An anti-icing and de-icing coating with excellent durability and its preparation method

Abstract

This invention belongs to the field of anti-icing and de-icing technology, specifically relating to an anti-icing and de-icing coating with excellent durability and its preparation method. The preparation method of this invention first involves adding a SiO2 dispersion to an elastomer made of PDMS and a room-temperature curing agent, mixing them uniformly to obtain a coating solution; the room-temperature curing agent is a room-temperature curing agent without carbon-carbon triple bonds; the SiO2 particles account for 1% to 15% of the mass ratio of the elastomer solution; finally, the coating solution is slowly and uniformly coated onto a substrate to form a film of less than or equal to 220 micrometers, thus obtaining an anti-icing and de-icing coating with excellent durability.

Description

[0001] Divisional application

[0002] This application is a divisional application of Chinese invention patent application No. CN2023114115230, filed on October 27, 2023, entitled "A large-area anti-icing and de-icing coating with excellent durability and its preparation method". Technical Field

[0003] This invention belongs to the field of anti-icing and de-icing technology, specifically relating to an anti-icing and de-icing coating with excellent durability and its preparation method. Background Technology

[0004] Aircraft and wind turbine blades typically operate continuously in cold and harsh environments, making their surfaces prone to icing. Surface icing alters the shape of the blade surface, increases surface roughness, and causes changes in aerodynamic performance. In severe cases, icing can even lead to flight malfunctions, endangering the lives of the entire crew. Furthermore, persistent icing can cause blade overload and uneven distribution of ice load on the blade surface, leading to wind turbine malfunctions or even shutdowns.

[0005] Traditional de-icing technologies include spraying anti-icing solutions, mechanical de-icing, and thermal melting, but these methods generally suffer from low efficiency and high manufacturing costs, limiting their practical application in large-area de-icing. On the other hand, the academic community has proposed biomimetic superhydrophobic and superlubricating coatings as effective methods for preventing or delaying icing. This is because the micro-nano structure of superhydrophobic coatings contains numerous air cushions, effectively delaying icing and reducing ice adhesion strength. For example, when ice comes into contact with the surface of a superlubricating coating, it is isolated by the lubricant layer, significantly reducing ice adhesion strength. However, the ice adhesion of superhydrophobic and superlubricating coatings is positively correlated with the icing area; as the icing area increases, the ice adhesion also increases. Therefore, when used on large-area structures such as aircraft and wind turbine blades, they do not perform well in de-icing. Furthermore, the durability of superhydrophobic and superlubricating coatings is generally poor. The rough structure of superhydrophobic coatings is easily damaged, leading to loss of anti-icing performance; the lubricant in superlubricating coatings is lost during use, further reducing their anti-icing performance. Therefore, commonly used traditional de-icing technologies and ordinary superhydrophobic / superlubricating coatings are difficult to apply to large-area surfaces such as aircraft and wind turbine blades.

