate a micron-scale papillary array that is complementary to the template structure.
[0013] Optionally, the adhesive transition layer is formed by mixing bisphenol A type epoxy resin and polyamide curing agent at a mass ratio of (1.5-2.5):1, applying and curing it using an airless spraying process, and its wet film thickness is 50-80μm.
[0014] Optionally, the fluorination treatment is a gas-phase fluorination treatment, specifically including: After demolding, the substrate with the functional layer as the main body is placed in a sealed container, and perfluorodecyltrimethoxysilane is placed at the bottom of the container. Heat the container to 80-100°C and treat the surface of the functional layer substrate with perfluorodecyltrimethoxysilane vapor for 0.5-1.5 hours. After removal, heat treatment is carried out at 145-155℃ for 25-35 minutes to chemically bond the fluorocarbon chain molecular layer to the surface of the micron-scale papillary array.
[0015] In another aspect of this disclosure, a low-ice-adhesion superhydrophobic icing-repellent functional layer for wind turbine blades is proposed, wherein the low-ice-adhesion superhydrophobic icing-repellent functional layer for wind turbine blades is prepared by the preparation method described above.
[0016] The present invention has the following beneficial effects: 1. This invention constructs a stress-responsive oil release mechanism, enabling the functional layer to release low surface energy lubricating media on demand under icing conditions. Unlike traditional coatings that rely on static surface properties, this mechanism involves the internally encapsulated lubricating media being squeezed out to the surface and form a molecular lubricating layer when micro-stress generated by ice crystal growth acts on the flexible micron-sized protrusions, thereby reducing the interfacial bonding strength between the ice layer and the substrate. Simultaneously, the sealing design of the nano-container controls the release rate of the lubricating media, preventing its ineffective loss under non-icing conditions. As the ice layer detaches, the flexible protrusions recover their original shape through their own elasticity, enabling the functional layer to be used multiple times. This dynamic response characteristic allows the functional layer to maintain low ice adhesion performance in repeated freeze-thaw environments, extending the protection cycle.
[0017] 2. This invention uses a flexible polymer to construct a micron-level papillary array and combines it with a stress-induced oil release mechanism to maintain a molecular-level lubricating film on the surface during the freezing process, avoiding direct contact between ice crystals and the solid surface. The design of the micro-nano composite structure provides a physical basis for reducing viscosity and also provides favorable conditions for the spread and retention of the lubricating medium. The synergistic effect of this physical structure and chemical oil release enables the functional layer to maintain stable low ice adhesion characteristics under high humidity conditions, adapting to the special requirements of anti-icing coatings in complex climatic environments.
[0018] 3. This invention uses a flexible polymer with a glass transition temperature lower than that of the service environment as the functional layer matrix, ensuring that the micron-sized papillary array still has good elastic deformation capability at low temperatures. This mechanical property enables the papillary to respond to the micro-stress generated by ice crystal growth, achieving reversible deformation and recovery, avoiding irreversible damage to the rigid structure under stress. The modulus transition design between the flexible matrix and the blade body structure, combined with the epoxy resin adhesive transition layer, enhances the interfacial bonding strength between the functional layer and the blade substrate, reducing the risk of peeling due to temperature difference or mechanical vibration. The mechanical adaptability of the functional layer enables it to undergo minor deformations during blade operation without structural damage. Attached Figure Description
[0019] Figure 1 This is a schematic flowchart illustrating the preparation method of a low-ice adhesion superhydrophobic ice-repellent functional layer for wind turbine blades according to a specific embodiment of this disclosure. Detailed Implementation
[0020] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.
[0021] Please see Figure 1 As shown, one aspect of the present invention proposes a method for preparing a low-ice-adhesion superhydrophobic ice-repellent functional layer for wind turbine blades, the method comprising the following steps: Step S1: Pretreatment of blade substrate Step S11: Clean and activate the surface area of the wind turbine blades to be treated; use a high-pressure water gun to rinse the blade surface to remove dust and stains, and then use a lint-free cloth soaked in acetone to carefully wipe the blade surface to thoroughly remove grease and release agent residue; Step S12: Allow the blades to air dry naturally in a clean environment for 25-35 minutes; then, use an atmospheric plasma treatment device to scan the cleaned blade surface. The treatment power is 2.5-3.5kW, the distance between the nozzle and the blade surface is maintained at 10-15mm, and the scanning speed is 5m / min. This step aims to introduce active hydroxyl functional groups and significantly improve the surface energy of the substrate, laying the foundation for the firm adhesion of subsequent coatings. After plasma treatment, the next coating step should be carried out within a certain time (e.g., preferably about 4 hours) to avoid a decrease in surface activity.
