A method for preparing a porous hydrophobic liquid film coating for anti-icing and its application

Abstract

The present invention discloses a method for preparing a porous hydrophobic liquid film coating for anti-icing and its application; the porous hydrophobic liquid film coating adopts femtosecond laser micromachining technology, and can quickly prepare microcavity holes with a wide bottom and narrow top structure on the surface of a material that needs to be modified by the hydrophobic liquid film coating, forming a cavity structure for oil storage; the microcavity holes with a wide bottom and narrow top structure can use air pressure to seal the oil film inside the microcavity, and the surface oil film formed by the oil storage is used to reduce the ice adhesion strength; then, through OTS surface modification, the surface of the material becomes rough and hydrophobic, thereby improving the anti-icing ability. The hydrophobic liquid film coating finally prepared has good anti-icing performance and oil film durability, and the overall process is simpler, suitable for large-scale industrial production, and has excellent promotion prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing and surface coating, and in particular to a method for preparing a porous hydrophobic liquid film coating for anti-icing and its application. Background Art

[0002] With the development of aviation, higher standards are being placed on aircraft safety. Icing on aircraft can seriously impact flight safety. One such technology, known as a "liquid film isolation" slip-on anti-icing coating, injects an oil film onto the surface, reducing ice adhesion and ensuring easy detachment. However, this type of oil film coating exhibits poor mechanical properties, suffers significant wear at high altitudes, and is complex to prepare. Designing and fabricating a specialized oil film coating structure has been a research hotspot in recent years.

[0003] For example, prior art 1, CN110240855A, discloses hydrophobic modification of bentonite using vacuum evaporation. Polycarbonate, polyvinyl chloride, and the modified bentonite are then heated and stirred, sprayed, and dried to create a super-hydrophobic porous resin film. Finally, silicone oil is injected into the porous structure to create an oil film coating. This anti-icing coating method requires extensive equipment and chemical reagents, resulting in a complex chemical treatment process that is not suitable for large-scale production. Furthermore, the resulting coating exhibits high ice adhesion, reaching 100 kPa, resulting in poor anti-icing effectiveness.

[0004] For example, the second prior art: the MET method is used to manufacture citrus peel-like microcavity surfaces, which is divided into four steps: microfluidic emulsion generation, emulsion deposition, solvent evaporation, and droplet template removal. PVA is then cross-linked with glutaraldehyde (GA) by a liquid phase method. The surface is then immersed in octadecyltrichlorosilane (OTS) dissolved in toluene for 4 hours, and then baked in a drying oven at 60°C for 1 hour to make the surface hydrophobic. After surface modification, silicone oil is injected into the surface to make a slip coating. (Han Xing; Tang Xin; Chen Rifei; Li Wei; Zhu Pingan; Wang Liqiu. Citrus-peel-like durable slippery surfaces[J]. Chemical Engineering Journal. Volume 420, Issue P1.2021). The MET method used in this method to prepare the coating has a very cumbersome four-step process, and a large number of toxic chemical reagents are used to treat the coating surface, which can easily cause harm to the human body; therefore, the method is difficult to prepare the coating and is not suitable for large-scale production.

[0005] Therefore, there is an urgent need to design and process a special oil film coating structure that has good anti-icing performance and oil film durability, and the overall process is simpler and suitable for large-scale industrial production. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a porous hydrophobic liquid film coating for anti-icing and its application; the porous hydrophobic liquid film coating adopts femtosecond laser micromachining technology, and can quickly prepare microcavity holes with a wide bottom and narrow top structure on the surface of the material that needs to be modified by the hydrophobic liquid film coating, forming a cavity structure for oil storage. The microcavity holes with a wide bottom and narrow top structure can use fewer chemical reagents for subsequent modification; the microcavity holes can use air pressure to seal the oil film inside the microcavity, and the surface oil film formed by the oil storage can reduce the ice adhesion strength, and then through OTS surface modification, the material surface becomes rough and hydrophobic, thereby improving the anti-icing ability. The hydrophobic liquid film coating finally prepared has good anti-icing performance and oil film durability, and the overall process is simpler, suitable for large-scale industrial production, and has excellent promotion prospects.

