Method for depositing a hydrophobic film applied to atmospheric plasma deposition

Abstract

This invention discloses a method for depositing hydrophobic films using atmospheric pressure plasma deposition, belonging to the field of workpiece surface treatment. The method involves atomizing a composite precursor, all in liquid state, in an atomizing device, carrying it with a working gas into a plasma excitation device, and then ejecting it from an atmospheric pressure plasma coating spray gun. The composite precursor comprises 5-9 parts of perfluoroacrylate monomer, 1-5 parts of non-fluoroacrylate monomer, and 0.1-2 parts of acrylate crosslinking agent. This method can produce dense organic hydrophobic films using atmospheric pressure plasma jet equipment. The resulting films exhibit high droplet angle, low roll-off angle, and high light transmittance, as well as good weather resistance and abrasion resistance. The film thickness and droplet angle decrease very little over time. Furthermore, the liquid precursor reduces contamination and safety risks in open environments. These advantages facilitate the deposition of hydrophobic films on workpieces using atmospheric pressure plasma chemical vapor deposition technology on continuous production lines.

Description

Technical Field

[0001] This invention relates to a method for depositing hydrophobic films using atmospheric pressure plasma deposition, belonging to the field of workpiece surface treatment. Background Technology

[0002] As the application scenarios of electronic products continue to expand, the demand for waterproofing in 3C products is also increasing. Currently, most 3C product treatments utilize traditional coatings or vacuum plasma chemical vapor deposition (VPV). Compared to traditional coatings, VPV offers advantages such as stronger adhesion, easier coating structure design, and greater versatility. However, vacuum technology has significant drawbacks when applied to industrial production. When processing workpieces using VPV, the workpiece must leave the continuous production line and enter the vacuum chamber; furthermore, the VPV processing time is relatively long. These drawbacks combined significantly impact production efficiency in assembly line manufacturing.

[0003] Atmospheric pressure plasma chemical vapor deposition (PSCVD) coating technology has advantages such as high production efficiency and simple operation process, and can be carried out online on the production line. However, due to the shortcomings such as short deposition time and deposition temperature being limited by the open environment, the performance of films obtained by atmospheric pressure plasma chemical vapor deposition is currently inferior to that of films obtained by vacuum plasma chemical vapor deposition. The main problems are insufficient film density, poor weather resistance, and poor wear resistance. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a method for depositing hydrophobic films using atmospheric pressure plasma deposition, which can improve the performance of hydrophobic films obtained by atmospheric pressure plasma chemical vapor deposition.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A method for depositing hydrophobic films using atmospheric pressure plasma deposition involves atomizing a composite precursor, which is entirely in liquid state, in an atomizing device, then carrying it into a plasma excitation device with a working gas, and finally spraying it out from an atmospheric pressure plasma coating gun. The composite precursor comprises, by mass, 5-9 parts of perfluoroacrylate monomer, 1-5 parts of non-fluoroacrylate monomer, and 0.1-2 parts of acrylate crosslinking agent.

[0007] The hydrophobic film deposition method for atmospheric pressure plasma deposition provided in this application uses a specially formulated liquid precursor to deposit the hydrophobic film, which enables the formation of dense organic hydrophobic films using atmospheric pressure plasma jet equipment. The resulting film has good weather resistance and wear resistance, and the film thickness and water droplet angle decrease with time to a very small degree. Furthermore, the liquid precursor reduces pollution and safety risks in open environments, which is beneficial for depositing hydrophobic films on workpieces on continuous production lines.

[0008] Furthermore, the working gas is selected from at least one of N2, O2, Ar, He, and compressed air.

[0009] Furthermore, the working gas is selected from at least one of N2, Ar, and He, which helps to avoid the generation of -OH groups that may affect the hydrophobic properties of the membrane layer during use by compressed air and O2.

[0010] Further, the perfluoroacrylate monomer is selected from at least one of perfluoroalkyl ethyl acrylate, perfluorooctylpropyl acrylate, 2-perfluorooctyl ethyl acrylate, 1H,1H,2H,2H-perfluorooctyl acrylate, perfluorocyclohexyl methacrylate, perfluorohexyl ethyl acrylate, and perfluorobutyl ethyl methacrylate; the fluorine-free acrylate monomer is selected from at least one of n-hexyl methacrylate, n-hexyl acrylate, butyl acrylate, lauryl acrylate, lauryl methacrylate, and 1,6-hexanediol dimethacrylate; the acrylate crosslinking agent is selected from at least one of 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, hexanediol dimethacrylate, trimethylolpropane trimethacrylate, and glycidyl methacrylate.

