Hydrophobic membrane and method for using hydrophobic membrane

Abstract

The invention discloses a hydrophobic membrane and a use method of the hydrophobic membrane. The hydrophobic membrane comprises a hardened layer, the hardened layer comprises a substrate and a protruding structure arranged on the substrate, the protruding structure comprises a plurality of strip-shaped protrusions arranged at intervals in the first direction, a groove is formed between every two adjacent strip-shaped protrusions, and the grooves are used for guiding liquid drops on the surface of the hydrophobic membrane to slide; and the hydrophobic layer is arranged on the substrate and the convex structures. The grooves are formed between the adjacent strip-shaped protrusions, and the grooves are used for guiding liquid drops on the surface of the hydrophobic membrane to slide.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrophobic structures, and in particular to a hydrophobic film and a method of using the same. BACKGROUND

[0002] Nowadays, in the consideration of aesthetics, air conditioners are usually placed in the wall. However, the surface of the wall near the air conditioner is relatively low in temperature, and especially in the plum rain season, a large amount of water vapor condenses on the surface of the wall to form small droplets, causing the wall to mold and rot, affecting the service life of the wall and personal health, and having a great impact on the living environment. In addition, for outdoor display devices, when it rains or snows, the display effect is affected, and the small droplets on the surface of the display also affect the service life of the display device. SUMMARY

[0003] The present application provides a hydrophobic film and a method of using the same. Adjacent strip-shaped protrusions form grooves, and the grooves are used to guide the sliding of droplets on the surface of the hydrophobic film.

[0004] In a first aspect, the present application provides a hydrophobic film, comprising:

[0005] a hardening layer, the hardening layer comprising a substrate and protrusion structures arranged on the substrate, the protrusion structures comprising a plurality of strip-shaped protrusions arranged at intervals along a first direction, adjacent strip-shaped protrusions forming grooves therebetween, the grooves being used to guide the sliding of droplets on the surface of the hydrophobic film;

[0006] a hydrophobic layer arranged on the substrate and the protrusion structures.

[0007] In some embodiments, the width of the strip-shaped protrusions in the first direction is set as a protrusion width, the width of the gap between two adjacent strip-shaped protrusions in the first direction is set as a protrusion spacing, and the ratio of the protrusion spacing to the protrusion width is 1-2.

[0008] In some embodiments, the height of the strip-shaped protrusions beyond the substrate on the side close to the strip-shaped protrusions in the extension direction of the hardening layer to the hydrophobic layer is set as a protrusion height, and the ratio of the protrusion height to the protrusion spacing is 1-2.

[0009] In some embodiments, the protrusion width is set to 10-30 μm.

[0010] In some embodiments, the side of the strip-shaped protrusions away from the substrate is set as a plane.

[0011] In some embodiments, the water contact angle of the surface of the hydrophobic layer is greater than or equal to 120°.

[0012] In some embodiments, the substrate is provided with strip-shaped grooves on the side away from the protruding structures, and the strip-shaped grooves correspond to the strip-shaped protrusions one by one.

[0013] In some embodiments, the hardening layer is integrally formed with the hydrophobic layer.

[0014] In some embodiments, the height of the hydrophobic layer in the extension direction of the hardening layer to the hydrophobic layer is 20 nm-3 μm.

[0015] In a second aspect, the application provides a use method of the hydrophobic film, and provides the hydrophobic film according to any one of the above, the hydrophobic film is arranged on the surface of an object to be protected, and the use method of the hydrophobic film comprises: setting the extension direction of the strip-shaped protrusions of the hydrophobic film to be the same as the direction of gravity in the application scenario.

[0016] The hydrophobic film and the use method of the hydrophobic film provided by the embodiments of the application are characterized in that: a plurality of strip-shaped protrusions are arranged at intervals along a first direction, and a groove is formed between adjacent strip-shaped protrusions, the groove is used for guiding the sliding of liquid drops on the surface of the hydrophobic film, and the surfaces of the plurality of strip-shaped protrusions form a lotus effect, which is helpful for the flow of liquid drops. BRIEF DESCRIPTION OF DRAWINGS

[0017] The technical solutions and other beneficial effects of the application will be apparent from the following detailed description of the specific embodiments of the application, combined with the accompanying drawings.

