Super-hydrophobic high-efficiency condensation heat transfer nano-interface and preparation method thereof

Abstract

The present invention discloses a super-hydrophobic high-efficiency condensation heat transfer nano-interface and a preparation method thereof. The super-hydrophobic high-efficiency condensation heat transfer nano-interface is composed of a metal nanowire array, the metal nanowires in the metal nanowire array are connected laterally to avoid local collapse, and there are no microcavity defects formed by the collapse or agglomeration of the metal nanowires inside; the preparation of the metal nanowire array is achieved by a metal nano-electrodeposition process using an anodic aluminum oxide nanopore template with controllable nano-scale side pore distribution, and the material of the metal nanowires includes any one of copper, nickel, gold, and silver or a combination of two or more; the super-hydrophobic high-efficiency condensation heat transfer nano-interface is given low-viscosity super-hydrophobic properties through low-surface energy chemical modification. The preparation process provided by the present invention is simple and controllable, and the super-hydrophobic high-efficiency condensation heat transfer nano-interface developed based on this process has excellent water vapor penetration resistance, condensation droplet fusion self-ejection removal and high-efficiency condensation heat transfer functions under steam conditions.

Description

Technical Field

[0001] The present invention belongs to the research fields of nanotechnology and functional interface materials, and specifically relates to a super-hydrophobic high-efficiency condensation heat transfer nano-interface and a preparation method thereof. Background Art

[0002] In recent years, the miniaturization, integration, and high-power development of electronic devices have created an urgent need for high heat flux dissipation in small spaces. The design and development of efficient condensation heat transfer interfaces and next-generation high-performance vapor chambers have garnered widespread attention both domestically and internationally. Inspired by biological processes, researchers have achieved significant breakthroughs in the development of efficient copper-based condensation heat transfer interfaces. In 2013, Professor Evelyn Wang's team at the Massachusetts Institute of Technology (MIT) first proposed and confirmed that in situ construction of superhydrophobic copper oxide blade-like nanostructures on copper surfaces can achieve the self-ejection removal of small-scale condensation droplets and improve the droplet condensation heat transfer performance by 30% (Nano Lett, 2013, 13, 179). In 2015, the team of Researcher Gao Xuefeng from the Suzhou Institute of Nanotechnology, Chinese Academy of Sciences, in situ constructed superhydrophobic copper hydroxide grooved nanoneedles on copper surfaces, which can achieve the self-ejection removal function of small-scale condensation droplets. The condensation heat transfer coefficient is improved by 125% compared with blank hydrophobic copper (ACS Appl. Mater. Interfaces, 2015, 7, 10660). In 2018, they further reported that in situ construction of superhydrophobic densely packed zinc oxide nanoneedle array structures on copper surfaces can improve the condensation heat transfer coefficient by 320% (Adv. Funct. Mater, 2018, 28, 1800634). In principle, constructing a low-viscosity super-hydrophobic nano-interface on the surface of copper can indeed achieve the self-removal of condensed droplets at a smaller scale. Reducing the condensed droplet removal diameter from the millimeter level to the micron level not only reduces the droplet's own thermal resistance, but also dynamically releases more exposed sites for phase change heat transfer. Compared with ordinary hydrophobic copper surfaces, the nano-interface also has a higher specific surface area and nucleation sites. The synergy of these interfacial effects leads to super-hydrophobic nano-interfaces having more excellent condensation heat transfer performance. Obviously, although these super-hydrophobic inorganic nano-film layers with different configurations can be used for conceptual verification and understanding how to design super-hydrophobic nano-interfaces to achieve efficient condensation mass transfer and heat transfer, these functional films do not match the thermal expansion coefficient of the copper substrate and there is a risk of instability, making it difficult to have practical value.

[0003] As we all know, truly practical and efficient condensation heat transfer nanointerfaces must not only pursue a high heat transfer coefficient, but also comprehensively consider the stability of the nanointerface's low-viscosity superphobic effect under steam conditions and its thermal expansion compatibility with the substrate itself. For copper materials, the in-situ construction of a low-viscosity superphobic nanointerface of the same material on a copper-based surface to significantly improve condensation heat transfer performance remains a major challenge. In 2017, Professor Yang Ronggui's team at the University of Colorado, USA, used an anodic aluminum oxide template-assisted electroplating technique to in-situ construct a superhydrophobic copper nanowire array structure with condensation droplet fusion and self-ejection removal on a copper surface. The condensation heat transfer coefficient was improved by up to 100% compared to blank hydrophobic copper (NanoEnergy, 2017, 33, 177). However, during the processing of copper nanowires, capillary aggregation occurs. The collapse or aggregation of the nanowires inevitably creates countless micron-sized cavities. These micro-defects can be penetrated by high-temperature or highly supercooled steam. The loss of the low-viscosity superphobic effect at these sites is clearly detrimental to efficient condensation mass and heat transfer. To eliminate the numerous randomly distributed micro-defects between copper nanowires, they cleverly utilized a novel anodized aluminum template with nano-sized side pores in its pores to design and fabricate a more densely packed, aligned copper nanowire. The nanowires are interconnected by multiple nano-protrusions (Joule, 2018, 2, 269). This innovative design effectively prevents water vapor from penetrating, and the condensed droplet fusion and self-ejection removal function persists even when the supercooling temperature is increased to 28K. However, the problem lies in the fact that the location and number of nano-sized side pores within the nano-pore channels of the anodized aluminum template they employed are uncontrollable and randomly distributed. This is because the aluminum foil they used to fabricate the anodized aluminum template is not high-purity aluminum (99.999%), but rather ordinary aluminum foil (99%) containing a significant amount of impurities. While these elemental impurities can induce the formation of nano-sized side pores during the anodization process, the uncontrollable size and spatial distribution within the aluminum foil inevitably result in uncontrollable location and number of the formed nano-sized side pores. In other words, the copper-based, non-protruding nanowires fabricated using this technology inevitably face uncontrollable quality. Furthermore, the specialized, ordinary aluminum foil used in this article comes from a US manufacturer and is unavailable domestically. Using domestically produced ordinary aluminum foil of similar purity and the same preparation process reported in the literature failed to produce unbending copper nanowires. Clearly, achieving controllable nanoscale side pore locations and number within the nanopores of the anodized aluminum template and, based on this, developing higher-quality, super-hydrophobic copper nanointerface materials for efficient condensation and heat transfer presents a pressing technical challenge. Summary of the Invention

[0004] The main purpose of the present invention is to provide a super-hydrophobic high-efficiency condensation heat transfer nano-interface and a preparation method thereof, so as to overcome the shortcomings of the prior art.