[0007] In order to achieve the above technical effects, the following technical solutions are adopted:

[0008] A method for preparing a porous hydrophobic liquid film coating for anti-icing, comprising the following steps:

[0009] Step S1: Femtosecond laser processing of oil storage microcavity:

[0010] Oil storage microcavity single-side structure processing:

[0011] The plate is fixed on the long hypotenuse of the right-angled triangular prism block, the angle between the right-angled triangular prism block and the horizontal plane is α, and the right-angled triangular prism block is placed horizontally on the motion platform of the femtosecond laser processor, and the right-angled surface is in contact with the horizontal plane of the motion platform; at this time, the laser emitter emits laser perpendicular to the horizontal plane to enter the right-angled triangular prism block, that is, the upward part of the long hypotenuse of the right-angled triangular prism of the plate and the laser beam form a fixed angle of 90°-α, and this angle is the design angle of the oil storage microcavity structure; the laser scans and carves according to the set oil storage microcavity aperture size and shape to prepare a single oil storage microcavity Side structure, a single-sided structure with a microcavity diameter D is formed on the surface of the plate, the right-angled side direction of the right-angled triangular prism block in contact with the horizontal plane is set to the Y axis, the right-angled side direction of the right-angled triangular prism block not in contact with the horizontal plane is set to the Z axis, the direction perpendicular to both the Y axis and the Z axis is set to the X axis, the spacing between the vertical microcavities in the direction of the long hypotenuse of the right-angled triangular prism is set to P, and the spacing between the horizontal microcavities perpendicular to the long hypotenuse of the right-angled triangular prism is set to Q. When processing the single-sided structure of the vertical microcavity, the spacing of the vertical microcavities is controlled by controlling the Y-axis movement step y. The relationship between y and P The formula is: y = P * cos α; where y is the Y-axis movement step, P is the spacing between the vertical microcavities in the direction of the long hypotenuse of the triangular prism, and α is the angle between the right triangular prism block and the horizontal plane; by controlling the Z-axis movement step z to control the laser focus position, the prepared microcavity effect is the best, the relationship is: z = P * sin α, where z is the Z-axis movement step, P is the spacing between the vertical microcavities in the direction of the long hypotenuse of the triangular prism, and α is the angle between the right triangular prism block and the horizontal plane; by controlling the movement of the Y and Z axes, a single row of vertical microcavities in the direction of the long hypotenuse of the triangular prism can be processed. side structure, and then control the X-axis movement step x to control the spacing between the horizontal rows of microcavities perpendicular to the long hypotenuse of the right triangular prism. The relationship between x and P is: x = Q, where x is the X-axis movement step, and Q is the spacing between the horizontal rows of microcavities perpendicular to the long hypotenuse of the right triangular prism. After the x-axis moves once, repeat the processing process of the single-sided structure of the vertical microcavities in the direction of the long hypotenuse of the single row of triangular prisms, and then repeat the processing process of the single-sided structure of the vertical microcavities in the direction of the long hypotenuse of the single row of triangular prisms after the x-axis moves again. Repeat this process, according to the processing design, to complete the processing of all the single-sided microcavity structures on the entire plate.

[0012] Step S2: Structural processing on the other side of the oil storage microcavity:

[0013] The plate prepared in step S1 is then rotated 180° along the long hypotenuse plane of the right-angled triangular prism block and fixed to the long hypotenuse of the triangular prism block. The laser is completely aligned with the microcavity aperture, that is, the microcavity aperture remains unchanged. The process in step S1 is repeated, and the other side structure of all microcavities on the entire plate is processed by controlling the movement of the X, Y, and Z axes, ultimately forming a porous plate with oil storage microcavities having a wider bottom and a narrower top after femtosecond laser processing.

[0014] Step S3: The porous plate with a lower-wide and upper-narrow oil storage microcavity processed by femtosecond laser is subjected to hydrophobic treatment:

[0015] A solution of octadecyltrimethoxysilane (OTS) was dissolved in n-hexane solvent and stirred to uniformly dissolve the OTS. During the stirring process, a small amount of water was dripped into the solution dropwise to form a hydrophobic modifier. A porous sheet with a wide bottom and narrow top oil storage microcavity processed by femtosecond laser was then immersed in the hydrophobic modifier. After immersion, the treated sheet was completely dried to obtain a hydrophobicized porous sheet.

[0016] Step S4: Oil film injection into the hydrophobized porous plate:

[0017] Dimethyl silicone oil is injected into the surface of the hydrophobic treated porous plate to obtain a porous hydrophobic liquid film coating plate for anti-icing.

[0018] Furthermore, the plate is an aluminum plate; and the angle α between the right-angled triangular prism block and the horizontal plane is 30°-60°.

[0019] Furthermore, the laser power is 6-15W. After the processing of step S1 and step S2, there will be raised defects on the bottom of the oil storage microcavity due to the laser power or the different angles between the right triangular prism block and the horizontal plane. At this time, an additional laser incident is performed, that is, the laser is perpendicular to the plate and enters the oil storage microcavity aperture, and the oil storage microcavity is engraved again to eliminate the raised defects on the bottom of the oil storage microcavity.

