A super-hydrophobic modified metal substrate, coating and preparation method and application thereof

Abstract

The application relates to the technical field of super-hydrophobic surface material preparation, in particular to a super-hydrophobic modified metal base material, a coating and a preparation method and application thereof. Nano-SiO2 particles, epoxy resin, PVDF and an organic solvent are mixed and stirred until the nano-SiO2 particles are completely dispersed, an emulsified suspension is obtained, fluoralkylsilane is added in batches, a curing agent is added after ultrasonic treatment, and secondary ultrasonic treatment is carried out, so that an ER-SiO2 / PVDF / SFT coating is obtained. After the metal base material is subjected to surface pretreatment and surface etching, the super-hydrophobic modified coating is dip-coated, and a super-hydrophobic modified metal base material is obtained. Compared with the prior art, the application can be applied to industrial wastewater heat exchange, can effectively prevent dirt in the evaporation heat exchange process of high-salt wastewater, and still maintains good hydrophobic performance under high-temperature conditions.

Description

Technical Field

[0001] This invention relates to the field of superhydrophobic surface material preparation technology, and in particular to a superhydrophobic modified metal substrate, coating, preparation method and application thereof. Background Technology

[0002] With the rapid development of my country's industry, the resulting large amount of high-salinity wastewater has become an urgent environmental problem. High-salinity wastewater refers to wastewater with a total dissolved solids (TDS) mass fraction greater than 3.5%. In recent years, with the deepening promotion of the "zero discharge" concept, thermal evaporation technology has been widely used in the desalination of industrial high-salinity wastewater. As a core and key piece of equipment, the anhydrous heat exchanger plays a crucial role in the evaporation and concentration process. 2+ Mg 2+ Ions readily react with CO3 2- Scale buildup on equipment surfaces, combined with the adhesion of small amounts of organic matter in wastewater to metal pipe surfaces, increases thermal resistance and significantly reduces the operating efficiency of treatment and heat exchange equipment. According to feedback from actual engineering projects, over 90% of thermal evaporation processes fail due to system collapse caused by heat exchanger scaling.

[0003] Scale buildup on the surface of heat exchange pipes affects the heat transfer coefficient and reduces heat transfer efficiency through fouling thermal resistance. It can also clog flow channels and increase resistance to medium flow. Therefore, advanced anti-fouling technology for heat exchangers plays a crucial role in implementing the "zero-emission" concept. The application of coating materials can effectively reduce fouling on metal heat exchange surfaces without damaging them, thus helping to maintain the equipment's heat exchange performance over the long term.

[0004] Traditional polymer coatings are easily wetted under high-salt conditions. Once salt water penetrates and diffuses, the coating loses its original protective ability and may even accelerate the damage to metal materials. Although traditional superhydrophobic coatings prepared with nanoparticles (nano SiO2, nano TiO2, etc.) as the main filler can ensure excellent superhydrophobicity, the exposed nanoparticles on their surface are easily eroded and damaged, making them difficult to adapt to complex high-salt wastewater environments.

[0005] Patent publication number CN116948469A discloses a method for preparing a superhydrophobic, scale-resistant, and corrosion-resistant composite coating on a metal substrate. However, this coating uses TiO2 whiskers as filler to adsorb PAO into a superhydrophobic PVDF coating, resulting in a superhydrophobic, scale-resistant, and corrosion-resistant composite coating PAO / PVDF / TiO2. This superhydrophobic, scale-resistant, and corrosion-resistant composite coating is applied to the surface of the metal substrate via a spraying method. Furthermore, the preparation process of the superhydrophobic substrate using a spraying method is difficult to implement in the internal pipes of heat exchangers, and thus cannot meet the practical needs of engineering applications.

[0006] Therefore, there is an urgent need to develop a simple superhydrophobic coating that can be adapted to operation inside heat exchanger tubes and its preparation method. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art by providing a superhydrophobic modified metal substrate, coating, preparation method and application thereof, which can be applied to industrial wastewater heat exchange, effectively preventing fouling during the evaporation heat exchange process of high-salt wastewater, and maintaining good hydrophobic properties under high temperature conditions.

[0008] Superhydrophobic metal substrates prepared by modification with superhydrophobic coatings exhibit excellent hydrophobic and glycol-repellent properties. Droplets on their surface roll easily into spherical shapes and remain unwetted even in high-salt environments. This effectively inhibits scale growth on metal heat exchanger tubes, extending the service life of metal heat exchangers. Superhydrophobic coatings hold promise as a novel scale inhibition technology for addressing scaling issues during heat exchange and evaporation processes in high-salt wastewater.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] One of the technical solutions of the present invention is to provide a method for preparing a superhydrophobic modified coating for a metal substrate. Nano-silica (SiO2) particles, epoxy resin, polyvinylidene fluoride (PVDF), and organic solvent are mixed and stirred until the nano-SiO2 particles are completely dispersed to obtain an emulsion suspension. Fluoroalkylsilane is added in portions, and after sonication, a curing agent is added and sonicated a second time to obtain an ER-SiO2 / PVDF / SFT coating, i.e., a superhydrophobic modified coating.

[0011] Furthermore, the superhydrophobic modified coating comprises 0.7% to 1.2% by mass of nano-SiO2 particles, 0.7% to 1.2% by mass of PVDF, 2.0% to 2.5% by mass of epoxy resin, 0.5% to 1.0% by mass of curing agent, 1.0% to 3.0% by mass of fluoroalkylsilane, and 85% to 90% by mass of organic solvent.

[0012] Furthermore, the epoxy resin includes: bisphenol A type epoxy resin, bisphenol F type epoxy resin, etc.;

[0013] The curing agents include phenolic amine epoxy curing agents and polyether amine epoxy resin curing agents;

[0014] The organic solvents mentioned include methanol, ethanol, isopropanol, and acetone;

[0015] The fluoroalkylsilanes include 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0016] Furthermore, the epoxy resin exists in the form of an epoxy resin organic solution with a mass concentration of 1.2–2 g / L, and the organic solvent includes methanol, ethanol, isopropanol, and acetone.

[0017] Furthermore, the curing agent exists in the form of an organic curing agent solution with a mass concentration of 0.3–0.5 g / L, and the organic solvent includes methanol, ethanol, isopropanol, and acetone.

[0018] Furthermore, the ultrasound duration is 0.5–1 hour.

[0019] Furthermore, the temperature of the secondary ultrasound is 0–20°C, and the time is >0.5 h.