[0005] An embodiment of the present invention provides a super-hydrophobic and efficient condensation and heat transfer nano-interface, which is composed of a metal nanowire array, wherein the metal nanowires in the metal nanowire array are connected laterally, and there are no microcavity defects inside the metal nanowire array due to the collapse or agglomeration of the metal nanowires; the preparation of the metal nanowire array is achieved by a metal nano-electrodeposition process using an anodized aluminum oxide nanopore template with controllable nanoscale side pore distribution, and the material of the metal nanowires includes any one or a combination of two or more of copper, nickel, gold, and silver; the super-hydrophobic and efficient condensation and heat transfer nano-interface is given low-viscosity super-hydrophobic properties through low-surface energy chemical modification, and the super-hydrophobic and efficient condensation and heat transfer nano-interface has the functions of preventing water vapor penetration and efficient condensation and heat transfer.

[0006] In some preferred embodiments, the interior of the anodized aluminum oxide nanopore template includes a plurality of columnar nanopore channels (also referred to as "longitudinal nanopore channels"), the nanopore channels are vertically parallel and do not cross, the center spacing of the nanopore channels is 60nm to 500nm, and the length is 500nm to 60μm; the nanopore channels are provided with nanoscale side holes with controllable orientation and number, the nanoscale side holes are distributed in layers, and the number of layers of the layered distribution includes one or more layers.

[0007] Furthermore, the nanoscale side holes are distributed in layers to form more than one lateral side hole layer.

[0008] Furthermore, the pore diameter of the nano side pores along the longitudinal direction of the nanowires ranges from 10 nm to 1000 nm.

[0009] The embodiment of the present invention also provides a method for preparing an anodic aluminum oxide nanopore template with controllable nanoscale side pore distribution, which comprises: the anodic aluminum oxide nanopore template is realized by introducing one or more instantaneous high voltage anodic oxidation during the preparation process of the anodic aluminum oxide nanopore template through a programmable power supply; wherein the process conditions during the preparation process of the anodic aluminum oxide nanopore template include: the electrolyte includes one or more combinations of sulfuric acid, oxalic acid, phosphoric acid, oxalic acid, and malonic acid; the ratio of the instantaneous high voltage to the anodic oxidation intrinsic voltage is 1.3 to 2, and the instantaneous high voltage is 1.3 to 2. The high voltage reaction time is 1 to 5 seconds. The center spacing of the columnar nanopore channels in the anodized aluminum nanopore template is determined by different formula electrolytes and matching anodizing voltages. The depth of the columnar nanopore channels is determined by the anodizing time as needed. The pore size of the columnar nanopore channels of the anodized aluminum nanopore template is determined by the pore expansion time as needed. The size of the nanoscale side pores is controlled by the voltage value and reaction time of the artificially introduced instantaneous high voltage anodizing. The number of layers of the layered distribution of the nanoscale side pores is determined by the number of instantaneous high voltage anodizing times.

[0010] Furthermore, the value of the instantaneous high voltage is 15-400V.

[0011] Furthermore, the value of the anodic oxidation intrinsic voltage is 10 to 300V.

[0012] In some preferred embodiments, the preparation method of the super-hydrophobic high-efficiency condensation heat transfer nano-interface includes: polishing of high-purity aluminum foil, one-step anodization (introducing instantaneous high voltage during the oxidation process), aluminum stripping treatment, removal of the barrier layer and pore expansion treatment, electroplating of metal nanowires, removal of the template, and super-hydrophobic modification.

[0013] In some more specific embodiments, the method for preparing the super-hydrophobic high-efficiency condensation heat transfer nano-interface may include:

[0014] (1) High-purity aluminum foil polishing: A high-purity aluminum substrate with a purity greater than 99.999% was electrochemically polished in a polishing solution consisting of perchloric acid and ethanol in a volume ratio of 1:5. The platinum sheet was used as the cathode and the high-purity aluminum sheet as the anode. The polishing voltage was 20 V and the polishing was carried out in a 0°C water bath for 8 minutes at a current density of approximately 0.175 A·cm -2 , polishing for 8 minutes to obtain a polished aluminum substrate with mirror reflection.

[0015] (2) One-step anodization: A polished aluminum substrate is used as the anode and a platinum sheet is used as the cathode. The aluminum substrate is placed in an electrolyte and anodized under circulating water cooling at 0°C. Working voltage setting: During the process of applying the anodization intrinsic voltage (also referred to as "low voltage"), a transient high voltage (also referred to as "high voltage") is introduced one or more times.

[0016] (3) Aluminum stripping treatment: The aluminum substrate after anodizing treatment is placed in an aluminum stripping solution under the condition of a water bath temperature of less than 10°C until the aluminum is completely removed to obtain an anodized aluminum nanopore template with a single-side opening.

[0017] (4) Removing the barrier layer and expanding the pores: Under a water bath temperature of 40° C., the barrier layer side of the anodized aluminum oxide nanopore template with a single-side opening obtained in step (3) is brought into contact with a phosphoric acid solution to remove the barrier layer and expand the pores to obtain an anodized aluminum oxide nanopore template with controllable nanoscale side pore distribution.