[0018] Figure 1 is an axonometric view of the hydrophobic film in an embodiment of the application;

[0019] Figure 2 is a partial schematic view of the protruding structure in an embodiment of the application;

[0020] Figure 3 is a cross-sectional schematic view of the hydrophobic film in an embodiment of the application; Figure 3 is a cross-sectional schematic view of the hydrophobic film in an embodiment of the application;

[0021] Figure 4 is a cross-sectional schematic view of the hydrophobic film in an embodiment of the application; Figure 3 is a cross-sectional schematic view of the hydrophobic film in an embodiment of the application;

[0022] Figure 5 is a top view of the hydrophobic film in an embodiment of the application.

[0023] LIST OF ELEMENTS IN THE DRAWINGS

[0024] 1, hardening layer; 11, substrate; 12, protruding structure; 121, strip-shaped protrusion; 13, groove; 14, strip-shaped groove; 2, hydrophobic layer. DETAILED DESCRIPTION

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0028] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0029] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplifying the present application, the components and arrangements of the specific examples described herein are intended to be examples only. Of course, they are not meant to limit the present application in any way. Furthermore, the present application can be practiced in various embodiments other than the specific examples described herein, as will be apparent to one of ordinary skill in the art. For example, the present application can be implemented in hardware, software, or a combination thereof. The various embodiments described herein can be implemented in one or more computer programs that are executable on a computer system. In particular, the present application is implemented by a computer program that is executed on a computer system comprising one or more processors. The program comprises instructions that are executed by the computer system to carry out the methods described herein.

[0030] Referring to Figure 1 , the embodiment of the present application provides a hydrophobic film, which comprises a hardening layer 1 and a hydrophobic layer 2. The hardening layer 1 comprises a substrate 11 and a protrusion structure 12 arranged on the substrate 11, the protrusion structure 12 comprises a plurality of strip-shaped protrusions 121, and the plurality of strip-shaped protrusions 121 are arranged at intervals along a first direction.

[0031] On the surface of the substrate 11 on which the protrusion structure 12 is arranged, a plurality of strip-shaped protrusions 121 are arranged along the first direction, but only one strip-shaped protrusion 121 is arranged along a second direction, which is a direction perpendicular to the first direction on the surface of the substrate 11 on which the protrusion structure 12 is arranged. Therefore, a strip-shaped groove 13 is formed between adjacent strip-shaped protrusions 121, and the groove 13 is used to guide the sliding of droplets on the surface of the hydrophobic film and reduce the aggregation of droplets on the hydrophobic film.

[0032] The hydrophobic layer 2 is arranged on the substrate 11 and the protrusion structure 12, that is, the hydrophobic layer 2 covers the substrate 11 and the protrusion structure 12. The structure of the hardening layer 1 is to accelerate the drainage of small droplets based on the groove 13 between adjacent strip-shaped protrusions 121, so that the small droplets do not stay on the surface of the hydrophobic film for too long to affect the service life. The hydrophobic layer 2 has a hydrophobic function, which is used to reduce the condensation of droplets on the surface of the hydrophobic film.

[0033] In one embodiment, as shown in Figure 2 and Figure 3 , the width of the strip-shaped protrusion 121 in the first direction is set as a protrusion width h1, and the width of the gap between two adjacent strip-shaped protrusions 121 in the first direction is set as a protrusion spacing h2.

[0034] The size limit that can be distinguished by the human eye is about 100 μm, and if the size of the protrusion width h1 is set too large, a vertical stripe structure that is obviously visible to the human eye will be formed, which will affect the viewing and use effect, so the protrusion width h1 is set to 10 μm-30 μm.

[0035] In addition, if the size of the protrusion spacing h2 is too small, the air volume remaining in the groove 13 is too small, so that the surface of the protrusion structure 12 is similar to a plane after the uneven surface, a pinning effect is generated, the lotus leaf effect cannot be formed, and the liquid drop flow effect is poor. Therefore, the ratio of the protrusion spacing h2 to the protrusion width h1 is set to 1-2 to avoid the above problems. Preferably, the ratio of the protrusion spacing h2 to the protrusion width h1 is 1.3-1.7, which can make the surface of the hydrophobic film better form the lotus leaf effect and quickly guide the liquid drops on the surface of the hydrophobic film away.