[0020] The second technical solution of the present invention is to provide a superhydrophobic modified coating for a metal substrate, which is obtained by the methods described above.

[0021] The third technical solution of the present invention is to provide an application of a superhydrophobic modified coating for metal substrates in the field of industrial high-salt wastewater desalination.

[0022] Furthermore, when applied to the surface of heat exchange pipes in thermal evaporation processes, it can effectively reduce the adhesion of dirt to the metal heat exchange surface without damaging it, thus helping to maintain the heat exchange performance of the equipment over a long period of time.

[0023] The fourth technical solution of the present invention is to provide a superhydrophobic modified metal substrate, comprising a metal substrate, wherein the superhydrophobic modified coating is impregnated on the surface of the metal substrate.

[0024] Furthermore, the static water contact angle of the superhydrophobic modified metal substrate is 150° to 180°, preferably 152.5° to 154.8°, and the static ethylene glycol contact angle is 145° to 180°, preferably 147° to 150.6°.

[0025] The fifth technical solution of the present invention is to provide a method for preparing a superhydrophobic modified metal substrate, wherein the metal substrate is immersed in the superhydrophobic modified coating, then removed and dried at room temperature. This process is repeated 3 to 5 times, and then the substrate is cured at 120 to 180°C to obtain the superhydrophobic modified metal substrate.

[0026] Furthermore, the soaking time is 20–40 minutes.

[0027] Furthermore, the curing reaction takes 0.5 to 1 hour.

[0028] Furthermore, after surface pretreatment and surface etching, the metal substrate is dip-coated with the superhydrophobic modified coating to obtain a superhydrophobic modified metal substrate.

[0029] The surface pretreatment process is as follows: the surface of the metal substrate is polished to remove the surface oxide film, the surface dirt, including surface oil and metal powder, is cleaned with anhydrous ethanol, and then soaked in hydrochloric acid solution to remove the oxide film and taken out to complete the surface pretreatment.

[0030] The surface etching process is as follows: the surface-pretreated metal substrate is completely immersed in the ZnO thin film growth solution at 90-99°C for 1-2 hours for etching reaction. After the reaction is complete, it is taken out and dried at 50-60°C to complete the surface etching.

[0031] Furthermore, during the surface pretreatment process, the surface of the metal substrate is repeatedly sanded with sandpaper for 10-20 minutes, immersed in anhydrous ethanol for 5-10 minutes, rinsed with deionized water, dried at 50-60°C, then immersed in hydrochloric acid solution to remove the oxide film, removed, repeatedly rinsed with deionized water, and dried with nitrogen to complete the surface pretreatment; the volume fraction of the hydrochloric acid solution is 0.5%-3%.

[0032] Furthermore, the ZnO thin film growth solution is hexamethylenetetramine (C6H4O3). 12 A mixed solution of N4 standard solution and zinc nitrate (Zn(NO3)2) solution;

[0033] The volume ratio of the hexamethylenetetramine solution to the zinc nitrate solution is 1:(0.1-10);

[0034] The concentration of the hexamethylenetetramine solution is 0.01–0.1 mol / L;

[0035] The concentration of the zinc nitrate standard solution is 0.01–0.1 mol / L.

[0036] The sixth technical solution of the present invention is to provide an application of a superhydrophobic modified metal substrate in the field of industrial high-salt wastewater desalination.

[0037] Furthermore, as the surface of heat exchange pipes in the thermal evaporation process, it can effectively reduce the adhesion of dirt on the metal heat exchange surface, without damaging the heat exchange surface, and helps to maintain the heat exchange performance of the equipment for a long time.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] (1) In this invention, the chemical composition and nanostructure of the metal surface are adjusted and modified by doping with nanoparticles, resulting in excellent superhydrophobicity of the metal substrate surface. This superhydrophobic effect is similar to the "lotus effect". Nano-SiO2 creates micro / nanopapillary structures on the coating surface, forming a Cassie-like roughness. Fluorosilane and polyvinylidene fluoride co-form a protective film to prevent the micro / nanopapillary structures from being damaged by salt solutions. This excellent and durable superhydrophobic coating allows the metal substrate to maintain good salt resistance and scale inhibition performance in high-salt solutions.

[0040] (2) The present invention employs a two-step method of etching and immersion coating, which can realize the preparation of superhydrophobic coatings on various metal surfaces such as flat plates, inside pipes, and outside pipes, and has a wide range of applications.

[0041] (3) In this invention, a high-salt solution with a total dissolved solids content of ≥3% is used for scaling tests, which is closer to the industrial wastewater environment and can more intuitively reflect the salt resistance and scale inhibition effect of the superhydrophobic scale inhibitory coating developed in this invention in the industrial wastewater environment. Experiments show that the superhydrophobic coating prepared in this invention can extend the cleaning cycle of metal substrates by more than double and effectively improve its lifespan in high-salt wastewater. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the process preparation of the superhydrophobic modified metal substrate shown in Examples 1 and 2;

[0043] Figure 2 The diagram shows the static water contact angle and ethylene glycol contact angle of each substrate surface.

[0044] Figure 3 Here are scanning electron microscope (SEM) images of the surfaces of each substrate;

[0045] Figure 4 These are atomic force microscopy scans of the surfaces of each substrate.

[0046] Figure 5 The graph shows the changes in scale increment and scale inhibition rate of each substrate after 168 hours of scaling test in a scaling solution containing 3% ethylene glycol.

[0047] Figure 6 Scanning electron microscope images of each substrate after 168 hours of scaling test in a scaling solution containing 3% ethylene glycol.

[0048] Figure 7 The graph shows the changes in scale increment and scale inhibition rate of each substrate after 168 hours of scaling test in scaling solution containing 4% sodium sulfate.

[0049] Figure 8 Scanning electron microscope (SEM) images of each substrate after 168 hours of scaling test in a scaling solution containing 4% sodium sulfate. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. All other embodiments obtained by those skilled in the art based on the given embodiments without creative effort are within the scope of protection of this application.

[0051] Unless otherwise specified, the reagents, methods, instruments and equipment used in this invention are conventional reagents, methods, instruments and equipment in the art.