[0006] In addition, some researchers have prepared low-interface-toughness coatings with a certain degree of large-area de-icing performance. However, the preparation methods used for these coatings are mostly cumbersome, requiring the addition of multiple materials. The more types of materials used, the higher the requirements for the preparation method, and consequently, the higher the process cost. Moreover, some raw materials with low interface toughness are themselves expensive, thus hindering their application in large-scale industrial production. On the other hand, most of the currently reported low-interface-toughness coatings lack durability evaluation and proof. Patent application number CN202211540809.4, entitled "A Preparation Method of a Large-Area De-icing Coating," discloses a method of altering the surface structure of Ecofelx silicone coating by adding low-interface-toughness PVC powder to create wrinkles and protrusions, thereby generating local stress that reduces ice adhesion. Furthermore, the addition of glycerol, a plasticizer, reduces the shear modulus of the coating surface, thus overcoming the positive correlation between ice adhesion strength and ice area in traditional silicone rubber coatings. This results in ice adhesion strength gradually approaching a lower and more stable value as the ice area approaches infinity. However, this patented method requires an ice surface length of at least 80cm to achieve a relatively stable de-icing force. Furthermore, the de-icing force measurement in this patented method is incomplete; the corresponding paper, "Soft and Rigid Integrated Durable Coating for Large-Scale Deicing," shows that only a few distances were selected for measurement, and the 20 durability tests also used only a few distances. A patent application with application number CN202010100962.X, entitled "A Low-Interfacial-Toughness Porous Material for Large-Area De-icing and Its Preparation Method," discloses a method of introducing a uniform porous structure under a smooth polymer surface to reduce the material's interfacial toughness, thereby promoting the initiation and propagation of cracks at the ice-free interface, thus preparing a low-interfacial-toughness porous material for large-area de-icing. The porous elastic coating disclosed in this patent is obtained by first uniformly mixing components A and B of PDMS184 with pore-forming agents (Span 80, Tween 80) and then curing the mixture, followed by removing the pore-forming agents using anhydrous ethanol. However, during the removal of the pore-forming agent, the elastic coating is prone to detaching from the substrate, resulting in generally poor adhesion between the elastic coating and the substrate. Furthermore, while the porous structure of this coating facilitates crack initiation, it also reduces the coating's mechanical properties, making it susceptible to damage during external cyclic icing and de-icing processes. In conclusion, it can be inferred that the durability of this porous elastic coating is generally poor, and the patent indeed lacks evaluation and proof of its long-term durability. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a long-lasting, low-interfacial-toughness, large-area anti-icing and de-icing coating and its preparation method, the specific technical solution of which is as follows.

[0008] A method for preparing a durable, large-area anti-icing and de-icing coating includes the following steps:

[0009] Step 1: Mix a low-boiling-point organic solvent with SiO2 particles to obtain a SiO2 dispersion;

[0010] As a preferred method, magnetic stirring and / or ultrasonic dispersion can make the dispersion preparation faster or the dispersion more uniform.

[0011] Step 2: A uniform mixture of PDMS prepolymer and room-temperature curing agent is prepared to obtain an elastomer solution. The SiO2 dispersion is then added to the elastomer (PDMS prepolymer plus room-temperature curing agent) solution, and the mixture is stirred uniformly to obtain a coating solution. The PDMS prepolymer has a viscosity of 3000-4000 mPa•s and a molecular weight of 120000-130000. The mass ratio of the PDMS prepolymer to the room-temperature curing agent is 1:1, and the SiO2 particles account for 1%~15% of the mass ratio of the elastomer solution (PDMS prepolymer plus room-temperature curing agent).

[0012] Step 3: Slowly and evenly apply the coating solution obtained in Step 2 onto the substrate and cure at room temperature for 24-48 hours to form a large-area anti-icing and de-icing coating with a diameter of less than or equal to (≤) 220 micrometers.

[0013] As a preferred option, a large-area anti-icing and de-icing coating of 80-220 micrometers is formed by curing at room temperature for 24-48 hours.

[0014] Furthermore, the viscosity of the PDMS prepolymer is 3000-3500 mPa•s, including 3000 mPa•s, 3100 mPa•s, 3200 mPa•s, 3300 mPa•s, 3400 mPa•s and 3500 mPa•s.

[0015] Furthermore, the molecular weight of the PDMS prepolymer includes 120,000-121,000, 121,000-122,000, 122,000-123,000, 123,000-124,000, 124,000-125,000, 125,000-126,000, 126,000-127,000, 127,000-128,000, 128,000-129,000, and 129,000-130,000.

[0016] Furthermore, the substrate includes the surface of aircraft and / or wind turbine blades.

[0017] Furthermore, the low-boiling-point organic solvent includes tetrahydrofuran (boiling point 66°C), chloroform (boiling point 61°C), dichloromethane (boiling point 39.8°C), ethyl acetate (boiling point 76°C), or n-hexane (boiling point 69°C).

[0018] Furthermore, the SiO2 particles include micron-sized and / or nano-sized SiO2 particles with a particle size range of 500 nanometers to 1 micrometer or 3 to 40 nanometers.