[0020] Furthermore, the diameter D of the oil storage microcavity is 80-120 μm.

[0021] Furthermore, the spacing P between the vertical rows of microcavities in the direction of the long hypotenuse of the right-angled triangular prism is 220-330 μm, and Q is equal to or not equal to P.

[0022] Furthermore, the motion platform of the laser processor controls one, two or three of the X-axis movement step length x, the Y-axis movement step length y, and the Z-axis movement step length z, and the laser emitter controls one, two or three of the X-axis movement step length x, the Y-axis movement step length y, and the Z-axis movement step length z, and the processing of the porous plate is completed jointly or individually.

[0023] Furthermore, the mass concentration of the octadecyltrimethoxysilane OTS is 95%, and the rest are allotropes. The volume ratio of the octadecyltrimethoxysilane OTS solution to water is 400-500:1-2.

[0024] Furthermore, the octadecyltrimethoxysilane (OTS) solution is dissolved by stirring at 400 to 500 rpm for 8 to 15 minutes.

[0025] Furthermore, the method of immersing the porous plate having the oil storage microcavity having a wide bottom and a narrow top after femtosecond laser processing in a hydrophobic modifier is to immerse it in a lightless and low-temperature environment for more than 4 hours; the method of completely drying is to place the porous plate in a dryer, dry it with wind for 1-2 hours at a ventilation condition of 55°C-65°C, and dry it completely.

[0026] The porous hydrophobic liquid film coating prepared by the above-mentioned preparation method can be applied in the field of anti-icing of aviation panels.

[0027] The beneficial effects of the present invention are:

[0028] The present invention discloses a method for preparing a porous hydrophobic liquid film coating for anti-icing and its application. The porous hydrophobic liquid film coating uses femtosecond laser micromachining technology to quickly prepare microcavity holes with a wide bottom and narrow top structure on the surface of a material requiring hydrophobic liquid film coating modification, forming a cavity structure for oil storage. The microcavity holes with a wide bottom and narrow top structure can require less chemical reagents for subsequent modification. The microcavity holes can use air pressure to seal the oil film inside the microcavity, and the surface oil film formed by the oil storage can reduce the ice adhesion strength. Then, through OTS surface modification, the material surface becomes rough and hydrophobic, thereby improving the anti-icing ability. The hydrophobic liquid film coating finally prepared has good anti-icing performance and oil film durability.

[0029] 1. The modified coating prepared by the present invention for anti-icing has superhydrophobic properties before silicone oil is injected. Using an SCA system for testing, the front and rear contact angles of the water droplet can reach 157.6° and 157.4° when the water droplet is kept at 6 μL.

[0030] 2. After the silicone oil is injected into the modified coating prepared by the present invention, the modified coating still has a hydrophobic effect under the combined action of the modified coating and the silicone oil film, and its front and rear contact angles can reach 112.3° and 111.8°;

[0031] 3. The hydrophobic liquid film coating prepared on the plate material of the present invention has excellent anti-icing capabilities. Its ice adhesion strength reaches a maximum of only 11.3 kPa in an example where D×P×Q is 80 μm×220 μm×220 μm. The ice adhesion of the prepared coating is significantly lower than that of ordinary aluminum plates, oil-film aluminum plates, and existing technologies.

[0032] 4. The coating prepared by the present invention using a femtosecond laser processor has a simple preparation method and overall processing technology and has great industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the single-side structure of the oil storage microcavity processed in an embodiment of the present invention;

[0034] Figure 2Schematic diagram of the X-axis, Y-axis, and Z-axis when processing a single-sided oil storage microcavity structure in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the structure of the other side of the oil storage microcavity processed in an embodiment of the present invention;

[0036] Figure 4 Schematic diagram of a single oil storage microcavity structure processed in an embodiment of the present invention;

[0037] Figure 5 This is a microscopic photograph of a portion of a whole aluminum plate processed in an embodiment of the present invention;

[0038] Figure 6 This is a contact angle test diagram of a porous hydrophobic liquid film coated aluminum plate 1 with a D×P×Q of 80 μm×220 μm×220 μm processed in an embodiment of the present invention;

[0039] Figure 7 This is a contact angle test diagram of a porous hydrophobic liquid film-coated aluminum plate 1 with a D×P×Q of 80 μm×220 μm×220 μm processed in an embodiment of the present invention after being injected with silicone oil;

