WO2018133235A1 - Preparation method for liquid-proof coating adopting gradient decreasing structure - Google Patents

Abstract

A preparation method for a liquid-proof coating adopting a gradient decreasing structure, comprising the following steps: (1) placing a base material in a reaction cavity of a plasma chamber, continuously vacuumizing the reaction cavity till the vacuum degree in the reaction cavity is 10-200 millitorrs, and inflating an inert gas or nitrogen; (2) inflating first, second and third monomer steams at the same time, and starting plasma discharge to conduct chemical vapor deposition; (3) after discharge, turning off a plasma power source, stopping inflating the three monomer steams, continuously vacuumizing, and after the vacuum degree of the reaction cavity is kept at 10-200 millitorrs for 1-5 min, inflating the atmosphere one atmospheric pressure, and then taking out the base material, wherein the first monomer steam is a mono-functionality unsaturated fluorocarbon resin with the inflated flux of 10-1,000 μL/min; the second monomer steam is a polyfunctionality unsaturated hydrocarbon derivative with the inflated initial flux of 30-500 μL/min, and is decreasing in the rate of 1-10 μL/min; and the third monomer steam is a polyfunctionality unsaturated hydrocarbon derivative with the inflated initial flux of 30-500 μL/min, and is decreasing in the rate of 1-10 μL/min.

Description

 Preparation method of gradient decreasing structure liquid proof coating

 Technical field

 The invention belongs to the technical field of plasma chemical vapor deposition, and particularly relates to a preparation method of a liquid proof coating.

 Background technique

Plasma chemical vapor deposition is a technique in which a reactive gas is activated by a plasma to promote a chemical reaction on a surface of the substrate or in a near surface space to form a solid film. Plasma coating technology has the following advantages over other coating preparation methods: 1) Dry process, the resulting film is uniform without pinholes; (2) The coating preparation temperature is low, and can be carried out under normal temperature conditions, effectively avoiding damage to temperature sensitive devices; (3) The plasma process can not only prepare coatings with a thickness of micron and can prepare ultra-thin nano-scale coatings; (4) The plasma polymerized film is stable in chemical and physical properties such as solvent resistance, chemical corrosion resistance, heat resistance, and abrasion resistance; (5) the adhesion between the plasma polymerization film and the substrate is good.

 Fluorocarbon resin with a strong C-F The bond is a skeleton, and its heat resistance, chemical resistance, cold resistance, low temperature flexibility, weather resistance and electrical properties are better than other resins, and it also has non-adhesiveness and non-wetting property. Therefore, the fluorocarbon resin coating is particularly suitable for the protection of the surface of the material, not only can give the material good physical and chemical durability, but also can give the material excellent waterproof and oil proof functions. In recent years, the preparation of fluorocarbon protective coatings by plasma technology has been studied and applied in microelectronics, optics, medical, precision equipment and high-end clothing.

At present, thick coatings or ultra-thick coatings with dense structures and coatings having a multi-layer structure have significant advantages over thin coatings in terms of liquid, corrosion and liquid penetration resistance. However, thick coatings and ultra-thick coatings mostly have residual stresses, which are prone to stress cracking under conditions of temperature change and deformation, and poor compatibility between interfaces of multilayer structure coatings is also prone to peeling and cracking, and loss of barrier properties. In addition, uniform coatings usually have a single performance, and it is difficult to ensure that the coating has excellent bonding strength, mechanical properties, hydrophobic properties, and the like.

 Summary of the invention

The present invention provides a method for preparing a gradient-reducing structure liquid-repellent coating for solving the above technical problems, and preparing a liquid-repellent coating having a structural and composition gradient change by a plasma chemical vapor deposition technique by a multi-channel control method. In different time periods, the feeding mode of different monomer materials is controlled, and different process conditions are set at the same time to obtain a liquid-repellent coating with structural and composition gradient changes to achieve hydrophobicity, water repellency and long-term surface of the material. Effective regulation of resistance to underwater electricity.

