Asymmetric cross-shaped microstructure surface capable of regulating and controlling multi-directional wetting of fluid

Abstract

An asymmetric cross-shaped microstructure surface capable of regulating and controlling fluid multidirectional wetting comprises a substrate and a surface micro-texture on the substrate, each micro-texture unit comprises an asymmetric cross-shaped microstructure body, specifically comprises a cross-shaped body and pointed tails in different directions, is of a relatively simple plane structure and is convenient to manufacture on a large scale; and the plurality of asymmetric cross-shaped microstructure bodies are arranged in a linear array. A plurality of narrow channels with sharp edges are formed by the sharp tail parts of every two adjacent asymmetric cross-shaped microstructures which are reasonably arranged, and the structures play a role in hindering or promoting fluid guiding in different directions, so that pinning, one-way, two-way, three-way or four-way wettability regulation and control of fluid are achieved, and meanwhile, the structure is simple, and low-cost machining is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of fluid multi-directional wetting microstructure surface, and in particular to an asymmetric cross-shaped microstructure surface capable of regulating fluid multi-directional wetting. Background Art

[0002] In recent years, the wetting behavior of fluids on micro-nanostructure surfaces has become a research hotspot in the fields of microfluidics, biomedicine, energy storage, and smart surface interfaces. By designing specific micro-nanostructures, the wetting path, speed, and distribution of liquids on the surface can be regulated under specific conditions, achieving precise control of the wetting behavior of the fluid to meet the needs of different application scenarios. Existing microstructure wetting designs mostly focus on control in a single direction and lack effective control of multi-directional wetting behavior, and their application has certain limitations. Therefore, developing a microstructure surface that can achieve multi-directional fluid wetting control has scientific research value and application prospects.

[0003] Traditional fluid wetting control methods mostly rely on chemical modification of the material itself or the construction of complex three-dimensional microstructures to achieve fluid drive. However, these methods have certain limitations: first, chemical modification often requires complex process flows and is easily affected by environmental conditions (such as temperature, humidity, etc.), resulting in unstable wetting performance; second, complex three-dimensional microstructures are difficult to control their accuracy and consistency during the actual manufacturing process, and the processing cost is high. In addition, the design of traditional microstructures mainly focuses on fluid control in a single or fixed direction, such as a unidirectional liquid spreading surface texture imitating a pitcher plant disclosed in a patent application with a patent publication number of CN205999002U, and a design method and application of a three-dimensional porous inclined array structure for directional liquid transport disclosed in a patent application with a patent publication number of CN114547853A. Both of these belong to unidirectional wettability, and it is difficult to achieve multi-directional wetting regulation and control, and it is impossible to achieve the needs of multi-directional fluid distribution. There are obvious limitations in complex microfluidic systems and multifunctional smart surface interface applications. Therefore, how to achieve the controllable multi-directional wetting of fluids through simple and effective microstructure design has become an important challenge in current research. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an asymmetric cross-shaped microstructure surface that can regulate the multi-directional wetting of fluids. The surface microstructure presents a simple planar pattern, and a single microstructure is an asymmetric cross shape. The surface has the function of regulating the multi-directional wetting of fluids. At the same time, the structure is simple and easy to process at low cost.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] An asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid comprises a substrate 1 and a surface microstructure 2 arranged on the substrate 1, wherein the surface microstructure 2 comprises a plurality of microstructure bodies 211 arranged in a regular and uniform manner, and every four microstructure bodies 211 constitute a microstructure unit group 21, and the microstructure unit group 21 is arranged in a linear array.

[0007] The surface microstructure 2 is manufactured by photolithography, laser marking, 3D printing, micro-nano imprinting or molding.

[0008] The microstructures 211 are arranged uniformly in a regular pattern, and a single microstructure 211 is in an asymmetric cross shape, including a cross body and pointed tails in different directions, which can achieve complete pinning of the fluid and unidirectional, bidirectional, tridirectional or quadridirectional controllable wetting and spreading.