[0019] Furthermore, the room temperature curing agent is a curing agent that does not contain carbon-carbon triple bonds but contains cross-linking groups (in this invention, this mainly refers to cross-linking with PDMS prepolymer), and the cross-linking groups include amino, hydroxyl and / or carboxyl groups.

[0020] Preferably, the room temperature curing agent includes methyltriethoxysilane, methyltripropoxysilane, butyl diphenylcarbamate (dbp), or benzoyl peroxide (bpo), etc.

[0021] Furthermore, the SiO2 particles account for 1%, 3%, 5%, 10%, or 15% of the mass of the elastomer (PDMS prepolymer plus room temperature curing agent).

[0022] Preferably, the SiO2 particles account for 1%, 3%, or 5% of the mass of the elastomer (PDMS prepolymer plus room temperature curing agent).

[0023] Furthermore, the mass ratio of SiO2 particles in the SiO2 dispersion to the low-boiling-point organic solvent is 0.5% to 8.0%.

[0024] Furthermore, the operation of mixing the low-boiling-point organic solvent with SiO2 particles in step 1 includes first performing magnetic stirring at a rate of 300~500 r / min for 5~15 min, and then performing ultrasonic vibration at a power of 300~1000 W for 5~15 min.

[0025] Furthermore, in step 2, the process of adding the SiO2 dispersion to the PDMS prepolymer and the room temperature curing agent and mixing them evenly includes first performing magnetic stirring at a rate of 300~500 r / min for 5-10 min, and then performing ultrasonic vibration at a power of 300~1000W for 5-10 min.

[0026] Furthermore, the method of applying the coating solution to the substrate in step 3 includes direct pouring, dripping, scraping, bar coating, spin coating, brush coating, and / or spraying.

[0027] The large-area anti-icing and de-icing coating is prepared by the above method.

[0028] Preferably, the large-area anti-icing and de-icing coating prepared by the present invention contains 1% or 3% SiO2 particles by mass, and the coating thickness is less than or equal to 220 micrometers.

[0029] The large-area anti-icing and de-icing coating can be used for long-term anti-icing and de-icing in scenarios such as aircraft and wind turbine blades.

[0030] Beneficial technical effects:

[0031] 1) This invention utilizes a simplified material ratio, crosslinking an elastomer with a PDMS prepolymer of specific viscosity and molecular weight and a room-temperature curing agent free of carbon-carbon triple bonds to obtain an elastomer. A specific proportion of SiO2 microparticles are then added to the elastomer, and finally, a coating of a specific thickness is applied to a substrate, resulting in a large-area anti-icing and de-icing coating (film) with excellent durability and low interfacial toughness. The micron- or nano-sized SiO2 microparticles used in this invention are hard and do not inherently possess low interfacial toughness. Compared to PVC powder (soft), a material with low interfacial toughness, they are cheaper. However, the coating prepared using these hard SiO2 microparticles and the elastomer still exhibits low constant de-icing force and ice adhesion strength after 120 icing / de-icing cycles. Furthermore, this invention demonstrates that when the prepared coating film thickness is less than 220 micrometers, its constant de-icing force and interfacial toughness are very low. The constant de-icing force is lower than that of other studies published in core journals in this field, proving that the coating prepared by this invention has excellent durability and low interfacial toughness, making it suitable for large-area surface icing and de-icing of aircraft and / or wind turbine blades.

[0032] 2) This invention crosslinks PDMS prepolymers with specific molecular weights and viscosities with a curing agent that does not contain carbon-carbon triple bonds, and adds SiO2 microparticles in a specific mass ratio to obtain a stable elastomer-microparticle hybrid coating. When the amount of SiO2 microparticles added is 3%, the constant de-icing force of the coating decreases after multiple icing / de-icing cycle experiments, proving that the addition of SiO2 microparticles can significantly improve the durability of the coating.