[0022] Step S2: Coating and curing of the adhesive transition layer To enhance the long-term adhesion between the functional layer and the blade substrate (usually fiberglass or carbon fiber composite), an epoxy resin bonding transition layer needs to be coated on the activated blade surface; the specific steps are as follows: Step S21: Mix bisphenol A type epoxy resin (E-51 type) and polyamide curing agent (651 type) at a mass ratio of (1.5-2.5):1, and stir at 800 rpm for 3-7 minutes using a high-speed disperser until the mixture is uniformly milky white; Step S22: Use an airless spraying device to uniformly spray the mixture onto the blade surface, control the spraying pressure to be 0.4-0.6MPa and the nozzle diameter to be 1.5mm, so as to obtain a wet film with a thickness of 50-80μm; after spraying, place the blade in a room temperature (25±5℃) environment for static curing for 10-14 hours to ensure that the transition layer is completely cross-linked and cured.
[0023] This step aims to coat the activated substrate surface with an epoxy resin bonding transition layer and cure it to enhance the long-term adhesion between the functional layer and the blade substrate.
[0024] Step S3: Preparation of stress-responsive functional slurry Step S31: Preparation of hollow mesoporous silica nanocontainers encapsulated with low molecular weight polydimethylsiloxane (PDMS): Take 3-7 grams of hollow mesoporous silica nanoparticles with an average pore size of 4-6 nm and a particle size of 150-250 nm, and place them in a vacuum reactor; under a vacuum of 0.01 MPa, slowly drop 8-12 grams of low molecular weight PDMS with a viscosity of 45-55 cSt through a dropping funnel, and continue stirring for 1.5-2.5 hours to allow the PDMS to fully fill the hollow channels of the mesoporous silica under capillary action; Step S32: After filling, in-situ sol-gel sealing is performed on the surface of the nanoparticles using tetraethyl orthosilicate (TEOS) to form a thin silica shell, controlling the release of PDMS only under stress rather than natural diffusion; then, the pressure is restored to normal, and the product is collected by centrifugation (8000 rpm, 10 minutes), and then washed three times with n-hexane to remove the physically adsorbed PDMS on the surface. Finally, it is vacuum dried at 55-65℃ for 3.5-4.5 hours to obtain the PDMS@MSNs nanocontainer; Step S33: Preparation of flexible polymer matrix: In a reaction vessel, add 90-110 parts by mass of hydroxyl-terminated polydimethylsiloxane (hydroxyl silicone oil, molecular weight 15000-25000, preferably 20000), 3-7 parts by mass of methyltriethoxysilane as a crosslinking agent, and 0.5-1.5 parts by mass of dibutyltin dilaurate as a catalyst; under nitrogen protection, stir and react at 75-85℃ for 2.5-3.5 hours to form a flexible polysiloxane elastomer prepolymer with a certain degree of crosslinking and a glass transition temperature below -50℃; Step S34: Add 5-15 parts by weight of the prepared PDMS@MSNs nanocontainers and 0.3-0.8 parts by weight of fumed silica thickener to 100 parts by weight of flexible polysiloxane elastomer prepolymer; use a three-roll mill to grind and disperse the nanocontainers, controlling the roller gap to be 10 μm, and grind 3 times until the slurry fineness is ≤20 μm, ensuring that the nanocontainers are uniformly dispersed in the viscous elastomer matrix without agglomeration, and finally obtain a uniform stress-responsive functional slurry; the obtained functional slurry has the triple characteristics of high elasticity, low modulus, and stress-responsive oil release after curing.
[0025] This step aims to prepare a stress-responsive functional slurry by uniformly mixing hollow mesoporous silica nanocontainers encapsulated with low molecular weight polydimethylsiloxane with a flexible polysiloxane elastomer.
