Hydrophilic and hydrophobic composite wetting microstructure steam cavity and manufacturing method thereof

Abstract

The invention provides a hydrophilic and hydrophobic composite wetting microstructure steam cavity and a manufacturing method thereof, and relates to the technical field of heat dissipation devices. The hydrophilic and hydrophobic composite wetting microstructure steam cavity comprises an evaporation end and a condensation end, the surface of the evaporation end comprises a micro-channel hydrophilic area and a micro-array hydrophilic area, and the micro-channel hydrophilic area surrounds the micro-array hydrophilic area; the surface of the condensation end comprises condensation hydrophilic areas and condensation hydrophobic areas which are distributed at intervals, and the evaporation end and the condensation end are assembled to form a flat plate structure with a cavity in the middle. Different wettability surfaces of the condensation hydrophilic area and the condensation hydrophobic area are compounded, rapid nucleation condensation can be achieved, droplet-shaped condensation heat transfer of rapid falling of liquid drops in the condensation hydrophobic area and capillary suction rapid liquid discharge of the micro-channel hydrophilic area at the evaporation end are combined, condensation heat transfer of a working medium is enhanced, liquid backflow circulation is accelerated, and the condensation efficiency is improved. The temperature uniformity of the hydrophilic and hydrophobic composite wetting microstructure steam cavity is greatly improved, and batch forming of large-area microstructure functional surfaces is achieved through the in-situ heating imprinting forming micro-imprinting technology.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation devices, and in particular to a hydrophilic-hydrophobic composite wetting microstructure steam chamber and a manufacturing method thereof. Background Art

[0002] At present, the capillary wick inside the steam chamber is the key to achieve phase change heat transfer, including sintering type, wire mesh type and groove microstructure type. The groove microstructure type is more stable and reliable. The microstructure functional surface with adjustable wettability in the groove microstructure type can enhance the condensation / boiling heat transfer of the working fluid in the heat dissipation device such as the steam chamber. However, the microstructure functional surface of the steam chamber is still dominated by a single hydrophilic or hydrophobic structure. The single hydrophilic or hydrophobic microstructure surface has different disadvantages. The droplets on the fully hydrophobic surface are easy to fall off, forming droplet condensation, resulting in higher heat transfer efficiency, but the nucleation rate is low, so it is not conducive to rapid nucleation condensation cycle; the fully hydrophilic surface has a small nucleation energy barrier and the droplet nucleation rate increases, but the condensate is not removed in time, which is easy to cause the condensation surface to be submerged, resulting in large-area film condensation, which leads to the deterioration of the heat transfer effect. In addition, the microstructure surface is currently mostly processed and manufactured by micromechanics, laser micro-nano and other processing methods. The cost of preparing microstructures on the material surface by micromechanics, laser micro-nano and other processing methods is extremely high and inefficient. Summary of the invention

[0003] The present invention aims to solve the problem that droplets on a fully hydrophobic surface are easy to fall off, which is not conducive to a rapid nucleation and condensation cycle, and that the nucleation energy barrier on a fully hydrophilic surface is small, which deteriorates the heat transfer effect.

[0004] To this end, the present invention provides a hydrophilic-hydrophobic composite wetting microstructure steam chamber, including an evaporation end and a condensation end, the evaporation end and the condensation end are arranged opposite to each other, wherein:

[0005] The surface of the evaporation end facing the condensation end includes a microchannel hydrophilic area and a microarray hydrophilic area, the microchannel hydrophilic area surrounds the microarray hydrophilic area, the microchannel hydrophilic area has microchannels, and the directions of the microchannels all lead to the microarray hydrophilic area; and

[0006] The surface of the condensation end facing the evaporation end includes a plurality of trapezoidal edges arranged at intervals, and a V-shaped groove is formed between adjacent trapezoidal edges. The upper bottom surface of the trapezoidal edges is a condensation hydrophobic area, and the surface of the V-shaped groove is a condensation hydrophilic area.

[0007] The evaporation end and the condensation end are assembled to form a flat plate structure with a cavity in the middle.

[0008] Optionally, a supporting column is further included, and the two ends of the supporting column are respectively abutted against the evaporation end and the condensation end.

[0009] Optionally, it also includes a shell, which is a flat structure, the evaporation end is located at the inner bottom of the shell, and the condensation end is located at the inner top of the shell. The surfaces of the evaporation end and the condensation end are provided with grooved liquid absorption cores, and the grooved liquid absorption cores at least partially absorb the liquid working medium.

[0010] Optionally, the cross section of the trapezoidal edge perpendicular to the V-shaped groove is an isosceles trapezoidal structure, wherein the upper base length of the isosceles trapezoidal structure is 100-500 μm, the lower base length of the isosceles trapezoidal structure is 500-1000 μm, and the base angle of the isosceles trapezoidal structure is 70-85 degrees.

[0011] Optionally, the contact angle of the surface of the condensation hydrophobic area is ≥140°, and the contact angle of the surface of the V-shaped groove of the condensation hydrophilic area is ≤10°.

[0012] Optionally, the hydrophilic region of the microarray has a conical microarray structure.

[0013] Optionally, the width of the microchannel is 100-500 μm, and the aspect ratio of the microchannel is 2-3.

[0014] Optionally, the contact angle of the surface of the hydrophilic region of the microchannel is ≤10°, and the contact angle of the surface of the hydrophilic region of the microarray is ≤10°.