[0018] (5) Metal nanoelectrodeposition: The anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution obtained in step (4) is used as an auxiliary template for electrodeposition, and then the metal nanowires are constructed using the electrodeposition process.

[0019] (6) Removing the template: using a strong alkaline solution to remove the template used in step (5) to obtain a non-prostrating metal nanowire array.

[0020] (7) Superhydrophobic modification: The non-prostrated metal nanowire array in step (6) is immersed in a thiol solution for hydrophobic modification to obtain a superhydrophobic and efficient condensation and heat transfer nano-interface.

[0021] Furthermore, the dealuminization solution comprises 0.15 mol of copper chloride, 50 ml of hydrochloric acid (35-38 wt%), and 300 ml of deionized water.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The advantage of using high-purity aluminum to prepare an anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution in the present invention is that the size, number and spatial position of the side pores are controllable compared to the preparation of an anodic aluminum oxide template with side pores from impurity aluminum. At the same time, the one-step anodizing preparation method greatly shortens the preparation cycle (the general anodizing aluminum preparation scheme includes two anodizing steps, and the second step is a mild anodizing process that takes 6-72 hours). The one-step anodizing process only takes 5-30 minutes to prepare an anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution and a thickness of 10-60 μm. In addition, the method provided by the present invention can be used to prepare an anodic aluminum oxide template with different longitudinal channel center spacings, and has a wide range of applications.

[0024] (2) The present invention uses the obtained anodized aluminum oxide nanopore template with controllable nanoscale side pore distribution to prepare a nanoarray through an electroplating process. The nanoarray avoids local collapse through lateral connection, and there are no microcavity defects inside the nanointerface due to the collapse or agglomeration of nanowires, which improves the uniformity and stability of the nanointerface structure. Through hydrophobic modification, the prepared super-hydrophobic and efficient condensation heat transfer nanointerface has low viscosity super-hydrophobic properties, excellent water vapor penetration, condensation droplet fusion and self-ejection removal, and efficient condensation heat transfer functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1a This is a schematic diagram of the preparation process of the aligned copper nanowire array in Comparative Example 1;

[0027] Figure 1b This is a schematic diagram of the process for preparing a non-prostrate copper nanowire array according to a typical embodiment of the present invention;

[0028] Figure 2aThis is a front SEM image of a common anodized aluminum nanopore template used in preparing a collimated copper nanowire array in Comparative Example 1;

[0029] Figure 2b This is a SEM side view of a common anodized aluminum nanopore template used in preparing a collimated copper nanowire array in Comparative Example 1;

[0030] Figure 2c This is a front SEM image of the aligned copper nanowire array of Comparative Example 1;

[0031] Figure 2d This is a SEM side view of the aligned copper nanowire array in Comparative Example 1;

[0032] Figure 3a This is a front SEM image of an anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution used in preparing a non-prostrating copper nanowire array in Example 1 of the present invention;

[0033] Figure 3b SEM side view of the anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution used in preparing the non-prostrating copper nanowire array in Example 1 of the present invention;

[0034] Figure 3c A magnified SEM image of the nano-side pore region of the anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution used in preparing the non-prostrating copper nanowire array in Example 1 of the present invention;

[0035] Figure 3d 1 is a front SEM image of the non-prostrate copper nanowire array in Example 1 of the present invention;

[0036] Figure 3e is a SEM side view of the non-prostrate copper nanowire array in Example 1 of the present invention;

[0037] Figure 3f This is an enlarged SEM image of the lateral connection of the non-prostrated copper nanowire array in Example 1 of the present invention;

[0038] Figure 4a 1 is a front SEM image of the non-prostrate copper nanowire array in Example 2 of the present invention;

[0039] Figure 4b is a SEM side view of the non-prostrate copper nanowire array in Example 2 of the present invention;

[0040] Figure 4c This is an enlarged SEM image of the lateral connection of the non-prostrate copper nanowire array in Example 2 of the present invention;

[0041] Figure 4d 3 is a front SEM image of the non-prostrated copper nanowire array in Example 3 of the present invention;

[0042] Figure 4e is a SEM side view of the non-prostrated copper nanowire array in Example 3 of the present invention;

[0043] Figure 4f This is an enlarged SEM image of the lateral connection of the non-prostrate copper nanowire array in Example 3 of the present invention;

[0044] Figure 5a Schematic diagram of water vapor penetration mechanism of the collimated copper nanowire array under steam conditions in Comparative Example 1;

[0045] Figure 5b is a diagram showing the mass transfer phenomenon of the collimated copper nanowire array in comparative example 1 at supercooling ΔT = 2K;

[0046] Figure 5c This is a diagram showing the mass transfer phenomenon of the collimated copper nanowire array in comparative example 1 at supercooling ΔT = 15K;

[0047] Figure 5d Schematic diagram of the mechanism of the non-protruding copper nanowire array of the super-hydrophobic high-efficiency condensation heat transfer nano-interface in Example 1 preventing water vapor penetration under steam conditions;

[0048] Figure 5e This is a mass transfer phenomenon diagram of the superhydrophobic and efficient condensation heat transfer nano-interface of Example 1, showing the supercooling degree ΔT = 2K of the non-protruding copper nanowire array;

[0049] Figure 5f This is a mass transfer phenomenon diagram of the non-protruding copper nanowire array of the super-hydrophobic high-efficiency condensation heat transfer nano-interface in Example 1 at a supercooling degree ΔT = 15K;

[0050] Figure 5g This is a heat flux density test diagram of the super-hydrophobic high-efficiency condensation heat transfer nano-interface prepared in Example 1 of the present invention and the ordinary aligned copper nanowire interface in Comparative Example 1;

[0051] Figure 6a This is an SEM side view of an anodic aluminum oxide nanopore template with a nanopore center spacing of 300 nm and controllable nanoscale side pore distribution according to Example 5 of the present invention;