 The technical solution adopted by the present invention to achieve the above object is as follows:

 A method for preparing a gradient-reducing structure liquid-repellent coating, comprising: the following steps:

 (1) placing the substrate in the reaction chamber of the plasma chamber, continuously evacuating the reaction chamber, and pumping the vacuum in the reaction chamber. 10-200 mTorr, with inert gas or nitrogen to provide a stable plasma environment;

 (2) simultaneously introducing the first monomer vapor, the second monomer vapor, and the third monomer vapor, turning on the plasma discharge, and performing chemical vapor deposition;

 The first monomer vapor is: a monofunctional unsaturated fluorocarbon resin;

 The second monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative;

 The third monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative;

 The flow rate of the first monomer vapor is 10-1000 μL/min;

 The initial flow rate of the second monomer vapor is 30-500 μL/min The second monomer steam flow rate decreases, and the deceleration rate is 1-10 μL/min;

 The initial flow rate of the third monomer vapor is 30-500 μL/min The third monomer steam flow rate decreases, and the deceleration rate is 1-10 μL/min;

 (3) At the end of the discharge, the plasma power source is turned off, and the first monomer vapor, the second monomer vapor, and the third monomer vapor are stopped. Continue to evacuate, keep the vacuum of the reaction chamber at 10-200 mTorr for 1-5 min, then pass into the atmosphere to an atmospheric pressure, and then remove the substrate.

 The substrate in the step (1) is a solid material including an electronic component, an electrical component, a fabric or a garment.

 The volume of the plasma chamber in the step (1) is 50 to 1000 liters, and the temperature of the plasma chamber is controlled at 30 to 60. °C; the flow rate of the inert gas or nitrogen gas is 5 to 300 sccm, and the inert gas is one of argon gas or helium gas, or a mixture of argon gas and helium gas.

 In the step (2):

 The first monomer steam is introduced into the reaction chamber by atomization and volatilization through a feed pump, and is introduced into the reaction chamber from a low pressure of 10 to 200 mTorr;

 The second monomer steam is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and introducing the reaction chamber from a low pressure of 10 to 200 mTorr;

 The third monomer steam is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and introducing the reaction chamber from a low pressure of 10 to 200 mTorr.

 The monofunctional unsaturated fluorocarbon resin includes:

 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, 2-(perfluorodecyl) Ethyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorododecyl)ethyl acrylate, 2-perfluorooctyl acrylate, 1H, 1H, 2H, 2H- Perfluorooctyl acrylate, 2-(perfluorobutyl)ethyl acrylate, (2H-perfluoropropyl)-2-acrylate, (perfluorocyclohexyl) methacrylate, 3,3,3 - Trifluoro -1-propyne, 1-ethynyl-3,5-difluorobenzene or 4-ethynyltrifluorotoluene;

 The polyfunctional unsaturated hydrocarbon derivative includes:

Ethoxylated trimethylolpropane triacrylate, tripropylene glycol diacrylate, divinylbenzene, polyethylene glycol diacrylate, triethylene glycol divinyl ether, 1,6-hexanediol Acrylate, ethylene glycol diacrylate, Diethylene glycol divinyl ether or neopentyl glycol diacrylate.

 The power of the ion discharge is set to 2 to 500 W before the introduction of the monomer vapor in the step (2), and the continuous discharge time is 300~600s, carry out bombardment pretreatment of the substrate by glow discharge, clean the surface impurities of the substrate and activate the surface of the substrate.

 The power of the plasma discharge in the step (2) is 2~500W, and the continuous discharge time is 300~600s. The plasma discharge mode is radio frequency discharge, microwave discharge, intermediate frequency discharge or electric spark discharge.

 The plasma during radio frequency discharge The energy output mode of the control plasma RF is pulse or continuous output. When the energy output mode of the plasma RF is pulse output, the pulse width is 2μs-1ms, and the repetition frequency is 20Hz-10kHz. A pulsed voltage is applied to increase the uniformity of film formation and to reduce free radicals remaining in the coating.

