Super-hydrophobic surface for DNA synthesis and preparation method thereof

Abstract

According to the super-hydrophobic surface for DNA synthesis and the preparation method of the super-hydrophobic surface, a patterned hydrophobic microstructure and a super-hydrophobic coating are organically combined on the surface, and the surface hydrophobicity is remarkably enhanced. The super-hydrophobic coating is constructed by adopting a two-step method and comprises a hydrophobic resin coating and a silane hydrophobic coating, durability and hydrophobicity are both considered, the hydrophobic coating is not prepared by adopting a common fluorocarbon chain, and a synthetic surface which is efficient, durable, simple in structure and good in biological safety is provided for DNA synthesis.

Description

Technical Field

[0001] This invention relates to the fields of material surface modification and biosynthesis, specifically to a superhydrophobic surface for DNA synthesis and its preparation method. Background Technology

[0002] The phosphoramide process is currently the most widely used technology in DNA synthesis. This synthesis process relies not only on hydrophilic surfaces to promote product adsorption but also on hydrophobic surfaces to ensure the accuracy of the synthesis process. The conventional method for superhydrophobic surface treatment in existing DNA synthesis devices is to coat the substrate surface with fluorinated compounds to form a superhydrophobic coating (CN118022867). However, fluorides are difficult to degrade, causing serious environmental pollution. Given the environmental hazards of fluorinated compounds, the European Union introduced legislation restricting fluorinated compounds in 2023, further promoting the development of fluorine-free superhydrophobic coating technology. Considering that DNA synthesis involves life safety, especially the potential harm of fluorinated compounds to human health, DNA synthesis devices with fluorine-free superhydrophobic coatings have broad application prospects. Furthermore, the degradation of hydrophobic properties during use can significantly reduce the yield of DNA synthesis, thus affecting DNA synthesis efficiency. Therefore, the durability of superhydrophobic surfaces is a key factor affecting DNA synthesis efficiency. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a fluoride-free coating that combines hydrophobicity and durability into a superhydrophobic surface for DNA synthesis.

[0004] The superhydrophobic surface includes patterned hydrophobic microstructures and a superhydrophobic coating.

[0005] The patterned hydrophobic microstructures include surface-patterned nanopillars, nanomesh, or nanotruncated cones.

[0006] Preferably, the patterned hydrophobic microstructure includes nanopillars, nanogrids, or nanotruncated cones with regularly repeating triangles, arrows, stripes, or double inverted triangles on the surface.

[0007] The superhydrophobic coating comprises an underlying hydrophobic layer and a silane superhydrophobic coating.

[0008] Preferably, the underlying hydrophobic layer comprises a hydrophobic resin coating.

[0009] In another aspect, the present invention provides a method for preparing the superhydrophobic surface for DNA synthesis, the method comprising the steps of: a. constructing a hydrophobic microstructure; b. coating a hydrophobic layer.

[0010] The construction of hydrophobic microstructures includes constructing regularly repeating patterned micro / nano structures on the surface of a substrate material, specifically including the following steps: 1) constructing hydrophobic microstructures; 2) patterning the surface of the microstructures.

[0011] The construction of the microstructure includes etching microcylindrical arrays, mesh microstructures, or frustum microstructures on the surface of the substrate material.

[0012] Preferably, the microstructure is a microcylindrical array.

[0013] The surface patterning involves constructing regularly repeating hydrophobic patterns on the surface of the microstructure.

[0014] The regularly repeating hydrophobic patterns include triangular arrays, arrow arrays, bar arrays, or inverted double triangle arrays.

[0015] Preferably, the hydrophobic pattern is a triangular array.

[0016] The hydrophobic coating includes coating a composite superhydrophobic coating on the material surface, comprising the following steps: 1) coating a hydrophobic substrate A; 2) coating a silane superhydrophobic coating B on the hydrophobic substrate obtained in step 1).