[0040] Figure 8 This is a bar graph comparing the ice adhesion of all porous hydrophobic liquid film coated aluminum plates 1 processed in the embodiment of the present invention after being injected with silicone oil, ordinary aluminum plates, oil film aluminum plates, and prior art one;

[0041] Figure 9 Schematic diagram of a single oil storage microcavity processed in a comparative example of the present invention;

[0042] Figure 10 This is a contact angle test diagram of a porous hydrophobic liquid film coated aluminum plate 2 with a D×P×Q of 80 μm×220 μm×220 μm processed in a comparative example of the present invention;

[0043] Figure 11 This is a bar graph of ice adhesion after silicone oil is injected into the porous hydrophobic liquid film coated aluminum plate 2 processed in the comparative example of the present invention;

[0044] Figure 12 A bar graph comparing ice adhesion strength of a porous hydrophobic liquid film-coated aluminum plate 1 having a D×P×Q dimension of 80 μm×220 μm×220 μm before and after a durability test;

[0045] Figure 13 This is a bar graph comparing the ice adhesion strength of the porous hydrophobic liquid film coated aluminum plate 2 with D×P×Q of 80 μm×220 μm×220 μm before and after the durability test. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0047] Example 1:

[0048] The raw materials used in this embodiment are: aluminum plate, thickness of 1mm; design the oil storage microcavity diameter and microcavity vertical spacing and microcavity horizontal spacing;

[0049] The specific method is:

[0050] Step S1: Femtosecond laser processing of oil storage microcavity:

[0051] Oil storage microcavity single-side structure processing:

[0052] like Figure 1 As shown, the aluminum plate is fixed on the long hypotenuse of the right-angled triangular prism block, the angle between the right-angled triangular prism block and the horizontal plane is 30°, and the right-angled triangular prism block is placed horizontally on the motion platform of the femtosecond laser processor, and the right-angled surface is in contact with the horizontal plane of the motion platform; at this time, the laser emitter emits laser perpendicular to the horizontal plane to enter the right-angled triangular prism block, and the laser power is 9.7W, that is, the aluminum plate forms a fixed angle of 60° with the upward part of the long hypotenuse of the right-angled triangular prism and the laser beam, and this angle is the design angle of the oil storage microcavity structure; the laser scans and engraves according to the set oil storage microcavity aperture size of 80μm and circular shape to prepare one side structure of a single oil storage microcavity, and forms a cylindrical single-sided structure with a microcavity aperture of 80μm on the surface of the aluminum plate, as shown Figure 2As shown, the direction of the right-angled side of the right-angled triangular prism block in contact with the horizontal plane is set to the Y axis, the direction of the right-angled side of the right-angled triangular prism block not in contact with the horizontal plane is set to the Z axis, the direction perpendicular to both the Y axis and the Z axis is set to the X axis, the spacing between the vertical microcavities in the direction of the long hypotenuse of the right-angled triangular prism is set to P, P is 220 μm, the spacing between the horizontal microcavities perpendicular to the long hypotenuse of the right-angled triangular prism is set to Q, Q is 220 μm, when processing the single-sided structure of the vertical microcavity, the spacing of the vertical microcavities is controlled by controlling the Y-axis movement step y, and the relationship between y and P is: y = P*cos30°; where y is the Y-axis movement step, and P is the spacing between the vertical microcavities in the direction of the long hypotenuse of the triangular prism. The laser focus position is controlled by controlling the Z-axis movement step z to make the prepared microcavity have the best effect, and the relationship is : z = P*sin30°, where z is the Z-axis movement step length, and P is the spacing between the vertical microcavities in the direction of the long hypotenuse of the right triangular prism; by controlling the movement of the Y-axis and the Z-axis, the vertical microcavity unilateral structure in the direction of the long hypotenuse of the single row of triangular prisms is processed, and then the X-axis movement step length x is controlled to control the spacing of the horizontal microcavities perpendicular to the long hypotenuse of the right triangular prism, and the relationship between x and P is: x = Q, where x is the X-axis movement step length, and Q is the spacing between the horizontal microcavities perpendicular to the long hypotenuse of the right triangular prism; after the x-axis moves once, the processing process of the vertical microcavity unilateral structure in the direction of the long hypotenuse of the single row of triangular prisms is repeated, and then after the x-axis moves again, the processing process of the vertical microcavity unilateral structure in the direction of the long hypotenuse of the single row of triangular prisms is repeated, and so on, according to the processing design, the processing of all the microcavity unilateral structures on the entire aluminum plate is completed;