[0033] 3) The critical icing size of the coating prepared by the method of the present invention is only a few centimeters, which is smaller than the critical icing area / size of other coatings in the prior art, and also much smaller than the area of ​​aircraft wings or wind turbine blades. Therefore, it can fully achieve durable anti-icing and de-icing in this scenario. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale. Obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0035] Figure 1 Infrared spectra of different PDMS prepolymers and curing agents;

[0036] Figure 2 This describes the microstructure of the coating of the present invention.

[0037] Figure 3 The three-dimensional morphology and surface roughness of the coating of this invention;

[0038] Figure 4 Experimental diagrams for evaluating the wettability of the coating of this invention;

[0039] Figure 5 This is an experimental diagram showing the de-icing force of the coating of this invention;

[0040] Figure 6 This is an experimental diagram showing the apparent ice adhesion strength of the coating of this invention.

[0041] Figure 7 Experimental diagrams summarizing the constant de-icing force, critical length, interfacial toughness, and ice adhesion strength of the coating of this invention;

[0042] Figure 8 These are experimental diagrams illustrating the wettability and durability of the coating of this invention.

[0043] Figure 9 These are experimental diagrams illustrating the constant de-icing force and interfacial toughness and durability of the coating of this invention.

[0044] Figure 10 These are experimental figures illustrating the critical length of the coating and the durability of ice adhesion strength in this invention.

[0045] Figure 11 Experimental diagrams showing the de-icing force of different PDMS prepolymer coatings. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0047] In this document, "and / or" includes any and all combinations of one or more of the listed related items.

[0048] In this article, "multiple" means two or more, that is, it includes two, three, four, five, etc.

[0049] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus 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 apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0050] As used in this specification, the term "about" typically means + / -5% of the value, more typically + / -4% of the value, more typically + / -3% of the value, more typically + / -2% of the value, even more typically + / -1% of the value, and even more typically + / -0.5% of the value.

[0051] In this specification, certain embodiments may be disclosed in a range-bound format. It should be understood that this "range-bound" description is merely for convenience and brevity and should not be construed as a rigid limitation on the disclosed range. Therefore, the description of the range should be considered as having specifically disclosed all possible subranges and independent numerical values ​​within those ranges. For example, range 1... The description of 6 should be considered as having specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within this range, such as 1, 2, 3, 4, 5, and 6. The above rules apply regardless of the breadth of the range.

[0052] The "low-boiling-point organic solvent" mentioned in this invention refers to an organic solvent with a boiling point of less than 80°C.

[0053] The "room temperature curing agent" mentioned in this invention refers to a curing agent that can undergo a crosslinking reaction with PDMS prepolymer at room temperature, such as room temperature, without heating.

[0054] Example 1

[0055] Option 1: This option provides a method for preparing an anti-icing and de-icing coating that does not contain SiO2.

[0056] 1. Materials

[0057] The matrix material used was 1060 aluminum plate, measuring 20cm × 30cm × 1mm, provided by Shenzhen Hongnian Metal Materials Co., Ltd. The PDMS prepolymer, model C0030, with a molecular weight of 128449 and a viscosity of 3000 mPa•s, was provided by Hangzhou Weisichuang Technology Co., Ltd. Optional room-temperature curing agents included methyltriethoxysilane, methyltripropoxysilane, butyl diphenylcarbamate (dbp), or benzoyl peroxide (bpo), all free of carbon-carbon triple bonds (C≡C bonds). Tetrahydrofuran was provided by Chengdu Kelong Chemical Co., Ltd. Anhydrous ethanol was purchased from Chongqing Chuandong Chemical Co., Ltd. All reagents were used directly without purification.

