A wear-resistant composite network structure superhydrophobic surface

Abstract

The present invention proposes a wear-resistant composite network structure super-hydrophobic surface, which belongs to the technical field of polymer composite materials. The composite network structure is formed by filling a filling material in the holes of a porous substrate. The filling material and the substrate material have different wear resistance. The super-hydrophobic surface microstructure formed after friction and wear is generated by friction, so friction and wear will not only not destroy the hydrophobic structure of the surface, but can also play a role in updating the hydrophobic structure, even if it is worn to different degrees, it will not destroy its surface hydrophobicity, so it has the ability of wear resistance. In this structure, the substrate and the filling material can be prepared by materials with both hydrophobicity, or by materials with one side being hydrophobic and the other side being hydrophilic, to form an overall hydrophobic super-hydrophobic surface or a hydrophobic-hydrophilic alternating super-hydrophobic surface, so as to obtain super-hydrophobic surfaces with different functions.

Description

Technical Field

[0001] The invention belongs to the field of polymer composite materials. Background Art

[0002] Superhydrophobicity is a special kind of wettability. Water droplets can roll in a spherical shape on the superhydrophobic surface without wetting. The contact angle between water droplets and the superhydrophobic surface is generally greater than 150°. Superhydrophobic surfaces are widely used and have great application potential in waterproofing, self-cleaning, anti-icing, oil-water separation, biomedicine, etc. At present, superhydrophobic surfaces are generally achieved by forming special micro-nano structures on the solid surface, but the surface micro-nano structures are easily damaged after mechanical wear and impact. The main solution is to improve the mechanical strength of the superhydrophobic surface, but the above problems cannot be avoided after long-term impact or wear. Summary of the invention

[0003] In order to solve the problems of existing super-hydrophobic surfaces in terms of firmness and durability, the present invention proposes a wear-resistant composite network structure super-hydrophobic surface, wherein the composite network structure is formed by filling a filling material in the pores of a porous substrate, the porosity of the porous substrate is between 60-90%, and the pore size of the porous substrate is between 125-500μm; the wear amount of the filling material is different from that of the substrate material, and at least one of the substrate material and the filling material is a hydrophobic material.

[0004] Preferably, the porous substrate is made of silicone rubber or polyurethane, and the filling material is made of epoxy resin, polyurethane or silicone rubber.

[0005] A method for preparing a wear-resistant composite network structure super-hydrophobic surface comprises the following steps:

[0006] (1) preparing a porous substrate;

[0007] (2) filling the pores of the porous substrate with a filling material solution; the filling material solution comprises a filling material, a curing agent and a solvent; the mass ratio of the filling material to the solvent is (1-3): (1-2);

[0008] (3) solidifying the filling material to obtain the wear-resistant composite network structure super-hydrophobic surface.

[0009] Preferably, when the filling material is epoxy resin, the mass ratio of the filling material to the solvent is 3:1; when it is polyurethane, the mass ratio of the filling material to the solvent is 3:2; when it is silicone rubber, the mass ratio of the filling material to the solvent is 1:1.

[0010] Step (1) The steps of preparing the porous substrate are as follows:

[0011] a. mixing a base material of a porous substrate, a pore-forming agent, a curing agent and a solvent to obtain a mixed solution;

[0012] b. Pour the mixed solution into a mold and solidify it at room temperature;

[0013] c. After the mold is opened, heat it in a water bath at 60°C for 24 hours to dissolve the pore-forming agent;

[0014] d. After drying in an oven at 60°C, a porous substrate was obtained;

[0015] The pore-forming agent is preferably sodium chloride particles.

[0016] The material of the porous substrate is silicone rubber or polyurethane. When the base material of the porous substrate is silicone rubber, the mass ratio of silicone rubber to sodium chloride is 1:(2.75-3.5); when the base material of the porous substrate is polyurethane, the mass ratio of polyurethane to sodium chloride is 1:(6-9).

[0017] Beneficial effects of the present invention:

[0018] The surface hydrophobic structure of the composite network structure super-hydrophobic surface proposed by the present invention is formed through friction and wear. Therefore, friction and wear will not destroy the hydrophobic structure of the surface, but can play a role in renewing the hydrophobic structure. Even if it is subjected to different degrees of wear, its surface hydrophobicity will not be destroyed, so it has the ability of wear resistance.

[0019] The substrate and filling material of the super-hydrophobic surface of the composite network structure can be prepared by materials that are both hydrophobic, or by materials that are hydrophobic on one side and hydrophilic on the other side, to form an overall hydrophobic super-hydrophobic surface or a hydrophobic-hydrophilic alternating super-hydrophobic surface, so as to obtain super-hydrophobic surfaces with different functions.