 Compared with the prior art, the above technical solution of the present invention has the following advantages:

 ( 1 The invention prepares a nano-polymer graded coating with gradient changes in structure and composition, and achieves structural toughness of the coating by simultaneously introducing monomer vapor and controlling the flow rate of the monomer vapor at different rates. The hardness is a gradient change, which can reduce stress cracking and deformation, and has better barrier protection performance. The bottom layer of the coating layer is a dense layer structure, which can effectively block the contact between water vapor and the surface of the material, and impart excellent corrosion resistance to the film. From the surface of the substrate, the cross-linking effect of the monomer is gradually weakened, and the compactness of the coating is also relatively weakened, so that the coating has a continuous barrier to contact of water vapor with the surface of the material; the top layer of the coating is a low surface energy rough surface, Excellent hydrophobicity and low adhesion, which can reduce the accumulation and penetration of corrosive liquid on the surface of the coating.

 (2) The plasma facilitates cross-linking to form a network structure

When the plasma is subjected to glow discharge, the active groups with higher energy in the monomer component are broken to form active sites, and the additional active sites introduced are cross-linked in a plasma environment to form a network structure, a network structure. It has better compactness and can effectively improve the protective performance of the film.

 (3) Polyfunctional monomers facilitate the formation of crosslinked structures

In general, plasma polymerization uses a monofunctional monomer to obtain a loose coating structure. Moreover, the crosslinked structure is formed by a plurality of active sites formed by random interruption of the monomer during plasma glow discharge to form a crosslinked structure. The present invention introduces an additional cross-linking point by introducing other monomer components having a polyfunctional cross-linking structure to form a cross-linked structure, and the introduction of a cross-linking structure of the polyfunctional group, so that the coating forms a dense network structure, and the introduction is much The functional monomer accounts for the mass percentage of the monomer. 10-80%. Not only can the material be given good physical and chemical durability, but it can also impart excellent water and oil repellency to the material.

 ( 4 In the plasma environment, the surface is activated to obtain a plurality of active sites, and the active sites are combined with the active sites of the monomers with strong chemical bonds, so that the film obtained by the coating has superior bonding force and mechanical strength. .

 detailed description

 The invention will be described in detail below with reference to specific embodiments, but the invention is not limited to the specific embodiments.

 Example 1

 A method for preparing a gradient-reducing structure liquid-repellent coating, comprising: the following steps:

 (1) placing a substrate in a reaction chamber of a plasma chamber, the substrate being a solid material, the solid material being an electronic component, Continuously evacuating the reaction chamber, pumping the vacuum in the reaction chamber to 10 mTorr, and introducing nitrogen gas to provide a stable plasma environment;

 The plasma chamber volume is 50 liters, the plasma chamber temperature is controlled at 30 °C, and the nitrogen gas flow rate is 5 sccm.

 (2) simultaneously introducing the first monomer vapor, the second monomer vapor, and the third monomer vapor, turning on the plasma discharge, and performing chemical vapor deposition;

 The first monomer vapor is: a monofunctional unsaturated fluorocarbon resin, and the monofunctional unsaturated fluorocarbon resin is 2-perfluorooctyl acrylate. The first monomer steam is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and the flow rate of the first monomer vapor is 10 μL/min;

 The second monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative; the polyfunctional unsaturated hydrocarbon derivative is diethylene glycol divinyl ether, The second monomer vapor is introduced to atomize and volatilize the monomer through a feed pump, and is introduced into the reaction chamber from a low pressure of 10 mTorr. The initial flow rate of the second monomer vapor is 30 μL/min. The second monomer steam flow decreases, and the deceleration rate is 1 μL/min;

 The third monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative; the polyfunctional unsaturated hydrocarbon derivative is ethylene glycol diacrylate, The third monomer vapor is introduced into the reaction chamber by atomization and volatilization through a feed pump, and the initial flow rate of the third monomer vapor is 180 μL/min. The third monomer steam flow rate decreases, and the deceleration rate is 3 μL/min;

 Set the ion discharge power to 2W and the continuous discharge time to 600s. The glow discharge is performed on the substrate by bombardment pretreatment to clean the surface impurities of the substrate and activate the surface of the substrate.

 The plasma discharge has a power of 2 W and a sustained discharge time of 600 s, and the plasma discharge mode is radio frequency.

