A diamond-like hydrophilic coating and its preparation method and application

Abstract

The present invention discloses a diamond-like hydrophilic coating, a preparation method, and an application thereof. The preparation method comprises the following steps: using magnetron sputtering technology to sputter a mosaic target with oxygen and an inert gas, controlling the oxygen flow rate to 5 to 25 sccm, and depositing the diamond-like hydrophilic coating on the substrate surface, i.e., obtaining the diamond-like hydrophilic coating on the substrate surface; the mosaic target is made by uniformly embedding a silicon target in a graphite target. By selecting a mosaic target, the present invention avoids the problem of poor repeatability caused by using a silicon / graphite spliced ​​target in which silicon is concentrated in the upper right corner of the spliced ​​target. Furthermore, when preparing the diamond-like hydrophilic coating, the present invention controls the atomic content ratio of silicon and oxygen in the diamond-like hydrophilic coating by regulating the oxygen flow rate to obtain sufficient hydrophilic Si-O-Si bonds, thereby improving the hydrophilicity of the diamond-like coating.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrophilic coatings, and more particularly to a diamond-like hydrophilic coating and a preparation method and application thereof. Background Art

[0002] Hydrophilic coating is a multifunctional coating with important applications in the field of surface protection. For example, hydrophilic coating has a self-cleaning effect. Hydrophilic coating can use water droplets sliding on the coating surface to carry away pollutants. The water droplets will spread completely on the coating surface to form a water film, isolating the pollutants from the coating surface. Under the action of external forces such as wind or gravity, the pollutants will automatically fall off to achieve a self-cleaning effect. Hydrophilic coating has an anti-fog effect. Car windshields and rearview mirrors often condense into water droplets on their surfaces due to fog. When light passes through the water droplets, it will form a certain amount of refraction and reflection, resulting in blurred vision. Hydrophilic coating can reduce the refraction and reflection of light by water droplets by reducing the contact angle of water droplets on the glass surface, which can effectively achieve an anti-fog effect. In addition, in the fields of microfluidic devices and microdevices, hydrophilic coatings can also be used to regulate liquid transport and conduction.

[0003] Diamond-like carbon (DLC) coating is made of sp 2 -C and sp 3 -C hybrid bonds, it has excellent properties such as extremely high hardness and wear resistance, low friction coefficient and thermal expansion coefficient, high elastic modulus, and good chemical stability. It is widely used in the field of surface protection. However, DLC coatings usually exhibit certain hydrophobic properties (contact angle greater than 60°), which limits its application in some hydrophilic hard functional surface protection fields. The article (Wei Dai, Liang Wu and Qimin Wang. Structure and Property of Diamond-like Carbon Coating with Si and O Co-Doping Deposited by Reactive Magnetron Sputtering [J]. J. Compos. Sci. 2023, 7, 180.) used magnetron sputtering technology to sputter a silicon / graphite spliced ​​target using a mixed gas of C2H2, O2 and Ar to prepare a Si and O co-doped diamond-like coating. This method has poor reproducibility because the silicon of the silicon / graphite spliced ​​target used is concentrated in the upper right corner of the spliced ​​target, which places high operational requirements on technicians. Therefore, if the influence of the positional relationship between the substrate and the silicon / graphite spliced ​​target on the Si and O content of the prepared diamond-like coating is not fully understood, the Si and O content of the diamond-like coating prepared each time will change; in addition, the hydrophilicity of the diamond-like coating is not strong.

[0004] Therefore, it is of great significance to develop a method for preparing a diamond-like hydrophilic coating that has strong repetitive stability and makes the diamond-like coating highly hydrophilic. Summary of the Invention

[0005] The primary purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art methods, such as poor repeatability and poor hydrophilicity of the diamond-like coating, and to provide a method for preparing a diamond-like hydrophilic coating.

[0006] Another object of the present invention is to provide a diamond-like hydrophilic coating.