[0036] It should be noted that, as shown in Figure 5 In order to improve the liquid drop guiding effect of the groove 13, in the actual application scene of the hydrophobic film, the angle between the surface of the substrate 11 and the direction of gravity is not 90°, that is, the angle between the surface of the substrate 11 and the direction of gravity is set to an acute angle, and preferably the extension direction of the strip-shaped protrusion 121 of the hydrophobic film is parallel to the direction of gravity. Then the water drop guiding layer is formed based on the groove 13 between the strip-shaped protrusions 121, and compared with the "pinning" effect of the liquid drops on the flat surface, the scheme of the present embodiment can make the liquid drops drop along the extension direction of the groove 13 under the action of gravity on the basis of the lotus leaf effect, and compared with the isometric grid pattern, it can be observed that the liquid drops drop faster.

[0037] In one embodiment, for a liquid on a rough surface, there are two modes, one is called Cassie mode, and one is called Wenzel mode, the former still has a gap between the liquid and the rough solid, and the latter is completely in contact with the solid. We need to reduce the transition of the liquid drops from the Cassie state to the Wenzel state, that is, we need to keep the liquid drops in the Cassie state as much as possible, so that there is still a gap between the liquid and the rough solid to facilitate the flow of the liquid drops. As shown in Figure 2 and Figure 3 As shown in the drawings, the height of the strip-shaped protrusion 121 on the side close to the strip-shaped protrusion 121 in the extension direction of the hardening layer 1 to the hydrophobic layer 2 is set to the protrusion height h3. For the surface of the hydrophobic film, under the condition that the volume of the liquid drops is unchanged, increasing the proportion of air filled in the groove 13, increasing the surface roughness, that is, increasing the depth ratio (h3 / h2) or reducing the groove 13 spacing can make the contact angle between the actual liquid drops and the surface of the hydrophobic film further increase, that is, the more air under the water drops, the better the hydrophobicity, and therefore the ratio of the protrusion height h3 to the protrusion spacing h2 is set to 1-2. Preferably, the ratio of the protrusion height h3 to the protrusion spacing h2 is set to 1.4-1.8.

[0038] In one embodiment, the hardness of the hardening layer 1 is greater than 2H to cope with the scratch problem in daily life. The material of the hardening layer 1 can use the composition of acrylic resin or epoxy main body resin, and the process convex structure 12 can be patterned and formed on the surface of the substrate 11 using the method of engraving roller impression, that is, the convex structure 12 is integrally formed with the substrate 11. As shown in Figure 4 The side of the substrate 11 away from the convex structure 12 is provided with a strip-shaped groove 14, and the strip-shaped groove 14 corresponds to the strip-shaped convex 121 one by one.

[0039] In one embodiment, the contact angle of a liquid on the surface of a solid material is an important parameter for measuring the wetting performance of the liquid on the material surface. If the water contact angle is <90°, the solid surface is hydrophilic, that is, the liquid is easy to wet the solid, and the smaller the angle, the better the wettability; if the water contact angle is >90°, the solid surface is hydrophobic, that is, the liquid is not easy to wet the solid and is easy to move on the surface.