[0026] Step S4: Preparation and Imprinting of Micron-Scale Papillary Array Template To achieve precise construction of surface microstructures, this invention employs soft template imprinting technology; Step S41: Prepare a silicon master mold with inverted pyramid-shaped micropores by photolithography. The micropores are designed as a regular array with a side length of 20-50μm, a depth of 15-30μm, and a spacing of 10-25μm. For example, a regular array with a side length of 20μm, a depth of 15μm, and a spacing of 10μm is preferred. Of course, other sizes of regular arrays are also preferred, and there is no specific limitation. Step S42: Pour polydimethylsiloxane prepolymer (Dow Corning Sylgard 184, main agent to curing agent mass ratio 10:1) onto a silicone master mold, cure at 75-85℃ for 1.5-2.5 hours and then peel it off to obtain a PDMS soft template with micron-level protrusion structure. Step S43: The stress-responsive functional slurry prepared in step S3 is uniformly coated onto the adhesive transition layer that has been cured in step S2. The coating thickness is controlled at 90-110 μm, for example, preferably 100 μm. Step S44: Immediately attach the prepared PDMS soft template (with the raised side of the template facing the slurry) gently onto the wet film, and apply a uniform pressure of 0.02-0.05 MPa to ensure that the slurry completely fills the recessed part of the template; place this blade component with the template into a vacuum oven and allow it to cure at 55-65℃ and -0.08 MPa for 7.5-8.5 hours; the vacuum environment helps to eliminate trace air bubbles in the slurry and allows the flexible polymer to fully crosslink and solidify.
[0027] This step aims to coat the functional paste onto the surface of the transition layer, construct a micron-scale papillary array using a soft stencil imprinting process, and then cure it under vacuum conditions.
[0028] Step S5: Demolding and Surface Fluorination Treatment Step S51: After curing, remove the blade from the oven and allow it to cool naturally to room temperature. Using tweezers, starting from the edge, slowly peel off the PDMS soft template at a 30° angle to the blade surface. At this point, a micron-scale papilla array composed of flexible elastomers, complementary to the template structure, is formed on the blade surface. Due to the slight shrinkage of the slurry during the curing process, finer nanoscale wrinkles will naturally form on the top of the papilla, forming a micro-nano composite structure. The resulting papilla array can undergo reversible elastic deformation under microscopic external force, thereby achieving the compression and release of the internal nano-container. Step S52: To further reduce surface energy and enhance the spreadability of PDMS oil on the surface, the formed microstructure surface is subjected to vapor-phase fluorination treatment. The blade is placed in a sealed reaction vessel, and an open container containing 2 ml of perfluorodecyltrimethoxysilane (FAS-17) is placed at the bottom of the vessel. The vessel is heated to 80-100°C and kept at atmospheric pressure. The surface of the blade is treated with the vapor volatilized from FAS-17 for 0.5-1.5 hours. After treatment, the blade is removed and heat-treated in an oven at 145-155°C for 25-35 minutes to firmly graft a dense fluorocarbon chain molecular layer onto the microstructure surface in a chemically bonded manner. The fluorinated layer is covalently bonded to the microstructure and does not affect the stress response or the PDMS oil exudation channels.
[0029] This step aims to perform vapor-phase fluorination on the microstructure surface after template removal, grafting fluorocarbon chain molecular layers through chemical bonding to further reduce surface energy.
[0030] This invention constructs a stress-responsive functional layer composed of a flexible polymer micron-scale papillary array and a nano-container encapsulating a low surface energy lubricating medium. Under freezing rain conditions, the functional layer can utilize the micro-stress generated by ice crystal growth to trigger the on-demand release of the lubricating medium, forming a dynamic molecular lubricating layer on the surface. This solves the problem that existing superhydrophobic coatings fail in high-humidity freezing rain environments due to the microstructure being filled with water vapor, leading to increased ice adhesion strength.
[0031] In another aspect, the present invention proposes a low-ice adhesion superhydrophobic ice-repellent functional layer for wind turbine blades, which is prepared by the method described above. For details, please refer to the above description.
[0032] It should be noted that the main body of the functional layer in this embodiment is configured such that when the surface freezes, the micro-stress generated by the growth of ice crystals can squeeze the nanocontainer, causing it to release the encapsulated low surface energy lubricating medium to the surface of the micron-scale papillary array, forming a lubricating layer that reduces ice adhesion.