[0017] Specifically, the hydrophobic undercoating includes the following steps: 1) cleaning the substrate material; 2) preparing the undercoating hydrophobic solution; 3) applying the undercoating hydrophobic coating A.

[0018] The underlying hydrophobic aqueous solution comprises a hydrophobic resin, low molecular weight modified particles, and a solvent.

[0019] Preferably, the mass ratio of the hydrophobic resin, low molecular weight modified particles, and solvent is between 0.1~0.5:0.02~0.5:1.

[0020] The hydrophobic resin includes polycarbonate-type polyurethane, polysiloxane polyurethane, silicone-modified resin, or silicone.

[0021] Preferably, the hydrophobic resin includes polysiloxane polyurethane or silicone.

[0022] The low-molecular-weight modified particles include silica, talc, modified calcium carbonate, polysilsesquioxane, stearic acid, or oleic acid.

[0023] Preferably, the low-molecular-weight modified particles include talc or modified calcium carbonate.

[0024] Specifically, the silane superhydrophobic coating process includes: 1) preparing a silane superhydrophobic solution and 2) coating a silane superhydrophobic coating B onto a hydrophobic substrate material.

[0025] The silane superhydrophobic aqueous solution comprises a mixture of methyldimethoxysilane, methanol, tetraethoxysilane, malonic acid aqueous solution, and ammonia.

[0026] The ratio of the methyldimethoxysilane, methanol, tetraethoxysilane, malonic acid aqueous solution and ammonia water by mass is between 3~15:80~120:1~5:3~8:3~8.

[0027] In this application, steps a and b are used only to indicate differences, not their order. The surface microstructure construction and superhydrophobic layer coating steps are not sequential.

[0028] The beneficial effects of this invention are that, compared with the prior art, it organically combines a superhydrophobic coating with a patterned hydrophobic surface and employs a two-step method to construct the superhydrophobic coating, thereby enhancing the hydrophobic properties of the coating while solving the problem of poor durability of the superhydrophobic coating. Furthermore, the coating of this invention does not contain conventional technologies such as fluorocarbon chains commonly used in the prior art, meeting the requirements of green and environmentally friendly practices. It provides a simple, efficient, biosafety-friendly, and durable hydrophobic surface and its preparation method for DNA synthesis. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the process for preparing superhydrophobic surfaces according to the present invention, wherein (a) is a scheme of first performing coating treatment and then constructing microstructure, and (b) is a scheme of first constructing microstructure and then performing coating treatment.

[0031] Figure 2 This is a schematic diagram of the hydrophobic patterned surface in this invention.

[0032] Figure 3 This is a schematic diagram of a superhydrophobic surface in this invention where a coating process is performed first, followed by the construction of a microstructure.

[0033] Figure 4 This is a schematic diagram of a superhydrophobic surface in this invention, where a microstructure is first constructed and then coated. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and specific examples.

[0035] 1. Preparation of superhydrophobic coatings

[0036] 1.1) Cleaning the substrate material: In a gaseous atmosphere such as air, set the vacuum degree to 25-50pa, the temperature to 30-45℃, and the gas flow rate to 50-100sscm, and perform plasma cleaning on the substrate surface for 100-300s.

[0037] The substrate material can be a polymer, metal or silicone, or other commonly used substrate materials in the art. This application does not limit the choice of substrate material, but stainless steel and polystyrene are used as examples.

[0038] 1.2) Preparation of bottom layer hydrophobic solution: Mix hydrophobic resin, low molecular weight modified particles and solvent in a mass ratio of 0.1~0.5:0.02~0.5:1 to obtain bottom layer hydrophobic solution A.

[0039] The hydrophobic resin includes polycarbonate-type polyurethane, polysiloxane polyurethane, silicone-modified resin or silicone, and this application uses polysiloxane polyurethane as an example; the low molecular weight modified particles include silica, talc, modified calcium carbonate, polysilsesquioxane, stearic acid, oleic acid, etc., and this application uses talc and modified calcium carbonate as examples.