[0053] Step S2: Structural processing on the other side of the oil storage microcavity:

[0054] like Figure 3 As shown, the aluminum plate prepared in step S1 is then rotated 180° along the long hypotenuse plane of the right-angled triangular prism block and fixed on the long hypotenuse of the triangular prism block. The laser is completely aligned with the microcavity aperture, that is, the microcavity aperture remains unchanged. The process in step S1 is repeated, and the other side structure of all the microcavities on the entire aluminum plate is processed by controlling the movement of the X, Y, and Z axes. Finally, a porous aluminum plate with oil storage microcavities that are wide at the bottom and narrow at the top is formed after femtosecond laser processing. The oil storage microcavity aperture is 80 μm, the vertical spacing of the microcavities is 220 μm, and the horizontal spacing of the microcavities is 220 μm. Figure 4 The figure shows a schematic diagram of a single oil storage microcavity structure after processing. The two incident lasers carve out cross holes on the aluminum plate. There are small raised defects at the bottom of the holes. Since it does not affect the technical effect, it can be further processed to form a single oil storage microcavity that is wide at the bottom and narrow at the top.

[0055] Step S3: The porous aluminum plate with a lower-wide and upper-narrow oil storage microcavity processed by femtosecond laser is subjected to hydrophobic treatment:

[0056] First, dissolve 4ml of OTS solution (95%, the rest being allotropes) in n-hexane solvent and place it on a magnetic stirrer. Stir at 400-500 rpm for approximately 10 minutes to ensure uniform dissolution of the OTS. While stirring, use a fine syringe to draw 10μl of water dropwise into the solution. Then, immerse the prepared aluminum plate in the solution in a dark, low-temperature environment for at least 4 hours. Finally, place the treated aluminum plate in a dryer and dry it at 60°C with ventilation for 1 hour to completely dry it, thereby obtaining a modified coating.

[0057] Step S4: Injecting oil film into the porous aluminum plate after hydrophobic treatment:

[0058] Dimethyl silicone oil was injected into the surface of the hydrophobic treated porous aluminum plate to obtain the final porous hydrophobic liquid film coated aluminum plate 1 for anti-icing (i.e., the porous hydrophobic liquid film coated aluminum plate 1 with D×P×Q of 80 μm×220 μm×220 μm).

[0059] The same method was used to prepare porous hydrophobic liquid film coated aluminum plates with D×P×Q of 100μm×220μm×220μm; D×P×Q of 100μm×250μm×250μm; D×P×Q of 100μm×300μm×300μm; and D×P×Q of 120μm×330μm×330μm.

[0060] The performance of the porous hydrophobic liquid film coated aluminum plate 1 with a D×P×Q of 80μm×220μm×220μm was evaluated:

[0061] 1. If Figure 5 The figure shows a microscopic photograph of a portion of the entire aluminum plate after processing. The microcavities are generally circular in diameter, and the vertical and horizontal rows of microcavities occupy the entire aluminum plate according to the designed spacing.

[0062] 2. If Figure 6 As shown, the aluminum plate 1 has superhydrophobic properties before being injected with silicone oil. Using the SCA system for detection, the front and rear contact angles of the water droplet can reach 157.6° and 157.4° when the water droplet is kept at 6 μL.

[0063] 3. If Figure 7 As shown, after the aluminum plate 1 is injected with dimethyl silicone oil, it still has a hydrophobic effect under the combined effect of the modified coating and the silicone oil film, and its front and rear contact angles can reach 112.3° and 111.8°;

[0064] 4. If Figure 8As shown, the porous hydrophobic liquid film coated aluminum plate 1 with D×P×Q of 80μm×220μm×220μm prepared by the present invention has good anti-icing ability, the average ice adhesion strength is 9.7KPa, and the maximum value is only 11.3KPa. The ice adhesion effect of the prepared coating is far less than that of ordinary aluminum plates, oil film aluminum plates and the prior art one.

[0065] Comparative Example:

[0066] The raw materials used in this comparative example are: aluminum plate with a thickness of 1 mm (the same as in Example 1); the designed oil storage microcavity diameter, microcavity vertical spacing, and microcavity horizontal spacing are consistent with those in Example 1;

[0067] The specific method is:

[0068] Step S1: Femtosecond laser processing of oil storage microcavity:

[0069] The aluminum plate is placed horizontally on the horizontal motion platform of the femtosecond laser processor. At this time, the laser emitter emits laser light directly perpendicular to the horizontal plane of the femtosecond laser processor and enters the aluminum plate. That is, the laser is directly perpendicular to the aluminum plate for processing. The laser power is 9.7W. The laser scans and carves according to the set oil storage microcavity diameter of 80μm and circular shape to prepare a single oil storage microcavity, such as Figure 9 As shown, a cylindrical structure with a microcavity diameter of 80 μm is formed on the surface of the aluminum plate. According to the X-axis and Y-axis setting method in Example 1, the spacing between the vertical microcavities on the Y axis of the aluminum plate is set to P, P is 220 μm, and the spacing between the horizontal microcavities on the X axis of the aluminum plate is set to Q, Q is 220 μm. When processing the vertical microcavities, the spacing of the vertical microcavities is controlled by controlling the Y-axis movement step y. The relationship between y and P is: y = P; where y is the Y-axis movement step, and P is The spacing between the vertical microcavities on the Y axis of the aluminum plate is then controlled by controlling the X axis movement step length x to control the spacing between the horizontal microcavities on the X axis of the aluminum plate. The relationship between x and P is: x = Q, where x is the X axis movement step length and Q is the spacing between the horizontal microcavities on the X axis of the aluminum plate. After the x axis moves once, the processing process of a single row of vertical microcavities on the Y axis is repeated. Then, after the x axis moves again, the processing process of a single row of vertical microcavities on the Y axis is repeated. This process is repeated according to the processing design to complete the processing of all microcavities on the entire aluminum plate.

[0070] Step S2: hydrophobicizing the porous aluminum plate with the oil storage microcavity after femtosecond laser processing:

[0071] First, dissolve 4ml of OTS solution (95%, the rest being allotropes) in n-hexane solvent and place it on a magnetic stirrer. Stir at 400-500 rpm for approximately 10 minutes to ensure uniform dissolution of the OTS. While stirring, use a fine syringe to draw 10μl of water dropwise into the solution. Then, immerse the prepared aluminum plate in the solution in a dark, low-temperature environment for at least 4 hours. Finally, place the treated aluminum plate in a dryer and dry it at 60°C with ventilation for 1 hour to completely dry it, thereby obtaining a modified coating.

[0072] Step S3: Injecting oil film into the porous aluminum plate after hydrophobic treatment:

[0073] Dimethyl silicone oil was injected into the surface of the hydrophobic treated porous aluminum plate to obtain a porous hydrophobic liquid film coated aluminum plate 2 (i.e., a porous hydrophobic liquid film coated aluminum plate 2 with D×P×Q of 80 μm×220 μm×220 μm) for anti-icing.

[0074] The performance of the porous hydrophobic liquid film coated aluminum plate 2 with a D×P×Q of 80μm×220μm×220μm was evaluated:

[0075] 1. If Figure 10 As shown, after the aluminum plate 2 is injected with dimethyl silicone oil, it still has a hydrophobic effect under the combined effect of the modified coating and the silicone oil film, and its front and rear contact angles can reach 109.1° and 113.2°, which is comparable to the hydrophobic performance of the porous hydrophobic liquid film coated aluminum plate 1 with a D×P×Q of 80μm×220μm×220μm prepared in Example 1;

[0076] 2. If Figure 11 As shown, the porous hydrophobic liquid film coated aluminum plate 2 with D×P×Q of 80μm×220μm×220μm prepared in the present invention has good anti-icing ability, and its average ice adhesion strength is 10.5KPa and the maximum value is 13.2KPa, which is equivalent to the anti-icing ability of the porous hydrophobic liquid film coated aluminum plate 1 with D×P×Q of 80μm×220μm×220μm prepared in Example 1.

[0077] The durability evaluation and comparison of the porous hydrophobic liquid film coated aluminum plate 1 with a D×P×Q of 80μm×220μm×220μm and the porous hydrophobic liquid film coated aluminum plate 2 with a D×P×Q of 80μm×220μm×220μm were conducted:

[0078] Durability evaluation process ("weakening" test):

[0079] After freezing porous hydrophobic liquid film-coated aluminum plates 1 and 2 at -15°C to -10°C for 8-15 minutes, spray water mist directly onto the aluminum plates (placed vertically) using a sprayer, with a distance of 30mm and a spray rate of 40ml / h. Continue spraying for 1-2 minutes. Place in a drying oven and air dry at 50-60°C for 30-45 minutes. Once any remaining water droplets have evaporated, retest the aluminum plates for ice adhesion strength. Repeat this "weakening" process 10 times.