[0052] Figure 6b This is an enlarged SEM image of the side pore region of the anodic aluminum oxide nanopore template with a nanopore center spacing of 300 nm and controllable nanoscale side pore distribution in Example 5 of the present invention;

[0053] Figure 6c This is a front SEM image of an anodic aluminum oxide nanopore template with a nanopore center spacing of 300 nm and controllable nanoscale side pore distribution according to Example 5 of the present invention;

[0054] Figure 6dThis is an SEM side view of an anodic aluminum oxide nanopore template with a nanopore center spacing of 100 nm and controllable nanoscale side pore distribution according to Example 6 of the present invention;

[0055] Figure 6e This is an enlarged SEM image of the side pore region of the anodic aluminum oxide nanopore template with a nanopore center spacing of 100 nm and controllable nanoscale side pore distribution in Example 6 of the present invention;

[0056] Figure 6f This is a front SEM image of an anodic aluminum oxide nanopore template with a nanopore center spacing of 100 nm and controllable nanoscale side pore distribution according to Example 6 of the present invention;

[0057] Figure 7a This is a diagram showing the super-hydrophobic effect of the aligned copper nanowire array in comparative example 1;

[0058] Figure 7b This is a diagram showing the super-hydrophobic effect of the non-protruding copper nanowire array of the super-hydrophobic high-efficiency condensation heat transfer nano-interface in Example 1 of the present invention. DETAILED DESCRIPTION

[0059] Example 1

[0060] This embodiment provides a copper-based super-hydrophobic high-efficiency condensation heat transfer nano-interface, whose copper nanowire array has two layers of lateral connections and is used in condensation heat transfer tests to verify its effect of enhancing condensation heat transfer.

[0061] (1) High-purity aluminum foil polishing: High-purity aluminum with a thickness of 0.3 mm and a diameter of 5 cm and a purity greater than 99.999% was electrochemically polished in a polishing solution consisting of perchloric acid and ethanol in a volume ratio of 1:5. The platinum sheet was used as the cathode and the high-purity aluminum sheet as the anode. The polishing voltage was 20 V and the polishing was carried out in a 0°C water bath for 8 min. The current density was approximately 0.175 A·cm -2 , polishing for 8 minutes to obtain a polished aluminum substrate with mirror reflection.

[0062] (2) One-step anodization: The electrolyte composition was 0.015 mol sulfuric acid, 0.3 mol oxalic acid, and 1 L deionized water. A polished aluminum substrate was used as the anode, and a platinum sheet was used as the cathode. Anodization was performed under circulating water cooling at 0°C. The operating voltage settings were: low voltage 110 V, high voltage 190 V, and the voltage operating sequence was: 110 V reaction for 1200 s, 190 V reaction for 2 s, 110 V reaction for 120 s, 190 V reaction for 2 s, and 110 V reaction for 120 s.

[0063] (3) Aluminum stripping treatment: A stripping solution consisting of 0.15 mol copper chloride, 50 ml hydrochloric acid (35-38 wt%), and 300 ml deionized water was placed in the stripping solution in a water bath temperature <10°C until the aluminum was completely removed, yielding an anodized aluminum nanoporous template with a single-side opening.

[0064] (4) Removing the barrier layer and expanding the pores: Under a water bath temperature of 40°C, the barrier layer side of the anodic aluminum oxide nanoporous template with a single-side opening in step (3) was exposed to a 5 wt% phosphoric acid solution for 65 min to remove the barrier layer and expand the pores to obtain an anodic aluminum oxide nanoporous template with a controllable nanoscale side pore distribution. The longitudinal nanochannel spacing of the template is about 200 nm (e.g. Figure 3a As shown), the lateral side hole layer spacing is about 5μm (as shown Figures 3b-3c shown).

[0065] (5) Electroplating of copper nanowires: Potassium pyrophosphate, copper pyrophosphate, triammonium citrate, and deionized water were prepared into an electroplating solution in a mass ratio of 25:6:2:100. The anodized aluminum nanopore template with controllable nanoscale side pore distribution prepared in step (4) was used as an electroplating auxiliary template to construct copper nanowires. The condensation heat transfer test piece was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was -0.8V. The construction included two steps: riveting and growth. During riveting, the anodized aluminum nanopore template and the test piece were clamped by applying external force to promote the riveting of the anodized aluminum nanopore template and the condensation test piece together. The electroplating time was 15 minutes. After riveting, the clamping was canceled and the nanopore template was immersed in the solution for growth. The electroplating time was 30 minutes.

[0066] (6) Removing the template: Use 3 mol / L sodium hydroxide strong alkaline solution to remove the template used in step (5) to obtain a non-prostrate copper nanowire array. (As shown in Figures 3d-3f shown)

[0067] (7) Superhydrophobic modification: The copper nanowire array obtained in step (6) was immersed in a 1% by mass thiol alcohol solution, and reacted in a water bath at 60°C for 1 hour. After the reaction, the alcohol was removed, rinsed, and dried to obtain a superhydrophobic, efficient condensation and heat transfer nano-interface. The hydrophobic effect is shown in FIG. Figure 7b .

[0068] The schematic diagram of the preparation of the non-prostrate copper nanowires in this embodiment is as follows Figure 1a As shown, in this embodiment, the longitudinal nanochannel spacing of the anodic aluminum oxide nanopore template with controllable nanoscale side pore distribution is about 200 nm (as shown in FIG. Figure 3a As shown), there are two lateral side hole layers, and the spacing between each layer is about 5μm (as shown Figures 3b-3c As shown), the center spacing of the nanowires of the super-hydrophobic efficient condensation heat transfer nano-interface was 200nm, and the two layers were connected laterally (as shown Figures 3e-3f As shown) the spacing is about 5μm, and the total height is about 15μm (as shown) Figure 3e As shown), the front view of the non-prostrate copper nanowire array is shown Figure 3d shown.