[0040] 1.3) Preparation of silane superhydrophobic water solution: Methyldimethoxysilane, methanol, tetraethoxysilane, malonic acid aqueous solution and ammonia water are mixed in a mass ratio of 3~15:80~120:1~5:3~8:3~8 and stirred evenly to obtain supersilane superhydrophobic water solution B.

[0041] The concentration range of the malonic acid aqueous solution is selected to be 20%~30%, and the concentration range of the ammonia solution is selected to be 20%~30%.

[0042] 1.4) Apply coating solution A to the cleaned surface by dip coating or spray coating. After the coating solution has completely cured, apply coating solution B to the surface of coating A by dip coating or spray coating. After coating B has completely dried and cured, a superhydrophobic coating is obtained.

[0043] 2. Hydrophobic surface patterning

[0044] 2.1) Constructing hydrophobic micro / nano structures: Hydrophobic micro / nano structures are constructed on the surface of a substrate material using micro / nano fabrication technology. This application uses a nanocylindrical array as an example of the hydrophobic micro / nano structure.

[0045] 2.2) Surface Patterning: Using micro / nano fabrication techniques such as ion etching, hydrophobic patterns are etched onto the surface of the hydrophobic micro / nano structure constructed in the first step. See [link to relevant documentation]. Figure 2 The hydrophobic pattern includes a triangle array, an arrow array, a bar array, or an inverted double triangle array. This application uses a triangle array as an example.

[0046] The hydrophobic properties of a hydrophobic surface are evaluated by measuring the surface contact angle and roll-off angle. The larger the contact angle or the smaller the roll-off angle, the better the surface hydrophobic properties.

[0047] The specific implementation process for preparing the superhydrophobic surface is illustrated in the following example.

[0048] Example 1

[0049] The superhydrophobic surface was prepared according to the following steps:

[0050] 1. Stainless steel is selected as the base material. The surface of the base material is plasma cleaned in an air atmosphere. The treatment conditions are: vacuum degree 25pa, power 50W, temperature 25℃, treatment time 300s, and gas flow rate 100sscm.

[0051] 2. Mix 8g of polysiloxane polyurethane with 2.5g of talc particles and dissolve them in 4g of dimethyl sulfoxide to prepare hydrophobic resin coating solution A.

[0052] 3. Mix 10g of methyldimethoxysilane, 3g of tetraethoxysilane, and 80g of ethanol thoroughly. Add 20g of a 1×10⁻⁶ solution to the mixture. -4 A mol / L oxalic acid aqueous solution was stirred for half an hour, and then 25g of 25% ammonia solution was added. After stirring for another half hour, a silane hydrophobic coating solution B was obtained.

[0053] 4. Apply coating solution A onto the surface of the substrate that has been plasma cleaned. After 24 hours, the coating solution A has cured to obtain a hydrophobic resin coating. Apply coating solution B onto the hydrophobic resin coating and dry at room temperature for 30 minutes to obtain a surface with a superhydrophobic coating.

[0054] 5. A cylindrical hydrophobic structure is fabricated on a surface that has been coated with a superhydrophobic coating using micro-nano fabrication technology.

[0055] 6. Pattern the hydrophobic surface, such as... Figure 2 The triangle shown in the figure yields a superhydrophobic surface.

[0056] 7. The hydrophobicity of the hydrophobic surface was evaluated by measuring the surface contact angle and roll-off angle using a contact angle tester. The results are shown in Table 1.

[0057] Example 2

[0058] The superhydrophobic surface was prepared according to the following steps:

[0059] 1. Using stainless steel as the base material, a cylindrical hydrophobic structure is fabricated on the substrate using micro-nano processing technology.

[0060] 2. Pattern the hydrophobic surface, such as... Figure 2 The triangle shown in the figure yields a surface with a patterned hydrophobic structure.