[0033] The preparation method of the low-ice adhesion superhydrophobic ice-repellent functional layer for wind turbine blades will be further explained below with reference to specific embodiments: Example 1 Prepare a low-ice adhesion functional layer for wind turbine blades according to the above steps: Step S1: Pretreatment of blade substrate Take a sample of a fiberglass fan blade (300mm×300mm), and use a high-pressure water gun to wash the surface to remove dust. Then, use a lint-free cloth soaked in acetone to carefully wipe the blade surface to thoroughly remove grease and release agent residue. Allow it to air dry naturally in a clean environment for 30 minutes. Use an atmospheric plasma treatment device to scan the cleaned blade surface. The treatment power is 3kW, the distance between the nozzle and the blade surface is maintained at 12mm, and the scanning speed is 5m / min. The next coating step is carried out within 4 hours after plasma treatment.
[0034] Step S2: Coating and curing of the adhesive transition layer Bisphenol A type epoxy resin (E-51 type) and polyamide curing agent (651 type) were mixed at a mass ratio of 2:1 and stirred at 800 rpm for 5 minutes until homogeneous using a high-speed disperser. The mixture was then uniformly sprayed onto the blade surface using an airless spraying device at a spraying pressure of 0.5 MPa and a spray gun nozzle diameter of 1.5 mm to obtain a wet film with a thickness of 65 μm. After spraying, the film was allowed to cure at room temperature (25±5℃) for 12 hours.
[0035] Step S3: Preparation of stress-responsive functional slurry Preparation of hollow mesoporous silica nanocontainers encapsulated with PDMS: 5 g of hollow mesoporous silica nanoparticles with an average pore size of 5 nm and a particle size of 200 nm were placed in a vacuum reactor. Under a vacuum of 0.01 MPa, 10 g of low molecular weight PDMS with a viscosity of 50 cSt was slowly added dropwise through a dropping funnel. The mixture was stirred continuously for 2 hours to allow the PDMS to fully fill the mesoporous channels. After filling, tetraethyl orthosilicate (TEOS) was used to perform in-situ sol-gel sealing on the surface of the nanoparticles to form a thin silica shell. After restoring to normal pressure, the product was collected by centrifugation (8000 rpm, 10 minutes). The product was washed three times with n-hexane to remove the physically adsorbed PDMS on the surface. Finally, the product was vacuum dried at 60 °C for 4 hours to obtain PDMS@MSNs nanocontainers. Preparation of flexible polymer matrix: 100 parts by mass of hydroxyl-terminated polydimethylsiloxane (hydroxyl silicone oil, molecular weight 20000), 5 parts by mass of methyltriethoxysilane crosslinking agent, and 1 part by mass of dibutyltin dilaurate catalyst were added to a reaction vessel and stirred at 80°C for 3 hours under nitrogen protection to form a flexible polysiloxane elastomer prepolymer. Ten parts by weight of PDMS@MSNs nanocontainers and 0.5 parts by weight of fumed silica thickener were added to 100 parts by weight of flexible polysiloxane elastomer prepolymer. The mixture was then dispersed by grinding with a three-roll mill with a roller gap of 10 μm and the milling was repeated three times until the slurry fineness was ≤20 μm, resulting in a uniform stress-responsive functional slurry.
[0036] Step S4: Preparation and Imprinting of Micron-Scale Papillary Array Template A silicon master mold with inverted pyramid-shaped micropores was prepared by photolithography. The micropores had a side length of 20 μm, a depth of 15 μm, and a spacing of 10 μm. Polydimethylsiloxane prepolymer (Dow Corning Sylgard 184, main agent: curing agent = 10:1) was poured onto the silicon master mold and cured at 80°C for 2 hours before being peeled off to obtain a PDMS soft template with a micron-scale protrusion structure. The functional slurry prepared in step S3 is uniformly coated onto the adhesive transition layer cured in step S2, with a coating thickness of 100 μm. Immediately, the PDMS soft template (with the raised side facing the slurry) is attached to the wet film, and a uniform pressure of 0.035 MPa is applied to ensure that the slurry completely fills the template depression. The blade component with the template is placed in a vacuum oven and cured for 8 hours at 60°C and a vacuum degree below -0.08 MPa (gauge pressure).