[0011] The perfluoroacrylate monomers contain a large number of hydrophobic -F groups, ensuring the hydrophobic properties of the film. The unsaturated acrylate structure can break and form bonds under plasma bombardment, creating a polyacrylate-like structure. The non-fluorinated acrylate monomers and acrylate crosslinking agents selected in the formulation can improve the crosslinking degree after the perfluoroacrylate monomers polymerize, increasing the film's density and optimizing other film properties. The selection of the above composite precursors allows for vaporization in an industrially applicable and energy-efficient manner, avoiding problems such as insufficient active groups and poor film quality that may occur with liquid feed methods.

[0012] Furthermore, the composite precursor comprises, by weight, 7-9 parts perfluoroacrylate monomer, 1-2.5 parts non-fluoroacrylate monomer, and 0.1-0.5 parts acrylate crosslinking agent.

[0013] Furthermore, the composite precursor contains a polymerization inhibitor, the amount of which is equivalent to 50ppm-100ppm of the total mass of the perfluoroacrylate monomer, the non-fluoroacrylate monomer, and the acrylate crosslinking agent. The polymerization inhibitor is selected from at least one of chain transfer type polymerization inhibitors and free radical type polymerization inhibitors. Even further, the polymerization inhibitor is selected from p-hydroxyanisole, phenothiazine, or 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical.

[0014] Acrylic ester monomers all have a certain tendency to self-polymerize. Adding a small amount of polymerization inhibitor to the composite precursor can adapt to industrial production and enable the composite system to be stored stably for a long time. The dosage of 50ppm-100ppm can avoid the self-polymerization deformation of the precursor and also prevent the polymerization inhibitor from affecting the film-forming effect.

[0015] Furthermore, the preparation steps of the composite precursor include:

[0016] The perfluoroacrylate monomer and the non-fluoroacrylate monomer are mixed to obtain a mixed monomer;

[0017] Dissolve the polymerization inhibitor in 1 ml-2 ml of alcohol, ether or ester to obtain a polymerization inhibitor solution;

[0018] Add the polymerization inhibitor solution to the mixed monomers and stir at 200 rpm-400 rpm for 15 min-30 min;

[0019] Continue adding the acrylate crosslinking agent and stir at 200 rpm-400 rpm for 30 min-60 min to obtain the composite precursor.

[0020] Before introducing the acrylate crosslinking agent, a polymerization inhibitor is added to limit the degree of self-polymerization of the mixed monomers. The polymerization inhibitor is dissolved in a solvent to facilitate uniform mixing of the inhibitor and the mixed monomers. At the same time, the amount of solvent is strictly limited to avoid introducing too many hydroxyl groups, ether bonds, etc., which would affect the coating effect of the system.

[0021] Furthermore, the composite precursor is atomized at a rate of 20 μL / min-500 μL / min. The working gas is divided into a plasma gas source and a carrier gas flow. The plasma gas source enters the plasma excitation device directly at a flow rate of 20 SLM-70 SLM, while the carrier gas flows through the atomization device at a flow rate of 1 SLM-20 SLM before entering the plasma excitation device. The excitation power of the plasma excitation device is 100W-500W, and the atmospheric pressure plasma coating spray gun is 1mm-15mm away from the workpiece surface.

[0022] Furthermore, the composite precursor is atomized at a rate of 50 μL / min-200 μL / min, the plasma gas source enters the plasma excitation device directly at a flow rate of 40 SLM-70 SLM, and the carry gas flows through the atomization device at a rate of 1 SLM-5 SLM before entering the plasma excitation device. The excitation power of the plasma excitation device is 150W-350W, and the atmospheric pressure plasma coating spray gun is 1mm-5mm away from the workpiece surface. These process conditions are more suitable for the specific precursor formulation in this application and virtually eliminate the attenuation of film thickness and water droplet angle after deposition.