[0061] 3. Plasma cleaning: Plasma cleaning is performed on the surface of a substrate with a patterned hydrophobic structure in an air atmosphere. The processing conditions are: vacuum degree 25pa, power 50W, temperature 25℃, processing time 300s, and gas flow rate 100sscm.

[0062] 4. Mix 8g of polysiloxane polyurethane with 2.5g of talc particles and dissolve them in 4g of dimethyl sulfoxide to prepare hydrophobic resin coating solution A.

[0063] 5. Mix 10g of methyldimethoxysilane, 3g of tetraethoxysilane, and 80g of ethanol thoroughly. Add 20g of a 1×10⁻⁶ solution to the mixture. -4 A mol / L oxalic acid aqueous solution was stirred for half an hour, and then 25g of 25% ammonia solution was added. After stirring for another half hour, a silane hydrophobic coating solution B was obtained.

[0064] 6. Apply coating solution A onto the surface of a substrate with patterned hydrophobic structure that has been plasma cleaned. After coating solution A has cured, apply coating solution B and dry at room temperature for 30 minutes to obtain a superhydrophobic surface.

[0065] 7. The hydrophobicity of the hydrophobic surface was evaluated by measuring the surface contact angle and roll-off angle using a contact angle tester. The results are shown in Table 1.

[0066] Example 3

[0067] The superhydrophobic surface was prepared according to the following steps:

[0068] 1. Stainless steel is selected as the base material. The surface of the base material is plasma cleaned in an air atmosphere. The treatment conditions are: vacuum degree 25pa, power 50W, temperature 25℃, treatment time 300s, and gas flow rate 100sscm.

[0069] 2. Mix 10g of polysiloxane polyurethane with 1g of talc particles and dissolve them in 4g of dimethyl sulfoxide to prepare hydrophobic resin coating solution A.

[0070] 3. Mix 8g of methyldimethoxysilane, 2g of tetraethoxysilane, and 80g of ethanol thoroughly to form a mixed solution; add 20g of a 1×10⁻⁶ solution to the mixed solution. -4 A mol / L oxalic acid aqueous solution was stirred for half an hour, and then 25g of 40% ammonia solution was added and stirred for another half hour to obtain silane hydrophobic coating solution B.

[0071] 4. Apply coating solution A onto the surface of the plasma-cleaned substrate. After 24 hours of curing, coating solution A is obtained. Apply coating solution B onto the hydrophobic resin coating and dry at room temperature for 30 minutes to obtain a surface with a superhydrophobic coating. 5. Use micro-nano fabrication technology to process a cylindrical hydrophobic structure on the coated substrate.

[0072] 6. Pattern the hydrophobic surface, such as... Figure 2 The triangle shown in the figure yields a superhydrophobic surface.

[0073] 7. The hydrophobicity of the hydrophobic surface was evaluated by measuring the surface contact angle and roll-off angle using a contact angle tester. The results are shown in Table 1.

[0074] Example 4

[0075] The superhydrophobic surface was prepared according to the following steps:

[0076] 1. Polystyrene was selected as the substrate material. The substrate surface was plasma cleaned in an air atmosphere. The treatment conditions were: vacuum degree 50pa, power 100W, temperature 25℃, treatment time 300s, and gas flow rate 100sscm.

[0077] 2. Mix 10g of polysiloxane polyurethane with 2g of modified calcium carbonate and dissolve in 4g of dimethyl sulfoxide to prepare hydrophobic resin coating solution A.

[0078] 3. Mix 8g of methyldimethoxysilane, 2g of tetraethoxysilane, and 80g of ethanol thoroughly to form a mixed solution; add 20g of a 1×10⁻⁶ solution to the mixed solution. -4 A mol / L oxalic acid aqueous solution was stirred for half an hour, and then 25g of 40% ammonia solution was added. After stirring for another half hour, a silane hydrophobic coating solution B was obtained.