[0007] Another object of the present invention is to provide an application of a diamond-like hydrophilic coating in the field of surface protection.

[0008] The above technical objectives of the present invention are achieved through the following technical solutions:

[0009] A method for preparing a diamond-like hydrophilic coating comprises the following steps:

[0010] The magnetron sputtering technology is used to sputter the embedded target with oxygen and inert gas, and the oxygen flow rate is controlled to be 5-25 sccm to deposit on the substrate surface, that is, the diamond-like hydrophilic coating is obtained on the substrate surface;

[0011] The mosaic target is made by uniformly embedding a silicon target in a graphite target.

[0012] The mosaic target selected in the present invention is to evenly distribute the silicon target on the graphite target, which is convenient for technicians to operate. If an ordinary silicon / graphite spliced ​​target is used, because the silicon in the spliced ​​target is concentrated in the upper right corner of the silicon / graphite spliced ​​target, the operator needs to understand the influence of the positional relationship between the substrate and the silicon / graphite spliced ​​target on the Si and O contents of the prepared diamond-like coating, in order to obtain a coating with stable Si and O contents. However, the present application uses a mosaic target to replace the silicon / graphite spliced ​​target. Ordinary technicians do not need to understand the influence of the positional relationship between the substrate and the silicon / graphite spliced ​​target on the Si and O contents of the prepared diamond-like coating, that is, a diamond-like coating with stable Si and O contents can be prepared, that is, the method of the present application has strong repeatability and stability, which avoids the problem of poor repeatability of the method caused by the use of spliced ​​targets.

[0013] Prior art uses a mixed gas of C2H2, O2, and Ar to sputter a silicon / graphite spliced ​​target to produce a Si and O co-doped diamond-like coating. This Si and O co-doped diamond-like coating contains four elements: carbon, silicon, oxygen, and hydrogen, and exhibits C-C, Si-C, Si-O-Si, C=C, Si-H, and OH bonds, as well as CH2. The present invention uses a hydrophilic diamond-like coating prepared by sputtering a mosaic target with O2 and an inert gas (such as Ar) to contain only three elements: carbon, silicon, and oxygen, and primarily exhibits C-C, Si-C, and Si-O-Si bonds. When the atomic content of silicon and oxygen in the diamond-like hydrophilic coating of the present invention is the same as or similar to the atomic content of silicon and oxygen in the Si and O co-doped diamond-like coating of the prior art, although the diamond-like hydrophilic coating of the present invention lacks hydrophilic OH bonds, which affects the hydrophilicity of the coating, the present invention does not use C2H2, which greatly reduces the content of hydrophobic C=C bonds in the diamond-like hydrophilic coating, and prevents silicon and oxygen from combining with hydrogen, promoting the combination of silicon and oxygen to form more hydrophilic Si-O-Si bonds, thereby greatly improving the hydrophilicity of the coating.

[0014] In addition, when preparing a diamond-like hydrophilic coating by sputtering a mosaic target with oxygen and an inert gas, the present invention controls the atomic content ratio of silicon and oxygen elements in the diamond-like hydrophilic coating (0.83 to 2.80) by regulating the oxygen flow rate (5 to 25 sccm), thereby obtaining sufficient hydrophilic Si-O-Si bonds, thereby improving the hydrophilicity of the diamond-like coating.

[0015] Specifically, when the oxygen flow rate is 5 to 25 sccm, that is, the atomic content ratio of silicon and oxygen elements (Si / O) in the diamond-like coating is in the range of (0.83 to 2.80), the diamond-like hydrophilic coating has sufficient hydrophilic Si-O-Si bonds, which is beneficial to improving the hydrophilicity of the diamond-like hydrophilic coating.

[0016] Specifically, the flow rate of the oxygen gas is 10 to 20 sccm.