[0023] Furthermore, the atomization method of the atomizing device is heating evaporation, and the carrying gas flow is kept warm between the atomizing device and the plasma excitation device.

[0024] The beneficial effects of this invention are: This invention can use atmospheric pressure plasma jet equipment to produce dense organic hydrophobic films. The resulting films have a high droplet angle, a low roll-off angle, and high light transmittance. They have good waterproof effect, do not affect the product appearance, and have good weather resistance and wear resistance. The film thickness and droplet angle decrease with time to a very small degree. On the other hand, the liquid precursor reduces pollution and safety risks in open environments. In summary, these advantages make it easier to deposit hydrophobic films on workpieces using atmospheric pressure plasma chemical vapor deposition technology on continuous production lines.

[0025] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application can be realized and obtained from the written description. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below in conjunction with the embodiments of this disclosure. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this invention.

[0027] It should be understood that, without conflict, any and all embodiments of the present invention can be combined with technical features of any other embodiment or multiple other embodiments to obtain other embodiments. The present invention includes such combinations to obtain other embodiments.

[0028] In this specification, groups and their substituents may be selected by those skilled in the art to provide stable structural moieties and compounds. When a substituent is described by a conventional chemical formula written from left to right, the substituent also includes chemically equivalent substituents obtained when the structural formula is written from right to left.

[0029] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter pertains. Where multiple definitions exist for a term, the definition herein shall prevail.

[0030] The efficiency of depositing hydrophobic films on 3C products using vacuum plasma chemical vapor deposition (VCD) is low, not only because it requires leaving the production line, but also because VCD often deposits double or single-layer films, requiring cleaning to remove surface impurities before and after each layer. Atmospheric pressure plasma chemical vapor deposition (APCVD), on the other hand, not only avoids leaving the production line but also allows for the simultaneous deposition of multiple components, eliminating the need for multi-layer films. However, due to its inherent characteristics, ACVD, when using conventional fluorocarbon materials, results in insufficient film density. This leads to film thickness and water droplet angle degradation over time or with changes in storage temperature and humidity conditions; the film quality is good immediately after deposition but significantly deteriorates after a period of time. Furthermore, insufficient film density also affects wear resistance, failing to meet the performance requirements of 3C products and other applications. The composite precursor formulation proposed in this invention significantly improves upon these shortcomings.

[0031] This application provides a method for depositing a hydrophobic film using atmospheric pressure plasma deposition. The composite precursor, which is entirely in liquid state, is atomized in an atomizing device, carried into a plasma excitation device by a working gas, and then ejected from an atmospheric pressure plasma coating spray gun. The composite precursor comprises, by mass, 5-9 parts of perfluoroacrylate monomer, 1-5 parts of non-fluoroacrylate monomer, and 0.1-2 parts of acrylate crosslinking agent.

[0032] Taking mobile phones as an example, the process of coating a hydrophobic film on a mobile phone is as follows: After the mobile phone passes through the previous process, it does not need to leave the production line. Instead, it enters the cabinet of the atmospheric pressure plasma coating equipment in this stage. Through plasma discharge, the composite precursor will form a relatively dense film layer on the mobile phone shell. Then, it leaves the cabinet and enters the next process.

[0033] The specific process conditions are as follows:

[0034] After passing through the previous process, the mobile phone enters the cabinet of the atmospheric pressure plasma coating equipment along the production line. The robotic arm or special fixture moves the mobile phone through the atmospheric pressure plasma coating spray gun at a certain speed and trajectory to perform whole-machine coating.

[0035] The atmospheric pressure plasma coating spray gun is kept running continuously in this process. The working gas is divided into plasma gas source and carry gas flow. The plasma gas source enters the plasma excitation device directly at a flow rate of 20SLM-70SLM and is excited by the plasma excitation device at 100W-500W. The composite precursor is atomized at a rate of 20μL / min-500μL / min. The carry gas flow enters the plasma excitation device after passing through the atomization device at a flow rate of 1SLM-20SLM. The atmospheric pressure plasma coating spray gun (specifically referring to the spray gun outlet) is 1mm-15mm away from the mobile phone surface.

[0036] After the deposition process is completed, the mobile phone will be taken to the next production process by a robotic arm or a transfer fixture.