 The plasma during radio frequency discharge The energy output mode of the control plasma RF is pulse or continuous output. When the energy output mode of the plasma RF is pulse output, the pulse width is 2μs and the repetition frequency is 20Hz. A pulsed voltage is applied to increase the uniformity of film formation and to reduce free radicals remaining in the coating.

 (3) At the end of the discharge, the plasma power supply is turned off, the monomer vapor is stopped, and the vacuum is continuously applied to maintain the vacuum of the reaction chamber at 10 mTorr. After 1 min, it is introduced into the atmosphere to an atmospheric pressure, and then the substrate is taken out.

 Example 2

 This embodiment is the same as the basic process steps of Embodiment 1, and the different process parameters are as follows:

 1. The substrate in step (1) is a solid material, and the solid material is an electrical component, and the vacuum in the reaction chamber is drawn to 200. The mTorr was introduced with an inert gas; the plasma chamber volume was 1000 liters, the plasma chamber temperature was controlled at 60 ° C; the inert gas flow rate was 300 sccm, and the inert gas was argon gas.

 2. In step (2):

 The first monomer vapor is: a monofunctional unsaturated fluorocarbon resin, and the monofunctional unsaturated fluorocarbon resin is 2-(perfluorodecyl) Ethyl methacrylate, the first monomer vapor is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and the flow rate of the first monomer vapor is 1000. μ L/min ;

 The second monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative; the polyfunctional unsaturated hydrocarbon derivative is ethylene glycol diacrylate, The second monomer vapor is introduced to atomize and volatilize the monomer through a feed pump, and is introduced into the reaction chamber from a low pressure of 200 mTorr. The initial flow rate of the second monomer vapor is 500 μL/min. The second monomer steam flow decreases, and the deceleration rate is 10 μL/min;

 The third monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative; and the polyfunctional unsaturated hydrocarbon derivative is neopentyl glycol diacrylate. The third monomer steam is introduced to atomize and volatilize the monomer through the feed pump, and is introduced into the reaction chamber from a low pressure of 200 mTorr, and the initial flow rate of the third monomer vapor is 500 μL/min. The third monomer steam flow rate decreases, and the deceleration rate is 10 μL/min;

 Set the power of the ion discharge to 500W and the continuous discharge time to 300s. The glow discharge is performed on the substrate by bombardment pretreatment to clean the surface impurities of the substrate and activate the surface of the substrate.

 The power of the plasma discharge in step (2) is 500W, and the continuous discharge time is 300s. The plasma discharge mode is microwave discharge.

 3. In step (3), keep the vacuum of the reaction chamber at 200 mTorr for 5 min and then pass to the atmosphere to an atmospheric pressure.

 Example 3

 This embodiment is the same as the basic process steps of Embodiment 1, and the different process parameters are as follows:

 1. The substrate in step (1) is a solid material, the solid material is a fabric, and the vacuum in the reaction chamber is drawn to 50. The mTorr was introduced with an inert gas; the plasma chamber volume was 200 liters, the plasma chamber temperature was controlled at 40 ° C; the inert gas flow rate was 100 sccm, and the inert gas was helium gas.

 2. In step (2):

 The first monomer vapor is: a monofunctional unsaturated fluorocarbon resin, and the monofunctional unsaturated fluorocarbon resin is 1-ethynyl-3,5- Difluorobenzene, the first monomer vapor is introduced to atomize and volatilize the monomer through a feed pump, and is introduced into the reaction chamber from a low pressure of 40 mTorr, and the flow rate of the first monomer vapor is 300 μL/ Min ;

 The second monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative; the polyfunctional unsaturated hydrocarbon derivative is diethylene glycol divinyl ether, The second monomer vapor is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and the initial flow rate of the second monomer vapor is 400 μL/min. The second monomer steam flow rate decreases, and the deceleration rate is 5 μL/min;

 The third monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative; and the polyfunctional unsaturated hydrocarbon derivative is polyethylene glycol diacrylate. The third monomer steam is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and the initial flow rate of the third monomer vapor is 500 μL/min. The third monomer steam flow rate decreases, and the deceleration rate is 10 μL/min;

 Set the ion discharge power to 300W and the continuous discharge time to 450s. The glow discharge is performed on the substrate by bombardment pretreatment to clean the surface impurities of the substrate and activate the surface of the substrate.