[0015] The present invention also provides a method for preparing a hydrophilic-hydrophobic composite wetting microstructure steam chamber. The method for preparing the hydrophilic-hydrophobic composite wetting microstructure steam chamber comprises the following specific steps:

[0016] S1. Preparation of blanks at the condensation end and the evaporation end: Select metal materials and process them into sheet blanks;

[0017] S2. Microstructure embossing of the condensation end and the evaporation end: using the plate blank to prepare trapezoidal edges and V-shaped grooves by micro-embossing technology to obtain the condensation end; using the plate blank to prepare microchannels and microarrays by micro-embossing technology to obtain the evaporation end;

[0018] S3, overall hydrophobic modification of the condensation end: using a hydrophobic silica-methanol-ethanol mixed solution for surface hydrophobic modification;

[0019] S4, hydrophilic modification of condensation hydrophilic area: attaching a stripe-shaped photomask to the condensation hydrophobic area to shield the condensation hydrophobic area, laser scanning the condensation hydrophilic area to induce surface hydrophilic modification of the condensation hydrophilic area, and obtaining a hydrophilic-hydrophobic composite wetting microchannel condensation end;

[0020] S5, overall hydrophilic modification of the evaporation end: laser scanning of the evaporation end surface induces hydrophilic modification of the evaporation end surface;

[0021] S6. Assembly: The evaporation end and the condensation end are assembled to form a hydrophilic-hydrophobic composite wetting microstructure steam cavity with a cavity in the middle.

[0022] Optionally, in step S4 and step S5, the energy density of the laser scanning is 12.0-18.0 J / cm 2 , scanning speed is 1000-2000mm / s.

[0023] Compared with the prior art, the beneficial effects of the hydrophilic-hydrophobic composite wetting microstructure steam chamber and the manufacturing method thereof of the present invention are as follows: the condensation end surface includes condensation hydrophilic areas and condensation hydrophobic areas distributed at intervals, the V-shaped groove is the condensation hydrophilic area, and the upper bottom edge of the trapezoidal structure is the condensation hydrophobic area. The steam first condenses and nucleates in the condensation hydrophilic area, and the liquid increases and spreads, and is sucked back under the action of capillary force. At the same time, the condensation hydrophobic area also condenses to form droplets, and the small droplets will fall off directly to form droplet-shaped condensation heat transfer. The droplet-shaped condensation heat transfer efficiency is much greater than the film-shaped condensation heat transfer efficiency. Droplets with too large diameters that do not fall off in time contact the condensation hydrophilic area. Because the condensation hydrophobic area is located at the upper bottom edge of the trapezoidal structure, the junction between the condensation hydrophobic area and the condensation hydrophilic area is a trapezoidal obtuse angle, which makes the droplets contacting the condensation hydrophilic area easily discharged by the capillary force, reducing The small droplet detachment diameter improves the droplet condensation heat transfer performance. The regional combination of the condensation hydrophilic area and the condensation hydrophobic area with alternating distribution optimizes the condensation mode at the condensation end. At the same time, it has the ability of droplet condensation heat transfer and rapid suction and drainage, which strengthens the condensation heat transfer and accelerates the reflux of the working fluid. The surface of the evaporation end includes a microchannel hydrophilic area and a microarray hydrophilic area. The microchannel hydrophilic area surrounds the microarray hydrophilic area. The microarray hydrophilic area in the central area stores liquid working fluid. When the steam liquefies at the condensation end and returns to the evaporation end, it is rapidly sucked by the capillary action of the microchannel. The directions of the microchannels all lead to the microarray hydrophilic area. The microchannels radiate to the surrounding areas. The radial microchannel hydrophilic area shortens the suction path, and can quickly suck the liquid to the central microarray hydrophilic area for storage, participate in boiling heat transfer, accelerate the phase change cycle, and improve the heat transfer efficiency. The surfaces with different wettability of the condensation hydrophilic area and the condensation hydrophobic area are composited to achieve rapid nucleation and condensation. The droplet-like condensation heat transfer with rapid shedding of droplets in the condensation hydrophobic area and the rapid liquid drainage by capillary suction in the hydrophilic area of ​​the evaporation end microchannel are combined to enhance the condensation heat transfer of the working fluid, accelerate the liquid reflux circulation, and greatly improve the temperature uniformity of the steam cavity of the hydrophilic-hydrophobic composite wetting microstructure. In addition, the micro-imprinting technology of in-situ heating imprinting is used to realize the batch forming of large-area microstructure functional surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the hydrophilic-hydrophobic composite wetting microstructure steam chamber of the present invention;

[0025] Figure 2 It is a cross-sectional schematic diagram of the trapezoidal edge of the condensation end of the present invention;

[0026] Figure 3 It is a schematic diagram of the surface structure of the condensation end of the hydrophilic-hydrophobic composite wetting microstructure steam cavity of the present invention;

[0027] Figure 4 for Figure 3 A partial enlarged view of part A;

[0028] Figure 5 for Figure 4 A top view of

[0029] Figure 6 This is a schematic diagram of the structure of attaching a mask to the condensation end of the present invention for laser scanning;

[0030] Figure 7 It is a schematic diagram of the working medium reflux in the microchannel of the evaporation end of the present invention;

[0031] Figure 8 It is a schematic structural diagram of the evaporation end of the hydrophilic-hydrophobic composite wetting microstructure steam chamber of the present invention;

[0032] Fig. 9 for Figure 8 A partial enlarged view of part B;

[0033] Fig.10 for Fig. 9 Bottom view of

[0034] Fig.11 for Figure 8 A partial enlarged view of part C in the middle;

[0035] Fig.12 for Figure 8 A partial enlarged view of part D in the middle;

[0036] Fig.13 for Figure 8 A partial enlarged view of part E in the middle;

[0037] Fig.14 It is a flow chart of the method for manufacturing the hydrophilic-hydrophobic composite wetting microstructure steam chamber of the present invention;

[0038] Fig.15 It is a schematic structural diagram of the micro-embossing forming device 8 of the present invention.