[0017] When the oxygen flow rate is too high (>20 sccm), the oxygen atom content in the diamond-like hydrophilic coating is too high, and O and Si form amorphous a-SiO x The amorphous phase will cause a certain degree of decrease in the hydrophilicity and hardness of the coating. When the oxygen flow rate is too low (<10sccm), the oxygen atom content in the diamond-like hydrophilic coating is too low and the silicon atom content is too high. The low oxygen atom content is not conducive to the formation of sufficient hydrophilic Si-O-Si bonds, which will affect the hydrophilicity of the diamond-like hydrophilic coating; while the high silicon atom content will cause the excess Si to combine with C to form Si-C bonds, destroying the carbon network structure of the diamond hydrophilic coating and causing a decrease in hardness.

[0018] The oxygen used in the present invention is high-purity oxygen.

[0019] Specifically, the total flow rate of the oxygen gas and the inert gas is 300 sccm.

[0020] Specifically, the flow rate of the inert gas is 275-295 sccm.

[0021] Furthermore, the flow rate of the inert gas is 280-290 sccm.

[0022] Specifically, the inert gas is argon.

[0023] In the present invention, the thickness of the silicon target used to prepare the mosaic target is consistent with the thickness of the graphite target.

[0024] When preparing the mosaic target in the present invention, the silicon target used can be of any shape, including common cylinders, cones, cubes, cuboids, truncated cones, prisms, etc.; the material of the silicon target used is a silicon-containing target material, including a high-purity silicon target; the number of silicon targets used is at least 1.

[0025] Furthermore, when the silicon target is cylindrical, its diameter is 4 to 6 mm.

[0026] Furthermore, the row spacing of the silicon target is 20-30 mm, and the column spacing is 40-50 mm.

[0027] When preparing the mosaic target of the present invention, the graphite target used can be of any shape, including common cylinders, cones, cubes, cuboids, truncated cones, prisms, etc.; the material of the graphite target used is a target material containing graphite, including a high-purity graphite target; the number of graphite targets used is at least one.

[0028] When the graphite target is in the shape of a cuboid, its length is 300-380 mm and its width is 60-80 mm.

[0029] When the ratio of the number of the graphite targets to the number of the silicon targets is 1:(1-48).

[0030] Specifically, in the mosaic target, the surface area of ​​the silicon target accounts for 0.07 to 3.5% of the surface area of ​​the graphite target.

[0031] Specifically, in the diamond-like hydrophilic coating, the atomic content ratio of silicon element Si to oxygen element O (Si / O) is 0.83 to 2.80, and can be 0.83, 1.23, 2.01, 2.25 or 2.80.

[0032] Specifically, in the diamond-like hydrophilic coating, the atomic content of silicon element Si is 11.2-15.2%.

[0033] Furthermore, in the diamond-like hydrophilic coating, the atomic content of silicon element Si is 12.5-14.5%.

[0034] Specifically, in the diamond-like hydrophilic coating, the atomic content of oxygen element O is 6.4-13.5%.

[0035] Furthermore, in the diamond-like hydrophilic coating, the atomic content of oxygen element O is 6.4-10.2%.

[0036] In the present invention, atomic content refers to the content in terms of the number of atoms, and atomic content ratio refers to the percentage of the content in terms of the number of atoms.

[0037] The magnetron sputtering technology of the present invention can be implemented by conventional magnetron sputtering equipment in the art, and the conventional magnetron sputtering equipment can be a magnetron sputtering coating machine.

[0038] Specifically, the substrate is made of one or more of silicon, cemented carbide, glass or stainless steel.

[0039] Furthermore, the substrate needs to be cleaned before use.

[0040] Furthermore, the cleaning includes at least ultrasonic cleaning and glow cleaning.

[0041] In the present invention, the cleaning agent used in the ultrasonic cleaning is one or both of an organic solvent and water; the organic solvent used is a conventional solvent used for cleaning substrates in the art, including anhydrous ethanol, acetone, and the like.

[0042] The ultrasonic cleaning method of the present invention comprises the following steps: ultrasonically cleaning a substrate with an organic solvent, then rinsing the substrate with water, and then drying the substrate.