[0069] Comparative Example 1: Preparation method of aligned copper nanowire array

[0070] (1) High-purity aluminum foil polishing: High-purity aluminum with a thickness of 0.3 mm and a diameter of 5 cm and a purity greater than 99.999% was electrochemically polished in a polishing solution consisting of perchloric acid and ethanol in a volume ratio of 1:5. The platinum sheet was used as the cathode and the high-purity aluminum sheet as the anode. The polishing voltage was 20 V and the polishing was carried out in a 0°C water bath for 8 min. The current density was approximately 0.175 A·cm -2 , polished for 8 minutes to obtain high-purity aluminum with mirror reflection.

[0071] (2) Primary Anodization: A polished aluminum substrate was used as the anode and a platinum sheet was used as the cathode. Anodization was performed under circulating water cooling at 0°C. Operating voltage setting: Low voltage 110V - 1800s. Electrolyte composition: 0.015 mol sulfuric acid, 0.3 mol oxalic acid, 1 L deionized water.

[0072] (3) Removal of Oxide Layer: The high-purity aluminum sheet with an oxide layer obtained in step 2 was placed in a 70°C phosphochromic acid solution and soaked for 3 hours to remove the oxide layer, thereby obtaining a pre-patterned high-purity aluminum substrate with honeycomb-shaped nano-pits. The phosphochromic acid composition includes: 20 g phosphoric acid, 6 g chromium trioxide, and 300 ml deionized water.

[0073] (4) Secondary Anodization: The pre-patterned high-purity aluminum substrate obtained in step 3 was subjected to secondary anodization. The pre-patterned high-purity aluminum substrate was used as the anode and a platinum sheet was used as the cathode. Anodization was carried out under circulating water cooling at 0°C. The operating voltage was 110V for 8 hours. The electrolyte composition was 0.015 mol / L oxalic acid solution.

[0074] (3) Aluminum stripping treatment: A stripping solution consisting of 0.15 mol copper chloride, 50 ml hydrochloric acid (35-38 wt%), and 300 ml deionized water was placed in the stripping solution in a water bath at <10°C until the aluminum was completely removed, yielding an anodized aluminum nanoporous template with a single-side opening.

[0075] (4) Barrier layer and pore expansion: Under a water bath temperature of 40° C., one side of the barrier layer of the anodic aluminum oxide nanoporous template obtained in step (3) was contacted with a 5 wt % phosphoric acid aqueous solution and treated for 65 min to remove the barrier layer and expand the pores to obtain an anodic aluminum oxide nanoporous template having a longitudinal nanochannel spacing of about 200 nm (e.g., Figure 2a-2b shown).

[0076] (5) Electroplating of copper nanowires: Potassium pyrophosphate, copper pyrophosphate, triammonium citrate, and deionized water were prepared into an electroplating solution in a mass ratio of 25:6:2:100. The anodized aluminum oxide nanopore template prepared in step (4) was used as an electroplating auxiliary template to construct copper nanowires. The condensation heat transfer test piece was the cathode, the copper sheet was the anode, and the electroplating voltage was -0.8V. The construction included two steps: riveting and growth. During riveting, the anodized aluminum oxide nanopore template and the test piece were clamped by applying external force to promote the riveting of the anodized aluminum oxide nanopore template and the condensation test piece together. The electroplating time was 15 minutes. After riveting, the clamping was canceled and the growth was carried out in the immersion solution. The electroplating time was 30 minutes.

[0077] (6) Removing the template: Using a 3 mol / L sodium hydroxide strong alkaline solution to remove the template used in step (5), a collimated nanowire array (such as Figure 2c-2d shown).

[0078] (7) Superhydrophobic modification: The aligned copper nanowire array obtained in step (6) was immersed in a 1% mass fraction of thiol alcohol solution in a water bath at 60°C for 1 hour. After the end, the alcohol was removed and rinsed and dried. The superhydrophobic high-efficiency condensation heat transfer nano-interface prepared in Example 1 and the ordinary aligned copper nanowire interface of Comparative Example 1 (the preparation process diagram is shown in FIG. Figure 1a As shown in the figure, a heat transfer interface was prepared and a condensation heat transfer test was performed under 80°C steam conditions to record the condensation mass transfer phenomenon under different subcooling degrees (as shown in the figure). Figures 5e-5f and Figures 5b-5c ) and heat flux (as shown Figure 5g shown); Figure 5d and Figure 5a Schematic diagrams illustrating the difference in heat transfer between a super-hydrophobic, high-efficiency condensation heat transfer nanointerface and a collimated copper nanowire interface. The nanowires in the super-hydrophobic, high-efficiency condensation heat transfer nanointerface are interconnected, preventing water vapor from penetrating. Condensate droplets remain at the tips of the copper wires, resulting in a small size, low thermal resistance, high self-ejection efficiency, and high heat transfer efficiency. In contrast, gaps form between the collimated copper nanowire interfaces, allowing large droplets to remain, resulting in high thermal resistance, low refresh rate, and low heat transfer efficiency.

[0079] Example 2

[0080] This embodiment provides a copper-based super-hydrophobic high-efficiency condensation heat transfer nano-interface, wherein the copper nanowire array has a layer of lateral connection.

[0081] (1) High-purity aluminum foil polishing: High-purity aluminum with a thickness of 0.3 mm and a diameter of 5 cm and a purity greater than 99.999% was electrochemically polished in a polishing solution consisting of perchloric acid and ethanol in a volume ratio of 1:5. The platinum sheet was used as the cathode and the high-purity aluminum sheet as the anode. The polishing voltage was 20 V and the polishing was carried out in a 0°C water bath for 8 min. The current density was approximately 0.175 A·cm-2 , polishing for 8 minutes to obtain a polished aluminum substrate with mirror reflection.