[0037] Step S5: Demolding and Surface Fluorination Treatment After curing, the PDMS soft template was naturally cooled to room temperature. Using tweezers, the template was slowly peeled off from the edge at a 30° angle to the blade surface, forming a micron-scale papillary array composed of flexible elastomers on the blade surface. The blade was then placed in a sealed reaction vessel with an open dish containing 2 ml of perfluorodecyltrimethoxysilane (FAS-17) at the bottom. The mixture was heated to 90°C and fluorinated with FAS-17 vapor at atmospheric pressure for 1 hour. The blade was then removed and dried in an oven at 150°C for 30 minutes to allow the fluorocarbon chain molecular layers to chemically bond to the microstructure surface.
[0038] Example 2 The preparation process is basically the same as in Example 1, except that in step S3, TEOS in-situ sol-gel sealing treatment was not performed when preparing PDMS@MSNs nanocontainers.
[0039] Example 3 The preparation process is basically the same as in Example 1, except that in step S3, the flexible polymer matrix is a polyurethane elastomer prepolymer with a glass transition temperature (Tg) of -20°C, instead of a flexible polysiloxane elastomer with a Tg ≤ -50°C.
[0040] Example 4 The preparation process is basically the same as in Example 1, except that in step S4, the microporous structure of the soft template is changed to a regular array with a side length of 50 μm, a depth of 30 μm, and a spacing of 25 μm.
[0041] Example 5 The preparation process is basically the same as in Example 1, except that in step S4, the template imprinting pressure is adjusted to 0.005 MPa.
[0042] Example 6 The preparation process is basically the same as that in Example 1, except that the temperature of the gas phase fluorination treatment in step S5 is adjusted to 150°C.
[0043] Example 7 The preparation process is basically the same as in Example 1, except that in step S3, the hollow mesoporous silica nanocontainer encapsulated with PDMS is replaced with an equal mass of unencapsulated ordinary mesoporous silica nanoparticles (only physically adsorbing PDMS, without a sealing layer).
[0044] Example 8 The preparation process is basically the same as in Example 1, except that in step S3, the amount of PDMS@MSNs nanocontainers added is adjusted from 10 parts by mass to 2 parts by mass.
[0045] Example 9 The preparation process is basically the same as in Example 1, except that in step S3, the amount of PDMS@MSNs nanocontainers added is adjusted from 10 parts by mass to 25 parts by mass.
[0046] Example 10 The preparation process is basically the same as that in Example 1, except that in step S4, a flat coating is directly formed by conventional scraping process, and a micron-scale papillary array is not constructed by soft template imprinting.
[0047] Comparative Example 1 The preparation process is basically the same as in Example 1, except that in step S3, PDMS@MSNs nanocontainers are not added, and the functional slurry is only a pure flexible polysiloxane elastomer.
[0048] Comparative Example 2 The preparation process is basically the same as in Example 1, except that in step S3, the flexible polymer matrix is replaced with rigid epoxy resin (E-51 type epoxy resin and polyamide curing agent 2:1 curing, Tg>60℃).
[0049] Comparative Example 3 The preparation process is basically the same as in Example 1, except that the fluorination treatment in step S5 is omitted.
[0050] Comparative Example 4 The preparation process is basically the same as in Example 1, except that in step S2, no epoxy resin bonding transition layer is coated, and the functional slurry is directly coated onto the plasma-treated blade substrate.
[0051] Comparative Example 5 The preparation process is basically the same as that in Example 1, except that in step S1, only acetone is used for wiping and cleaning, and atmospheric plasma activation treatment is not performed.
[0052] Comparative Example 6 Using commercially available superhydrophobic anti-icing coatings as a control, the same specifications of fiberglass blade samples were sprayed according to the product instructions and cured for 24 hours.
[0053] Comparative Example 7 Using commercially available silicone oil-lubricated anti-icing coatings as a control, the same specifications of fiberglass blade samples were coated according to the product instructions and cured for 24 hours.
[0054] Comparative Example 8 The preparation process is basically the same as in Example 1, except that in step S3, the encapsulation medium is replaced by high molecular weight PDMS (10000cSt) instead of low molecular weight PDMS (50cSt).
[0055] Comparative Example 9 The preparation process is basically the same as in Example 1, except that in step S3, the encapsulation medium is replaced by mineral oil instead of low molecular weight PDMS.