[0040] The hydrophobic layer 2 is a hydrophobic coating layer with hydrophobic function. If the surface of the hardening layer 1 is not coated with a hydrophobic coating layer, the hydroxyl group -OH on the surface of the hardening layer 1 will attract water molecules in the air, causing them to condense and form droplets on the surface of the hardening layer 1. A smaller water contact angle will also cause the water droplets to spread out and increase the water film area, promoting more water to collect on the surface. The hydroxyl group content on the surface of the hydrophobic layer 2 is lower, and the surface attraction is weaker. The small clusters of water molecules that hit the surface will return to the gas phase. Only when a large enough water molecule cluster encounters the surface will it eventually adhere to the surface of the hardening layer 1 and continue to grow and diffuse. The condensation and collection rate of water vapor is relatively low, and the water contact angle of the surface of the hydrophobic layer 2 is larger, which will not spread on the film to increase the contact area of the droplets, reducing the condensation of the droplets on the surface of the film material. Using CHARMM software for molecular dynamics simulation, the attraction of -CF3 and -OH groups to water molecules can prove the above conclusion. Therefore, the water contact angle of the surface of the hydrophobic layer 2 needs to be greater than 120°, and a smaller water contact angle has poor water repellency and cannot achieve good results. In addition, the side of the strip-shaped convex 121 away from the substrate 11 can be a flat surface to achieve a larger water contact angle on the surface of the hydrophobic layer 2, as shown in the cross-section Figure 5 The cross-section of the strip-shaped convex 121 is rectangular.

[0041] In one embodiment, the hardening layer 1 and the hydrophobic layer 2 are integrally formed. In this embodiment, a fluorine-containing or silicon-containing additive is added to the material of the hardening layer 1, and then dry film forming is used. The material used in dry film forming is a low surface energy material, mainly inorganic materials containing fluorine atoms and silicon atoms, preferably perfluoropolyether, PDMS, perfluoropolyether silane, and the film forming thickness is 20-500 nm.

[0042] In addition, wet coating film forming can also be used, mainly for organic materials containing fluorine atoms, silicon atoms, such as grafting fluorine atom or silicon atom containing molecular segments on the resin surface of the hardening layer 1 material, or adding fluorine atom or silicon atom containing resin additives to the coating and then coating, preferably fluorine or silicon containing acrylate copolymer, film forming thickness 1-3 μm.

[0043] It should be noted that whether dry film forming or wet coating film forming, the purpose is to make the hardening layer 1 and the hydrophobic layer 2 integrally formed, that is, to combine the functions of the hardening layer 1 and the hydrophobic layer 2 into one, to reduce the cost, but the water-repellent and hydrophobic effect is relatively poor.

[0044] In this embodiment, the plurality of strip-shaped protrusions 121 are arranged at intervals along the first direction, the surfaces of the plurality of strip-shaped protrusions 121 form a lotus effect, which helps the flow of liquid droplets. The grooves 13 are formed between adjacent strip-shaped protrusions 121, and the grooves 13 are used to guide the sliding of liquid droplets on the surface of the hydrophobic film. In addition, the water contact angle of the surface of the hydrophobic layer 2 is large, which reduces the aggregation of liquid droplets on the surface of the film material.

[0045] The application provides a use method of the hydrophobic film, and provides the hydrophobic film according to any one of the preceding embodiments, as shown in the figure, the hydrophobic film is arranged on the surface of an object to be protected, and the use method of the hydrophobic film comprises: setting the extension direction of the strip-shaped protrusions 121 of the hydrophobic film to be the same as the direction of gravity in the application scene. Figures 1 to 5

[0046] In addition, by attaching the hydrophobic film of the embodiment to the surface of an article that needs to be waterproof through adhesive or the like, the amount of water vapor condensed on the surface is reduced, and at the same time, the small liquid droplets condensed on the surface can be quickly guided out, reducing the residence time of the liquid droplets on the surface and prolonging the service life. In addition, a self-cleaning function is realized, and oily particles such as dust fibers can be guided out synchronously with the liquid droplets, reducing the time consumed by manual wiping and avoiding safety risks brought by high-altitude work.

[0047] In some embodiments, the hydrophobic film comprises:

[0048] The hardening layer 1 comprises a substrate 11 and a protrusion structure 12 arranged on the substrate 11, the protrusion structure 12 comprises a plurality of strip-shaped protrusions 121 arranged at intervals along a first direction, and grooves 13 are formed between adjacent strip-shaped protrusions 121, the grooves 13 are used to guide the sliding of liquid droplets on the surface of the hydrophobic film;

[0049] The hydrophobic layer 2 is arranged on the substrate 11 and the protrusion structure 12.