 The power of the plasma discharge in step (2) is 100W, and the continuous discharge time is 400s. The plasma discharge mode is a spark discharge.

 3. In step (3), keep the vacuum of the reaction chamber at 50 mTorr for 2 min and then pass to the atmosphere to an atmospheric pressure.

 Example 4

 This embodiment is the same as the basic process steps of Embodiment 1, and the different process parameters are as follows:

 1. The substrate in step (1) is a solid material, and the solid material is a garment, and the vacuum in the reaction chamber is drawn to 150. a millitorr, an inert gas is introduced; the plasma chamber has a volume of 600 liters, the temperature of the plasma chamber is controlled at 45 ° C; the flow rate of the inert gas is 150 sccm, and the inert gas is a mixture of argon and helium.

 2. In step (2):

 The first monomer vapor is: a monofunctional unsaturated fluorocarbon resin, and the monofunctional unsaturated fluorocarbon resin is 2-(perfluorohexyl) Ethyl methacrylate, the first monomer vapor is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and the flow rate of the first monomer vapor is 550. μ L/min ;

 The second monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative; the polyfunctional unsaturated hydrocarbon derivative is diethylene glycol divinyl ether, The second monomer vapor is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and the initial flow rate of the second monomer vapor is 300 μL/min. The second monomer steam flow rate decreases, and the deceleration rate is 6 μL/min;

 The third monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative; and the polyfunctional unsaturated hydrocarbon derivative is 1,6- The hexanediol diacrylate is introduced into the third monomer vapor to atomize and volatilize the monomer through the feed pump, and is introduced into the reaction chamber from a low pressure of 100 mTorr. The initial flow rate of the third monomer vapor is 30 μ L/min; the third monomer steam flow decreases, the deceleration rate is 1 μL/min;

 Set the ion discharge power to 400W and the continuous discharge time to 350s. The glow discharge is performed on the substrate by bombardment pretreatment to clean the surface impurities of the substrate and activate the surface of the substrate.

 In step (2), the plasma discharge power is 250W, and the continuous discharge time is 450s. The plasma discharge mode is an intermediate frequency discharge.

 3. In step (3), keep the vacuum of the reaction chamber at 100 mTorr for 3 min and then pass to the atmosphere to an atmospheric pressure.

 Embodiment 1 to Embodiment 4 above The coating prepared by the method has excellent hydrophobicity, oleophobicity, low adhesion, resistance to organic solvent dissolution, and water-resistant electrical conductivity. The test results are as follows:

 1, hydrophobic, oleophobic, low adhesion test

Hydrophobic / oleophobic / low adhesion
	Example 1	Example 2	Example 3	Example 4
Water contact angle	93°	115°	103°	128°
Adhesion	High adhesion, water droplets slip easily	Low adhesion, water droplets are easy to slip	Low adhesion, water droplets are easy to slip	Low adhesion, water droplets slip easily
Oil contact angle	30°	70°	75°	95°

 2, resistance to organic solvent dissolution test

Organic solvent resistant (IPA) solubility
	Film thickness
Before soaking	Soak for 48h
Example 1	198nm	200nm
Example 2	118nm	100nm
Example 3	100nm	90nm
Example 4	203nm	200nm
Organic solvent resistant (ethanol) solubility
	Film thickness
Before soaking	Soak for 48h
Example 1	118nm	120nm
Example 2	120nm	110nm
Example 3	105nm	108nm
Example 4	118nm	120nm

 3, water resistance conductivity

Water resistance
	Current up to 1mA at 12.5V
Example 1	65min
Example 2	15min
Example 3	25min
Example 4	70min

Claims (8)

1. 1 . A method for preparing a gradient-reducing structure liquid-repellent coating, comprising: the following steps:

   (1) placing the substrate in the reaction chamber of the plasma chamber, continuously evacuating the reaction chamber, and pumping the vacuum in the reaction chamber to 10-200. MTorr, with inert gas or nitrogen;

   (2) simultaneously introducing the first monomer vapor, the second monomer vapor, and the third monomer vapor, turning on the plasma discharge, and performing chemical vapor deposition;