[0056] Comparative Example 10 A blank fiberglass blade sample without any coating was used as a control.
[0057] Furthermore, the samples from the above embodiments and comparative examples were tested using the following methods: Initial ice adhesion strength test: The samples prepared in each example and comparative example were placed in an ice wind tunnel and frozen for 30 minutes under the conditions of -5℃, wind speed of 10m / s, average supercooled water droplet size of 30μm, and liquid water content of 1.0g / m³, forming an ice layer with a thickness of about 5mm. The ice layer was pushed tangentially along the blade surface at a speed of 10mm / min using a push-pull force gauge, and the peak force of the ice layer falling off was recorded. The ice adhesion strength (kPa) was obtained by dividing the peak force by the contact area between the ice layer and the coating. Five samples were tested in each group, and the average value was taken.
[0058] Durability test (ice adhesion strength after freezing rain cycle): Place the sample in a freezing rain cycle test chamber. Each cycle includes: freezing rain spray at -5℃ for 2 hours (to form an ice layer), natural melting (standing at room temperature for 1 hour), freezing at -20℃ for 1 hour, and heating to -5℃. Repeat the above cycle 50 times, and then test the ice adhesion strength again using the above method.
[0059] Microstructure retention rate: The morphological changes of the micron-scale papillary array on the coating surface before and after the durability test were observed using scanning electron microscopy (SEM). The percentage of papillary arrays that did not collapse or break was counted as the microstructure retention rate (%).
[0060] PDMS release test: The samples of each example and comparative example were placed in an environment of -5℃, covered with ice, and subjected to periodic micro-vibration (simulating blade operating conditions) for 24 hours. The intensity of the characteristic peak of PDMS on the coating surface was detected by Fourier transform infrared spectroscopy (FTIR), and the relative value of the release was calculated by comparing it with the initial state.
[0061] Table 1 Performance test results of each embodiment and comparative example
[0062] As can be seen from the data in Table 1, Example 1 (the optimal solution of the present invention) exhibits the lowest initial ice adhesion strength (5.2 kPa) and the best durability (only rising to 6.1 kPa after 50 freezing rain cycles), with a microstructure retention rate as high as 97.2% and a moderate PDMS release (35.2%), proving that the in-situ microstructure sacrifice-regeneration mechanism successfully achieves stress-responsive oil release, and that the TEOS sealing controls the PDMS release rate. The key role of the sealing layer: The PDMS release in Example 2 (no sealing) and Example 7 (no sealing + ordinary mesoporous) was significantly higher (52.3% and 58.7%, respectively), which led to a significant increase in ice adhesion after the durability test, proving that the sealing layer is the key to controlling long-term performance.
[0063] Necessity of flexible substrates: The ice adhesion performance of Example 3 (high Tg) and Comparative Example 2 (rigid substrate) was poor and the microstructure retention rate was low (82.5% and 52.3%, respectively), which proves that a low Tg flexible substrate is a necessary condition for achieving stress response and reversible structural deformation.
[0064] Significant contribution of microstructure: The initial ice adhesion (15.8 kPa) of Example 10 (without microstructure) was significantly higher than that of Example 1, demonstrating the synergistic effect of micron-scale papillary array and oil release mechanism.
[0065] Optimization windows for various process parameters: Examples 4-6 and 8-9 show that there are optimal ranges for microstructure size, imprinting pressure, fluorination temperature, and nanocontainer addition amount. Deviating from the optimal value will lead to a decrease in performance.
[0066] Advantages compared to traditional technologies: The ice adhesion strength of Comparative Examples 6-7 (commercially available products) and Comparative Example 10 (blank) exceeds that of Example 1, demonstrating the superiority of the present invention under high humidity freezing rain conditions in the mountainous areas of Southwest China.
[0067] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0068] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.
Claims
1. A method for preparing a low-ice adhesion superhydrophobic ice-repellent functional layer for wind turbine blades, characterized in that, The preparation method includes: Provide wind turbine blade substrates and pre-treat their surfaces; An adhesive transition layer is coated onto the pretreated substrate surface and then cured. Prepare a stress-responsive functional slurry, the functional slurry comprising a flexible polymer matrix and a nanocontainer uniformly dispersed in the flexible polymer matrix and encapsulated with a low surface energy lubricating medium; The functional slurry is coated onto the surface of the cured substrate bonding transition layer, and a micron-scale papillary array is constructed on the surface of the functional slurry by a template imprinting process. The functional slurry is then cured to form a functional layer body with a micron-scale papillary array. Remove the template and fluorinate the surface of the functional layer body.