[0037] The workpiece (mobile phone) does not require pretreatment processes such as plasma cleaning (activation), nor does it require any special chemical or physical treatment. Compared to other processes that require connection to another plasma cleaner or a prior plasma cleaning (activation) step, this process offers advantages in saving production costs and improving production efficiency. The workpiece simply needs to be coated in a designated area along a set trajectory, without the need for specific masking methods or masking fixtures.

[0038] The working gas is typically one or more of N2, O2, Ar, He, and compressed air, while the carry gas is a gas with the same composition as the plasma source. Chemically reactive gases can interfere with the film composition during plasma chemical vapor deposition, especially the -OH groups that may be generated during the use of compressed air and O2, which will affect the hydrophobic properties of the film. Preferably, the plasma source and carry gas are a mixture of one or more of N2, Ar, and He.

[0039] Plasma is essentially an ionized charged mass. In this embodiment, the atomization method used is heating evaporation. Compared to the liquid and gaseous mixtures formed by ultrasonic atomization, heating evaporation can vaporize the precursor material more thoroughly. Compared to liquid or gas-liquid mixtures, gaseous precursors are more easily excited by plasma to generate active particles, which is beneficial for subsequent vapor deposition. Liquid in the liquid tank (a container temporarily storing the composite precursor in the cabinet of the atmospheric pressure plasma coating equipment) is dripped into the atomization chamber at a low flow rate via a mass flow controller. Preferably, the heating temperature of the atomization device is adjusted according to the boiling point of the liquid precursor. An observation window ensures that the set heating temperature can completely evaporate the composite precursor dripped in at the process parameters. The heated and evaporated composite precursor is carried into the plasma excitation device by a carry gas flow. During the process, the vaporized composite precursor is kept warm throughout to prevent re-liquefaction. The increased carry gas flow helps guide the flow of the gaseous precursor material, allowing it to enter the plasma excitation device at a relatively controllable or relatively stable flow rate.

[0040] Preferably, the composite precursor is atomized at a rate of 50 μL / min-200 μL / min, the plasma gas source enters the plasma excitation device directly at a flow rate of 40 SLM-70 SLM, and the carry gas flows through the atomization device at a rate of 1 SLM-5 SLM before entering the plasma excitation device. The excitation power of the plasma excitation device is 150W-350W, and the atmospheric pressure plasma coating spray gun continuously sprays the excited composite precursor and working gas at a distance of 1mm-5mm from the workpiece surface.

[0041] Specifically, the perfluoroacrylate monomer is selected from at least one of perfluoroalkyl ethyl acrylate, perfluorooctylpropyl acrylate, 2-perfluorooctyl acrylate, 1H,1H,2H,2H-perfluorooctyl acrylate, perfluorocyclohexyl methacrylate, perfluorohexyl ethyl acrylate, and perfluorobutyl ethyl methacrylate. The non-fluorinated acrylate monomer is selected from at least one of n-hexyl methacrylate, n-hexyl acrylate, butyl acrylate, lauryl acrylate, lauryl methacrylate, and 1,6-hexanediol dimethacrylate. The acrylate crosslinking agent is selected from at least one of 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, hexanediol dimethacrylate, trimethylolpropane trimethacrylate, and glycidyl methacrylate. The perfluoroacrylate monomers contain a large number of hydrophobic -F groups, ensuring the hydrophobic properties of the film. The unsaturated acrylate structure can break and form bonds under plasma bombardment, creating a polyacrylate-like structure. The non-fluorinated acrylate monomers and acrylate crosslinking agents selected in the formulation can improve the crosslinking degree after the perfluoroacrylate monomers polymerize, increasing the film's density and optimizing other film properties. The selection of the above composite precursors allows for vaporization in an industrially applicable and energy-efficient manner, avoiding problems such as insufficient active groups and poor film quality that may occur with liquid feed methods.

[0042] Preferably, the composite precursor comprises, by weight, 7-9 parts perfluoroacrylate monomer, 1-2.5 parts non-fluoroacrylate monomer, and 0.1-0.5 parts acrylate crosslinking agent. The embodiments of this application use a mixed precursor with a certain proportion, which can improve the shortcomings of conventional single materials such as fluorinated esters or silanes prepared under normal pressure plasma chemical vapor deposition conditions, such as poor weather resistance and poor wear resistance.