[0043] In the present invention, the glow cleaning is to perform glow etching on the substrate by using an ion source using a magnetron sputtering technology under vacuum conditions.

[0044] The glow etching process of the present invention comprises the following steps: using magnetron sputtering technology, placing the ultrasonically cleaned substrate on a work support in a vacuum chamber, and evacuating the vacuum chamber to a vacuum degree of less than 5.0×10 -3 Pa, turn on the ion source, introduce 100-400 sccm of inert gas, maintain the strong pressure at 0.8-1.0 Pa, set the ion source power to 1.5 kW, set the workpiece support bias to -500-1000 V, and the etching cleaning process lasts for 5-30 minutes.

[0045] A diamond-like hydrophilic coating is prepared by the above preparation method.

[0046] The application of the above-mentioned diamond-like hydrophilic coating in the field of surface protection should also be within the protection scope of the present invention.

[0047] The surface protection field of the present invention relates to self-cleaning, oil-water separation, anti-fog, intelligent controllable water penetration, water collection and biomedicine.

[0048] The present invention has the following beneficial effects:

[0049] The preparation method of the diamond-like hydrophilic coating of the present invention avoids the problem of poor repeatability of the method caused by using a silicon / graphite spliced ​​target in which silicon is concentratedly distributed on the upper right side of the spliced ​​target by selecting a mosaic target in which silicon targets are evenly distributed on the graphite target.

[0050] The method for preparing a diamond-like hydrophilic coating of the present invention comprises the following steps: when preparing the diamond-like hydrophilic coating by sputtering a mosaic target with oxygen and an inert gas, the atomic content ratio of silicon and oxygen in the diamond-like hydrophilic coating is controlled (0.83 to 2.80) by regulating the oxygen flow rate (5 to 25 sccm), thereby obtaining sufficient hydrophilic Si-O-Si bonds, thereby improving the hydrophilicity of the diamond-like coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a top view of the structural schematic diagram of the mosaic target.

[0052] Figure 2 This is the infrared spectrum of the diamond-like hydrophilic coating of Example 1.

[0053] Figure 3 3 are contact angle diagrams of Example 1 and Comparative Examples 1 and 3, Figure a is the contact angle diagram of Example 1, Figure b is the contact angle diagram of Comparative Example 1, and Figure c is the contact angle diagram of Comparative Example 3. DETAILED DESCRIPTION

[0054] The present invention is further described below with reference to the examples. These examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Experimental methods in the following examples where specific conditions are not specified are generally performed in accordance with conventional conditions in the art or the conditions recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from conventional markets. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection claimed in the present invention.

[0055] In various embodiments and comparative examples of the present invention:

[0056] The oxygen used is high-purity oxygen;

[0057] The mosaic target is prepared by the following steps: 14 high-purity silicon targets with a cylindrical shape and a diameter of 5 mm are evenly embedded in a high-purity graphite target with a rectangular shape, a length (L) of 360 mm, and a width (W) of 75 mm, wherein the high-purity silicon target and the high-purity graphite target have the same thickness of 5 mm; in the mosaic target, the surface area of ​​the high-purity silicon target accounts for 1.0% of the surface area of ​​the high-purity graphite target; the row spacing of the high-purity silicon targets is 30 mm, and the column spacing is 40 mm.

[0058] Figure 1 It is a top view of the schematic diagram of the structure of the mosaic target.

[0059] Example 1

[0060] This embodiment provides a diamond-like hydrophilic coating, the preparation method of which includes the following steps:

[0061] S1. Ultrasonic cleaning:

[0062] The polished silicon wafer was ultrasonically cleaned with acetone and anhydrous ethanol in sequence, then rinsed with deionized water, and then dried with ordinary nitrogen.