   The first monomer vapor is: a monofunctional unsaturated fluorocarbon resin;

   The second monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative;

   The third monomer vapor is: a polyfunctional unsaturated hydrocarbon derivative;

   The flow rate of the first monomer vapor is 10-1000 μL/min;

   The initial flow rate of the second monomer vapor is 30-500 μL/min; the second monomer steam flow is decreased, and the deceleration rate is 1-10 μ. L/min;

   The initial flow rate of the third monomer vapor is 30-500 μL/min; the third monomer steam flow is decreased, and the deceleration rate is 1-10 μ. L/min;

   (3) At the end of the discharge, the plasma power supply is turned off, the first monomer vapor, the second monomer vapor, and the third monomer vapor are stopped, and the vacuum is continuously applied to maintain the vacuum of the reaction chamber. After 10-500 mTorr for 1-5 min, it is introduced into the atmosphere to an atmospheric pressure, and then the substrate is taken out.
2. The method for preparing a gradient-reducing structure liquid-repellent coating according to claim 1, wherein the step (1) The medium substrate is a solid material including electronic parts, electrical parts, fabrics or garments.
3. The method for preparing a gradient-reducing structure liquid-repellent coating according to claim 1, wherein the volume of the plasma chamber in the step (1) is 50~1000 liters, the temperature of the plasma chamber is controlled at 30~60 °C; the flow rate of inert gas or nitrogen is 5~300sccm The inert gas is one of argon or helium or a mixture of argon and helium.
4. The method for preparing a gradient-reducing structure liquid-repellent coating according to claim 1, wherein: in the step (2):

   The first monomer steam is introduced into the reaction chamber by atomization and volatilization through a feed pump, and is introduced into the reaction chamber from a low pressure of 10 to 200 mTorr;

   The second monomer steam is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and introducing the reaction chamber from a low pressure of 10 to 200 mTorr;

   The third monomer steam is introduced into the reaction chamber by atomizing and volatilizing the monomer through a feed pump, and introducing the reaction chamber from a low pressure of 10 to 200 mTorr.
5. According to claim 1 The method for preparing a gradient-reducing structure liquid-repellent coating, characterized in that the monofunctional unsaturated fluorocarbon resin comprises:

   3-(perfluoro-5-methylhexyl)-2-hydroxypropyl methacrylate, 2-(perfluorodecyl)ethyl methacrylate, 2-( Perfluorohexyl) ethyl methacrylate, 2-(perfluorododecyl)ethyl acrylate, 2-perfluorooctyl acrylate, 1H, 1H, 2H, 2H-perfluorooctyl acrylate , 2-( Perfluorobutyl)ethyl acrylate, (2H-perfluoropropyl)-2-acrylate, (perfluorocyclohexyl) methacrylate, 3,3,3-trifluoro-1-propyne, 1 - ethynyl -3,5-difluorobenzene or 4-ethynylbenzotrifluoride;

   The polyfunctional unsaturated hydrocarbon derivative includes:

   Ethoxylated trimethylolpropane triacrylate, tripropylene glycol diacrylate, divinylbenzene, polyethylene glycol diacrylate, triethylene glycol divinyl ether, 1,6- Hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol divinyl ether or neopentyl glycol diacrylate.
6. The method for preparing a gradient-reducing structure liquid-repellent coating according to claim 1, wherein: the step (2) is set before the monomer steam is introduced. The power of the ion discharge is 2~500W, and the continuous discharge time is 300~600s. The substrate is subjected to bombardment pretreatment by glow discharge.
7. The method for preparing a gradient-reducing structure liquid-repellent coating according to claim 1, wherein the power of the plasma discharge in the step (2) is 2~500W, the continuous discharge time is 300~600s, and the plasma discharge mode is radio frequency discharge, microwave discharge, medium frequency discharge or electric spark discharge.
8. A method for preparing a gradient-reducing structure liquid-repellent coating according to claim 7, wherein: said plasma RF discharge process The energy output mode of the control plasma RF is pulse or continuous output. When the energy output mode of the plasma RF is pulse output, the pulse width is 2μs-1ms and the repetition frequency is 20Hz-10kHz.