An easy-to-release concrete test mold with super-hydrophobic / super-slippery inner wall and its preparation method

Abstract

The present invention discloses a kind of easy demoulding concrete test mold with super-hydrophobic / super-slip performance on inner wall and its preparation method, the method comprises the following steps: a, spin coating negative photoresist, and by the mode of ultraviolet lithography, obtain inner wall with the substrate of inverted trapezoidal micron structure;b, vacuum evaporation deposits metal layer;c, the metal layer on the upper surface of the inverted trapezoidal micron structure of substrate inner wall is removed;d, obtain micro-nano hierarchical structure on the metal layer coated by the inverted trapezoidal micron structure of substrate inner wall;e, spin coating molten wax, after cooling, solid wax fills in the micron-level pores between the inverted trapezoidal structures;f, spin coating positive photoresist, and carry out ultraviolet lithography;g, the solid wax in micron-level pores is discharged, obtains the substrate with super-hydrophobic surface structure;h, substrate is assembled to obtain the easy demoulding concrete test mold with super-hydrophobic performance. The present invention reduces the cohesion between concrete and test mold inner wall, makes concrete easily detach from concrete test mold inner wall.

Description

Technical Field

[0001] The present invention relates to the field of concrete test molds, in particular to an easy-to-release concrete test mold with an inner wall having super-hydrophobic / super-slip properties, and a preparation method of the easy-to-release concrete test mold. Background Art

[0002] Concrete is a commonly used composite material in civil engineering, typically made from cement as a binder, sand or gravel as aggregate, and a certain amount of water. The mixture is uniformly mixed, compacted, and hardened. Its strength and durability are key factors affecting project quality in practical applications. Therefore, it's crucial to perform strength testing using standard concrete test blocks before construction.

[0003] Concrete test molds are used to produce standard concrete specimens for concrete mechanical strength and durability testing. They are primarily categorized into compression molds, flexural molds, axial compression molds, axial tensile molds, and splitting tensile molds. Currently, there are two common types of concrete test molds. One is a one-piece concrete test mold, typically made of plastic, consisting of four vertical panels and a base plate. The other is a removable concrete test mold, typically made of cast iron or steel, consisting of a base plate, side plates, partition shafts, bracket pivot bolts, and butterfly nuts.

[0004] When making concrete specimens, the cement hydration process will produce hydration products with gelling properties, which increases the friction between the concrete and the inner wall of the mold, making it easy for the concrete to stick to the inner wall of the test mold, making it difficult to demold the concrete, and even causing damage to the concrete specimen after demolding.

[0005] In order to solve the problem of difficulty in demoulding concrete specimens after molding, there are generally the following treatment methods in the prior art:

[0006] (1) A detachable concrete mold is used, but there is still a lot of friction between the detachable mold plate and the concrete. When demolding, the concrete easily adheres to the mold plate, resulting in incomplete concrete specimens after demolding. In addition, the detachable mold needs to be installed before each use, resulting in low work efficiency. In addition, the residual concrete adhering to the mold plate needs to be cleaned in time, wasting manpower and material resources.

[0007] (2) Applying a release agent to the inner wall of the mold: When preparing concrete test blocks, a release agent needs to be applied to the inner wall of the mold in advance, which reduces work efficiency. In addition, the release agent will make the concrete surface darker, easily absorb bubbles, increase the surface tension of the bubbles, and make the bubbles difficult to break and discharge, which can easily leave a large number of bubble cavities on the concrete surface. In addition, the release agent is mostly an oily liquid, which easily absorbs impurities during storage, making it difficult to clean the mold.

[0008] (3) Demolding the concrete with the help of demoulding tools or by knocking; this method can easily cause damage to the concrete specimen and the mold itself, and also reduce work efficiency. Summary of the Invention

[0009] In order to solve the above technical problems, the present invention provides an easy-to-release concrete test mold with an inner wall having super-hydrophobic properties, and a method for preparing the easy-to-release concrete test mold.