[0052] In the following embodiments, the metal substrate is selected as pure aluminum sheet 1060, with a size of 20×20mm, manufactured by Guangzhou Xinhong New Material Technology Co., Ltd.; the epoxy resin is bisphenol A type epoxy resin, CAS number 1675-54-3, manufactured by Qingdao Yousuo Chemical Technology Co., Ltd.; the curing agent is phenolic amine epoxy curing agent, model T-31, manufactured by Qingdao Yousuo Chemical Technology Co., Ltd.; the PVDF has CAS number 24937-79-9, average Mw 1,000,000, suspension polymerization, and is PVDF. 5130, purchased from Shanghai Adamas Reagent Co., Ltd.; CAS number 83048-65-1, 97%+, of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, purchased from Shanghai Adamas Reagent Co., Ltd.; CAS number 101947-16-4, 97%+, of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, purchased from Shanghai Adamas Reagent Co., Ltd.

[0053] A method for preparing a superhydrophobic modified coating for a metal substrate involves mixing and stirring nano-SiO2 particles, epoxy resin, PVDF, and an organic solvent until the nano-SiO2 particles are completely dispersed to obtain an emulsion suspension. Fluoroalkylsilane is added in portions, followed by sonication. After sonication, a curing agent is added, and the mixture is sonicated a second time to obtain an ER-SiO2 / PVDF / SFT coating, i.e., a superhydrophobic modified coating.

[0054] As one specific implementation method, the superhydrophobic modified coating includes 0.7% to 1.2% by mass nano-SiO2 particles, 0.7% to 1.2% by mass polyvinylidene fluoride particles, 2.0% to 2.5% by mass epoxy resin, 0.5% to 1.0% by mass curing agent, 1.0% to 3.0% by mass fluoroalkyl silane, and 85% to 90% by mass organic solvent.

[0055] As one specific embodiment, the epoxy resin includes bisphenol A type epoxy resin and bisphenol F type epoxy resin;

[0056] The curing agents include phenolic amine epoxy curing agents and polyether amine epoxy resin curing agents;

[0057] The organic solvents mentioned include methanol, ethanol, isopropanol, and acetone;

[0058] The fluoroalkylsilanes include 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0059] As one specific implementation method, the epoxy resin exists in the form of an epoxy resin organic solution with a mass concentration of 1.2 to 2 g / L, and the organic solvent includes methanol, ethanol, isopropanol, and acetone.

[0060] As one specific implementation method, the curing agent exists in the form of an organic curing agent solution with a mass concentration of 0.3 to 0.5 g / L, and the organic solvent includes methanol, ethanol, isopropanol, and acetone.

[0061] As one specific implementation method, the ultrasound duration is 0.5 to 1 hour.

[0062] As one specific implementation method, the temperature of the secondary ultrasound is 0-20℃ and the time is >0.5h.

[0063] A method for preparing a superhydrophobic modified coating for a metal substrate, wherein the coating is prepared by the above-mentioned method.

[0064] Application of a superhydrophobic modified coating for metal substrates in the desalination of industrial high-salt wastewater.

[0065] As one specific implementation method, coating the surface of heat exchange pipes in the thermal evaporation process can effectively reduce the adhesion of dirt on the metal heat exchange surface, without damaging the heat exchange surface, and help maintain the heat exchange performance of the equipment for a long time.

[0066] A superhydrophobic modified metal substrate includes a metal substrate on which the superhydrophobic modified coating is impregnated and coated.

[0067] As one specific embodiment, the static water contact angle of the superhydrophobic modified metal substrate is 150° to 180°, preferably 152.5° to 154.8°, and the static ethylene glycol contact angle is 145° to 180°, preferably 147° to 150.6°.

[0068] A method for preparing a superhydrophobic modified metal substrate involves immersing the metal substrate in the superhydrophobic modified coating, removing it, air-drying it at room temperature, repeating this process 3 to 5 times, and then subjecting it to a curing reaction at 120 to 180°C to obtain the superhydrophobic modified metal substrate.

[0069] As one specific implementation method, the soaking time is 20 to 40 minutes.

[0070] As one specific implementation method, the curing reaction time is 0.5 to 1 hour.

[0071] As one specific implementation method, the metal substrate is pretreated and etched on the surface before being dip-coated with the superhydrophobic modified coating.

[0072] The surface pretreatment process is as follows: the surface of the metal substrate is polished to remove the surface oxide film, the surface dirt, including surface oil and metal powder, is cleaned with anhydrous ethanol, and then soaked in hydrochloric acid solution to remove the oxide film and taken out to complete the surface pretreatment.

[0073] The surface etching process is as follows: the surface-pretreated metal substrate is completely immersed in the ZnO thin film growth solution at 90-99°C for 1-2 hours for etching reaction. After the reaction is complete, it is taken out and dried at 50-60°C to complete the surface etching.

[0074] As one specific implementation method, during the surface pretreatment process, the surface of the metal substrate is repeatedly sanded with sandpaper for 10-20 minutes, immersed in anhydrous ethanol for 5-10 minutes, rinsed with deionized water, dried at 50-60°C, then immersed in hydrochloric acid solution to remove the oxide film, and then taken out, repeatedly rinsed with deionized water, and dried with nitrogen to complete the surface pretreatment; the volume fraction of the hydrochloric acid solution is 0.5%-3%.

[0075] As one specific implementation method, the ZnO thin film growth solution is hexamethylenetetramine (C6H4O2). 12 A mixed solution of N4 standard solution and zinc nitrate (Zn(NO3)2) solution;

[0076] The volume ratio of the hexamethylenetetramine solution to the zinc nitrate solution is 1:(0.1-10);

[0077] The concentration of the hexamethylenetetramine solution is 0.01–0.1 mol / L;

[0078] The concentration of the zinc nitrate standard solution is 0.01–0.1 mol / L.

[0079] Application of a superhydrophobic modified metal substrate in the desalination of industrial high-salt wastewater.

[0080] As one specific implementation method, as the surface of heat exchange pipes in the thermal evaporation process, it can effectively reduce the adhesion of dirt on the metal heat exchange surface, without damaging the heat exchange surface, and help maintain the heat exchange performance of the equipment for a long time.

[0081] Example 1

[0082] A method for preparing a superhydrophobic modified coating for a metal substrate, the preparation process is as follows, see below. Figure 1 :

[0083] (1) Surface pretreatment of metal substrate

[0084] A 20×20mm pure aluminum sheet (used as the substrate for preparing the hydrophobic coating) was repeatedly sanded for 20 minutes. It was then immersed in anhydrous ethanol and sonicated for 10 minutes, followed by rinsing with deionized water and drying in an oven at 50–60°C. Next, the aluminum sheet was immersed in 1% hydrochloric acid (by volume) until small bubbles appeared on the surface. It was then removed, repeatedly rinsed with deionized water, and dried with nitrogen gas for later use.