[0009] The overall length of the single microstructure 211 is L, the length of the cross body of the single microstructure 211 is D, the width of the cross body of the single microstructure 211 is d, L:D:d=35:20:4; the vertical angle between the left tip and tail of the single microstructure 211 and the cross body is α1, the horizontal angle between the upper tip and tail and the cross body is α2, the vertical angle between the right tip and tail and the cross body is α3, and the horizontal angle between the lower tip and tail and the cross body is α4, and α1, α2, α3 and α4 are 15° to 60° or 300° to 345°.

[0010] The overall length L of the single microstructure 211 is 35 μm, the length D of the cross body of the single microstructure 211 is 20 μm, the width d of the cross body of the single microstructure 211 is 4 μm, the width of the tip and tail of the single microstructure 211 gradually transitions from 4 μm to 2 μm, the vertical angle α1 between the left tip and tail of the single microstructure 211 and the cross body is 30° or 330°, the horizontal angle α2 between the upper tip and tail of the single microstructure 211 and the cross body is 30° or 330°, the vertical angle α3 between the right tip and tail of the single microstructure 211 and the cross body is 30° or 330°, and the horizontal angle α4 between the lower tip and tail of the single microstructure 211 and the cross body is 30° or 330°.

[0011] The spacing between the microstructure units 21 and the spacing W between the individual microstructures 211 are 3-20 μm.

[0012] The spacing between the microstructure units 21 and the spacing W between the individual microstructures 211 are 5 μm.

[0013] The design parameters of the microstructure unit 21 can be proportionally enlarged or reduced to achieve the effect that the asymmetric cross-shaped microstructure surface can regulate the multi-directional wetting of the fluid.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) The single microstructure of the present invention is in the shape of an asymmetric cross. By rationally designing the orientation of the tip and tail of the asymmetric cross structure, i.e., the angle, multi-directional wetting control of the fluid can be achieved. Specifically, the pinning, unidirectional spreading, bidirectional spreading, tridirectional spreading, or quadridirectional spreading of the fluid can be achieved, thus breaking through the technical limitations of current research that mainly focus on unidirectional spreading.

[0016] (2) The surface microstructure of the present invention is a planar pattern, and a single microstructure is an asymmetric cross shape, which has a simple structure and is easy to manufacture on a large scale.

[0017] (3) The surface microstructure of the present invention can be directly obtained by photolithography, laser marking, 3D printing, micro-nano imprinting or molding, and can be processed and manufactured on a large scale. It does not involve related chemical modifications and is not easily affected by environmental conditions (such as temperature, humidity, etc.), resulting in unstable wetting performance.

[0018] (4) The surface of the present invention lays a foundation for the intelligent development of complex microfluidics, surface interface engineering and other fields.

[0019] In summary, the present invention is based on the design concept of precursor membrane regulation. Under the premise of keeping the structure simple and easy to process at low cost, it realizes precise control of multi-directional wetting of fluids through geometric shape design, makes up for the shortcomings of existing symmetrical structures in wetting regulation, and provides a new technical solution for multi-directional wetting of fluids. It shows broad application prospects and lays the foundation for the intelligent and controllable development in the fields of microfluidics, surface and interface engineering, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of five structures of the present invention, among which Figure 1(a) is a schematic diagram of the pinning state structure, Figure 1(b) is a schematic diagram of the unidirectional wetting and spreading state structure; Figure 1(c) is a schematic diagram of the bidirectional wetting and spreading state structure; Figure 1(d) is a schematic diagram of the three-directional wetting and spreading state structure; Figure 1(e) is a schematic diagram of the four-directional wetting and spreading state structure.

[0021] Figure 2 Schematic diagrams of five combined structures of the microstructure unit group 21 of the present invention.

[0022] Figure 3 It is a schematic diagram of the arrangement of a single microstructure unit group 21 of the present invention.

[0023] Figure 4 FIG. 2 is a schematic diagram showing the dimensions of a single microstructure 211 of the present invention.

[0024] Figure 5 This is an optical image of the change of the pinning state of the surface fluid over time in the present invention.

[0025] Figure 6 This is an optical image of the unidirectional spreading behavior of the surface fluid of the present invention changing with time.