[0039] In the figure: 1, evaporation end; 11, microchannel hydrophilic area; 111, microchannel; 12, microarray hydrophilic area; 121, microarray; 13, second connection area; 2, condensation end; 21, condensation hydrophilic area; 22, condensation hydrophobic area; 221, mask; 23, first connection area; 3, cavity; 4, support column; 5, shell; 6, groove wick; 7, working medium; 8, micro-embossing forming device; 81, punch; 82, die; 83, heating element 84, power component; 85, heat insulation board; 861, upper frame; 862, lower frame; 87, guide column; 88, plate. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0041] It should be noted that in the description of the present invention, the directions or positional relationships indicated by “up”, “down”, “left”, “right”, “top”, “bottom”, “front”, “back”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, it should not be understood as limiting the scope of protection of the present invention.

[0042] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0043] Moreover, although the present invention is described with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention, and many modifications can be made to the exemplary embodiments, and other embodiments can be designed. As long as they do not deviate from the core concept and scope of the present invention as defined by the attached claims, they fall within the scope of protection of the present invention.

[0044] To solve the above problems, the present invention provides a hydrophilic-hydrophobic composite wetting microstructure steam chamber and a manufacturing method thereof, which are used in heat dissipation devices and the like. The steam chamber utilizes the phase change heat transfer of the internal liquid working medium 7, steam diffusion, condensation reflux to achieve heat dissipation of electronic components, and has the advantages of excellent thermal conductivity, large heat transfer area, good temperature uniformity and high reliability, and is the primary way to solve the heat dissipation problem of electronic equipment.

[0045] like Figures 1 to 7 As shown, the present invention provides a hydrophilic-hydrophobic composite wetting microstructure steam chamber, comprising an evaporation end 1 and a condensation end 2, the evaporation end 1 and the condensation end 2 are arranged opposite to each other, wherein:

[0046] like Figure 7 As shown, the surface of the evaporation end 1 facing the condensation end 2 includes a microchannel hydrophilic area 11 and a microarray hydrophilic area 12, the microchannel hydrophilic area 11 surrounds the microarray hydrophilic area 12, the microchannel hydrophilic area 11 has microchannels 111, and the directions of the microchannels 111 all lead to the microarray hydrophilic area 12;

[0047] like Figures 2 to 6As shown, the surface of the condensation end 2 facing the evaporation end 1 includes a plurality of trapezoidal edges arranged at intervals, and a V-shaped groove is formed between adjacent trapezoidal edges. The upper bottom surface of the trapezoidal edge is a condensation hydrophobic area 22, and the surface of the V-shaped groove formed between two adjacent trapezoidal edges is a condensation hydrophilic area 21; wherein, Figure 3 : is a schematic diagram of the partial structure of the surface of the condensation end 2 facing the evaporation end 1. The width of the bottom surface of the trapezoidal edge and the width of the V-shaped groove in the surface of the condensation end 2 facing the evaporation end 1 are both small, resulting in a dense microchannel structure on the surface of the condensation end 2. Figure 3 The surface of the condensation end 2 is not clearly shown, so it is attached Figure 3 A partial enlarged view is provided to clearly illustrate the surface of the condensation end 2.

[0048] like Figure 1 As shown, the evaporation end 1 and the condensation end 2 are assembled to form a flat plate structure with a cavity 3 in the middle. Specifically, the evaporation end 1 and the condensation end 2 can be welded up and down to obtain a flat plate structure with a cavity 3 in the middle.

[0049] "Trapezoidal ridge" is an ridge structure with a trapezoidal cross section. Multiple ridge structures extend in parallel, and a V-shaped groove is formed between adjacent ridge structures. "The upper base surface of the trapezoidal ridge" refers to the plane where the upper base of the trapezoid is located. If the trapezoidal ridge is regarded as a convex structure, the "upper base surface of the trapezoidal ridge" can also be called the top surface of the ridge structure.