[0085] (2) Etching of metal substrate surface

[0086] Take equal amounts of C6H 12 N4 standard solution and Zn(NO3)2 standard solution, C6H 12 The concentrations of both the N4 standard solution and the Zn(NO3)2 standard solution are 0.05 mol / L. Use a dropper to slowly add C6H... 12 N4 solution is added dropwise to Zn(NO3)2 solution, while stirring to ensure uniform mixing. A pre-treated pure aluminum sheet is placed vertically in the prepared etching solution, sealed, and then placed in a 95°C water bath for 2 hours. When the surface turns silvery-white, the etched pure aluminum is removed, rinsed repeatedly with deionized water, and dried in a 60°C oven.

[0087] (3) Preparation of epoxy resin alcohol solution and curing agent alcohol solution

[0088] Epoxy resin and curing agent were dissolved separately in a certain amount of ethanol solution at a mass ratio of 4:1, and ultrasonically dispersed for 1 hour to obtain a 2 g / L epoxy resin ethanol solution and a 0.5 g / L curing agent ethanol solution. The mass fraction of epoxy resin was 2.3%, and the mass fraction of curing agent was 0.6%. Then, the mixture was continuously stirred with a magnetic stirrer until a uniform suspension was formed.

[0089] (4) Preparation of superhydrophobic modified coating

[0090] 0.3g of nano-SiO2 particles and 0.3g of polyvinylidene fluoride (PVDF) particles were taken at a mass ratio of 1:1, with both nano-SiO2 particles and PVDF having a mass fraction of 0.7%. 10mL of epoxy resin ethanol solution was added, followed by 40mL of ethanol solution. The mixture was magnetically stirred for 1 hour until the nano-SiO2 particles were completely dispersed. Then, 3.0% (by mass) of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (SFT) was added in two batches and sonicated for 1 hour each time. Finally, 10mL of curing agent ethanol solution was added and the mixture was sonicated at 15°C to obtain the ER-SiO2 / PVDF / SFT coating solution, i.e., the superhydrophobic modified coating.

[0091] (5) Preparation of superhydrophobic modified metal substrates

[0092] After surface etching, the pure aluminum sheet is immersed in the ER-SiO2 / PVDF / SFT coating solution for 30 minutes, then removed and air-dried at room temperature. The above steps are repeated 5 times. Then, the pure aluminum sheet is placed in a 150℃ oven for curing reaction for 1 hour to obtain the metal substrate with modified coating, which is denoted as ER-SiO2 / PVDF / SFT-aluminum sheet.

[0093] Example 2

[0094] A method for preparing a superhydrophobic modified coating for a metal substrate, the preparation process is as follows, see below. Figure 1 :

[0095] (1) Surface pretreatment of metal substrate

[0096] A 20×20mm pure aluminum sheet (used as the substrate for preparing the hydrophobic coating) was repeatedly sanded for 20 minutes. It was then immersed in anhydrous ethanol and sonicated for 10 minutes, followed by rinsing with deionized water and drying in an oven at 50–60°C. Next, the aluminum sheet was immersed in 1% hydrochloric acid (by volume) until small bubbles appeared on the surface. It was then removed, repeatedly rinsed with deionized water, and dried with nitrogen gas for later use.

[0097] (2) Etching of metal substrate surface

[0098] Take equal amounts of C6H 12 N4 standard solution and Zn(NO3)2 standard solution, C6H 12 The concentrations of both the N4 standard solution and the Zn(NO3)2 standard solution are 0.05 mol / L. Use a dropper to slowly add C6H... 12 N4 solution is added dropwise to Zn(NO3)2 solution, while stirring to ensure uniform mixing. A pre-treated pure aluminum sheet is placed vertically in the prepared etching solution, sealed, and then placed in a 95°C water bath for 2 hours. When the surface turns silvery-white, the etched pure aluminum is removed, rinsed repeatedly with deionized water, and dried in a 60°C oven.

[0099] (3) Preparation of epoxy resin alcohol solution and curing agent alcohol solution

[0100] Epoxy resin and curing agent were dissolved separately in a certain amount of ethanol solution at a mass ratio of 4:1, and ultrasonically dispersed for 1 hour to obtain a 2 g / L epoxy resin ethanol solution and a 0.5 g / L curing agent ethanol solution. The mass fraction of epoxy resin was 2.3%, and the mass fraction of curing agent was 0.6%. Then, the mixture was continuously stirred with a magnetic stirrer until a uniform suspension was formed.

[0101] Then use a magnetic stirrer to continue stirring until a uniform suspension is formed.

[0102] (4) Preparation of superhydrophobic modified coating

[0103] 0.3 g of nano-SiO2 particles and 0.3 g of polyvinylidene fluoride (PVDF) particles were taken at a mass ratio of 1:1, with both nano-SiO2 particles and PVDF having a mass fraction of 0.7%. After adding 10 mL of epoxy resin ethanol solution, 40 mL of ethanol solution was added, and the mixture was magnetically stirred for 1 hour until the nano-SiO2 particles were completely dispersed. Then, 3.0% (by mass) of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (SFT) was added in two separate batches. e Ultrasonication for 1 hour; finally, add 10 mL of curing agent ethanol solution and sonicate at 15°C to obtain ER-SiO2 / PVDF / SFT. e The coating solution, i.e. the superhydrophobic modified coating, is complete.

[0104] (5) Preparation of superhydrophobic modified metal substrates

[0105] The surface-etched pure aluminum sheet is immersed in ER-SiO2 / PVDF / SFT. e After immersing in the coating solution for 30 minutes, remove and air dry at room temperature. Repeat the above steps 5 times. Then, place the pure aluminum sheet in a 150℃ oven for 1 hour to cure and react, thus obtaining the metal substrate with the modified coating, denoted as ER-SiO2 / PVDF / SFT. e - Aluminum sheet.

[0106] Example 3

[0107] Most of the components are the same as in Example 1, except that the mass fraction of nano-SiO2 particles is adjusted to 1.0%.

[0108] Example 4

[0109] Most of the components are the same as in Example 1, except that the mass fraction of nano-SiO2 particles is adjusted to 1.2%.

[0110] Example 5

[0111] Most of the components are the same as in Example 1, except that the mass fraction of PVDF is adjusted to 1.0%.

[0112] Example 6

[0113] Most of the components are the same as in Example 1, except that the mass fraction of PVDF is adjusted to 1.2%.