[0058] 2. Preparation process

[0059] First, the 1060 aluminum plate was soaked and cleaned with tetrahydrofuran and anhydrous ethanol respectively to remove residual stains on the surface. Then, it was cleaned with deionized water to remove excess tetrahydrofuran and anhydrous ethanol. After cleaning, the aluminum plate was placed in an oven to dry. The mass of PDMS prepolymer and room-temperature curing agent was 12g each (1:1). The PDMS prepolymer and room-temperature curing agent were mixed to prepare an elastomer solution. The thoroughly mixed elastomer solution was slowly and evenly poured onto an aluminum plate tilted at 45°, and then the aluminum plate was placed vertically for 5 minutes to remove excess solution. Finally, it was cured at room temperature for 36 hours to form a 101μm film structure. Heating can accelerate the curing time.

[0060] Option 2: This option provides a method for preparing anti-icing and de-icing coatings with different SiO2 contents.

[0061] 1. Materials

[0062] The matrix material used was 1060 aluminum plate, with dimensions of 20cm × 30cm × 1mm, provided by Shenzhen Hongnian Metal Materials Co., Ltd. The PDMS prepolymer, model C0030, with a molecular weight of 128449 and a viscosity of 3000 mPa·s, was provided by Hangzhou Weisichuang Technology Co., Ltd. Optional curing agents included methyltriethoxysilane, methyltripropoxysilane, butyl diphenylcarbamate (dbp), or benzoyl peroxide (bpo), free of carbon-carbon triple bonds (C≡C bonds). Silica powder with an average particle size of 3-40nm was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. (SiO2 particles with a particle size of 500 nm to 1 μm can also be used). Tetrahydrofuran was provided by Chengdu Kelong Chemical Co., Ltd. (other low-boiling-point organic solvents provided in this invention can also be used). Anhydrous ethanol was purchased from Chongqing Chuandong Chemical Co., Ltd. All reagents were used directly without purification.

[0063] 2. Preparation process

[0064] First, the 1060 aluminum plate was soaked and cleaned with tetrahydrofuran and anhydrous ethanol respectively to remove residual stains on the surface. Then, it was cleaned with deionized water to remove excess tetrahydrofuran and anhydrous ethanol from the surface. After cleaning, the aluminum plate was dried in an oven for later use. 50g of tetrahydrofuran and different masses of SiO2 particles were placed in a beaker (the mass ratio of SiO2 particles in tetrahydrofuran was 0.5%~8.0%). The mixture was first magnetically stirred at a rate of 300~500 r / min for 10 minutes, and then ultrasonically vibrated at a power of 500~1000W for 10 minutes to obtain a SiO2 dispersion. Next, a PDMS prepolymer and a room-temperature curing agent with a mass ratio of 1:1 were mixed evenly to prepare an elastomer solution (the mass of both the PDMS prepolymer and the room-temperature curing agent was 12g). SiO2 dispersion was then added, and the mixture was magnetically stirred at a rate of 300~500 r / min and ultrasonically vibrated at a power of 500~1000W for 5 minutes each to obtain a uniformly mixed coating solution.

[0065] To prepare coatings with different mass fractions (0%, 1%, 3%, 5%, 10%, 15%, 20%, and 25%), the added SiO2 powder masses were 0.00 g, 0.25 g, 0.75 g, 1.26 g, 2.67 g, 4.23 g, 6.00 g, and 8.00 g, respectively. The final coating solution was slowly and uniformly poured onto an aluminum plate tilted at 45°, and then the plate was placed vertically for 5 minutes to remove excess solution. Finally, it was cured at room temperature for 36 hours to form a large-area anti-icing and de-icing coating with an 80-220 micrometer film structure. Heating can accelerate the curing time.

[0066] Example 2

[0067] This embodiment provides another method for preparing an anti-icing and de-icing coating that does not contain SiO2.

[0068] 1. Materials

[0069] The matrix material used was 1060 aluminum plate, measuring 20cm × 30cm × 1mm, provided by Shenzhen Hongnian Metal Materials Co., Ltd. The PDMS prepolymer, model C105, with a molecular weight of 30981 and a viscosity of 5000 mPa·s, was provided by Hangzhou Weisichuang Technology Co., Ltd. Optional room-temperature curing agents containing carbon-carbon triple bonds included methyldiphenylethynylsilane, organopolysilazane, diethynyl-terminated silazane, or alkynyl polyethylene glycol silane, etc. Tetrahydrofuran was provided by Chengdu Kelong Chemical Co., Ltd. Anhydrous ethanol was purchased from Chongqing Chuandong Chemical Co., Ltd. All reagents were used directly without purification.