[0050] like Figure 1 As shown, the function of the heat dissipation device is realized by condensation / boiling heat transfer of the working fluid 7 in the steam chamber of the hydrophilic / hydrophobic composite wetting microstructure. The condensation end 2 is composed of condensation hydrophilic areas 21 and condensation hydrophobic areas 22 with different wettability strengths. The V-shaped grooves of the condensation hydrophilic areas 21 form a microchannel structure. The evaporation end 1 is composed of partitioned microchannels 111 and microarrays 121. The surface of the condensation end 2 includes condensation hydrophilic areas 21 and condensation hydrophobic areas 22 distributed at intervals. The V-shaped grooves are the condensation hydrophilic areas 21, and the upper bottom surface of the trapezoidal edges is the condensation hydrophobic area 22. Figure 2As shown, the steam first condenses and nucleates in the condensation hydrophilic area 21, and the liquid increases and spreads, and is sucked back under the capillary force of the V-shaped groove. At the same time, the condensation hydrophobic area 22 also condenses to form droplets, and the small droplets will fall off directly to form droplet-like condensation heat transfer. The droplet-like condensation heat transfer efficiency is much greater than the film-like condensation heat transfer efficiency. Droplets with too large diameters that do not fall off in time contact the condensation hydrophilic area 21. Because the condensation hydrophobic area 22 is located on the upper bottom surface of the trapezoidal edge, the junction of the condensation hydrophobic area 22 and the condensation hydrophilic area 21 is a trapezoidal obtuse angle, which makes the droplets contacting the condensation hydrophilic area 21 easily drained by the capillary force, reducing the droplet detachment diameter, thereby improving the droplet-like condensation heat transfer performance. The combination of the condensation hydrophilic area 21 and the condensation hydrophobic area 22 with intervals optimizes the condensation mode of the condensation end 2, and has both droplet-like condensation heat transfer and rapid suction and drainage. The evaporation end 1 surface comprises a microchannel hydrophilic area 11 and a microarray hydrophilic area 12, the microchannel hydrophilic area 11 surrounds the microarray hydrophilic area 12, the microarray hydrophilic area 12 in the central area comprises an array microstructure for storing the liquid working medium 7, the microchannel hydrophilic area 111 comprises a plurality of microchannels radially extending around the microarray hydrophilic area 12 as the center, when the steam is liquefied at the condensation end 2 and returns to the evaporation end 1, it is rapidly sucked by the capillary action of the microchannel hydrophilic area 111, the channel extension directions of the microchannel hydrophilic area 111 all lead to the microarray hydrophilic area 12, the microchannel hydrophilic area 11 radially shortens the suction path, and can quickly suck the liquid to the central microarray hydrophilic area 12 for storage, participate in boiling heat transfer, accelerate the phase change cycle, and improve the heat transfer efficiency.

[0051] Alternatively, if Figure 1 As shown, it also includes a support column 4, both ends of which are respectively abutted against the evaporation end 1 and the condensation end 2.

[0052] like Figure 3 As shown, the surface of the condensation end 2 is provided with a plurality of first connection areas 23 for connecting the support columns 4, such as Figure 8 As shown, the surface of the evaporation end 1 is provided with a plurality of second connection areas 13 for connecting the support column 4, and the positions of the first connection area 23 and the second connection area 13 correspond to each other, so that when the two ends of the support column 4 are respectively connected to the first connection area 23 and the second connection area 13, the support column 4 is perpendicular to the surface of the condensation end 2 and the surface of the evaporation end 1. The number of the support columns 4 is selected according to the size of the surface of the condensation end 2 and the surface of the evaporation end 1, so that the flat plate structure obtained by the evaporation end 1 and the condensation end 2 is stable.

[0053] Alternatively, if Figure 1 As shown, it also includes a shell 5, which is a flat structure. The evaporation end 1 is located at the inner bottom of the shell 5, and the condensation end 2 is located at the inner top of the shell 5. The surfaces of the evaporation end 1 and the condensation end 2 are both provided with a grooved liquid absorption core 6, and the grooved liquid absorption core 6 at least partially absorbs the liquid working medium 7.

[0054] The shell 5 encloses the flat plate structures of the evaporation end 1 and the condensation end 2 to form a closed steam chamber, so that the working medium 7 in the steam chamber evaporates or liquefies inside the steam chamber to achieve heat dissipation. Among them, the groove wick 6 can be directly formed on the plate of the evaporation end 1 and the condensation end 2 by plastic micro-forming, i.e., micro-structure embossing, without the welding and sintering process of the screen and sintered wicks, thus reducing the contact thermal resistance. Compared with the traditional screen wick, it has higher strength, is more stable and reliable. The working cycle of the hydrophilic-hydrophobic composite wetting microstructure steam chamber is as follows: Figure 1 As shown, the working medium 7 absorbs heat from the heat source at the evaporation end 1 and evaporates into the steam chamber. The vapor working medium 7 in the steam chamber is pushed by the vapor pressure difference in the vacuum steam chamber, and after encountering the condensation end 2, it is condensed and changes into liquid working medium 7, and flows back to the evaporation end 1 under the capillary force of the groove wick 6, circulating the heat dissipation.

[0055] Alternatively, if Figure 2 As shown, the cross section of the trapezoidal edge perpendicular to the V-shaped groove direction is an isosceles trapezoidal structure, wherein the upper base length of the isosceles trapezoidal structure is 100-500 μm, the lower base length of the isosceles trapezoidal structure is 500-1000 μm, and the base angle of the isosceles trapezoidal structure is 70-85 degrees.

[0056] Specifically, the two parallel sides of the trapezoidal structure are called bases, the shorter base is called the upper base, and the longer base is called the lower base; the two non-parallel sides of the trapezoidal structure are called waists, the lengths of the two waists can be the same or different, when the lengths of the two waists are the same, the trapezoidal structure is an isosceles trapezoidal structure, the angle between the upper base and the waist of the trapezoidal structure is called the vertex angle, the angle between the lower base and the waist of the trapezoidal structure is called the base angle, the two vertex angles of the isosceles trapezoidal structure have the same angle, and the two base angles of the isosceles trapezoidal structure have the same angle. The upper base length of the isosceles trapezoidal structure formed by the arrangement of the condensation hydrophilic area 21 and the condensation hydrophobic area 22 is 100-500μm, the lower base length of the isosceles trapezoidal structure is 500-1000μm, and when the base angle of the isosceles trapezoidal structure is 70-85 degrees, the isosceles trapezoidal microstructure of this size is very suitable for microstructure embossing molding, has good structural stability, and has excellent capillary suction performance, which is very conducive to efficient condensation and evaporation / boiling. If the size of the upper base is too small (for example, less than 100μm) or the base angle is too large (for example, greater than 85 degrees), the use of microstructure embossing will result in poor filling effect, difficulty in demolding, and easy damage to the punch.