[0114] Example 7

[0115] It is largely the same as Example 1, except that the mass fraction of epoxy resin is adjusted to 2.0%.

[0116] Example 8

[0117] Most of the components are the same as in Example 1, except that the mass fraction of epoxy resin is adjusted to 2.5%.

[0118] Example 9

[0119] Most of the components are the same as in Example 1, except that the mass fraction of the curing agent is adjusted to 0.5%.

[0120] Example 10

[0121] Most of the components are the same as in Example 1, except that the mass fraction of the curing agent is adjusted to 1.0%.

[0122] Example 11

[0123] Most of the results are the same as in Example 1, except that the mass fraction of SFT is adjusted to 1.0%.

[0124] Example 12

[0125] Most of the results are the same as in Example 1, except that the mass fraction of SFT is adjusted to 2.0%.

[0126] Comparative Example 1

[0127] (1) Surface pretreatment of metal substrate

[0128] A 20×20mm pure aluminum sheet (used as the substrate for preparing the hydrophobic coating) was repeatedly sanded for 20 minutes. It was then immersed in anhydrous ethanol and sonicated for 10 minutes, followed by cleaning with deionized water and drying in a 60°C oven. Next, the aluminum sheet was immersed in 1% hydrochloric acid (by volume) until small bubbles appeared on the surface. It was then removed, repeatedly cleaned with deionized water, and dried with nitrogen gas for later use.

[0129] (2) Etching of metal substrate surface

[0130] Take equal amounts of C6H 12N4 standard solution and Zn(NO3)2 standard solution, C6H 12 The concentrations of both the N4 standard solution and the Zn(NO3)2 standard solution are 0.05 mol / L. Use a dropper to slowly add C6H... 12 N4 solution is added dropwise to Zn(NO3)2 solution, while stirring to ensure uniform mixing. A pre-treated pure aluminum sheet is placed vertically in the prepared etching solution, sealed, and then placed in a 95°C water bath for 2 hours. When the surface turns silvery-white, the etched pure aluminum is removed, rinsed repeatedly with deionized water, and dried in a 60°C oven.

[0131] (3) Preparation of epoxy resin alcohol solution and curing agent alcohol solution

[0132] Epoxy resin and curing agent were dissolved in a certain amount of ethanol solution at a mass ratio of 4:1 and ultrasonically dispersed for 1 hour to obtain 2 g / L epoxy resin ethanol solution and 0.5 g / L curing agent ethanol solution. Then, the mixture was continuously stirred with a magnetic stirrer until a uniform suspension was formed.

[0133] (4) Coating preparation

[0134] Take 10 mL of epoxy resin ethanol solution, add 40 mL of ethanol solution, and sonicate to obtain an emulsion suspension; then add 10 mL of curing agent ethanol solution and sonicate at 15°C to obtain the ER coating solution.

[0135] (5) Preparation of modified metal substrate

[0136] After the surface etching of the pure aluminum sheet is immersed in the ER coating solution for 30 minutes, it is taken out and dried at room temperature. The above steps are repeated 5 times. Then the pure aluminum sheet is placed in an oven at 150℃ for 1 hour to cure and react, thus obtaining the metal substrate with the modified coating, which is denoted as ER-aluminum sheet.

[0137] Comparative Example 2

[0138] (1) Surface pretreatment of metal substrate

[0139] A 20×20mm pure aluminum sheet (used as the substrate for preparing the hydrophobic coating) was repeatedly sanded for 20 minutes. It was then immersed in anhydrous ethanol and sonicated for 10 minutes, followed by cleaning with deionized water and drying in a 60°C oven. Next, the aluminum sheet was immersed in 1% hydrochloric acid (by volume) until small bubbles appeared on the surface. It was then removed, repeatedly cleaned with deionized water, and dried with nitrogen gas for later use.

[0140] (2) Etching of metal substrate surface

[0141] Take equal amounts of C6H 12 N4 standard solution and Zn(NO3)2 standard solution, C6H 12The concentrations of both the N4 standard solution and the Zn(NO3)2 standard solution are 0.05 mol / L. Use a dropper to slowly add C6H... 12 N4 solution is added dropwise to Zn(NO3)2 solution, while stirring to ensure uniform mixing. A pre-treated pure aluminum sheet is placed vertically in the prepared etching solution, sealed, and then placed in a 95°C water bath for 2 hours. When the surface turns silvery-white, the etched pure aluminum is removed, rinsed repeatedly with deionized water, and dried in a 60°C oven.

[0142] (3) Preparation of epoxy resin alcohol solution and curing agent alcohol solution

[0143] Epoxy resin and curing agent were dissolved in a certain amount of ethanol solution at a mass ratio of 4:1 and ultrasonically dispersed for 1 hour to obtain 2 g / L epoxy resin ethanol solution and 0.5 g / L curing agent ethanol solution. Then, the mixture was continuously stirred with a magnetic stirrer until a uniform suspension was formed.

[0144] (4) Coating preparation

[0145] Take 0.3g of nano-SiO2 particles, add 10mL of epoxy resin ethanol solution, then add 40mL of ethanol solution, stir magnetically and sonicate until the nano-SiO2 particles are completely dispersed to obtain an emulsion suspension; finally add 10mL of grease curing agent ethanol solution and sonicate at 15℃ to obtain ER-SiO2 coating solution.

[0146] (5) Preparation of modified metal substrate

[0147] After the surface etching of the pure aluminum sheet is immersed in the ER-SiO2 coating solution for 30 minutes, it is taken out and dried at room temperature. The above steps are repeated 5 times. Then the pure aluminum sheet is placed in a 150℃ oven for 1 hour to cure and react, thus obtaining the metal substrate with the modified coating, which is denoted as ER-SiO2-aluminum sheet.

[0148] Comparative Example 3

[0149] (1) Surface pretreatment of metal substrate

[0150] A 20×20mm pure aluminum sheet (used as the substrate for preparing the hydrophobic coating) was repeatedly sanded for 20 minutes. It was then immersed in anhydrous ethanol and sonicated for 10 minutes, followed by cleaning with deionized water and drying in a 60°C oven. Next, the aluminum sheet was immersed in 1% hydrochloric acid (by volume) until small bubbles appeared on the surface. It was then removed, repeatedly cleaned with deionized water, and dried with nitrogen gas for later use.