[0010] The technical solution adopted by the present invention is:

[0011] The invention discloses an easy-to-release concrete test mold with an inner wall having super-hydrophobic properties, comprising four vertical plates and a bottom plate, wherein the inner walls of the vertical plates and the bottom plate are both provided with a super-hydrophobic surface structure.

[0012] Preferably, the super-hydrophobic surface structure is a micro-nano structure.

[0013] A method for preparing an easy-to-release concrete test mold with an inner wall having super-hydrophobic properties comprises the following steps:

[0014] a. Spin-coating a negative photoresist and performing ultraviolet lithography to obtain a substrate having an inner wall with an inverted trapezoidal microstructure;

[0015] b. Vacuum evaporation deposition of metal layer

[0016] The substrate having the inverted trapezoidal microstructure is subjected to metal coating; after the coating is completed, the substrate having the inverted trapezoidal microstructure after the metal layer is evaporated is taken out;

[0017] c. removing the metal layer on the upper surface of the inverted trapezoidal microstructure on the inner wall of the substrate;

[0018] d. A micro-nano hierarchical structure is obtained on the metal layer covered by the inverted trapezoidal microstructure on the inner wall of the substrate by chemical immersion;

[0019] e. Spin-coating molten wax on the substrate treated in step d. After cooling to room temperature, the solid wax fills the micrometer-sized pores between the inverted trapezoidal structures.

[0020] f. Spin-coat positive photoresist and perform UV lithography;

[0021] g. Expelling the solid wax from the micron-sized pores to obtain a substrate with a super-hydrophobic surface structure;

[0022] h. Assemble the base to obtain an easy-to-release concrete test mold with super-hydrophobic properties.

[0023] Preferably, step a specifically includes the following steps:

[0024] a1. Use the vertical plate or bottom plate as the base and clean it with acetone, ethanol and deionized water in sequence;

[0025] a2. Spin-coating a layer of negative photoresist on the inner wall surface of the substrate;

[0026] a3. Performing the first tilted UV lithography using a UV light source;

[0027] a4. Rotate the UV light source 180° and perform a second tilted UV lithography;

[0028] a5. After the photolithography is completed, the substrate is immediately placed in a developer compatible with the negative photoresist for development, and then rinsed with deionized water and dried to obtain a substrate with an inverted trapezoidal microstructure on the inner wall.

[0029] Preferably, when performing tilted UV lithography, a UV light source and a reflective lens are used, and a reflective lens is placed at an angle opposite the UV light source so that the UV light can be irradiated obliquely onto the UV photoresist to complete the first UV lithography; then the UV light source and the reflective lens are synchronously rotated 180° to perform the second UV lithography.

[0030] Preferably, in step b: the evaporated metal layer is a Mg, Zn, Cu or Al metal layer.

[0031] Preferably, in step c: removing the metal layer on the upper surface of the inverted trapezoidal microstructure by chemical etching;

[0032] First prepare a nitric acid solution, then place the side of the substrate with the inverted trapezoidal structure horizontally downward and slowly move it horizontally downward. When the substrate just contacts the nitric acid solution, keep it still to ensure that the metal layer on the upper surface of the inverted trapezoidal micron-scale structure can contact the nitric acid solution, while the metal layer on the side does not contact the nitric acid solution; after the reaction is completed, rinse with deionized water and dry.

[0033] Preferably, in step d: placing the substrate in a silver nitrate solution or a copper chloride solution, taking it out after the reaction, rinsing it with deionized water and drying it in air, thereby obtaining a micro-nano structure on the metal layer on the side of the inverted trapezoidal structure.

[0034] Specifically, if the evaporated metal is Cu, Mg, Zn or other metals, the substrate is placed in a silver nitrate solution with a concentration of 0.01-0.1 mol / L. After reacting for 1-10 minutes, it is slowly taken out, rinsed with deionized water and placed in the air to dry, and a dendritic micro-nano hierarchical structure is obtained on the metal layer on the side of the inverted trapezoidal structure.

[0035] If the evaporated metal is aluminum, the substrate is placed in a 1-2 mol / L copper chloride solution (or a 1-2 mol / L hydrochloric acid solution), reacted for 60 seconds, then slowly removed, immediately ultrasonically cleaned with deionized water and dried in air to obtain a micro-nano stepped structure on the metal layer on the side of the inverted trapezoidal structure.