[0057] Optionally, the contact angle of the surface of the condensation hydrophobic area 22 is ≥140°, and the contact angle of the V-shaped groove surface of the condensation hydrophilic area 21 is ≤10°.

[0058] At the interface of solid, liquid and gas, the angle from the solid-liquid interface through the liquid to the gas-liquid interface is called the contact angle, also known as the wetting angle. When the contact angle is 180 degrees, it is completely non-wetting (the droplets on the plane are spherical at this time), and when the contact angle is 0 degrees, it is completely wetting (the droplets on the plane are spread out along the plane and extend infinitely). In this way, the larger the contact angle, the stronger the hydrophobicity of the surface, and the smaller the contact angle, the stronger the hydrophilicity of the surface. The contact angle of the surface of the condensation hydrophobic area 22 is ≥140°, achieving strong hydrophobicity, and the contact angle of the V-groove surface is ≤10°, achieving strong hydrophilicity.

[0059] Alternatively, if Figure 8 , Fig. 9 and Fig.10 As shown, the microarray hydrophilic region 12 has a conical microarray 121 structure. Figure 8 1 is a schematic diagram of a partially real structure of the surface of the evaporation end 1 facing the condensation end 2. The microchannel 111 and the microarray 121 structures in the surface of the evaporation end 1 facing the condensation end 2 are both relatively small, resulting in a dense structure on the surface of the evaporation end 1. Figure 8 The surface of the evaporation end 1 is not clearly shown, so it is attached Figures 9 to 13 A partial enlarged view is provided to clearly illustrate the surface of the evaporation end 1.

[0060] In this way, the conical microarray 121 structure can store the liquid working medium 7. When the liquefied working medium 7 returns to the steam end, it can be quickly sucked by the capillary action of the conical microarray 121 structure, participate in boiling heat transfer, accelerate the phase change cycle, and improve the heat transfer efficiency.

[0061] Alternatively, if Figures 11 to 13 As shown, the width of the microchannel 111 is 100-500 μm, and the aspect ratio of the microchannel 111 is 2-3.

[0062] In this way, the microchannel 111 is very suitable for microstructure embossing molding, has good structural stability, and has excellent capillary suction performance, which is very conducive to evaporation / boiling. If the width scale is too small (for example, less than 100μm) or the aspect ratio is too large (greater than 4-5), the use of microstructure embossing will lead to poor filling effect, difficult demolding, and easy damage to the punch.

[0063] Alternatively, if Figures 7 to 13As shown, the microarray hydrophilic area 12 of the evaporation end 1 is square, having four corners and four sides, the microchannels 111 of the microchannel hydrophilic area 11 on the diagonal area of ​​the microarray hydrophilic area 12 extend in the diagonal direction and form an angle of 45 degrees with the horizontal direction, and the microchannels 111 of the microchannel hydrophilic area 11 in the horizontal and vertical areas of the microarray hydrophilic area 12 also extend in the horizontal and vertical directions respectively to the microarray hydrophilic area 12 in the central area, when the steam liquefies and returns to the evaporation end 1, it is quickly sucked by the capillary action of the microchannel 111 of the microchannel hydrophilic area 11, and the radial microchannels 111 shorten the suction path, and can quickly suck the liquid to the microarray hydrophilic area 12 in the central area for storage, participate in boiling heat transfer, accelerate the phase change cycle, and improve the heat transfer efficiency.

[0064] Optionally, the contact angle of the surface of the microchannel hydrophilic region 11 is ≤10°, and the contact angle of the surface of the microarray hydrophilic region 12 is ≤10°. In this way, the surface of the microchannel hydrophilic region 11 has strong hydrophilicity.

[0065] The present invention also provides a method for preparing a hydrophilic-hydrophobic composite wetting microstructure steam cavity, and the method comprises preparing the hydrophilic-hydrophobic composite wetting microstructure steam cavity. Fig.14 As shown, the specific steps include:

[0066] S1. Preparation of blanks for the condensation end 2 and the evaporation end 1: Select metal materials to form sheet blanks; specifically, the blanks for the condensation end 2 and the evaporation end 1 can be metal materials such as aluminum, copper, magnesium and their alloys, and select metal materials to process sheet blanks of 12×12×3cm. Use acetone or alcohol to ultrasonically clean the surface of the sheet blank to remove surface impurities.

[0067] S2, microstructure embossing of the condensation end 2 and the evaporation end 1: take the plate blank and use the micro-embossing technology to prepare trapezoidal edges and V-shaped grooves to obtain the condensation end 2; take the plate blank and use the micro-embossing technology to prepare microchannels 111 and microarrays 121 to obtain the evaporation end 1; specifically, the parameters of the micro-embossing technology are: temperature of 350-380°C, forming pressure of 70-75t, loading speed of 0.1-0.5mm / s.

[0068] The plate blank is taken and the trapezoidal edges and V-shaped grooves are prepared by micro-embossing technology to obtain the condensation end 2; the plate blank is taken and the micro-embossing technology is used to prepare the microchannel 111 and the microarray 121 to obtain the evaporation end 1; the micro-embossing technology is a low-cost mass production technology, which has higher adaptability to the batch processing of large-area microstructures. The condensation end 2 and the evaporation end 1 can be formed at one time by micro-embossing technology, which has simple process, high material utilization rate, low cost, suitable for the batch production of large-area devices, high production efficiency, high forming accuracy, and good mechanical properties of the formed microstructure. Micro-embossing technology can be selected to use molding or roller pressing.