[0043] In addition, because acrylate monomers all have a certain tendency to self-polymerize, in order to adapt to industrial production and ensure the long-term stable preservation of the composite system, a polymerization inhibitor is mixed into the composite precursor. The amount of polymerization inhibitor is equivalent to 50ppm-100ppm of the total mass of the perfluoroacrylate monomer, the non-fluoroacrylate monomer, and the acrylate crosslinking agent. The polymerization inhibitor is selected from at least one of chain transfer type polymerization inhibitors and free radical type polymerization inhibitors. For example, p-hydroxyanisole, phenothiazine, or 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical, preferably 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical. The amount of polymerization inhibitor added should not be too much. The film formation principle of acrylate materials in the field of plasma chemical vapor deposition is the polymerization of acrylate materials. A small amount of polymerization inhibitor is added to avoid the denaturation of the material due to self-polymerization when it is not excited by plasma. Excessive addition will affect the coating effect of the composite material.

[0044] The composite precursor is prepared by the following steps: Perfluoroacrylate monomers and non-fluoroacrylate monomers are mixed in a preferred ratio, and then a polymerization inhibitor is added. The polymerization inhibitor can be dissolved in 1-2 mL of alcohol, ether, or ester before being added to the system. The amount of solvent should not be excessive to avoid introducing too many hydroxyl groups or ether bonds, which could affect the coating effect. After continuing low-speed mechanical stirring at room temperature for 15-30 minutes, an acrylate crosslinking agent in a preferred ratio is added to the mixture, and low-speed stirring is continued for another 30-60 minutes. During this process, the stirring speed is preferably 200-400 rpm to avoid potential changes in the system's properties due to vigorous mechanical stirring.

[0045] Example 1: N2 plasma gas was introduced into the generator section at a flow rate of 60 SLM and excited by 270 W of power. Perfluoroalkyl ethyl acrylate, n-hexyl acrylate, and glycidyl methacrylate were thoroughly mixed in a mass ratio of 8.5:1:0.5. The added polymerization inhibitor was 80 ppm of 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical (dissolved in 2 mL of ethanol). The mechanical stirring speed was 300 rpm, and the total stirring time was 60 min. The composite precursor was introduced into the atomizing device at a flow rate of 80 μL / min. The evaporation temperature of the atomizing device was set to 100 °C, and no liquid residue was observed in the atomizing chamber through the observation window. The composite precursor was carried into the generator section by N2 carrier gas at a flow rate of 2.0 SLM and coated on silicon wafers and PC sheets at a height of 2 mm. The operating speed of the robotic arm holding the substrates (silicon wafers and polycarbonate sheets) was adjusted to 80 mm / s. After coating, the samples were removed for testing.

[0046] The film thickness was measured using a thin film thickness meter, and the thickness of the silicon wafer in this coating was 34.2637 nm. The water droplet angle was measured using a water droplet angle meter; the water droplet angle of the silicon wafer sample was 117.774°, and the water droplet angle of the PC sheet sample was 117.324°, with a roll-off angle of 9°. After 1000 cycles of friction, the water droplet angle of the PC sheet was 104.329° (compared to 86.761° for the blank sample), indicating that the film layer has good hydrophobicity and a certain degree of wear resistance. The silicon wafer sample was placed at room temperature for 24 hours. The film thickness was measured to be 34.4821 nm, the water droplet angle was 117.556°, the film thickness change rate was 0.637%, and the water droplet angle decreased by 0.218°. After 72 hours, the film thickness was measured again to be 34.1742 nm, the water droplet angle was 117.203°, the film thickness change rate compared to the original value reached -0.261%, and the water droplet angle decreased by 0.571° compared to the original value.

[0047] Example 2 The other steps of Example 2 are the same as those of Example 1, except that the running speed of the robotic arm is adjusted to 100mm / s.