[0020] The present invention can obtain super-hydrophobic surfaces with different mechanical and chemical properties by using different substrates and filling materials, so as to achieve the regulation of physical and chemical properties such as elastic modulus, tensile modulus, acid and alkali resistance, etc., to meet different needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the wear resistance principle of the super-hydrophobic surface of the composite network structure in the present invention;

[0022] Figure 2 Result diagram of contact angle test on silicone rubber-epoxy resin composite surface in Example 1; (a) is a photograph of the silicone rubber-epoxy resin composite surface in Example 1, (b) is the surface contact angle test structure, and (c) is the surface contact angle test result after sandpaper friction;

[0023] Figure 3Example 2: Surface contact angle test results of silicone rubber-polyurethane composite surface; (a) is a photo of the silicone rubber-epoxy resin composite surface of Example 2, (b) is the surface contact angle test structure, and (c) is the surface contact angle test result after sandpaper friction;

[0024] Figure 4 Graph showing the test results of the polyurethane-PDMS composite surface contact angle of Example 3; (a) is a photograph of the polyurethane-PDMS composite surface of Example 3, (b) is the surface contact angle test structure, and (c) is the surface contact angle test result after sandpaper friction. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further explained and illustrated in the form of specific embodiments below.

[0026] Example 1

[0027] Using porous silicone rubber as the base material, epoxy resin is filled to form a silicone rubber-epoxy resin composite surface, forming a super hydrophobic surface with alternating hydrophobicity and hydrophilicity. The specific preparation method is as follows:

[0028] (1) Weigh 20 g of silicone rubber, add 0.2 g of curing agent, 55 g of sodium chloride and 10 g of ethyl acetate, and stir evenly to obtain a silicone rubber-sodium chloride mixed solution;

[0029] (2) Pour the silicone rubber-sodium chloride mixture into the mold, fill the mold completely with the mixture, and cure at room temperature for 24 hours;

[0030] (3) After the mold is opened, a solid silicone rubber containing sodium chloride is obtained, which is heated in a water bath at 60° C. for 24 hours to dissolve the sodium chloride particles; the water is changed every 2 hours to accelerate the dissolution of the sodium chloride;

[0031] (4) drying the solid silicone rubber from which sodium chloride has been removed in an oven at 60° C. to obtain silicone rubber having a porous structure;

[0032] (5) Weigh 30 g of epoxy resin, add 10 g of curing agent and 10 g of ethyl acetate, and stir to obtain epoxy resin dilution;

[0033] (6) soaking the silicone rubber with a porous structure in a diluted epoxy resin solution, placing it in a vacuum drying oven and repeatedly evacuating the air bubbles in the silicone rubber to allow the epoxy resin to completely fill the porous structure;

[0034] (7) The porous silicone rubber immersed in the epoxy resin is taken out and placed in an oven at 60° C. to accelerate the curing of the epoxy resin, thereby obtaining a silicone rubber-epoxy resin composite surface.

[0035] Example 2

[0036] Using porous silicone rubber as the base material, filling polyurethane to form a silicone rubber-polyurethane composite surface, forming an overall hydrophobic super-hydrophobic surface, the specific preparation method is as follows:

[0037] (1) Weigh 20 g of silicone rubber, add 0.2 g of curing agent, 55 g of sodium chloride and 10 g of ethyl acetate, and stir evenly to obtain a silicone rubber-sodium chloride mixed solution;

[0038] (2) Pour the silicone rubber-sodium chloride mixture into the mold, fill the mold completely with the mixture, and cure at room temperature for 24 hours;

[0039] (3) After the mold is opened, a solid silicone rubber containing sodium chloride is obtained, which is heated in a water bath at 60° C. for 24 hours to dissolve the sodium chloride particles; the water is changed every 2 hours to accelerate the dissolution of the sodium chloride;

[0040] (4) drying the solid silicone rubber from which sodium chloride has been removed in an oven at 60° C. to obtain silicone rubber having a porous structure;

[0041] (5) Weigh 30 g of polyurethane, add 3 g of curing agent and 20 g of ethyl acetate, and stir evenly to obtain a polyurethane dilution;

[0042] (6) soaking the silicone rubber with a porous structure in a polyurethane dilution solution, placing it in a vacuum drying oven and repeatedly evacuating the air bubbles in the silicone rubber to allow the polyurethane to completely fill the porous structure;

[0043] (7) The porous silicone rubber immersed in polyurethane is taken out and placed in an oven at 60° C. to accelerate the curing of polyurethane, thereby obtaining a silicone rubber-polyurethane composite surface.