[0069] S3. Overall hydrophobic modification of the condensation end 2: using a hydrophobic silica-methanol-ethanol mixed solution to perform surface hydrophobic modification; obtaining a fully hydrophobic microchannel condensation end 2 surface with a contact angle ≥ 140°.

[0070] S4, condensation hydrophilic area 21 hydrophilic modification: Figure 5 As shown, the condensation hydrophobic area 22 is attached with a stripe-shaped photomask 221 to shield the condensation hydrophobic area 22, and the laser scans the condensation hydrophilic area 21 to induce the hydrophilic modification of the surface of the condensation hydrophilic area 21, so as to obtain the hydrophilic-hydrophobic composite wetting microchannel condensation end 2; specifically, a stripe-shaped photomask 221 matching the microchannel of the condensation end 2 is prepared, and the stripe-shaped photomask 221 is covered on the surface of the condensation hydrophobic area 22 to shield the condensation hydrophobic area 22, and then the laser is used for laser scanning at an energy density of 12.0-18.0 J / cm 2 , ultrafast laser scanning at a scanning speed of 1000-2000 mm / s was performed twice to obtain a hydrophilic-hydrophobic composite wetting microchannel condensation end 2 in which the contact angle of the condensation hydrophobic area 22 was ≥140° and the contact angle of the V-shaped groove of the condensation hydrophilic area 21 was ≤10°.

[0071] S5. Overall hydrophilic modification of the evaporation end 1: Laser scanning the surface of the evaporation end 1 induces hydrophilic modification of the surface of the evaporation end 1; specifically, the laser is scanned at an energy density of 12.0-18.0 J / cm 2 , ultrafast laser scanning at a scanning speed of 1000-2000 mm / s was performed twice to obtain a hydrophilic microstructure evaporation end 1 with a contact angle of ≤10°.

[0072] S6, assembly: the evaporation end 1 and the condensation end 2 are assembled to form a hydrophilic-hydrophobic composite wetting microstructure steam cavity with a cavity 3 in the middle. Specifically, the evaporation end 1 and the condensation end 2 are welded together up and down to form a hydrophilic-hydrophobic composite wetting microstructure steam cavity with a cavity 3 in the middle.

[0073] Optionally, the surfaces of the evaporation end 1 and the condensation end 2 are both provided with a grooved liquid wick 6, which at least partially absorbs the liquid working medium 7, and further comprises a shell 5, which encloses the flat plate structure composed of the evaporation end 1 and the condensation end 2 to form a closed steam chamber, wherein the evaporation end 1 is located at the bottom of the steam chamber, and the condensation end 2 is located at the top of the steam chamber, so that the working medium 7 in the steam chamber evaporates or liquefies inside the steam chamber to achieve heat dissipation. Among them, the grooved liquid wick 6 can be directly formed on the plates of the evaporation end 1 and the condensation end 2 at one time by plastic microforming, i.e., microstructure embossing.

[0074] Optionally, in step S4 and step S5, the energy density of the laser scanning is 12.0-18.0 J / cm 2 , scanning speed is 1000-2000mm / s.

[0075] like Fig.15 As shown, the micro-embossing forming device 8 is used for in-situ heating molding of the surface of the evaporation end 1, the surface of the condensation end 2 and the groove wick 6 through micro-embossing technology, so that the microarray 121 structure and the microchannel 111 structure are formed on the surface of the evaporation end 1, and the trapezoidal structure microchannel is formed on the surface of the condensation end 2, so that the groove wick 6 can be directly formed on the plate 88 of the evaporation end 1 and the condensation end 2 at one time, without the need for welding and sintering processes of screen type and sintered wicks, thereby reducing contact thermal resistance. The micro-embossing forming device 8 includes a power component 84, a forming component, a heating element 83 and a guiding mechanism. The forming component includes a male mold 81 and a female mold 82. The male mold 81 and the female mold 82 emboss a plate 88. According to the finished product structure to be embossed on the surface of the plate 88, a suitable male mold 81 or female mold 82 is selected. The male mold 81 and the female mold 82 are filled with a heating element 83. The heating element 83 can choose to use an electric heating rod to achieve hot pressing of the plate 88 by the male mold 81 and the female mold 82. The power component 84 is connected to the male mold 81 and / or the female mold 82 to achieve the power component 84 driving the male mold 81 and / or the female mold 82 to move so as to hot press the plate 88. In order to avoid the situation where the temperature of the male mold 81 and the female mold 82 is too high and damages the power component 84 connected thereto, A heat insulation plate 85 is arranged between the power component 84 and the punch 81 and / or the die 82. The guide mechanism may include a frame and a guide column 87. The frame includes an upper frame 861 and a lower frame 862. The guide column 87 may be fixedly connected to the lower frame 862. A hole is reserved on the upper frame 861 for passing through the guide column 87, so that the upper frame 861 can move up and down relative to the guide column 87. The upper frame 861 can be used to support the power component 84, and the lower frame 862 can support the forming component. The upper frame 861 has a storage space for the power component 84, so that the power component 84 can drive the upper frame 861 to move up and down relative to the guide column 87. When the power component 84 pushes the forming component, it pushes the forming component up and down along the direction of the guide column 87 to hot press the plate 88.