2. The preparation method according to claim 1, characterized in that, The preparation of the stress-responsive functional slurry includes: Hollow mesoporous silica nanocontainers encapsulated with low molecular weight polydimethylsiloxane were prepared as nanocontainers. A flexible polysiloxane elastomer prepolymer with a glass transition temperature below -50℃ was prepared as a flexible polymer matrix; The nanocontainer and thickener are added to the flexible polysiloxane elastomer prepolymer and then ground and dispersed evenly to obtain the functional slurry.
3. The preparation method according to claim 2, characterized in that, The preparation of hollow mesoporous silica nanocontainers encapsulated with low molecular weight polydimethylsiloxane includes: Hollow mesoporous silica nanoparticles are placed in a vacuum reactor, and low molecular weight polydimethylsiloxane is dropped in under vacuum conditions, so that the polydimethylsiloxane fills the channels of the mesoporous silica. After filling, tetraethyl orthosilicate is used to carry out an in-situ sol-gel reaction on the surface of the nanoparticles to form a coating layer to seal the pore openings; After separation, washing, and drying, hollow mesoporous silica nanocontainers encapsulated with low molecular weight polydimethylsiloxane were obtained; wherein, The hollow mesoporous silica nanoparticles have an average pore size of 4-6 nm and a particle size of 150-250 nm; the low molecular weight polydimethylsiloxane has a viscosity of 45-55 cSt.
4. The preparation method according to claim 2, characterized in that, The preparation of the flexible polysiloxane elastomer prepolymer with a glass transition temperature below -50°C includes: Using hydroxyl-terminated polydimethylsiloxane as raw material, a crosslinking agent and a catalyst are added, and the mixture is stirred and reacted at 75-85℃ for 2.5-3.5 hours under nitrogen protection to obtain a prepolymer.
5. The preparation method according to claim 4, characterized in that, The molecular weight of the hydroxyl-terminated polydimethylsiloxane is 15,000-25,000, the crosslinking agent is methyltriethoxysilane, and the catalyst is dibutyltin dilaurate.
6. The preparation method according to claim 2, characterized in that, The mass ratio of the nanocontainer to the flexible polysiloxane elastomer prepolymer is (5-15):100; The thickener is fumed silica.
7. The preparation method according to claim 1, characterized in that, The template imprinting process includes: Prepare soft templates with micron-scale cavities or protrusions; After the functional slurry is coated onto the adhesive transition layer surface of the substrate, the soft template is immediately attached to the surface of the functional slurry and a uniform pressure of 0.02 to 0.05 MPa is applied. The substrate with the template is placed in a vacuum oven with a vacuum degree of less than -0.08 MPa gauge pressure and cured at 55-65°C for 7.5-8.5 hours to allow the functional slurry to crosslink and solidify, and to replicate a micron-scale papillary array that is complementary to the template structure.
8. The preparation method according to claim 1, characterized in that, The adhesive transition layer is formed by mixing bisphenol A type epoxy resin and polyamide curing agent at a mass ratio of (1.5-2.5):1, applying and curing it using an airless spraying process, and its wet film thickness is 50-80μm.
9. The preparation method according to claim 1, characterized in that, The fluorination treatment is a gas-phase fluorination treatment, specifically including: After demolding, the substrate with the functional layer as the main body is placed in a sealed container, and perfluorodecyltrimethoxysilane is placed at the bottom of the container. Heat the container to 80-100°C and treat the surface of the functional layer substrate with perfluorodecyltrimethoxysilane vapor for 0.5-1.5 hours. After removal, heat treatment is carried out at 145-155℃ for 25-35 minutes to chemically bond the fluorocarbon chain molecular layer to the surface of the micron-scale papillary array.
10. A low-ice adhesion superhydrophobic de-icing functional layer for wind turbine blades, characterized in that, The low-ice adhesion superhydrophobic ice-repellent functional layer of the wind turbine blade is prepared by the preparation method described in any one of claims 1-9.