[0079] 4. Apply coating solution A onto the surface of the substrate that has been plasma cleaned. After 24 hours, the coating solution A is cured to obtain a hydrophobic resin coating. Apply coating solution B onto the hydrophobic resin coating and dry at room temperature for 30 minutes to obtain a surface with a superhydrophobic coating.

[0080] 5. A cylindrical hydrophobic structure is fabricated on a pre-coated substrate using micro-nano fabrication technology.

[0081] 6. Pattern the hydrophobic surface, such as... Figure 2 The triangle shown in the figure yields a superhydrophobic surface.

[0082] 7. The hydrophobicity of the hydrophobic surface was evaluated by measuring the surface contact angle and roll-off angle using a contact angle tester. The results are shown in Table 1.

[0083] Example 5

[0084] The superhydrophobic surface was prepared according to the following steps:

[0085] 1. Using polystyrene as the base material, a cylindrical hydrophobic structure is fabricated on the substrate using micro-nano fabrication technology.

[0086] 2. Pattern the hydrophobic surface, such as... Figure 2 The triangle shown in the figure yields a surface with a patterned hydrophobic structure.

[0087] 3. Plasma cleaning is performed on the surface of the substrate with patterned hydrophobic structure in an air atmosphere. The treatment conditions are: vacuum degree 25pa, power 50W, temperature 25℃, treatment time 300s, and gas flow rate 100sscm.

[0088] 4. Mix 8g of polysiloxane polyurethane with 2.5g of talc particles and dissolve them in 4g of dimethyl sulfoxide to prepare hydrophobic resin coating solution A.

[0089] 5. Mix 10g of methyldimethoxysilane, 3g of tetraethoxysilane, and 80g of ethanol thoroughly. Add 20g of a 1×10⁻⁶ solution to the mixture. -4 A mol / L oxalic acid aqueous solution was stirred for half an hour, and then 25g of 25% ammonia solution was added. After stirring for another half hour, a silane hydrophobic coating solution B was obtained.

[0090] 6. Apply coating solution A onto the surface of a substrate with patterned hydrophobic structure that has been plasma cleaned. After coating solution A has cured, apply coating solution B and dry at room temperature for 30 minutes to obtain a superhydrophobic surface.

[0091] 7. The hydrophobicity of the hydrophobic surface was evaluated by measuring the surface contact angle and roll-off angle using a contact angle tester. The results are shown in Table 1.

[0092] Example 6

[0093] The superhydrophobic surface was prepared according to the following steps:

[0094] 1. Using polystyrene as the base material, a cylindrical hydrophobic structure is fabricated on the substrate using micro-nano fabrication technology.

[0095] 2. Pattern the hydrophobic surface, such as... Figure 2 The triangle shown in the figure yields a surface with a patterned hydrophobic structure.

[0096] 3. Plasma cleaning is performed on the surface of the substrate with patterned hydrophobic structure in an air atmosphere. The treatment conditions are: vacuum degree 25pa, power 50W, temperature 25℃, treatment time 300s, and gas flow rate 100sscm.

[0097] 4. Mix 8g of polysiloxane polyurethane with 2.5g of sesquioxane and dissolve in 4g of dimethyl sulfoxide to prepare hydrophobic resin coating solution A.

[0098] 5. Mix 12g of methyldimethoxysilane, 5g of tetraethoxysilane, and 80g of ethanol thoroughly to form a mixed solution; add 20g of a 1×10⁻⁶ solution to the mixed solution. -4 A mol / L oxalic acid aqueous solution was stirred for half an hour, and then 25g of 25% ammonia solution was added. After stirring for another half hour, a silane hydrophobic coating solution B was obtained.

[0099] 6. Apply coating solution A onto the surface of a substrate with patterned hydrophobic structure that has been plasma cleaned. After coating solution A has cured, apply coating solution B and dry at room temperature for 30 minutes to obtain a superhydrophobic surface.