[0080] like Figure 12 As shown, it is a bar graph comparing the ice adhesion strength of the porous hydrophobic liquid film coated aluminum plate 1 with a D×P×Q of 80 μm×220 μm×220 μm before and after the durability test;

[0081] like Figure 13 As shown, it is a bar graph comparing the ice adhesion strength of the porous hydrophobic liquid film coated aluminum plate 2 with a D×P×Q of 80 μm×220 μm×220 μm before and after the durability test;

[0082] The experimental results show that the ice adhesion strength of the porous hydrophobic liquid film coated aluminum plate 1 with a D×P×Q of 80μm×220μm×220μm has basically changed little before and after the durability test, indicating that its durability is excellent. Microcavities with a wide bottom and narrow top structure are quickly prepared on the surface of the aluminum plate material to form a cavity structure for oil storage. The microcavities with a wide bottom and narrow top structure can use air pressure to seal the oil film inside the microcavity, significantly improving its durability. The ice adhesion strength of the porous hydrophobic liquid film coated aluminum plate 2 with a D×P×Q of 80μm×220μm×220μm changes greatly before and after the durability test. Since the oil storage microcavity of the porous hydrophobic liquid film coated aluminum plate 2 with a D×P×Q of 80μm×220μm×220μm is a straight pore structure, it has no oil storage durability performance. After the durability test, the oil film is consumed and cleared, and it cannot play a good anti-icing performance. Its durability performance is far inferior to the porous hydrophobic liquid film coated aluminum plate 1 with a D×P×Q of 80μm×220μm×220μm.

[0083] In summary, the present invention discloses a method for preparing a porous hydrophobic liquid film coating for anti-icing and its application; the porous hydrophobic liquid film coating adopts femtosecond laser micromachining technology, and can quickly prepare microcavity holes with a wide bottom and narrow top structure on the surface of the material that needs to be modified by the hydrophobic liquid film coating, forming a cavity structure for oil storage. The microcavity holes with a wide bottom and narrow top structure can use air pressure to seal the oil film inside the microcavity, and reduce the ice adhesion strength through the surface oil film formed by the oil storage. Then, through OTS surface modification, the surface of the material becomes rough and hydrophobic, thereby improving the anti-icing ability. The hydrophobic liquid film coating finally prepared has good anti-icing performance and oil film durability, and the overall process is simpler, suitable for large-scale industrial production, and has excellent promotion prospects.

[0084] At this point, those skilled in the art will recognize that, although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications consistent with the principles of the present invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