[0151] (2) Etching of metal substrate surface

[0152] Take equal amounts of C6H 12N4 standard solution and Zn(NO3)2 standard solution, C6H 12 The concentrations of both the N4 standard solution and the Zn(NO3)2 standard solution are 0.05 mol / L. Use a dropper to slowly add C6H... 12 N4 solution is added dropwise to Zn(NO3)2 solution, while stirring to ensure uniform mixing. A pre-treated pure aluminum sheet is placed vertically in the prepared etching solution, sealed, and then placed in a 95°C water bath for 2 hours. When the surface turns silvery-white, the etched pure aluminum is removed, rinsed repeatedly with deionized water, and dried in a 60°C oven.

[0153] (3) Preparation of epoxy resin alcohol solution and curing agent alcohol solution

[0154] Epoxy resin and curing agent were dissolved in a certain amount of ethanol solution at a mass ratio of 4:1 and ultrasonically dispersed for 1 hour to obtain 2 g / L epoxy resin ethanol solution and 0.5 g / L curing agent ethanol solution. Then, the mixture was continuously stirred with a magnetic stirrer until a uniform suspension was formed.

[0155] (4) Coating preparation

[0156] Take 0.3g of nano-SiO2 particles, add 10mL of epoxy resin ethanol solution, then add 40mL of ethanol solution, stir magnetically and sonicate until the nano-SiO2 particles are completely dispersed to obtain an emulsion suspension; then add 3.0% of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (SFT) in two batches and sonicate for 1h; finally add 10mL of ester curing agent ethanol solution and sonicate at 15℃ to obtain ER-SiO2 / SFT coating solution.

[0157] (5) Preparation of modified metal substrate

[0158] After the surface etching of the pure aluminum sheet is immersed in the ER-SiO2 / SFT coating solution for 30 minutes, it is taken out and dried at room temperature. The above steps are repeated 5 times. Then the pure aluminum sheet is placed in a 150℃ oven for curing reaction for 1 hour to obtain the metal substrate with modified coating, which is denoted as ER-SiO2 / SFT-aluminum sheet.

[0159] Performance testing:

[0160] I. Static water contact angle test and static ethylene glycol contact angle test

[0161] 5 μL water droplets and 5 μL ethylene glycol droplets were collected using a contact angle meter (JC2000d) to test the ER-SiO2 / PVDF / SFT prepared in Examples 1 and 2 and Comparative Examples 1, 2, and 3. e-Water contact angle and ethylene glycol contact angle of aluminum sheet, ER-SiO2 / PVDF / SFT-aluminum sheet and ER-aluminum sheet, ER-SiO2-aluminum sheet, ER-SiO2 / SFT-aluminum sheet samples.

[0162] Five different regions were tested for each sample, and the average value was calculated as the average contact angle of the sample. The results are shown in Table 1 and 2. Figure 2 As shown. Figure 2 (d1) and Figure 2 As shown in (d2), the static water contact angle of the prepared superhydrophobic ER-SiO2 / PVDF / SFT-aluminum sheet is 154.3°±0.5°, and the static ethylene glycol contact angle is 148.8°±1.8°; Figure 2 (e1) and Figure 2 As shown in (e2), the superhydrophobic ER-SiO2 / PVDF / SFT prepared is e - The static water contact angle of the aluminum sheet is 153.0°±0.5°, and the static ethylene glycol contact angle is 149.3°±1.0°. Water droplets and ethylene glycol droplets can form rolling droplets on its surface.

[0163] Table 1 Static water contact angle and static ethylene glycol contact angle of different aluminum sheets

[0164]

[0165] The surface morphology of the ER-SiO2 / PVDF / SFT-aluminum sheet, ER-aluminum sheet, and ER-SiO2-aluminum sheet prepared in Example 1 and Comparative Examples 1 and 2 was scanned using SEM. The results are as follows: Figure 3 As shown. By Figure 3 (c) It can be seen that the surface of the superhydrophobic ER-SiO2 / PVDF / SFT-aluminum sheet exhibits a distinct woven mesh structure. This porous mesh structure provides a hydrophobic surface, and a buffer layer is formed within this three-dimensional mesh structure, capable of trapping and capturing a large number of cavitation cavities to form a relatively thick bound air layer. The incorporation of fluorosilane and polyvinylidene fluoride together constructs a porous molecular film, further reducing the surface energy of the substrate. Compared to ER-aluminum sheet ( Figure 3 (a)) and ER-SiO2-aluminum sheet ( Figure 3 (b)) The porous molecular film on the surface of the ER-SiO2 / PVDF / SFT-aluminum sheet can protect the nano-SiO2 aggregate structure from being damaged by the salt solution to the greatest extent, so that the papillary structure on its surface can continue to play a superhydrophobic role.

[0166] The ER-SiO2 / PVDF / SFT-aluminum sheet, ER-aluminum sheet, and ER-SiO2-aluminum sheet prepared in Example 1 and Comparative Examples 1 and 2 were subjected to three-dimensional scanning using atomic force microscopy (AFM). The results are as follows: Figure 4 As shown. By Figure 4 (c) It can be seen that the superhydrophobic ER-SiO2 / PVDF / SFT-aluminum sheet has a distinct papillary shape and large surface fluctuations, with an average surface roughness of 545 nm. Compared to ER-aluminum sheet ( Figure 4 (a)) and ER-SiO2-aluminum sheet ( Figure 4 (b) The surface micro-nano roughness increased by 1.2 times and 1.0 times, respectively.

[0167] II. Scale inhibition performance test under scale-inhibiting solution containing 3% ethylene glycol

[0168] Furthermore, to verify the ER-SiO2 / PVDF / SFT-aluminum sheets and ER-SiO2 / PVDF / SFT-aluminum sheets prepared in Examples 1 and 2... e - The scale inhibition performance of the aluminum sheet was tested in a scaling solution containing 3% ethylene glycol, examining the changes in scale formation. The preparation method is as follows:

[0169] Preparation of a 3% ethylene glycol-containing scaling solution: Measure 60 mL of ethylene glycol into a volumetric flask and dilute to 2000 mL with deionized water to obtain a 3% ethylene glycol solution. This solution will replace deionized water in subsequent steps to dissolve the scaling particles. Anhydrous calcium chloride, anhydrous magnesium chloride, and sodium bicarbonate particles are weighed out in a molar ratio of 1:1:2 and dissolved together in 2000 mL of the prepared ethylene glycol solution to obtain the final scaling test solution. The relevant chemical equations are as follows:

[0170] CaCl2+2NaHCO3→CaCO3↓+2NaCl+H2O+CO2↑

[0171] MgCl2+2NaHCO3→MgCO3↓+2NaCl+H2O+CO2↑

[0172] Among them, calcium carbonate and magnesium carbonate are slow precipitates.