[0100] 7. The hydrophobicity of the hydrophobic surface was evaluated by measuring the surface contact angle and roll-off angle using a contact angle tester. The results are shown in Table 1.

[0101] Compare with Example 1

[0102] Prepare a hydrophobic surface using the following steps:

[0103] 1. Stainless steel was selected as the substrate material. The substrate surface was plasma cleaned in an air atmosphere under the following conditions: vacuum degree 25 Pa, power 50 W, temperature 25℃, processing time 300 s, and gas flow rate 100 s / cm. 2. 8 g of polysiloxane polyurethane was dissolved in 80 g of dimethylformamide solvent to prepare a hydrophobic resin coating solution.

[0104] 3. Apply the coating solution onto the surface of the substrate that has been plasma cleaned. After the coating solution has cured, a hydrophobic surface with a hydrophobic resin coating is obtained.

[0105] 4. The hydrophobicity of the hydrophobic surface was evaluated by measuring the surface contact angle and roll-off angle using a contact angle tester. The results are shown in Table 1.

[0106] Compare with Example 2

[0107] Prepare a hydrophobic surface using the following steps:

[0108] 1. Stainless steel is selected as the base material. The surface of the base material is plasma cleaned in an air atmosphere. The treatment conditions are: vacuum degree 25pa, power 50W, temperature 25℃, treatment time 300s, and gas flow rate 100sscm.

[0109] 2. Dissolve 8g of methyltrimethoxysilane in 80g of dimethylformamide to prepare a coating solution.

[0110] 3. Apply the coating solution onto the surface of the substrate that has been plasma cleaned. After the coating solution has cured, a hydrophobic surface with a silane hydrophobic coating is obtained.

[0111] 4. The hydrophobicity of the hydrophobic surface was evaluated by measuring the surface contact angle and roll-off angle using a contact angle tester. The results are shown in Table 1.

[0112] Table 1 Characterization of surface hydrophobicity

[0113] Contact angle / ° Rolling angle / ° Example 1 165 4 Example 2 153 7 Example 3 160 4 Example 4 168 4 Example 5 155 6 Example 6 157 5 Comparative Example 1 115 18 Comparative Example 2 130 13

[0114] Results Analysis

[0115] Examples 1 to 3 constructed hydrophobic microstructures on stainless steel surfaces and coated them with hydrophobic resin coatings and silane hydrophobic coatings; Examples 4 to 6 constructed hydrophobic microstructures on polystyrene surfaces and coated them with hydrophobic resin coatings and silane hydrophobic coatings; Comparative Example 1 used stainless steel as the substrate material and only coated it with a hydrophobic resin coating; Comparative Example 2 used stainless steel as the substrate material and only coated it with a silane hydrophobic coating; Examples 1, 3, and 4 first applied a hydrophobic layer, while Examples 2, 5, and 6 constructed patterned hydrophobic structures and then applied a hydrophobic layer.

[0116] According to Table 1, the contact angles of the hydrophobic surfaces obtained in Examples 1, 2, and 3 are 165°, 153°, and 160°, respectively, and the roll-off angles are 4°, 7°, and 4°, respectively. The contact angles of the hydrophobic surfaces obtained in Examples 4, 5, and 6 are 168°, 158°, and 157°, respectively, and the roll-off angles are 4°, 6°, and 5°, respectively. Comparing the overall hydrophobic properties of the hydrophobic surfaces obtained in Examples 1, 2, 3, 4, 5, and 6, the hydrophobic effect is slightly better when the substrate material is polymer than when it is stainless steel. However, when using the same substrate material, the superhydrophobic surface obtained by first coating a hydrophobic layer and then constructing a hydrophobic microstructure has a larger contact angle and a smaller roll-off angle, resulting in a better hydrophobic effect. The contact angles of the hydrophobic surfaces obtained in Comparative Examples 1 and 2 are 115° and 130°, respectively, and the roll-off angles are 18° and 13°, respectively. It can be seen that the superhydrophobic surface prepared by the method described in this invention has superior hydrophobic effects, significantly better than the hydrophobic surface treated only with a hydrophobic coating.