[0026] Figure 7 This is an optical image of the bidirectional spreading behavior of the surface fluid of the present invention changing with time.

[0027] Figure 8 This is an optical image of the three-dimensional spreading behavior of the surface fluid of the present invention changing with time.

[0028] Fig. 9 This is an optical image of the four-way spreading behavior of the surface fluid of the present invention changing with time.

[0029] Table 1 is a detailed table of the angles between the tip and the tail of a single microstructure 211 of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0031] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit exemplary embodiments according to the present invention.

[0032] Embodiment 1

[0033] As shown in Figure 1(a), Figure 2 As shown in (a) in the figure, this embodiment provides an asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid, which comprises a substrate 1 and a surface microstructure 2 disposed on the substrate 1, wherein the surface microstructure 2 comprises a plurality of microstructures 211 arranged uniformly in a regular pattern, and every four microstructures 211 constitute a microstructure unit group 21, and the microstructure unit group 21 is arranged in a linear array. Referring to Table 1, the microstructure 211 of this embodiment is a combination of microstructures 211-1, 211-2, 211-3, and 211-4, referring to Figure 3 , Figure 4The overall length L of the single microstructure 211 is 35 μm, the length D of the cross body of the single microstructure 211 is 20 μm, the width d of the cross body of the single microstructure 211 is 4 μm, the width of the tip and tail of the single microstructure 211 gradually transitions from 4 μm to 2 μm, the vertical angle α1 between the left tip and tail of the single microstructure 211 and the cross body is 30° or 330°, the horizontal angle α2 between the upper tip and tail of the single microstructure 211 and the cross body is 30° or 330°, the vertical angle α3 between the right tip and tail of the single microstructure 211 and the cross body is 30° or 330°, the horizontal angle α4 between the lower tip and tail of the single microstructure 211 and the cross body is 30° or 330°, and the spacing between the microstructure units 21 and the spacing W between the single microstructures 211 are 5 μm. The surface microstructure 2 can be manufactured by photolithography, laser marking, 3D printing, micro-nano imprinting or molding.

[0034] The asymmetric cross-shaped microstructure surface with adjustable fluid multi-directional wetting described in this embodiment is treated with a plasma cleaning machine with a plasma cleaning power of 100 W and a continuous cleaning time of 60 s. After plasma cleaning, it is naturally left for 50 hours. The contact angle of deionized water on the surface after natural placement is about 35°.

[0035] About 5 μL of deionized water was dropped onto the asymmetric cross-shaped microstructure surface with adjustable fluid multi-directional wetting after the treatment described in this embodiment using a microsyringe. The deionized water was pinned on the surface, and the droplet shape was square. The two adjacent asymmetric cross-shaped microstructures with properly arranged tail parts formed a narrow channel with sharp edges. This type of structure hindered the guidance of deionized water in four directions. Therefore, the deionized water could not be guided on the surface and was in a fixed (pinned) state. Figure 5 , which illustrates that the asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid described in this embodiment can achieve wetting of the fluid in 0 directions.

[0036] Embodiment 2

[0037] As shown in Figure 1(b), Figure 2 As shown in (b) of FIG. 1 , this embodiment provides an asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid, which comprises a substrate 1 and a surface microstructure 2 disposed on the substrate 1, wherein the surface microstructure 2 comprises a plurality of microstructures 211 arranged uniformly in a regular pattern, and every four microstructures 211 constitute a microstructure unit group 21, and the microstructure unit group 21 is arranged in a linear array. Referring to Table 1, the microstructure 211 of this embodiment is a combination of microstructures 211-1 and 211-2, and the microstructure unit group 21 is arranged in a linear array. Figure 3 , Figure 4, the overall length L of the single microstructure 211 is 35 μm, the length D of the cross body of the single microstructure 211 is 20 μm, the width d of the cross body of the single microstructure 211 is 4 μm, the width of the tip of the single microstructure 211 gradually transitions from 4 μm to 2 μm, the vertical angle α1 between the left tip of the single microstructure 211 and the cross body is 30°, the horizontal angle α2 between the upper tip of the single microstructure 211 and the cross body is 30° or 330°, the vertical angle α3 between the right tip of the single microstructure 211 and the cross body is 330°, the horizontal angle α4 between the lower tip of the single microstructure 211 and the cross body is 30° or 330°, and the spacing between the microstructure units 21 and the spacing W between the single microstructures 211 is 5 μm. The surface microstructure 2 can be manufactured by photolithography, laser marking, 3D printing, micro-nano imprinting or mold reprinting.