[0036] Preferably, after obtaining the micro-nano structure on the metal layer on the side of the inverted trapezoidal structure, a low surface energy modification step is also included: the substrate with the micro-nano structure obtained on the metal layer on the side of the inverted trapezoidal structure is placed in a mixed solution of stearic acid and ethanol for hydrophobic modification, and then rinsed with deionized water and dried, thereby obtaining a micro-nano structure with super hydrophobicity on the inner surface of the micron-scale inverted trapezoid.

[0037] Preferably, in step g: the wax in the micron-sized pores is completely expelled by ultrasonic vibration. Specifically, the substrate after the second UV photolithography is placed in an ultrasonic cleaner; the ultrasonic cleaner is activated to gradually melt the wax inside the micron-sized structures (i.e., between the inverted trapezoidal structures) and expel it along with the water due to the ultrasonic vibration.

[0038] Another object of the present invention is to provide an easy-to-release concrete test mold with an inner wall having super-hydrophobic / super-slip properties, and a method for preparing the easy-to-release concrete test mold.

[0039] A test mold for easy-to-release concrete with an inner wall having super-hydrophobic / super-slip properties comprises four vertical plates and a bottom plate. The inner walls of the vertical plates and the bottom plate are both provided with micro-nano structures, and lubricating oil is injected into the pores of the micro-nano structures.

[0040] The method for preparing a superhydrophobic / superslippery, easy-to-release concrete test mold also follows steps a through g, differing in that it also includes step j: injecting lubricating oil into the substrate having the superhydrophobic surface structure, filling the pores to create a superslippery surface. The substrates are then assembled to produce a superhydrophobic / superslippery, easy-to-release concrete test mold.

[0041] A third object of the present invention is to provide a method for preparing an easy-to-release concrete test mold with an inner wall having super-hydrophobic properties, comprising the following steps:

[0042] Repeat steps a to e above.

[0043] Then, after filling the solid wax, instead of spin-coating the positive photoresist, aluminum is deposited by vacuum evaporation, and then anodized to obtain a porous metal aluminum surface. Finally, ultrasonic vibration is used to completely expel the wax in the micron-sized pores to obtain a superhydrophobic surface.

[0044] In the above method, vacuum evaporation deposition of aluminum specifically includes the following steps:

[0045] Fix the substrate on the substrate table and place the aluminum target in the evaporation boat; then set the parameters and start the coating operation; after the coating is completed, take out the aluminum-coated substrate.

[0046] In the above method, anodizing specifically comprises the following steps:

[0047] The aluminum-plated substrate is anodized in a phosphoric acid solution with a concentration of 0.1-0.5 mol / L, with the aluminum-plated substrate as the anode and stainless steel as the cathode, and the distance between the two electrodes is set to 20 mm; the anodization voltage is set to 120 V, and the anodization operation is started at an initial temperature of 50° C. After the anodization time lasts for 1-5 minutes, the anodized aluminum-plated substrate is removed, rinsed with deionized water and dried in air to obtain anodized aluminum with a porous structure.

[0048] In the above method, after anodizing, the following processing steps are also included:

[0049] The anodic aluminum oxide with a porous structure is placed in a mixed solution of stearic acid and ethanol for hydrophobic modification.

[0050] In the above method, the steps of ultrasonic vibration wax removal are as follows:

[0051] The anodized aluminum substrate with a porous structure is placed in an ultrasonic cleaning instrument; the ultrasonic cleaning instrument is started, and the wax inside the micron structure gradually melts and is discharged with water due to the effect of ultrasonic vibration.

[0052] A fourth object of the present invention is to provide a method for preparing an easy-to-release concrete test mold with an inner wall having superhydrophobic / superslip properties. The method utilizes the aforementioned processing steps, but further comprises the steps of injecting lubricating oil into the substrate having the superhydrophobic surface structure, filling the entire pore space thereof to obtain a superslippery surface. The substrates are then assembled to obtain an easy-to-release concrete test mold having superhydrophobic / superslip properties.