[0082] (2) One-step anodization: The electrolyte composition was 0.015 mol sulfuric acid, 0.3 mol oxalic acid, and 1 L deionized water. A polished aluminum substrate was used as the anode, and a platinum sheet was used as the cathode. Anodization was performed under circulating water cooling at 0°C. The operating voltage settings were: low voltage 110 V, high voltage 190 V, and the voltage operating sequence was: 110 V for 1200 s, 190 V for 2 s, and 110 V for 240 s.

[0083] (3) Aluminum stripping treatment: A stripping solution consisting of 0.15 mol copper chloride, 50 ml hydrochloric acid (35-38 wt%), and 300 ml deionized water was placed in the stripping solution in a water bath temperature <10°C until the aluminum was completely removed, yielding an anodized aluminum nanoporous template with a single-side opening.

[0084] (4) Removing the barrier layer and expanding the pores: Under a water bath temperature of 40°C, the barrier layer side of the anodized aluminum oxide nanopore template with a single-side opening in step (3) was contacted with a 5 wt% phosphoric acid solution and treated for 65 min to remove the barrier layer and expand the pores to obtain an anodized aluminum oxide nanopore template with controllable nanoscale side pore distribution, wherein the longitudinal nanochannel spacing of the template is about 200 nm.

[0085] (5) Electroplating of copper nanowires: Potassium pyrophosphate, copper pyrophosphate, triammonium citrate, and deionized water were prepared into an electroplating solution in a mass ratio of 25:6:2:100. The anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution prepared in step (4) was used as an electroplating auxiliary template to construct copper nanowires. Two copper sheets were used as the anode and cathode, respectively, and the electroplating voltage was -0.8V. The construction included two steps: riveting and growth. During riveting, the anodic aluminum oxide nanoporous template and the cathode copper sheet were clamped by applying external force to promote the riveting of the anodic aluminum oxide nanoporous template and the cathode copper sheet together. The electroplating time was 15 minutes. After riveting, the clamping was removed and the nanowires were grown in the immersion solution. The electroplating time was 30 minutes.

[0086] (6) Removing the template: using a 3 mol / L sodium hydroxide strong alkaline solution to remove the template used in step (5) to obtain a non-prostrating copper nanowire array.

[0087] (7) Superhydrophobic modification: The non-falling copper nanowire array obtained in step (6) was immersed in a 1% by mass thiol alcohol solution, and reacted in a water bath at 60°C for 1 hour. After the reaction, the alcohol was removed, rinsed, and dried to obtain a superhydrophobic, efficient condensation and heat transfer nano-interface with one layer of connection.

[0088] In this embodiment, a super-hydrophobic and efficient condensation and heat transfer nano-interface is prepared with a nanowire array having a center spacing of 200 nm and a layer of lateral connection sites (such as Figures 4a-4c As shown), the total height is about 15μm (as shown Figure 4b As shown), the front view of the non-prostrate metal nanowire array is as shown Figure 4a shown.

[0089] Example 3

[0090] This embodiment provides a copper-based super-hydrophobic high-efficiency condensation heat transfer nano-interface, wherein the copper nanowire array has three layers of lateral connections.

[0091] (1) High-purity aluminum foil polishing: High-purity aluminum with a thickness of 0.3 mm and a diameter of 5 cm and a purity greater than 99.999% was electrochemically polished in a polishing solution consisting of perchloric acid and ethanol in a volume ratio of 1:5. The platinum sheet was used as the cathode and the high-purity aluminum sheet as the anode. The polishing voltage was 20 V and the polishing was carried out in a 0°C water bath for 8 min. The current density was approximately 0.175 A·cm -2 , polishing for 8 minutes to obtain a polished aluminum substrate with mirror reflection.

[0092] (2) One-step anodization: The electrolyte composition was 0.015 mol sulfuric acid, 0.3 mol oxalic acid, and 1 L deionized water. A polished aluminum substrate was used as the anode, and a platinum sheet was used as the cathode. Anodization was performed under circulating water cooling at 0°C. The operating voltage settings were: low voltage 110 V, high voltage 190 V, and the voltage operating sequence was: 110 V reaction for 1200 s, 190 V reaction for 2 s, 110 V reaction for 90 s, 190 V reaction for 2 s, 110 V reaction for 90 s, 190 V reaction for 2 s, 110 V reaction for 90 s, 190 V reaction for 2 s, and 110 V reaction for 90 s.

[0093] (3) Aluminum stripping treatment: A stripping solution consisting of 0.15 mol copper chloride, 50 ml hydrochloric acid (35-38 wt%), and 300 ml deionized water was placed in the stripping solution in a water bath temperature <10°C until the aluminum was completely removed, yielding an anodized aluminum nanoporous template with a single-side opening.

[0094] (4) Removing the barrier layer and expanding the pores: Under a water bath temperature of 40°C, the barrier layer side of the anodized aluminum oxide nanopore template with a single-side opening in step (3) was contacted with a 5 wt% phosphoric acid solution and treated for 65 min to remove the barrier layer and expand the pores to obtain an anodized aluminum oxide nanopore template with controllable nanoscale side pore distribution, wherein the longitudinal nanochannel spacing of the template is about 200 nm.

[0095] (5) Electroplating of copper nanowires: Potassium pyrophosphate, copper pyrophosphate, triammonium citrate, and deionized water were prepared into an electroplating solution in a mass ratio of 25:6:2:100. The anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution prepared in step (4) was used as an electroplating auxiliary template to construct copper nanowires. Two copper sheets were used as the anode and cathode, respectively, and the electroplating voltage was -0.8V. The construction included two steps: riveting and growth. During riveting, the anodic aluminum oxide nanoporous template and the cathode copper sheet were clamped by applying external force to promote the riveting of the anodic aluminum oxide nanoporous template and the cathode copper sheet together. The electroplating time was 15 minutes. After riveting, the clamping was removed and the nanowires were grown in the immersion solution. The electroplating time was 30 minutes.

[0096] (6) Removing the template: using a 3 mol / L sodium hydroxide strong alkaline solution to remove the template used in step (5) to obtain a non-prostrating copper nanowire array.