[0038] The asymmetric cross-shaped microstructure surface with adjustable fluid multi-directional wetting described in this embodiment is treated with a plasma cleaning machine with a plasma cleaning power of 100 W and a continuous cleaning time of 60 s. After plasma cleaning, it is naturally left for 50 hours. The contact angle of deionized water on the surface after natural placement is about 35°.

[0039] Use a microsyringe to drop about 5 μL of deionized water onto the surface of an asymmetric cross-shaped microstructure with adjustable multi-directional wetting of a fluid after the treatment described in this embodiment. The deionized water spreads unidirectionally on the surface, and the droplets and the precursor film are in the shape of long strips. The pointed tails of two adjacent asymmetric cross-shaped microstructures arranged reasonably form a narrow channel with sharp edges. This type of structure hinders the guidance of deionized water in three directions, while the precursor film appears in one direction, which guides the deionized water. Therefore, the deionized water wets and spreads unidirectionally on the surface. Figure 6 , which illustrates that the asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid described in this embodiment can achieve wetting of the fluid in one direction.

[0040] Embodiment 3

[0041] As shown in Figure 1(c), Figure 2 As shown in (c) in the figure, this embodiment provides an asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid, which comprises a substrate 1 and a surface microstructure 2 disposed on the substrate 1, wherein the surface microstructure 2 comprises a plurality of microstructures 211 arranged uniformly in a regular pattern, and every four microstructures 211 constitute a microstructure unit group 21, and the microstructure unit group 21 is arranged in a linear array. Referring to Table 1, the microstructure 211 of this embodiment is a microstructure 211-2, and referring to Figure 3 , Figure 4, the overall length L of the single microstructure 211 is 35 μm, the length D of the cross body of the single microstructure 211 is 20 μm, the width d of the cross body of the single microstructure 211 is 4 μm, the width of the tip of the single microstructure 211 gradually transitions from 4 μm to 2 μm, the vertical angle α1 between the left tip of the single microstructure 211 and the cross body is 30°, the horizontal angle α2 between the upper tip of the single microstructure 211 and the cross body is 30°, the vertical angle α3 between the right tip of the single microstructure 211 and the cross body is 330°, the horizontal angle α4 between the lower tip of the single microstructure 211 and the cross body is 330°, and the spacing between the microstructure units 21 and the spacing W between the single microstructures 211 is 5 μm. The surface microstructure 2 can be manufactured by photolithography, laser marking, 3D printing, micro-nano imprinting or mold reprinting.

[0042] The asymmetric cross-shaped microstructure surface with adjustable fluid multi-directional wetting described in this embodiment is treated with a plasma cleaning machine with a plasma cleaning power of 100 W and a continuous cleaning time of 60 s. After plasma cleaning, it is naturally left for 50 hours. The contact angle of deionized water on the surface after natural placement is about 35°.

[0043] Use a microsyringe to drop about 5 μL of deionized water onto the surface of an asymmetric cross-shaped microstructure with adjustable multi-directional wetting of a fluid after the treatment described in this embodiment. The deionized water spreads bidirectionally on the surface, and the shape of the droplet and the precursor film is approximately square. The two adjacent asymmetric cross-shaped microstructures with properly arranged tail parts form a narrow channel with sharp edges. This type of structure hinders the guidance of deionized water in two directions, and produces a precursor film in the other two directions, which guides the deionized water. Therefore, the deionized water wets and spreads bidirectionally on the surface. Figure 7 , which illustrates that the asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid described in this embodiment can achieve wetting of the fluid in two directions.