[0053] The beneficial technical effects of the present invention are:

[0054] (1) First, a super-hydrophobic / super-slippery surface was prepared on the inner wall of the concrete mold by combining photolithography technology, vacuum evaporation deposition technology and chemical immersion method, and infusing lubricating oil. The super-hydrophobic surface has low adhesion, which reduces the adhesion between the concrete and the inner wall of the test mold, making it easy for the concrete to detach from the inner wall of the concrete test mold, facilitating the complete and intact demoulding of the concrete.

[0055] (2) The lubricating oil injected into the micro-nano structure has super-slip properties, which further reduces the adhesion between the concrete and the inner wall of the concrete test mold, making it easy for the concrete to be demolded, thus not causing damage to the concrete specimen.

[0056] (3) The micro-nano structure contains lubricating oil, so there is no need to apply release agent in advance when using it, which improves work efficiency.

[0057] (4) The prepared micron-scale inverted trapezoidal structure is a polymer with elasticity. After pouring concrete, it will be compressed downward under the action of the gravity of the concrete, thereby squeezing the lubricating oil stored in the micro-nano structure to the surface of the porous structure.

[0058] (5) The obtained micron-scale inverted trapezoidal structure and the micro-nanostructure attached to the surface of the microstructure can lock the lubricating oil and reduce the loss of lubricating oil, so that the concrete test mold has good durability during use.

[0059] (6) The superhydrophobic / superslippery surface has self-cleaning properties, which can reduce the residual concrete adhering to the inner wall of the concrete test mold, thereby keeping the inner wall of the mold clean, reducing daily maintenance and cleaning work, and thus improving work efficiency.

[0060] (7) The rough structure of the superhydrophobic / superslippery surface contains air and lubricating oil, respectively, which can effectively isolate the external corrosive medium. If the concrete mold is made of metal, the superhydrophobic surface can provide good corrosion protection for the substrate, thereby enhancing the service life of the concrete mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 Flow chart of the preparation of super-hydrophobic surface in Example 4;

[0062] Figure 2 Schematic diagram of the top view of the superhydrophobic surface;

[0063] Figure 3 Flow chart of the preparation of superhydrophobic / superslippery surface in Example 5;

[0064] Figure 4 Schematic top view of the superhydrophobic / superslippery surface.

[0065] In the figure: 1-concrete test template surface, 2-negative photoresist, 3-ultraviolet light source, 4-reflective lens, 5-metal layer, 6-rough micro-nano structure, 7-wax, 9-lubricating oil, 10-metal aluminum. DETAILED DESCRIPTION

[0066] In order to solve the problems of difficult demoulding of existing concrete test molds, strong adhesion between the mold plate and concrete, and easy damage to the concrete during demoulding, the present invention proposes an easy-to-demold concrete test mold with an inner wall having a super-hydrophobic / super-slippery surface.

[0067] First, by combining ultraviolet lithography, vacuum evaporation deposition technology and chemical immersion method, and infusing lubricating oil, a superhydrophobic / superslippery surface was prepared on the inner wall of the concrete test mold, resulting in a concrete test mold with low adhesion on the inner wall and easy demoulding.

[0068] Second, it makes the inner wall of the concrete test mold super-hydrophobic, reduces the adhesion of the inner wall of the concrete test mold, and enables the concrete to be smoothly separated from the template during demoulding, keeping the shape of the concrete intact.

[0069] Third, the micro-nanostructure on the inner wall of the concrete test mold helps lock in lubricating oil and reduce lubricating oil loss. In addition, because the micro-nanostructure is a polymer and has elasticity, after the concrete is poured, the lubricating oil stored in the microstructure is expelled under the extrusion of the concrete, providing a lubricating effect and facilitating the demoulding of the concrete.

[0070] 4. It makes the concrete test mold have excellent self-cleaning performance, reduces the residual concrete adhering to the inner wall of the concrete test mold, and improves the daily cleaning efficiency.