[0048] The film thickness was measured using a thin film thickness gauge, and the thickness of the silicon wafer in this coating was 33.9412 nm. The water droplet angle was measured using a water droplet angle meter; the water droplet angle of the silicon wafer was 117.897°, and the water droplet angle of the PC sample was 117.625°, with a roll-off angle of 9°. After 1000 rubbing tests, the water droplet angle of the PC sheet was 104.287°, indicating that the film layer has good hydrophobicity and a certain degree of wear resistance. The silicon wafer sample was placed at room temperature for 24 hours. The film thickness was measured to be 34.1742 nm, the water droplet angle was 117.529°, the film thickness change rate was 0.686%, and the water droplet angle decreased by 0.218°. After 72 hours, the film thickness was measured again to be 33.5076 nm, the water droplet angle was 117.113°, the film thickness change rate compared to the original value reached -1.278%, and the water droplet angle decreased by 0.784° compared to the original value.

[0049] Example 3: Plasma gas N2 was introduced into the generator section at a flow rate of 60 SLM and excited by 270 W of power. Monomers of perfluoroalkyl ethyl acrylate, n-hexyl acrylate, and glycidyl methacrylate were thoroughly mixed in a mass ratio of 5:4.5:0.5. The added polymerization inhibitor was 80 ppm of 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical (dissolved in 2 mL of ethanol). The mechanical stirring speed was 300 rpm, and the total stirring time was 60 min. The composite precursor was introduced into the atomizing device at a flow rate of 80 μL / min. The evaporation temperature of the atomizing device was set to 100 °C, and no liquid residue was observed in the atomizing chamber through the observation window. The composite precursor was carried into the generator section by N2 carrier gas at a flow rate of 2.0 SLM and coated on silicon wafers and PC wafers at a height of 2 mm. The robotic arm's operating speed was adjusted to 80 mm / s. After coating, the silicon wafers and PC wafers were removed for testing.

[0050] The film thickness was measured using a thin film thickness meter, and the thickness of the silicon wafer in this coating was 28.3049 nm. The water droplet angle was measured using a water droplet angle meter, and the water droplet angle of the silicon wafer in this coating was 105.831°, while that of the PC sample was 106.334°, and the roll-off angle was 32°. After 1000 rubbing tests, the water droplet angle was 96.623°, indicating that although the film layer has a certain degree of hydrophobicity, it does not have good wear resistance. Meanwhile, the silicon wafer sample was placed at room temperature for 24 hours. The film thickness was measured to be 28.3619 nm, the water droplet angle was 105.820°, the film thickness change rate reached 0.201%, and the water droplet angle decreased by 0.011°. After 72 hours, it was tested again. The film thickness was 28.0519 nm, the water droplet angle was 105.458°, the film thickness change rate compared to the original value reached -0.894%, and the water droplet angle decreased by -1.373° compared to the original value.

[0051] Comparative Example 1

[0052] The plasma gas source N2 was introduced into the generator section at a flow rate of 60 SLM and excited by 270 W of power. Perfluoroalkyl ethyl acrylate monomer was introduced into the atomizing device at a flow rate of 80 μL / min. The evaporation temperature of the atomizing device was set to 100 °C, and no liquid residue was observed in the atomizing chamber through the observation window. The precursor was carried into the generator section by N2 carrier gas at a flow rate of 2.0 SLM and coated on silicon wafers and PC wafers at a height of 2 mm. The robotic arm's operating speed was adjusted to 80 mm / s. After coating, the samples were removed for testing.

[0053] The film thickness was measured using a thin film thickness gauge, and the thickness of the silicon wafer in this coating was 33.9922 nm. The water droplet angle was measured using a water droplet angle meter; the water droplet angle of the silicon wafer was 118.916°, and the water droplet angle of the PC sample was 118.217°, with a roll-off angle of 9°. After 1000 rubbing tests, the water droplet angle of the PC sheet was 92.818°, indicating that although the film layer has good hydrophobicity, it does not possess excellent wear resistance. Meanwhile, the silicon wafer sample was placed at room temperature for 24 hours. The film thickness was measured to be 26.3288 nm, the water droplet angle was 115.517°, the film thickness change rate reached -22.545%, and the water droplet angle decreased by 3.399°. After 72 hours, it was tested again. The film thickness was 25.5822 nm, the water droplet angle was 113.406°, the film thickness change rate compared to the original value reached -24.741%, and the water droplet angle decreased by 5.51° compared to the original value.