[0063] S2. Glow cleaning:

[0064] The silicon wafer after ultrasonic cleaning was placed on the work stand of the vacuum chamber using a magnetron sputtering coating machine and the vacuum was pumped down to a vacuum degree of less than 5.0×10 -3 Pa, turn on the ion source, introduce 400 sccm of argon, maintain the strong pressure at 1.0 Pa, set the ion source power to 1.5 kW, set the workpiece support bias to -500 V, and the etching and cleaning process lasts for 20 minutes;

[0065] S3. Preparation of Diamond-Like Carbon Hydrophilic Coating:

[0066] A magnetron sputtering coating machine was used, the embedded target was turned on, oxygen with a flow rate of 15 sccm and argon with a flow rate of 285 sccm were introduced, the pressure was controlled to be 0.6 Pa, the workpiece support bias was -150 V, and the magnetron sputtering power supply power was 2.5 kW, and the substrate surface was deposited for 1.5 hours to obtain the diamond-like hydrophilic coating on the substrate surface.

[0067] Examples 2 to 5 and Comparative Example 1

[0068] Examples 2 to 5 provide a diamond-like hydrophilic coating, and Comparative Example 1 provides a diamond-like coating. Compared with Example 1, the difference between Examples 2 to 5 and Comparative Example 1 is that the flow rates of oxygen and argon introduced in step S3 are different, as shown in the following table:

[0069] Table 1 Flow rates of oxygen and argon introduced in step S3 of Examples 1 to 5 and Comparative Example 1

[0070] Oxygen flow rate (sccm) Argon flow rate (sccm) Example 1 15 285 Example 2 10 290 Example 3 20 280 Example 4 5 295 Example 5 25 275 Comparative Example 1 0 300

[0071] Comparative Example 2

[0072] This comparative example provides a diamond-like carbon coating. Compared with Example 1, the only difference in this comparative example is that a graphite target is used instead of a mosaic target in step S3, and pure oxygen is not introduced (the pure oxygen flow rate is 0 sccm).

[0073] Comparative Example 3

[0074] This comparative example provides a diamond-like hydrophilic coating, the preparation method of which comprises the following steps:

[0075] S1. Ultrasonic cleaning:

[0076] The polished silicon wafer was ultrasonically cleaned with acetone and anhydrous ethanol in sequence, then rinsed with deionized water, and then dried with ordinary nitrogen.

[0077] S2. Glow cleaning:

[0078] The silicon wafer after ultrasonic cleaning was placed on the work stand of the vacuum chamber using a magnetron sputtering coating machine and the vacuum was pumped down to a vacuum degree of less than 5.0×10 -3 Pa, turn on the ion source, introduce 400 sccm of argon, maintain the strong pressure at 1.0 Pa, set the ion source power to 1.5 kW, set the workpiece support bias to -500 V, and the etching and cleaning process lasts for 20 minutes;

[0079] S3. Preparation of Diamond-Like Carbon Hydrophilic Coating:

[0080] A magnetron sputtering coating machine was used, the embedded target was turned on, acetylene gas C2H2 with a flow rate of 30 sccm, oxygen with a flow rate of 15 sccm, and argon with a flow rate of 255 sccm were introduced, the pressure was controlled to be 0.6 Pa, the workpiece support bias was -150 V, and the magnetron sputtering power supply power was 2.5 kW, and the substrate surface was deposited for 1.5 hours to obtain the diamond-like hydrophilic coating on the substrate surface.

[0081] Performance Testing

[0082] 1. The diamond-like carbon hydrophilic coating of Example 1 was characterized by infrared spectroscopy.

[0083] Figure 2 This is the infrared spectrum of the diamond-like hydrophilic coating of Example 1. Figure 2 As shown, wave number 1000cm -1 The peak at is the characteristic peak of hydrophilic Si-O-Si bond, that is, the diamond-like hydrophilic coating in Example 1 has hydrophilic Si-O-Si bond.

[0084] The infrared spectra of the diamond-like hydrophilic coatings of Examples 2 to 5 are similar to those of Example 1. Figure 2 similar.