[0097] (7) Superhydrophobic modification: The non-falling copper nanowire array obtained in step (6) was immersed in a 1% by mass thiol alcohol solution, and reacted in a water bath at 60°C for 1 hour. After the reaction, the alcohol was removed, rinsed, and dried to obtain a superhydrophobic, efficient condensation and heat transfer nano-interface with three layers of connection.

[0098] In this embodiment, a super-hydrophobic and efficient condensation and heat transfer nano-interface is prepared with a center-to-center spacing of 200 nm and three layers of lateral connection sites (such as Figures 4e-4f As shown), the total height is about 15μm (as shown Figure 4e As shown), the front view of the non-prostrate copper nanowire array is shown Figure 4d shown.

[0099] Example 4

[0100] This embodiment provides a silver-based super-hydrophobic high-efficiency condensation heat transfer nanowire interface, wherein the silver nanowire array has three layers of lateral connections.

[0101] (1) High-purity aluminum foil polishing: High-purity aluminum with a thickness of 0.3 mm and a diameter of 5 cm and a purity greater than 99.999% was electrochemically polished in a polishing solution consisting of perchloric acid and ethanol in a volume ratio of 1:5. The platinum sheet was used as the cathode and the high-purity aluminum sheet as the anode. The polishing voltage was 20 V and the polishing was carried out in a 0°C water bath for 8 min. The current density was approximately 0.175 A·cm -2 , polishing for 8 minutes to obtain a polished aluminum substrate with mirror reflection.

[0102] (2) One-step anodization: The electrolyte composition was 0.015 mol sulfuric acid, 0.3 mol oxalic acid, and 1 L deionized water. A polished aluminum substrate was used as the anode, and a platinum sheet was used as the cathode. Anodization was performed under circulating water cooling at 0°C. The operating voltage settings were: low voltage 110 V, high voltage 190 V, and the voltage operating sequence was: 110 V reaction for 1200 s, 190 V reaction for 2 s, 110 V reaction for 90 s, 190 V reaction for 2 s, 110 V reaction for 90 s, 190 V reaction for 2 s, 110 V reaction for 90 s, 190 V reaction for 2 s, and 110 V reaction for 90 s.

[0103] (3) Aluminum stripping treatment: A stripping solution consisting of 0.15 mol copper chloride, 50 ml hydrochloric acid (35-38 wt%), and 300 ml deionized water was placed in the stripping solution in a water bath temperature <10°C until the aluminum was completely removed, yielding an anodized aluminum nanoporous template with a single-side opening.

[0104] (4) Removing the barrier layer and expanding the pores: Under a water bath temperature of 40°C, the barrier layer side of the anodized aluminum oxide nanopore template with a single-side opening in step (3) was contacted with a 5 wt% phosphoric acid solution and treated for 65 min to remove the barrier layer and expand the pores to obtain an anodized aluminum oxide nanopore template with controllable nanoscale side pore distribution, wherein the longitudinal nanochannel spacing of the template is about 200 nm.

[0105] (5) Electroplating of silver nanowires: The silver nanowire array was constructed using the anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution prepared in step (4). A 50 nm thick layer of silver was first deposited on one side of the aluminum oxide nanoporous membrane using magnetron sputtering. This membrane was then used as the cathode and graphite as the anode for electroplating. The plating solution consisted of 0.05 mol silver nitrate, 0.1 mol boric acid, and 1 L deionized water. The plating voltage was -1.2 V and the plating time was 5 min.

[0106] (6) Removing the template: using a 3 mol / L sodium hydroxide strong alkaline solution to remove the template used in step (5) to obtain a non-prostrate silver nanowire array.

[0107] (7) Superhydrophobic modification: The non-falling silver nanowire array obtained in step (6) was immersed in a 1% by mass thiol alcohol solution, and reacted in a water bath at 60°C for 1 hour. After the reaction, the silver nanowire array was removed, rinsed with alcohol, and blown dry to obtain a silver-based superhydrophobic, efficient condensation and heat transfer nano-interface with three layers of connection.

[0108] Example 5

[0109] This embodiment provides an anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution ( Figure 6a ), the longitudinal nanochannel center spacing is about 300nm ( Figure 6c ), 2 lateral side hole layers, with a spacing of about 5μm ( Figure 6b ).

[0110] (1) High-purity aluminum foil polishing: High-purity aluminum with a thickness of 0.3 mm and a diameter of 5 cm and a purity greater than 99.999% was electrochemically polished in a polishing solution consisting of perchloric acid and ethanol in a volume ratio of 1:5. The platinum sheet was used as the cathode and the high-purity aluminum sheet as the anode. The polishing voltage was 20 V and the polishing was carried out in a 0°C water bath for 8 min. The current density was approximately 0.175 A·cm -2 , polishing for 8 minutes to obtain a polished aluminum substrate with mirror reflection.

[0111] (2) One-step anodization: The electrolyte composition was 60 μL sulfuric acid, 0.3 mol oxalic acid, and 1 L deionized water. A polished aluminum substrate was used as the anode, and a platinum sheet was used as the cathode. Anodization was performed under circulating water cooling at 0°C. The operating voltage settings were: low voltage 110 V, high voltage 190 V, and the voltage operating sequence was: 140 V for 1200 s, 240 V for 2 s, 140 V for 120 s, 240 V for 2 s, and 140 V for 120 s.

[0112] (3) Aluminum stripping treatment: A stripping solution consisting of 0.15 mol copper chloride, 50 ml hydrochloric acid (35-38 wt%), and 300 ml deionized water was placed in the stripping solution in a water bath temperature <10°C until the aluminum was completely removed, yielding an anodized aluminum nanoporous template with a single-side opening.