[0044] Embodiment 4

[0045] As shown in Figure 1(d), Figure 2 As shown in (d) in the figure, this embodiment provides an asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid, which comprises a substrate 1 and a surface microstructure 2 disposed on the substrate 1, wherein the surface microstructure 2 comprises a plurality of microstructures 211 arranged uniformly in a regular pattern, and every four microstructures 211 constitute a microstructure unit group 21, and the microstructure unit group 21 is arranged in a linear array. Referring to Table 1, the microstructure 211 of this embodiment is a combination of microstructures 211-1 and 211-2, and the microstructure unit group 21 is arranged in a linear array. Figure 3 , Figure 4, the overall length L of the single microstructure 211 is 35 μm, the length D of the cross body of the single microstructure 211 is 20 μm, the width d of the cross body of the single microstructure 211 is 4 μm, the width of the tip of the single microstructure 211 gradually transitions from 4 μm to 2 μm, the vertical angle α1 between the left tip of the single microstructure 211 and the cross body is 30°, the horizontal angle α2 between the upper tip of the single microstructure 211 and the cross body is 30° or 330°, the vertical angle α3 between the right tip of the single microstructure 211 and the cross body is 330°, the horizontal angle α4 between the lower tip of the single microstructure 211 and the cross body is 30° or 330°, and the spacing between the microstructure units 21 and the spacing W between the single microstructures 211 is 5 μm. The surface microstructure 2 can be manufactured by photolithography, laser marking, 3D printing, micro-nano imprinting or mold reprinting.

[0046] The asymmetric cross-shaped microstructure surface with adjustable fluid multi-directional wetting described in this embodiment is treated with a plasma cleaning machine with a plasma cleaning power of 100 W and a continuous cleaning time of 60 s. After plasma cleaning, it is naturally left for 50 hours. The contact angle of deionized water on the surface after natural placement is about 35°.

[0047] Use a microsyringe to drop about 5 μL of deionized water onto the surface of an asymmetric cross-shaped microstructure with adjustable fluid multi-directional wetting after the treatment described in this embodiment. The deionized water spreads in three directions on the surface, and the shape of the droplet and the precursor film is approximately rectangular. The two adjacent asymmetric cross-shaped microstructures with properly arranged tail parts form a narrow channel with sharp edges. This type of structure hinders the guidance of deionized water in one direction, and produces a precursor film in the other three directions, which guides the deionized water. Therefore, the deionized water wets and spreads on the surface in three directions. Figure 8 , which illustrates that the asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid described in this embodiment can achieve wetting of the fluid in three directions.

[0048] Embodiment 5

[0049] As shown in Figure 1(e), Figure 2 As shown in (e) in the figure, this embodiment provides an asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid, which comprises a substrate 1 and a surface microstructure 2 disposed on the substrate 1, wherein the surface microstructure 2 comprises a plurality of microstructures 211 arranged uniformly in a regular pattern, and every four microstructures 211 constitute a microstructure unit group 21, and the microstructure unit group 21 is arranged in a linear array. Referring to Table 1, the microstructure 211 of this embodiment is a combination of microstructures 211-1, 211-2, 211-3, and 211-4, referring to Figure 3 , Figure 4 The overall length L of the single microstructure 211 is 35 μm, the length D of the cross body of the single microstructure 211 is 20 μm, the width d of the cross body of the single microstructure 211 is 4 μm, the width of the tip and tail of the single microstructure 211 gradually transitions from 4 μm to 2 μm, the angle α1 between the left tip and tail of the single microstructure 211 and the cross body in the vertical direction is 30° or 330°, the angle α2 between the upper tip and tail of the single microstructure 211 and the cross body in the horizontal direction is 30° or 330°, the angle α3 between the right tip and tail of the single microstructure 211 and the cross body in the vertical direction is 30° or 330°, the angle α4 between the lower tip and tail of the single microstructure 211 and the cross body in the horizontal direction is 30° or 330°, and the spacing between the microstructure units 21 and the spacing W between the single microstructures 211 are 5 μm. The surface microstructure 2 can be manufactured by photolithography, laser marking, 3D printing, micro-nano imprinting or molding.