[0070] 2. Preparation process

[0071] First, the 1060 aluminum plate was soaked and cleaned with tetrahydrofuran and anhydrous ethanol respectively to remove residual stains on the surface. Then, it was cleaned with deionized water to remove excess tetrahydrofuran and anhydrous ethanol. After cleaning, the aluminum plate was dried in an oven for later use. The mass of both the PDMS prepolymer and the room-temperature curing agent was 12g. The PDMS prepolymer and room-temperature curing agent were mixed to prepare control elastomer solution 1. The thoroughly mixed solution was slowly and evenly poured onto an aluminum plate tilted at 45°, and then the aluminum plate was placed vertically for 5 minutes to remove excess solution. Finally, it was cured at room temperature for 48 hours to form a 92.4μm film structure. Heating can accelerate the curing time.

[0072] Example 3

[0073] This embodiment provides another method for preparing an anti-icing and de-icing coating that does not contain SiO2.

[0074] 1. Materials

[0075] The matrix material used was 1060 aluminum plate, measuring 20cm × 30cm × 1mm, provided by Shenzhen Hongnian Metal Materials Co., Ltd. The PDMS prepolymer, model P184, with a molecular weight of 147757 and a viscosity of 3500 mPa·s, was provided by Guangzhou Optoelectronic New Materials Technology Co., Ltd. Optional room-temperature curing agents containing carbon-carbon triple bonds included methyldiphenylethynylsilane, organopolysilazane, diethynyl-terminated silazane, or alkynyl polyethylene glycol silane, etc. Tetrahydrofuran was provided by Chengdu Kelong Chemical Co., Ltd. Anhydrous ethanol was purchased from Chongqing Chuandong Chemical Co., Ltd. All reagents were used directly without purification.

[0076] 2. Preparation process

[0077] First, the 1060 aluminum plate was soaked and cleaned with tetrahydrofuran and anhydrous ethanol respectively to remove residual stains on the surface. Then, it was cleaned with deionized water to remove excess tetrahydrofuran and anhydrous ethanol. After cleaning, the aluminum plate was placed in an oven to dry. The mass of both the PDMS prepolymer and the room-temperature curing agent was 12g. A control elastomer solution 2 was prepared by mixing the PDMS prepolymer and the room-temperature curing agent. The thoroughly mixed solution was slowly and evenly poured onto an aluminum plate tilted at 45°, and then the aluminum plate was placed vertically for 5 minutes to remove excess solution. Finally, it was cured at room temperature for 48 hours to form a 107.9μm film structure. Heating can accelerate the curing time.

[0078] Example 4

[0079] Experimental verification

[0080] 1. Characterization

[0081] The microstructure and elemental distribution were characterized using scanning electron microscopy (SEM, Zeiss Auriga, Germany) and energy dispersive spectroscopy (EDS). The three-dimensional structure was observed and surface roughness was measured using a laser confocal microscope (LEXT OLS4000). The contact angle (CA) and contact hysteresis (CAH) were measured using a water contact angle meter (SINDIN SDC-100). The volume of the water droplet was approximately 5 μL, and measurements were taken at five locations, with the average value calculated.

[0082] Ice adhesion strength and de-icing force were measured using a 20cm × 40cm semiconductor cooling platform. Custom-made rectangular stainless steel molds of different sizes were used. The molds were 10mm wide and 10mm high, with lengths of 5mm, 10mm, 20mm, 40mm, 60mm, 80mm, 100mm, 125mm, 150mm, 175mm, 200mm, and 250mm. The molds were placed horizontally on the coating surface and filled with tap water to the same height. The cooling plate was set to -10℃ and maintained for at least one hour to ensure the water in the molds was completely frozen. A self-made horizontal moving guide rail was used to slowly push the mold at a speed of 74µm / s, separating it from the coating surface. The maximum thrust measured at this point was the de-icing force. The ice adhesion strength was calculated by dividing the de-icing force by the actual contact area between the ice and the coating. The contact point of the thrust gauge was 2mm above the coating surface. Measurements were repeated at least three times for all coatings.