[0117] In summary, this application provides a hydrophobic surface and its preparation method, which organically combines a superhydrophobic coating with a patterned hydrophobic surface. The structure is simple and highly reliable, which not only significantly improves the hydrophobic properties of the surface, but also has good biocompatibility.

[0118] The above embodiments are only used to help understand the methods, principles and core ideas of the present invention; for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A superhydrophobic surface for DNA synthesis, characterized in that, The surface includes patterned hydrophobic microstructures and a superhydrophobic coating.

2. The superhydrophobic surface according to claim 1, wherein the patterned hydrophobic microstructure comprises surface-patterned nanopillars, nanomesh, or nanofrustums.

3. The superhydrophobic surface according to claim 1, wherein the superhydrophobic coating comprises an underlying hydrophobic layer and a silane superhydrophobic coating.

4. A method for preparing a superhydrophobic surface for DNA synthesis, comprising the following steps: a. Construct patterned hydrophobic microstructures b. Coat with a hydrophobic layer.

5. The preparation method according to claim 4, wherein constructing the patterned hydrophobic microstructure includes constructing regularly repeating patterned micro / nano structures on the surface of the substrate material, specifically comprising the following steps: 1) Constructing microstructures; 2) Surface patterning.

6. The preparation method according to claim 4 or 5, wherein constructing the microstructure includes etching a microcylindrical array, a mesh microstructure, or a frustum microstructure on the surface of the substrate material, preferably, the microstructure is a microcylindrical array.

7. The preparation method according to any one of claims 4-6, wherein the surface patterning includes constructing a regularly repeating hydrophobic pattern on the surface of the microstructure, wherein the regularly repeating hydrophobic pattern includes a triangular array, an arrow array, a strip array, or an inverted double triangular array, preferably a triangular array.

8. The preparation method according to claim 4, wherein the surface coating treatment comprises: 1) Hydrophobic undercoating; 2) Silane superhydrophobic coating.

9. The preparation method according to claim 8, wherein the hydrophobic undercoating comprises the following steps: 1) Clean the substrate material 2) Prepare the bottom hydrophobic solution 3) Coat the hydrophobic layer.

10. The preparation method according to claim 8 or 9, wherein the bottom hydrophobic aqueous solution comprises a hydrophobic resin, low molecular weight modified particles and a solvent, and the mass ratio of the hydrophobic resin, low molecular weight modified particles and solvent is between 0.1~0.5:0.02~0.5:

1.

11. The preparation method according to claim 8 or 9, wherein the hydrophobic resin comprises polycarbonate-type polyurethane, polysiloxane polyurethane, silicone-modified resin or silica gel, preferably, the hydrophobic resin comprises polysiloxane polyurethane or silica gel; the low molecular weight modified particles comprise silica, talc, modified calcium carbonate, polysilsesquioxane, stearic acid or oleic acid, preferably, the low molecular weight modified particles comprise talc or modified calcium carbonate.

12. The preparation method according to claim 8 or 9, wherein the silane superhydrophobic coating comprises: 1) Prepare a silane superhydrophobic solution. 2) Coat the hydrophobic substrate with the silane superhydrophobic solution.

13. The method according to claim 12, wherein the silane superhydrophobic aqueous solution comprises a mixture of methyldimethoxysilane, methanol, tetraethoxysilane, malonic acid aqueous solution and ammonia, wherein the ratio of methyldimethoxysilane, methanol, tetraethoxysilane, malonic acid aqueous solution and ammonia, by mass, is between 3~15:80~120:1~5:3~8:3~8.

14. A superhydrophobic surface for DNA synthesis prepared by the method according to any one of claims 4-12.

15. A method for synthesizing DNA using a superhydrophobic surface as described in any one of claims 1-3 or 14.

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