[0085] 2. The coatings of each embodiment and comparative example were tested as follows:

[0086] (1) The atomic contents of silicon Si and oxygen O in the coatings of each embodiment and comparative example were measured using an energy dispersive spectrometer (EDS), and the atomic content ratio of silicon Si to oxygen O (Si / O) of each coating was calculated;

[0087] (2) Measure the contact angle of the coatings of each embodiment and comparative example using a contact angle meter;

[0088] (3) The hardness of the coatings of each embodiment and comparative example was measured using a nanoindenter.

[0089] Table 2 Test results of coatings in various embodiments and comparative examples

[0090]

[0091]

[0092] Figure 3 3 are contact angle diagrams of Example 1 and Comparative Examples 1 and 3, Figure a is the contact angle diagram of Example 1, Figure b is the contact angle diagram of Comparative Example 1, and Figure c is the contact angle diagram of Comparative Example 3.

[0093] From Table 2 and Figure 3 It can be seen that:

[0094] (1) By comparing Examples 1 to 5 and Comparative Examples 1 and 2, it can be seen that the present invention adopts magnetron sputtering technology to control the atomic content ratio of silicon and oxygen in the diamond-like hydrophilic coating (0.83 to 2.80) by regulating the oxygen flow rate (5 to 25 sccm) when sputtering a mosaic target with oxygen and an inert gas, thereby obtaining sufficient hydrophilic Si-O-Si bonds and thereby improving the hydrophilicity of the diamond-like coating. Moreover, when the oxygen flow rate is 10 to 20 sccm, the diamond-like coating has a higher hydrophilicity.

[0095] (2) By comparing Example 1 and Comparative Example 3, it can be seen that the addition of acetylene gas C2H2 will increase the content of hydrophobic C=C bonds in the diamond-like hydrophilic coating, and at the same time promote the combination of silicon and oxygen elements with hydrogen elements, reducing the number of hydrophilic Si-O-Si bonds formed by the combination of silicon and oxygen elements, thereby greatly reducing the hydrophilicity of the coating.

[0096] 3. Repeated stability test of the method

[0097] The experiment of Example 1 was repeated three times, and it was found that the Si content of the diamond-like coating prepared each time was 13.8% and the O content was 6.9%, indicating that the method of the present invention has strong repeatability. By selecting a mosaic target, the problem of poor repeatability of the method caused by using a silicon / graphite spliced ​​target in which silicon is concentrated in the upper right corner of the spliced ​​target is avoided.

[0098] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a diamond-like hydrophilic coating, characterized in that: The steps include: Using magnetron sputtering technology, oxygen and inert gas are used to sputter the embedded target, and the oxygen flow rate is controlled to be 5-25 sccm to deposit on the substrate surface, that is, the diamond-like hydrophilic coating is obtained on the substrate surface; The mosaic target is made by uniformly embedding a silicon target in a graphite target; In the diamond-like hydrophilic coating, the atomic content of silicon element Si is 11.2-15.2%, and the atomic content of oxygen element O is 5.4-13.5%; The atomic content ratio of silicon element Si and oxygen element O is 0.83~2.

80.

2. The preparation method according to claim 1, characterized in that The flow rate of the oxygen gas is 10-20 sccm.

3. The preparation method according to claim 1, characterized in that The total flow rate of the oxygen gas and the inert gas is 300 sccm.

4. The preparation method according to claim 1, characterized in that The flow rate of the inert gas is 275-295 sccm.

5. The preparation method according to claim 1, characterized in that In the diamond-like hydrophilic coating, the atomic content of oxygen element O is 6.4-13.5%.

6. The preparation method according to claim 1, characterized in that In the mosaic target, the surface area of ​​the silicon target accounts for 0.07-3.5% of the surface area of ​​the graphite target.

7. A diamond-like hydrophilic coating, characterized in that: Prepared by the preparation method according to any one of claims 1 to 4.

8. Use of the diamond-like hydrophilic coating according to claim 7 in the field of surface protection.

Images