[0173] The main parameters of the scaling solution containing 3% ethylene glycol are shown in Table 2.

[0174] Table 2. Main parameters of scaling solution containing 3% ethylene glycol

[0175]

[0176] The scaling study used a plate-coated method, specifically pure aluminum plates, ER-aluminum plates, ER-SiO2-aluminum plates, ER-SiO2 / SFT-aluminum plates, and ER-SiO2 / PVDF / SFT-aluminum plates, ER-SiO2 / PVDF / SFT-aluminum plates. e- Aluminum sheets were vertically immersed in the scaling solution to reduce the impact of gravity settling of floating scale in the solution. The substrate was vertically immersed in water, and a beaker was placed on a heating platform for constant heating at 80°C, with an external heat insulation cover. After every 24 hours of scaling, the sample was removed, cleaned, dried, weighed and recorded using an electronic balance, and then returned to the scaling solution to continue scaling. The total scaling test lasted 168 hours.

[0177] Scaling test results as follows Figure 5 As shown. By Figure 5 It can be seen that after 168 hours of scaling test in a scaling solution containing 3% ethylene glycol, the scaling of pure aluminum sheet, ER-aluminum sheet, ER-SiO2-aluminum sheet, ER-SiO2 / SFT-aluminum sheet, ER-SiO2 / PVDF / SFT-aluminum sheet, and ER-SiO2 / PVDF / SFT-aluminum sheet all showed significant scaling performance. e - The increase in scale on the aluminum sheet surface was 3.23 mg / cm³. 2 1.78 mg / cm 2 1.56 mg / cm 2 1.14 mg / cm 2 and 0.74 mg / cm 2 0.76 mg / cm 2 Compared to pure aluminum sheets, the scale inhibition rates of other aluminum sheets were 45%, 52%, 65% and 77%, 76%, respectively. It is clear that ER-SiO2 / PVDF / SFT aluminum sheets and ER-SiO2 / PVDF / SFT... e - Compared to ER-aluminum, ER-SiO2-aluminum and ER-SiO2 / SFT-aluminum, aluminum sheets exhibit superior scale inhibition performance in scaling solutions containing 3% ethylene glycol.

[0178] After immersion in two scaling solutions for 168 hours, the changes in the surface contact angles of the substrates in Examples 1 and 2 and Comparative Examples 1, 2, and 3 before and after scaling were measured using a contact angle meter. The test results are shown in Table 3. As can be seen from Table 3, the superhydrophobic ER-SiO2 / PVDF / SFT-aluminum sheets and ER-SiO2 / PVDF / SFTe-aluminum sheets maintained the best water contact angle and glycol contact angle after the scaling test, while the contact angles of the other substrates were all less than 120°, making it difficult to guarantee good hydrophobicity.

[0179] Table 3. Water contact angle and ethylene glycol contact angle of different aluminum sheets after scaling in a salt solution containing 3% ethylene glycol.

[0180]

[0181]

[0182] After a scaling test in a scaling solution containing 3% ethylene glycol for 168 hours, the deposited scale on different coating surfaces was analyzed using SEM, such as... Figure 6 As shown. By Figure 6 (a) It can be seen that, due to the influence of ethylene glycol, the surface of the pure aluminum sheet is almost entirely covered by CaCO3 whiskers. Furthermore, there is a layered stacking phenomenon between the whiskers; from Figure 6 (b) It can be seen that the crystals formed on the surface of the ER-aluminum sheet contain a small amount of calcite, but the main component is aragonite crystals; Figure 6 (c) It can be seen that the crystalline composition of the ER-SiO2-aluminum sheet surface is only aragonite crystals. At the observation scale of 20 μm, the aragonite crystals on the ER-SiO2-aluminum sheet surface are smaller in size than the aragonite crystal structure on the ER-aluminum sheet surface; Figure 6 (d) It can be seen that the CaCO3 crystals on the surface of the superhydrophobic ER-SiO2 / PVDF / SFT-aluminum sheet exhibit irregular clusters of aragonite crystals. Since the aragonite crystals float on the surface of the nano-aggregate structure, they are very easily removed by water flow. Therefore, the superhydrophobic ER-SiO2 / PVDF / SFT-aluminum sheet possesses excellent scale inhibition properties.

[0183] III. Scale inhibition performance test under scaling solutions containing 4% sodium sulfate

[0184] Furthermore, to verify the ER-SiO2 / PVDF / SFT-aluminum sheets and ER-SiO2 / PVDF / SFT-aluminum sheets prepared in Examples 1 and 2... e - The scale inhibition performance of the aluminum sheet was tested in a scaling solution containing 4% sodium sulfate, examining the changes in scale formation. The preparation method is as follows:

[0185] Preparation of a scaling solution containing 4% sodium sulfate: 80g of anhydrous sodium sulfate was dissolved in 1920g of deionized water. The solution was heated in a water bath at 60℃ with continuous stirring using a glass rod, resulting in 2000mL of a 4% sodium sulfate solution. This solution replaced deionized water in subsequent steps to dissolve the scaling particles. Anhydrous calcium chloride, anhydrous magnesium chloride, and sodium bicarbonate particles were weighed out in a molar ratio of 1:1:2 and dissolved together in 2000mL of the prepared sodium sulfate solution to obtain the scaling test solution. The relevant chemical equations are as follows:

[0186] CaCl2+2NaHCO3→CaCO3↓+2NaCl+H2O+CO2↑

[0187] MgCl2+2NaHCO3→MgCO3↓+2NaCl+H2O+CO2↑

[0188] Among them, calcium carbonate and magnesium carbonate are slow precipitates.

[0189] The main parameters of the scaling solution containing 4% sodium sulfate are shown in Table 4.

[0190] Table 4. Main parameters of scaling solution containing 4% sodium sulfate

[0191]

[0192] The scaling study used a plate-coated method, specifically pure aluminum plates, ER-aluminum plates, ER-SiO2-aluminum plates, ER-SiO2 / SFT-aluminum plates, and ER-SiO2 / PVDF / SFT-aluminum plates, ER-SiO2 / PVDF / SFT-aluminum plates. e - Aluminum sheets were vertically immersed in the scaling solution to reduce the impact of gravity settling of floating scale in the solution. The substrate was vertically immersed in water, and a beaker was placed on a heating platform for constant heating at 80°C, with an external heat insulation cover. After every 24 hours of scaling, the sample was removed, cleaned, dried, weighed and recorded using an electronic balance, and then returned to the scaling solution to continue scaling. The total scaling test lasted 168 hours.