[0076] Example 1: Preparation of hydrophilic-hydrophobic composite wetting microstructure steam chamber

[0077] S1. Preparation of the blanks at the condensation end and the evaporation end: Select 7075 aluminum alloy to process a 12×12×3 cm plate blank, and use acetone or alcohol to ultrasonically clean the surface of the plate blank to remove surface impurities.

[0078] S2. Microstructure embossing of the condensation end and the evaporation end: The plate blank is used to prepare trapezoidal edges and V-shaped grooves by micro-embossing technology to obtain the condensation end; the plate blank is used to prepare microchannels and microarrays by micro-embossing technology to obtain the evaporation end; specifically, the parameters of the micro-embossing technology are: temperature of 350°C, forming pressure of 70t, and loading speed of 0.1mm / s. Among them, the cross-section of the trapezoidal edge is an isosceles trapezoidal structure, the length of the upper base of the isosceles trapezoidal structure is 100μm, the length of the lower base of the isosceles trapezoidal structure is 500μm, and the bottom angle of the isosceles trapezoidal structure is 70 degrees. The microarray 121 at the evaporation end is square, having four corners and four sides. The microchannels 111 on the diagonal area of ​​the microarray 121 extend in the diagonal direction and are at a 45-degree angle to the horizontal direction. The microchannels in the horizontal and vertical areas of the microarray 121 also extend in the horizontal and vertical directions respectively to the microarray 121 in the central area. The width of the microchannel is 100 μm, and the aspect ratio of the microchannel is 2.

[0079] S3. Overall hydrophobic modification of the condensation end: using a hydrophobic silica-methanol-ethanol mixed solution to perform surface hydrophobic modification; obtaining a fully hydrophobic microchannel condensation end surface with a contact angle ≥140°.

[0080] S4, hydrophilic modification of the condensation hydrophilic area 21: attach a stripe-shaped photomask to the condensation hydrophobic area to shield the condensation hydrophobic area, and laser scan the condensation hydrophilic area to induce the surface hydrophilic modification of the condensation hydrophilic area to obtain the hydrophilic-hydrophobic composite wetting microchannel condensation end; specifically, prepare a stripe-shaped photomask matching the microchannel of the condensation end, cover the stripe-shaped photomask on the surface of the condensation hydrophobic area to shield the condensation hydrophobic area, and then use an energy density of 12.0 J / cm 2 , ultrafast laser scanning at a scanning speed of 1000 mm / s was performed twice to obtain a hydrophilic-hydrophobic composite wetting microchannel condensation end with a contact angle of ≥140° in the condensation hydrophobic area and a contact angle of ≤10° in the V-shaped groove in the condensation hydrophilic area.

[0081] S5. Overall hydrophilic modification of the evaporation end: Laser scanning the surface of the evaporation end induces hydrophilic modification of the surface of the evaporation end; specifically, the laser was scanned at an energy density of 12.0 J / cm 2 , ultrafast laser scanning at a scanning speed of 1000 mm / s was performed twice to obtain a hydrophilic microstructure evaporation end with a contact angle of ≤10°.

[0082] S6. Assembly: The evaporation end and the condensation end are welded together up and down to form a hydrophilic-hydrophobic composite wetting microstructure steam cavity with a cavity in the middle.

[0083] Example 2: Preparation of hydrophilic-hydrophobic composite wetting microstructure steam chamber

[0084] S1. Preparation of the blanks at the condensation end and the evaporation end: Select 7075 aluminum alloy to process a 12×12×3 cm plate blank, and use acetone or alcohol to ultrasonically clean the surface of the plate blank to remove surface impurities.

[0085] S2. Microstructure embossing of the condensation end and the evaporation end: The plate blank is taken and the trapezoidal edges and V-shaped grooves are prepared by micro-embossing technology to obtain the condensation end; the plate blank is taken and the micro-embossing technology is used to prepare the microchannels and microarrays to obtain the evaporation end; specifically, the parameters of the micro-embossing technology are: temperature is 380℃, forming pressure is 75t, and loading speed is 0.5mm / s. Among them, the cross-section of the trapezoidal edge is an isosceles trapezoidal structure, the upper bottom side length of the isosceles trapezoidal structure is 500μm, the lower bottom side length of the isosceles trapezoidal structure is 1000μm, and the bottom angle of the isosceles trapezoidal structure is 85 degrees. The microarray of the evaporation end is square, with four corners and four sides. The microchannels on the diagonal area of ​​the microarray extend in the diagonal direction and are at a 45-degree angle to the horizontal direction. The microchannels in the horizontal and vertical areas of the microarray also extend in the horizontal and vertical directions to the microarray in the central area, respectively. The width of the microchannel is 500μm, and the depth-to-width ratio of the microchannel is 3.

[0086] S3. Overall hydrophobic modification of the condensation end: using a hydrophobic silica-methanol-ethanol mixed solution to perform surface hydrophobic modification; obtaining a fully hydrophobic microchannel condensation end surface with a contact angle ≥140°.

[0087] S4. Hydrophilic modification of condensation hydrophilic area: a striped photomask is attached to the condensation hydrophobic area to shield the condensation hydrophobic area, and a laser is scanned on the condensation hydrophilic area to induce the surface hydrophilic modification of the condensation hydrophilic area to obtain the hydrophilic-hydrophobic composite wetting microchannel condensation end; specifically, a striped photomask matching the microchannel of the condensation end is prepared, and the striped photomask is covered on the surface of the condensation hydrophobic area to shield the condensation hydrophobic area, and then the energy density is 18.0 J / cm 2 , ultrafast laser scanning at a scanning speed of 2000 mm / s was performed twice to obtain a hydrophilic-hydrophobic composite wetting microchannel condensation end with a contact angle of ≥140° in the condensation hydrophobic area and a contact angle of ≤10° in the V-shaped groove in the condensation hydrophilic area.