[0044] Example 3

[0045] Using porous polyurethane as the base material, filling polydimethylsiloxane (PDMS) to form a polyurethane-PDMS composite surface, forming a super hydrophobic surface with alternating hydrophobicity and hydrophilicity. The specific preparation method is as follows:

[0046] (1) Weigh 10 g of polyurethane, add 1 g of curing agent, 70 g of sodium chloride and 10 g of ethyl acetate, and stir evenly to obtain a polyurethane-sodium chloride mixed solution;

[0047] (2) Pour the polyurethane-sodium chloride mixture into the mold, fill the mold completely with the mixture, and cure at room temperature for 24 hours;

[0048] (3) After the mold is opened, a solid polyurethane containing sodium chloride is obtained, which is heated in a water bath at 60° C. for 24 hours to dissolve the sodium chloride particles; the water is changed every 2 hours or so to accelerate the dissolution of the sodium chloride;

[0049] (4) drying the solid polyurethane from which sodium chloride has been removed in an oven at 60° C. to obtain a polyurethane having a porous structure;

[0050] (5) Weigh 20 g of PDMS, add 3 g of curing agent and 20 g of ethyl acetate, and stir to obtain a PDMS dilution solution;

[0051] (6) soaking the polyurethane with a porous structure in a PDMS dilution solution, placing it in a vacuum drying oven and repeatedly evacuating the air bubbles in the silicone rubber to allow the PDMS to completely fill the porous structure;

[0052] (7) The porous polyurethane immersed in PDMS was taken out and placed in an oven at 60° C. to accelerate the curing of the polyurethane, thereby obtaining a silicone rubber-polyurethane composite surface.

[0053] In the above specific implementation scheme, after many attempts, it was found that the best preparation for porous silicone rubber is to add 55-70g of sodium chloride to 20g of silicone rubber, and the best preparation for porous polyurethane is to add 60-90g of sodium chloride to 10g of polyurethane. Too little sodium chloride will cause the sodium chloride particles to be wrapped and unable to dissolve, and too much sodium chloride will cause the base material to be unable to solidify and easy to crush.

[0054] The most appropriate ratios of epoxy resin to solvent in the filling material are 3:1, polyurethane to solvent 3:2, and PDMS to solvent 1:1. Too little solvent will make the diluent viscous and difficult to fill, while too much solvent will cause severe volume shrinkage after curing.

[0055] like Figure 1 As shown, the composite network structure super-hydrophobic surface proposed by the present invention, after being subjected to friction and wear, the base materials and filling materials with different wear resistances fall off to different degrees, forming a rough hydrophobic structure to achieve a super-hydrophobic effect. Figure 2 to Figure 4 As shown, the surface of the present invention still has super hydrophobicity after being worn, which proves that it has a wear-resistant effect.

[0056] The present invention can obtain super-hydrophobic surfaces with different mechanical and chemical properties by using different substrates and filling materials, so as to achieve the regulation of physical and chemical properties such as elastic modulus, tensile modulus, acid and alkali resistance, etc., to meet different needs.

Claims

1. A wear-resistant composite network structure super-hydrophobic surface, characterized in that: The composite network structure is formed by filling the pores of a porous substrate with a filling material, the porosity of the porous substrate is between 60-90%, and the pore size of the porous substrate is between 125-500 μm; the wear amount of the filling material is different from that of the substrate material, and at least one of the substrate material and the filling material is a hydrophobic material; the material of the porous substrate is silicone rubber or polyurethane, and the material of the filling material is epoxy resin, polyurethane or silicone rubber.

2. A method for preparing a wear-resistant composite network structure super-hydrophobic surface as claimed in claim 1, characterized in that: The method comprises the following steps: (1) Preparation of porous substrate; (2) Filling the pores of the porous substrate with a filling material solution; the filling material solution is composed of a filling material, a curing agent and a solvent; the mass ratio of the filling material to the solvent is (1-3):(1-2); wherein when the filling material is epoxy resin, the mass ratio of the filling material to the solvent is 3:1; when the filling material is polyurethane, the mass ratio of the filling material to the solvent is 3:2; and when the filling material is silicone rubber, the mass ratio of the filling material to the solvent is 1:1; (3) solidifying the filling material to obtain the wear-resistant composite network structure super-hydrophobic surface; The steps of preparing the porous substrate in step (1) are as follows: a. mixing a base material of a porous substrate, a pore-forming agent, a curing agent and a solvent to obtain a mixed solution; b. Pour the mixed solution into a mold and solidify it at room temperature; c. After the mold is opened, heat it in a water bath at 60 °C for 24 h to dissolve the pore-forming agent; d. After drying in an oven at 60°C, a porous substrate was obtained; The pore-forming agent described in step a is sodium chloride particles; the material of the porous substrate is silicone rubber or polyurethane; when the base material of the porous substrate is silicone rubber, the mass ratio of silicone rubber to sodium chloride is 1: (2.75~3.5); when the base material of the porous substrate is polyurethane, the mass ratio of polyurethane to sodium chloride is 1: (6~9).

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