[0193] Scaling test results as follows Figure 7 As shown. By Figure 7 It can be seen that after 168 hours of scaling test in a scaling solution containing 4% sodium sulfate, the scaling of pure aluminum sheet, ER-aluminum sheet, ER-SiO2-aluminum sheet, ER-SiO2 / SFT-aluminum sheet, ER-SiO2 / PVDF / SFT-aluminum sheet, and ER-SiO2 / PVDF / SFT-aluminum sheet all showed significant scaling performance. e - The increase in scale buildup on the aluminum sheet surface was 3.00 mg / cm³. 2 1.85 mg / cm 2 1.38 mg / cm 2 1.33 mg / cm 2 and 0.94 mg / cm 2 0.90 mg / cm 2 Compared to pure aluminum sheets, the scale inhibition rates of other aluminum sheets were 38%, 54%, 56% and 69%, 70%, respectively. It is clear that ER-SiO2 / PVDF / SFT aluminum sheets and ER-SiO2 / PVDF / SFT... e - Compared to polymer-based ER-aluminum sheets, ER-SiO2-aluminum sheets, and ER-SiO2 / SFT-aluminum sheets, aluminum sheets exhibit superior scale inhibition performance in scaling solutions containing 4% sodium sulfate.

[0194] After immersion in two scaling solutions for 168 hours, the changes in the surface contact angle of each substrate in Examples 1 and 2 and Comparative Examples 1, 2, and 3 before and after scaling were measured using a contact angle meter. The test results are shown in Table 5. Table 5 shows that ER-SiO2 / PVDF / SFT-aluminum sheet and ER-SiO2 / PVDF / SFT... e- After the scaling test, the aluminum sheet can maintain the optimal water contact angle and ethylene glycol contact angle, both of which can reach above 140°, while the contact angles of other surfaces drop to below 130°.

[0195] Table 5. Water contact angle and ethylene glycol contact angle after different aluminum sheet structures.

[0196]

[0197] After a scaling test in a scaling solution containing 4% sodium sulfate for 168 hours, the deposited scale on different coating surfaces was analyzed using SEM, such as... Figure 8 As shown. By Figure 8 (a) It can be seen that cubic calcite crystals with a grain size of approximately 4 μm appeared on the surface of industrial pure aluminum 1060, and the crystal edges were rounded; Figure 8 As shown in (b) and (c), the surface solid deposits of ER-aluminum sheets and ER-SiO2-aluminum sheets are mostly platy calcite structures, with calcite crystals firmly grown in the surface grooves. The calcite crystals grown on ER-SiO2-aluminum sheets are smaller and thinner than those grown on ER-aluminum sheets. Figure 8 (d) It can be seen that the only dirt deposits on the surface of ER-SiO2 / PVDF / SFT-aluminum sheet are aragonite crystals. The crystal structure is a short rod-shaped hexagonal prism structure, and there is a well-preserved nano-aggregate structure on its surface. There are very fine nipple-like structures on the surface of the nano-aggregate structure.

[0198] In summary, the ER-SiO2 / PVDF / SFT coating prepared on the surface of a metal substrate by this invention has good superhydrophobicity and glycol-repellency, while also exhibiting excellent salt resistance and anti-scaling properties, thus providing better protection for the metal substrate.

[0199] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A superhydrophobic modified metal substrate, comprising a metal substrate, characterized in that, A superhydrophobic modified coating is impregnated onto the surface of the metal substrate; The superhydrophobic modified coating was prepared by the following method: Nano-SiO2 particles, epoxy resin, PVDF, and organic solvent are mixed and stirred until the nano-SiO2 particles are completely dispersed to obtain an emulsion suspension. Fluoroalkylsilane is added in portions, and after sonication, a curing agent is added and sonicated a second time to obtain an ER-SiO2 / PVDF / SFT coating, i.e., a superhydrophobic modified coating. The superhydrophobic modified coating comprises 0.7%~1.2% by mass of nano-SiO2 particles, 0.7%~1.2% by mass of PVDF, 2.0%~2.5% by mass of epoxy resin, 0.5%~1.0% by mass of curing agent, 1.0%~3.0% by mass of fluoroalkylsilane, and 85%~90% by mass of organic solvent; The fluoroalkylsilanes mentioned include one of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane or 1H,1H,2H,2H-perfluorodecyltriethoxysilane. The superhydrophobic modified metal substrate is prepared by the following method: After surface pretreatment and surface treatment, the metal substrate is immersed in a superhydrophobic modified coating, then removed and air-dried at room temperature. This process is repeated 3 to 5 times, and then the substrate is cured at 120 to 180°C to obtain a superhydrophobic modified metal substrate. The surface treatment process is as follows: the surface-pretreated metal substrate is completely immersed in the ZnO thin film growth solution at 90~99℃ for reaction. After the reaction is complete, it is taken out and dried at 50~60℃ to complete the surface treatment. The ZnO thin film growth solution is a mixture of hexamethylenetetramine solution and zinc nitrate solution, with a volume ratio of hexamethylenetetramine solution to zinc nitrate solution of 1:(0.1~10); the concentration of hexamethylenetetramine solution is 0.01~0.1mol / L, and the concentration of zinc nitrate solution is 0.01~0.1mol / L. The superhydrophobic modified metal substrate is used in the field of industrial high-salt wastewater desalination as the surface of heat exchange pipes in thermal evaporation processes.

2. The superhydrophobic modified metal substrate according to claim 1, characterized in that, The epoxy resin mentioned includes one of bisphenol A type epoxy resin or bisphenol F type epoxy resin.

3. The superhydrophobic modified metal substrate according to claim 1, characterized in that, The curing agent includes one of phenolic amine epoxy curing agent or polyether amine epoxy resin curing agent.

4. The superhydrophobic modified metal substrate according to claim 1, characterized in that, The organic solvents include one or more of methanol, ethanol, isopropanol, and acetone.

5. The superhydrophobic modified metal substrate according to claim 1, characterized in that, The surface pretreatment process is as follows: the surface of the metal substrate is polished, cleaned with anhydrous ethanol, immersed in hydrochloric acid solution and then taken out to complete the surface pretreatment.

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