[0088] S5. Overall hydrophilic modification of the evaporation end: Laser scanning the surface of the evaporation end induces hydrophilic modification of the surface of the evaporation end; specifically, the laser was scanned at an energy density of 18.0 J / cm 2 , ultrafast laser scanning at a scanning speed of 2000 mm / s was performed twice to obtain a hydrophilic microstructure evaporation end with a contact angle of ≤10°.

[0089] S6. Assembly: The evaporation end and the condensation end are welded together up and down to form a hydrophilic-hydrophobic composite wetting microstructure steam cavity with a cavity in the middle.

[0090] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A hydrophilic-hydrophobic composite wetting microstructure steam chamber, characterized in that: It includes an evaporation end and a condensation end, the evaporation end and the condensation end are arranged opposite to each other, wherein: The surface of the evaporation end facing the condensation end includes a microchannel hydrophilic area and a microarray hydrophilic area, the microchannel hydrophilic area surrounds the microarray hydrophilic area, the microchannel hydrophilic area has microchannels, and the directions of the microchannels all lead to the microarray hydrophilic area; and The surface of the condensation end facing the evaporation end includes a plurality of trapezoidal edges arranged at intervals, and a V-shaped groove is formed between adjacent trapezoidal edges, the upper bottom surface of the trapezoidal edges is the condensation hydrophobic area, and the surface of the V-shaped groove is the condensation hydrophilic area; Wherein, the evaporation end and the condensation end are assembled to form a flat plate structure with a cavity in the middle.

2. The hydrophilic-hydrophobic composite wetting microstructure steam chamber according to claim 1, characterized in that: It also includes a supporting column, and the two ends of the supporting column are respectively abutted against the evaporation end and the condensation end.

3. The hydrophilic-hydrophobic composite wetting microstructure steam chamber according to claim 1, characterized in that: It also includes a shell, which is a flat structure. The evaporation end is located at the inner bottom of the shell, and the condensation end is located at the inner top of the shell. The surfaces of the evaporation end and the condensation end are both provided with grooved liquid absorption cores, and the grooved liquid absorption core at least partially absorbs liquid working fluid.

4. The hydrophilic-hydrophobic composite wetting microstructure steam chamber according to claim 1, characterized in that: The cross section of the trapezoidal edge perpendicular to the V-shaped groove is an isosceles trapezoidal structure, the upper base length of the isosceles trapezoidal structure is 100-500 μm, the lower base length of the isosceles trapezoidal structure is 500-1000 μm, and the base angle of the isosceles trapezoidal structure is 70-85 degrees.

5. The hydrophilic-hydrophobic composite wetting microstructure steam chamber according to claim 1, characterized in that: The contact angle of the surface of the condensation hydrophobic area is ≥140°, and the contact angle of the surface of the V-shaped groove of the condensation hydrophilic area is ≤10°.

6. The hydrophilic-hydrophobic composite wetting microstructure steam chamber according to claim 1, characterized in that: The microarray hydrophilic region has a conical microarray structure.

7. The hydrophilic-hydrophobic composite wetting microstructure steam chamber according to claim 1, characterized in that: The width of the microchannel is 100-500 μm, and the aspect ratio of the microchannel is 2-3.

8. The hydrophilic-hydrophobic composite wetting microstructure steam chamber according to claim 1, characterized in that: The contact angle of the surface of the hydrophilic area of ​​the microchannel is ≤10°, and the contact angle of the surface of the hydrophilic area of ​​the microarray is ≤10°.

9. A method for preparing a hydrophilic-hydrophobic composite wetting microstructure steam chamber, characterized in that: The preparation of the hydrophilic-hydrophobic composite wetting microstructure steam chamber according to any one of claims 1 to 8 comprises the following specific steps: S1. Preparation of blanks for the condensation end and the evaporation end: Select metal materials and process them into sheet blanks; S2, microstructure embossing of the condensation end and the evaporation end: taking the plate blank and using micro-embossing technology to prepare the trapezoidal edges and the V-shaped grooves to obtain the condensation end; taking the plate blank and using micro-embossing technology to prepare the microchannel and the microarray to obtain the evaporation end; S3, the overall hydrophobic modification of the condensation end: using a hydrophobic silica-methanol-ethanol mixed solution to perform surface hydrophobic modification; S4, hydrophilic modification of the condensation hydrophilic area: attaching a stripe-shaped photomask to the condensation hydrophobic area to shield the condensation hydrophobic area, laser scanning the condensation hydrophilic area to induce surface hydrophilic modification of the condensation hydrophilic area, and obtaining a hydrophilic-hydrophobic composite wetting microchannel condensation end; S5, hydrophilic modification of the entire evaporation end: laser scanning the surface of the evaporation end to induce hydrophilic modification of the surface of the evaporation end; S6. Assembling: The evaporation end and the condensation end are assembled to form a hydrophilic-hydrophobic composite wetting microstructure steam cavity with a cavity in the middle.

10. The method for preparing the hydrophilic-hydrophobic composite wetting microstructure steam chamber according to claim 9, characterized in that: In step S4 and step S5, the energy density of the laser scanning is 12.0-18.0 J / cm 2 , scanning speed is 1000-2000mm / s.

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