[0083] 2. Results

[0084] 2.1 Effects of different PDMS on coating performance

[0085] Table 1 Properties of different elastomer coatings

[0086]

[0087] The interfacial toughness value is calculated based on the constant de-icing force, the ice modulus, and the ice thickness. Since the ice modulus and thickness remain constant throughout the experiment, interfacial toughness is positively correlated with the constant de-icing force. Lower interfacial toughness means a lower constant de-icing force, which is more conducive to de-icing. Furthermore, interfacial toughness also reflects the propagation ability of interfacial microcracks; a lower interfacial toughness value is more conducive to crack propagation, which is also beneficial for de-icing. However, a lower interfacial toughness value is not always better. When the interfacial toughness value is too low, the coating's durability performance is poor. Therefore, considering the overall performance of the coating, further optimization is needed.

[0088] Conclusion: This experiment only examined the constant de-icing force and interfacial toughness of the coating. It was found that the viscosity and molecular weight of different PDMS prepolymers affect the constant de-icing force and interfacial toughness of the prepared coating (film). Coatings (films) prepared from PDMS prepolymers with higher molecular weight and lower viscosity showed better de-icing performance. Furthermore, the type of chemical bonds in the curing agent also affects the crosslinking of the PDMS prepolymer. Therefore, the PDMS prepolymer with the lowest relative viscosity and molecular weight and the curing agent without C≡C bonds were selected to prepare the elastomer coating for further experiments. The infrared spectra of the PDMS prepolymer and curing agent in this example are shown below. Figure 1 .

[0089] 2.2 Effect of different SiO2 qualities

[0090] Based on the preparation method of Scheme 2 in Example 1, the various properties of adding SiO2 with different mass ratios were verified.

[0091] Table 2. Constant De-icing Force and Critical Length of Coating

[0092]

[0093] Conclusion: 1) The critical length in this experiment refers to the length of ice where the de-icing force no longer changes, see... Figure 5 After adding 20% ​​or more SiO2 particles, Figure 5 No constant de-icing force was observed in the curve, therefore no corresponding data were available for 20% and 25%. 2) As SiO2 particles were added, the constant de-icing force also increased. Therefore, 1%, 3%, and 5% SiO2 particle additions were selected to control the constant de-icing force within a small range.

[0094] Table 3. Coating ice adhesion strength and critical length

[0095]

[0096] Conclusion: The critical length in this experiment refers to the length of ice at which the ice adhesion strength no longer changes, as shown in Table 2. Experimental figures are available in Table 2. Figure 6 The appearance of the critical length causes the ice adhesion strength to begin to decrease, which is consistent with the changing trend of the de-icing force.

[0097] Table 4 Coating Durability

[0098]

[0099] Conclusion: This experiment investigated the number of icing / de-icing cycles, i.e., the durability of the coatings, at different SiO2 particle addition levels. Table 1 shows that the elastomer coating without SiO2 particles exhibited the best constant de-icing force and interfacial toughness. This experiment demonstrates that with increasing icing / de-icing cycle count, the constant de-icing force and ice adhesion strength of the elastomer coating without SiO2 particles exceeded those of the coating with an appropriate amount of SiO2. Specifically, when the icing / de-icing cycle count was 60 cycles, the constant de-icing force of the coating without SiO2 increased by approximately 173% compared to 0 cycles; the coating with 1% SiO2 increased by approximately 21.4% compared to 0 cycles; and the coating with 3% SiO2 increased by approximately 24% compared to 0 cycles. When the icing / de-icing cycle test was conducted for 120 cycles, the coating without SiO2 showed an approximately 254% increase in constant de-icing force compared to the first 0 cycles; the coating with 1% SiO2 showed an approximately 62% increase; and the coating with 3% SiO2 showed an approximately 20.5% increase. However, after 120 icing / de-icing cycles, the coating with 3% SiO2 showed a decrease in constant de-icing force compared to the first 60 cycles, indicating that adding an appropriate amount of SiO2 can significantly increase the coating's durability.