[0113] (4) Removing the barrier layer and expanding the pores: Under a water bath temperature of 40° C., the barrier layer side of the anodized aluminum oxide nanopore template with a single-side opening in step (3) was contacted with a 5 wt % phosphoric acid solution and treated for 70 min to remove the barrier layer and expand the pores to obtain an anodized aluminum oxide nanopore template with controllable nanoscale side pore distribution.

[0114] Example 6

[0115] This embodiment provides an anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution ( Figure 6d ), the longitudinal nanochannel center spacing is about 100nm ( Figure 6f ), 2 lateral side hole layers, with a spacing of about 2μm ( Figure 6e ).

[0116] (1) High-purity aluminum foil polishing: High-purity aluminum with a thickness of 0.3 mm and a diameter of 5 cm and a purity greater than 99.999% was electrochemically polished in a polishing solution consisting of perchloric acid and ethanol in a volume ratio of 1:5. The platinum sheet was used as the cathode and the high-purity aluminum sheet as the anode. The polishing voltage was 20 V and the polishing was carried out in a 0°C water bath for 8 min. The current density was approximately 0.175 A·cm -2 , polishing for 8 minutes to obtain a polished aluminum substrate with mirror reflection.

[0117] (2) One-step anodization: The electrolyte composition was 0.1 mol sulfuric acid and 1 L deionized water. A polished aluminum substrate was used as the anode and a platinum sheet was used as the cathode. Anodization was performed under circulating water cooling at 0°C. The operating voltage settings were: low voltage 110 V, high voltage 190 V, and the voltage operating sequence was: 40 V reaction for 1200 s, 55 V reaction for 2 s, 40 V reaction for 60 s, 55 V reaction for 2 s, and 40 V reaction for 120 s.

[0118] (3) Aluminum stripping treatment: A stripping solution consisting of 0.15 mol copper chloride, 50 ml hydrochloric acid (35-38 wt%), and 300 ml deionized water was placed in the stripping solution in a water bath temperature <10°C until the aluminum was completely removed, yielding an anodized aluminum nanoporous template with a single-side opening.

[0119] (4) Removing the barrier layer and expanding the pores: Under a water bath temperature of 40° C., the barrier layer side of the anodized aluminum oxide nanopore template with a single-side opening in step (3) was contacted with a 5 wt % phosphoric acid solution and treated for 45 min to remove the barrier layer and expand the pores to obtain an anodized aluminum oxide nanopore template with controllable nanoscale side pore distribution.

[0120] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments using other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0121] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical variations made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the scope of protection of the present invention.

Claims

1. Super-hydrophobic high-efficiency condensation heat transfer nano-interface, characterized by: The super-hydrophobic, high-efficiency condensation and heat transfer nano-interface is composed of a metal nanowire array. The metal nanowires in the metal nanowire array are connected laterally, and there are no microcavity defects inside the metal nanowire array caused by the collapse or agglomeration of the metal nanowires. The metal nanowire array is prepared by using an anodic aluminum oxide nanopore template with controllable nanoscale side pore distribution through a metal nanoelectrodeposition process. The material of the metal nanowires includes any one of copper, nickel, gold, and silver, or a combination of two or more. The metal nanowire array is given low-viscosity super-hydrophobic properties through low-surface-energy chemical modification. Among them, the anodized aluminum nanopore template with controllable nanoscale side pore distribution is achieved by introducing one or more instantaneous high-voltage anodizing by a programmable power supply during the preparation process of the anodized aluminum nanopore template; wherein the center spacing of the columnar nanopore channels of the anodized aluminum nanopore template is determined by the electrolyte and the matching anodizing voltage, and the process conditions in the preparation process of the anodized aluminum nanopore template include: the electrolyte includes one or more combinations of sulfuric acid, oxalic acid, phosphoric acid, oxalic acid, and malonic acid; the depth of the columnar nanopore channels of the anodized aluminum nanopore template is determined by the anodizing time as needed; the pore size of the columnar nanopore channels of the anodized aluminum nanopore template is determined by the pore expansion time as needed, and the size of the nanoscale side pores of the anodized aluminum nanopore template is controlled by the voltage value and reaction time of the introduced instantaneous high voltage, the ratio of the instantaneous high voltage to the anodizing intrinsic voltage is 1.3~2, and the reaction time of the instantaneous high voltage is 1~5s.

2. The super-hydrophobic high-efficiency condensation heat transfer nano-interface according to claim 1, characterized in that: The interior of the anodized aluminum oxide nanopore template includes a plurality of columnar nanopore channels, which are distributed vertically and parallel, with a center spacing of 60nm~500nm and a length of 500nm~60μm; the interior of the nanopore channel is provided with nanoscale side holes with controllable orientation and number, and the nanoscale side holes are distributed in layers, and the number of layers of the layered distribution includes one layer or more than two layers.

3. A method for preparing an anodic aluminum oxide nanoporous template with controllable nanoscale side pore distribution, characterized in that include: The anodized aluminum nanopore template is realized by introducing one or more instantaneous high-voltage anodizing by a programmable power supply during the preparation process of the anodized aluminum nanopore template; wherein, the center spacing of the columnar nanopore channels of the anodized aluminum nanopore template is determined by the electrolyte and the matching anodizing voltage, and the process conditions in the preparation process of the anodized aluminum nanopore template include: the electrolyte includes one or a combination of two or more of sulfuric acid, oxalic acid, phosphoric acid, oxalic acid, and malonic acid; the depth of the columnar nanopore channels of the anodized aluminum nanopore template is determined by the anodizing time as needed; the pore size of the columnar nanopore channels of the anodized aluminum nanopore template is determined by the pore expansion time as needed, the size of the nanoscale side pores of the anodized aluminum nanopore template is controlled by the voltage value and reaction time of the introduced instantaneous high voltage, the ratio of the instantaneous high voltage to the anodizing intrinsic voltage is 1.3~2, and the reaction time of the instantaneous high voltage is 1~5s; the number of layers formed by the nanoscale side pores is determined by the number of instantaneous high-voltage anodizing times.

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