[0054] Comparing Example 1 and Example 2, the film thickness obtained in Example 2 is slightly smaller than that in Example 1 due to the faster operating speed of the robotic arm. However, the droplet angle, wear resistance, and the degree of decay of the droplet angle and film thickness over time are all similar, indicating that the formulation and process design of this composite material can be adjusted within a certain range according to the operating speed of the production line, and is suitable for online industrial production.

[0055] Comparing Examples 1, 2, and 3, it can be seen that Examples 1 and 2, with their preferred formulations, exhibit better results. Example 3 shows inferior hydrophobicity compared to Examples 1 and 2, and its wear resistance is also affected accordingly. However, it is noteworthy that the water droplet angle and film thickness of the film in Example 3 show relatively small changes over time, indicating that the fluorine-free acrylate monomer and acrylate crosslinking agent used in the composite material help improve film formation and reduce the attenuation of the film thickness and water droplet angle. The content of the perfluoroacrylate monomer is crucial for the hydrophobic performance of the film.

[0056] Comparing Examples 1, 2, 3, and Comparative Example 1, it is shown that under the same evaporation and atomization conditions and with sufficient evaporation, the film density is poorer and the wear resistance is correspondingly affected when the composite material is not used. This demonstrates that the acrylate and acrylate crosslinking agent used in the composite material help improve film formation, wear resistance, and film thickness droplet angle attenuation.

[0057] This application utilizes an online atmospheric pressure plasma chemical vapor deposition (IPCVD) system, employing a one-step film formation process. The formulation and deposition parameters have been designed to produce films with excellent weather resistance, abrasion resistance, and light transmittance. It eliminates the need for vacuum PCVD, avoiding the complex multi-layer film formation required in vacuum PCVD. The method described in this application is highly efficient and has a very short processing time, making it well-suited for online production. It can be directly integrated with upstream and downstream production lines, and the equipment operating speed can be adjusted within a certain range based on the operating speeds of the upstream and downstream production lines (with minimal impact on film performance), thus meeting the requirements of high-efficiency production.

[0058] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0059] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for depositing hydrophobic films using atmospheric pressure plasma deposition, characterized in that, The composite precursor, which is entirely in liquid state, is atomized in an atomizing device, carried into a plasma excitation device by working gas, and then sprayed out from an atmospheric pressure plasma coating spray gun; the composite precursor comprises 8.5 parts perfluoroacrylate monomer, 1 part non-fluoroacrylate monomer and 0.5 parts acrylate crosslinking agent by mass. The composite precursor contains a polymerization inhibitor, the amount of which is equivalent to 50ppm-100ppm of the total mass of the perfluoroacrylate monomer, the non-fluoroacrylate monomer, and the acrylate crosslinking agent. The polymerization inhibitor is a 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical. The composite precursor is atomized at a rate of 20 μL / min-200 μL / min. The working gas is divided into a plasma gas source and a carrier gas flow. The plasma gas source enters the plasma excitation device directly at a flow rate of 40 SLM-70 SLM. The carrier gas flows through the atomization device at a flow rate of 1 SLM-5 SLM before entering the plasma excitation device. The excitation power of the plasma excitation device is 150W-350W. The atmospheric pressure plasma coating spray gun is 1mm-5mm away from the workpiece surface. The preparation steps of the composite precursor include: The perfluoroacrylate monomer and the non-fluoroacrylate monomer are mixed to obtain a mixed monomer; Dissolve the polymerization inhibitor in 1 ml-2 ml of alcohol, ether or ester to obtain a polymerization inhibitor solution; Add the polymerization inhibitor solution to the mixed monomers and stir at 200 rpm-400 rpm for 15 min-30 min; Continue adding the acrylate crosslinking agent and stir at 200 rpm-400 rpm for 30 min-60 min to obtain the composite precursor; The perfluoroacrylate monomer is perfluoroalkyl ethyl acrylate, the non-fluoroacrylate monomer is n-hexyl acrylate, and the acrylate crosslinking agent is glycidyl methacrylate.

2. The method for depositing hydrophobic films using atmospheric pressure plasma deposition according to claim 1, characterized in that, The working gas is selected from at least one of N2, Ar, and He.

3. The method for depositing hydrophobic films using atmospheric pressure plasma deposition according to claim 1, characterized in that, The atomization method of the atomizing device is heating evaporation, and the carrying gas flow is kept warm between the atomizing device and the plasma excitation device.