[0100] 2.3 Effect of different coating film thicknesses

[0101] In Example 1, Scheme 2, coating films of different thicknesses were prepared using a SiO2 mass fraction of 1%. The performance of coatings of different thicknesses was verified by de-icing force experiments.

[0102] Table 5. Effect of different coating film thicknesses

[0103]

[0104] Conclusion: This experiment investigated the constant deicing force and interfacial toughness of coating films of different thicknesses. The experiment found that the thicker the film, the greater the constant deicing force. However, thinner films place higher demands on the coating process and may lack durability. A previous study, "A promising self-assembly PTFE coating for effective large-scale deicing," published in the journal Progress in Organic Coatings, measured a minimum constant deicing force of 49.6 N / cm. Therefore, this invention uses 50 N / cm as the cutoff value, corresponding to a film thickness of approximately 221.2 micrometers. Thus, this invention selects a preparation method with a coating film thickness of 220 micrometers or less.

[0105] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for preparing a large-area anti-icing and de-icing coating with excellent durability, characterized in that, Includes the following steps: Step 1: A SiO2 dispersion is prepared by uniformly mixing a low-boiling-point organic solvent with SiO2 particles; the low-boiling-point organic solvent includes tetrahydrofuran, chloroform, dichloromethane, ethyl acetate, or n-hexane; the mass ratio of the SiO2 particles in the low-boiling-point organic solvent is 0.5%~8.0%; Step 2: Mix PDMS prepolymer and room temperature curing agent in a 1:1 mass ratio to prepare an elastomer solution; The room-temperature curing agent is methyltriethoxysilane or methyltripropoxysilane; the viscosity range of the PDMS prepolymer is 3000-4000 mPa·s, and the molecular weight range is 120000-130000; the SiO2 dispersion is then added to the elastomer solution and mixed evenly to obtain the coating solution; the SiO2 particles account for 3% of the mass of the elastomer solution. Step 3: Slowly and evenly apply the coating solution obtained in Step 2 onto the substrate and cure it at room temperature for 24-48 hours to form a large-area anti-icing and de-icing coating with a thickness of 80-220 micrometers.

2. The preparation method according to claim 1, characterized in that, The substrate includes the surface of aircraft and / or wind turbine blades.

3. The preparation method according to claim 1, characterized in that, The SiO2 particles include micron-sized and / or nanon-sized SiO2 particles with a particle size range of 500 nanometers to 1 micrometer or 3 to 40 nanometers.

4. The preparation method according to claim 1, characterized in that, The process of mixing the low-boiling-point organic solvent with SiO2 particles in step 1 includes first performing magnetic stirring at a rate of 300-500 r / min for 5-15 min, and then performing ultrasonic vibration at a power of 300-1000W for 5-15 min.

5. The preparation method according to claim 1, characterized in that, The process of adding the SiO2 dispersion in step 2 to the PDMS prepolymer and room temperature curing agent and mixing them evenly includes first magnetic stirring at a rate of 300~500 r / min for 5-10 min, and then ultrasonic vibration at a power of 300~1000W for 5-10 min.

6. The preparation method according to claim 1, characterized in that, Methods for applying the coating solution from step 3 to the substrate include direct pouring, dripping, scraping, bar coating, spin coating, brushing, and / or spraying.

7. The preparation method according to claim 1, characterized in that, The PDMS prepolymer, model C0030, has a molecular weight of 128449 and a viscosity of 3000 mPa·s, and was provided by Hangzhou Microsonic Technology Co., Ltd.

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