[0050] The asymmetric cross-shaped microstructure surface with adjustable fluid multi-directional wetting described in this embodiment is treated with a plasma cleaning machine with a plasma cleaning power of 100 W and a continuous cleaning time of 60 s. After plasma cleaning, it is naturally left for 50 hours. The contact angle of deionized water on the surface after natural placement is about 35°.

[0051] About 5 μL of deionized water was dropped onto the surface of an asymmetric cross-shaped microstructure with adjustable fluid multi-directional wetting after the treatment described in this embodiment using a microsyringe. The deionized water spread in four directions on the surface, and the droplet and the precursor film were approximately circular in shape. The tail parts of two adjacent asymmetric cross-shaped microstructures arranged reasonably formed a narrow channel with sharp edges. This type of structure produced a precursor film in four directions, which guided the deionized water. Therefore, the deionized water wetted and spread in four directions on the surface. Fig. 9 , which illustrates that the asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid described in this embodiment can achieve wetting of the fluid in four directions.

[0052] Table 1

[0053]

[0054] In summary, the asymmetric cross-shaped microstructure of the present invention provides the possibility of realizing multi-directional wetting control of fluids due to its special geometric shape and asymmetry. Based on the basic construction of the cross microstructure, the fluid precursor film is regulated by the tip-tail orientation design, thereby realizing precise control of the wetting behavior in different directions. In addition, the structure is a simple planar structure with the advantage of low processing cost.

Claims

1. An asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid, comprising a substrate (1) and a surface microstructure (2) arranged on the substrate (1), characterized in that: The surface microstructure (2) comprises a plurality of microstructure bodies 211 which are arranged in a regular and uniform manner. Every four microstructure bodies 211 constitute a microstructure unit group 21, and the microstructure unit group 21 is arranged in a linear array.

2. The asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid according to claim 1, characterized in that: The surface microstructure (2) is manufactured by photolithography, laser marking, 3D printing, micro-nano imprinting or molding.

3. The asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid according to claim 1, characterized in that: The microstructures (211) are arranged uniformly in a regular pattern, and a single microstructure (211) is in an asymmetric cross shape, including a cross body and pointed tails in different directions, and can achieve complete pinning of the fluid and unidirectional, bidirectional, tridirectional or quadridirectional controllable wetting and spreading.

4. The asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid according to claim 3, characterized in that: The overall length of the single microstructure (211) is L, the length of the cross body of the single microstructure (211) is D, the width of the cross body of the single microstructure (211) is d, and L:D:d=35:20:4; the vertical angle between the left tip and tail of the single microstructure (211) and the cross body is α1, the horizontal angle between the upper tip and tail and the cross body is α2, the vertical angle between the right tip and tail and the cross body is α3, and the horizontal angle between the lower tip and tail and the cross body is α4, and α1, α2, α3 and α4 are 15° to 60° or 300° to 345°.

5. The asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid according to claim 4, characterized in that: The overall length L of the single microstructure (211) is 35 μm, the length D of the cross body of the single microstructure (211) is 20 μm, the width d of the cross body of the single microstructure (211) is 4 μm, the width of the tip and tail of the single microstructure (211) gradually transitions from 4 μm to 2 μm, the vertical angle α1 between the left tip and tail of the single microstructure (211) and the cross body is 30° or 330°, the horizontal angle α2 between the upper tip and tail of the single microstructure (211) and the cross body is 30° or 330°, the vertical angle α3 between the right tip and tail of the single microstructure (211) and the cross body is 30° or 330°, and the horizontal angle α4 between the lower tip and tail of the single microstructure (211) and the cross body is 30° or 330°.

6. The asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid according to claim 5, characterized in that: The spacing between the microstructure units (21) and the spacing W between the individual microstructures (211) are 3 to 20 μm.

7. The asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid according to claim 6, characterized in that: The spacing between the microstructure units (21) and the spacing W between the individual microstructures (211) are 5 μm.

8. The asymmetric cross-shaped microstructure surface capable of regulating multi-directional wetting of a fluid according to claim 1, characterized in that: The design parameters of the microstructure unit (21) are proportionally enlarged or reduced to achieve the effect that the asymmetric cross-shaped microstructure surface can regulate the multi-directional wetting of the fluid.

Images