1. A method for preparing a porous hydrophobic liquid film coating for anti-icing, characterized in that: The preparation method comprises the following steps: Step S1: Femtosecond laser processing of oil storage microcavity: Oil storage microcavity single-side structure processing: The plate is fixed on the long hypotenuse of the right-angled triangular prism block, the angle between the right-angled triangular prism block and the horizontal plane is α, and the right-angled triangular prism block is placed horizontally on the motion platform of the femtosecond laser processor, and the right-angled surface is in contact with the horizontal plane of the motion platform; at this time, the laser emitter emits laser perpendicular to the horizontal plane to enter the right-angled triangular prism block, that is, the upward part of the long hypotenuse of the right-angled triangular prism of the plate and the laser beam form a fixed angle of 90°-α, and this angle is the design angle of the oil storage microcavity structure; the laser scans and carves according to the set oil storage microcavity aperture size and shape to prepare a single oil storage microcavity Side structure, a single-sided structure with a microcavity diameter D is formed on the surface of the plate, the right-angled side direction of the right-angled triangular prism block in contact with the horizontal plane is set to the Y axis, the right-angled side direction of the right-angled triangular prism block not in contact with the horizontal plane is set to the Z axis, the direction perpendicular to both the Y axis and the Z axis is set to the X axis, the spacing between the vertical microcavities in the direction of the long hypotenuse of the right-angled triangular prism is set to P, and the spacing between the horizontal microcavities perpendicular to the long hypotenuse of the right-angled triangular prism is set to Q. When processing the single-sided structure of the vertical microcavity, the spacing of the vertical microcavities is controlled by controlling the Y-axis movement step y. The relationship between y and P The formula is: y = P * cos α; where y is the Y-axis movement step, P is the spacing between the vertical microcavities in the direction of the long hypotenuse of the triangular prism, and α is the angle between the right triangular prism block and the horizontal plane; by controlling the Z-axis movement step z to control the laser focus position, the prepared microcavity effect is the best, the relationship is: z = P * sin α, where z is the Z-axis movement step, P is the spacing between the vertical microcavities in the direction of the long hypotenuse of the triangular prism, and α is the angle between the right triangular prism block and the horizontal plane; by controlling the movement of the Y and Z axes, a single row of vertical microcavities in the direction of the long hypotenuse of the triangular prism can be processed. side structure, and then control the X-axis movement step x to control the spacing between the horizontal rows of microcavities perpendicular to the long hypotenuse of the right triangular prism. The relationship between x and P is: x = Q, where x is the X-axis movement step, and Q is the spacing between the horizontal rows of microcavities perpendicular to the long hypotenuse of the right triangular prism. After the x-axis moves once, repeat the processing process of the single-sided structure of the vertical microcavities in the direction of the long hypotenuse of the single row of triangular prisms, and then repeat the processing process of the single-sided structure of the vertical microcavities in the direction of the long hypotenuse of the single row of triangular prisms after the x-axis moves again. Repeat this process, according to the processing design, to complete the processing of all the single-sided microcavity structures on the entire plate. Step S2: Structural processing on the other side of the oil storage microcavity: The plate prepared in step S1 is then rotated 180° along the long hypotenuse plane of the right-angled triangular prism block and fixed to the long hypotenuse of the triangular prism block. The laser is completely aligned with the microcavity aperture, that is, the microcavity aperture remains unchanged. The process in step S1 is repeated, and the other side structure of all microcavities on the entire plate is processed by controlling the movement of the X, Y, and Z axes, ultimately forming a porous plate with oil storage microcavities having a wider bottom and a narrower top after femtosecond laser processing. Step S3: The porous plate with a lower-wide and upper-narrow oil storage microcavity processed by femtosecond laser is subjected to hydrophobic treatment: A solution of octadecyltrimethoxysilane (OTS) was dissolved in n-hexane solvent and stirred to uniformly dissolve the OTS. During the stirring process, a small amount of water was dripped into the solution dropwise to form a hydrophobic modifier. A porous sheet with a wide bottom and narrow top oil storage microcavity processed by femtosecond laser was then immersed in the hydrophobic modifier. After immersion, the treated sheet was completely dried to obtain a hydrophobicized porous sheet. Step S4: Oil film injection into the hydrophobized porous plate: Dimethyl silicone oil is injected into the surface of the hydrophobic treated porous plate to obtain a porous hydrophobic liquid film coating plate for anti-icing; The plate is an aluminum plate; the angle α between the right-angled triangular prism block and the horizontal plane is 30°-60°; The laser power is 6-15W. After the processing of step S1 and step S2, there will be convex defects on the bottom of the oil storage microcavity due to the different laser power or the angle between the right triangular prism and the horizontal plane. At this time, an additional laser incident is performed, that is, the laser is incident perpendicularly to the plate into the oil storage microcavity aperture, and the oil storage microcavity is engraved again to eliminate the convex defects on the bottom of the oil storage microcavity. The mass concentration of the octadecyltrimethoxysilane OTS is 95%, and the rest are allotropes. The volume ratio of the octadecyltrimethoxysilane OTS solution to water is 400-500:1-2; The porous hydrophobic liquid film coating is used in the field of anti-icing of aviation panels.

2. A method for preparing a porous hydrophobic liquid film coating for anti-icing as claimed in claim 1, characterized in that: The diameter D of the oil storage microcavity is 80-120 μm.

3. The method for preparing a porous hydrophobic liquid film coating for anti-icing as claimed in claim 1, characterized in that: The spacing P between the vertical rows of microcavities in the direction of the long hypotenuse of the right-angled triangular prism is 220-330 μm, and Q is equal to or not equal to P.

4. A method for preparing a porous hydrophobic liquid film coating for anti-icing as claimed in claim 1, characterized in that: The motion platform of the laser processor controls one, two or three of the X-axis movement step length x, the Y-axis movement step length y, and the Z-axis movement step length z, and the laser emitter controls one, two or three of the X-axis movement step length x, the Y-axis movement step length y, and the Z-axis movement step length z, and the processing of the porous plate is completed jointly or individually controlled.

5. The method for preparing a porous hydrophobic liquid film coating for anti-icing as claimed in claim 1, characterized in that: The octadecyltrimethoxysilane (OTS) solution is dissolved by stirring at 400 to 500 rpm for 8 to 15 minutes.

6. A method for preparing a porous hydrophobic liquid film coating for anti-icing as claimed in claim 1, characterized in that: The method of immersing the porous plate with oil storage microcavities having a wide bottom and a narrow top after femtosecond laser processing in a hydrophobic modifier is to immerse it in a lightless and low-temperature environment for more than 4 hours; the method of completely drying is to place the porous plate in a dryer and dry it in the presence of wind for 1-2 hours at a temperature of 55°C-65°C with ventilation until it is completely dried.

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