[0050] ​In some embodiments, the width of the strip-shaped protrusion 121 in the first direction is set as a protrusion width h1, the width of the gap between two adjacent strip-shaped protrusions 121 in the first direction is set as a protrusion spacing h2, and the ratio of the protrusion spacing h2 to the protrusion width h1 is 1-2.

[0051] In some embodiments, the height of the strip-shaped protrusion 121 on the side close to the strip-shaped protrusion 121 of the substrate 11 in the extending direction of the hardening layer 1 to the hydrophobic layer 2 is set as a protrusion height h3, and the ratio of the protrusion height h3 to the protrusion spacing h2 is 1-2.

[0052] In some embodiments, the protrusion width h1 is set as 10-30 μm.

[0053] In some embodiments, the side of the strip-shaped protrusion 121 away from the substrate 11 is set as a plane.

[0054] In some embodiments, the surface water contact angle of the hydrophobic layer 2 is greater than or equal to 120°.

[0055] In some embodiments, the side of the substrate 11 away from the protrusion structure 12 is provided with a strip-shaped groove 14, and the strip-shaped groove 14 corresponds to the strip-shaped protrusion 121 one by one.

[0056] In some embodiments, the hardening layer 1 and the hydrophobic layer 2 are integrally formed.

[0057] In some embodiments, the height of the hydrophobic layer 2 in the extending direction of the hardening layer 1 to the hydrophobic layer 2 is set as 20 nm-3 μm.

[0058] In the above embodiments, the description of each embodiment is focused on, and the part not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0059] The technical features of the above embodiments can be combined arbitrarily, and in order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0060] The above describes in detail the hydrophobic film and the method for using the hydrophobic film provided by the embodiments of the present application, the principle and implementation manner of the present application are described by applying specific examples, and the above embodiment is only used to help understand the method and core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manner and application range will be changed, and in conclusion, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A hydrophobic membrane, characterized in that, include: A hardened layer, the hardened layer including a substrate and a protrusion structure disposed on the substrate, the protrusion structure including a plurality of strip-shaped protrusions spaced apart along a first direction, and a groove formed between adjacent strip-shaped protrusions, the groove being used to guide the sliding of droplets on the surface of the hydrophobic film; A hydrophobic layer is disposed on the substrate and the protruding structure.

2. The hydrophobic membrane as described in claim 1, characterized in that, The width of the strip-shaped protrusion in the first direction is defined as the protrusion width, and the width of the gap between two adjacent strip-shaped protrusions in the first direction is defined as the protrusion spacing. The ratio of the protrusion spacing to the protrusion width is 1-2.

3. The hydrophobic membrane as described in claim 2, characterized in that, The height of the strip-shaped protrusion extending beyond the substrate on the side closest to the strip-shaped protrusion in the extension direction from the hardened layer to the hydrophobic layer is defined as the protrusion height, and the ratio of the protrusion height to the protrusion spacing is 1-2.

4. The hydrophobic membrane as described in claim 2, characterized in that, The width of the protrusion is set to 10μm-30μm.

5. The hydrophobic membrane as described in claim 3, characterized in that, The side of the strip-shaped protrusion away from the substrate is designed as a plane.

6. The hydrophobic membrane as described in claim 5, characterized in that, The water contact angle on the surface of the hydrophobic layer is greater than or equal to 120°.

7. The hydrophobic membrane according to any one of claims 1 to 6, characterized in that, The base has a strip-shaped groove on the side away from the protrusion structure, and the strip-shaped groove corresponds one-to-one with the strip-shaped protrusion.

8. The hydrophobic membrane according to any one of claims 1 to 6, characterized in that, The hardened layer and the hydrophobic layer are integrally formed.

9. The hydrophobic membrane as described in claim 8, characterized in that, The height of the hydrophobic layer is set to 20 nm-3 μm in the direction of extension from the hardened layer to the hydrophobic layer.

10. A method of using a hydrophobic membrane, characterized in that, A hydrophobic membrane as described in any one of claims 1 to 9 is provided, the hydrophobic membrane being disposed on the surface of an object to be protected, and the method of using the hydrophobic membrane comprising: setting the extension direction of the strip-shaped protrusions of the hydrophobic membrane to be the same as the direction of gravity in an application scenario.

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