[0071] The invention provides an easy-to-release concrete test mold with an inner wall having super-hydrophobic / super-slip properties. The test mold comprises four vertical plates and a bottom plate, and the inner walls of the vertical plates and the bottom plate both have super-hydrophobic / super-slip surfaces.

[0072] The super-hydrophobic / super-slippery surface is obtained by the following steps:

[0073] 1) First, a layer of negative photoresist is spin-coated on the surface of the vertical plate and the bottom plate using photolithography technology, and UV lithography is performed twice under an inclined light source to obtain an inverted trapezoidal microstructure;

[0074] 2) Then, a metal layer is deposited on the surface of the inverted trapezoidal microstructure by vacuum evaporation deposition technology;

[0075] 3) removing the metal layer on the upper surface of the inverted trapezoidal structure by chemical etching;

[0076] 4) obtaining a micro-nano hierarchical structure on the inverted trapezoidal surface by immersing the surface in a chemical solution, and further performing low surface energy modification on the obtained micro-nano hierarchical structure by immersing the surface in a low surface energy solution;

[0077] 5) Spin-coating molten wax on the substrate surface to fill the pores of the microstructure;

[0078] 6) After the wax solidifies, a layer of positive photoresist is spin-coated on the surface and conventional UV lithography is performed to obtain a micron-scale porous structure;

[0079] 7) placing the substrate after the second UV lithography in an ultrasonic cleaning apparatus for ultrasonic cleaning, so that the wax inside the microstructure is subjected to the effect of ultrasonic vibration and is discharged along with the water, thereby obtaining a superhydrophobic surface;

[0080] 8) Lubricating oil is injected into the micro-nano structure so that it fills the entire pore to obtain an ultra-slippery surface.

[0081] The present invention will be further described below by means of specific examples.

[0082] Example 1

[0083] A method for preparing an easy-to-release concrete test mold with an inner wall having super-hydrophobic properties comprises the following steps:

[0084] a. Spin-coat negative photoresist and use ultraviolet lithography to obtain a substrate with an inverted trapezoidal microstructure on the inner wall.

[0085] Step a specifically includes the following steps:

[0086] a1. Use the vertical plate or bottom plate as the base and clean it with acetone, ethanol and deionized water in sequence.

[0087] a2. Spin-coat a layer of negative photoresist on the inner wall surface of the substrate.

[0088] a3. Use an ultraviolet light source to perform the first tilted ultraviolet lithography.

[0089] a4. Rotate the UV light source 180° and perform a second tilted UV lithography.

[0090] a5. After the photolithography is completed, the substrate is immediately placed in a developer corresponding to the negative photoresist for development, and then rinsed with deionized water and dried to obtain a substrate with an inverted trapezoidal microstructure on the inner wall.

[0091] In the above steps, when performing tilted UV lithography, a UV light source and a reflective lens are used, such as Figure 1 、 Figure 3 As shown in the figure, a reflective lens is placed at an angle opposite the UV light source so that the UV light can be irradiated on the UV photoresist at an angle, completing the first UV lithography. The UV light source and the reflective lens are then rotated 180 degrees synchronously to perform the second UV lithography.

[0092] b. Vacuum evaporation deposition of metal layer

[0093] The substrate with the inverted trapezoidal microstructure is subjected to metal coating. After the coating is completed, the substrate with the inverted trapezoidal microstructure after the metal layer is evaporated is taken out.

[0094] The evaporated metal layer is a Mg, Zn, or Cu metal layer.

[0095] c. Remove the metal layer on the upper surface of the inverted trapezoidal microstructure on the inner wall of the substrate.

[0096] Specifically, a chemical etching method is used to remove the metal layer on the upper surface of the inverted trapezoidal microstructure.

[0097] Prepare a 6 mol / L nitric acid solution. Place the substrate horizontally with the inverted trapezoidal structure facing downward and slowly move it horizontally downward. Once the substrate is in contact with the nitric acid solution, keep it still to ensure that the metal layer on the upper surface of the inverted trapezoidal microstructure is exposed to the solution while the metal layers on the side are shielded from it. After 5 seconds, rinse with deionized water and dry.

[0098] d. A micro-nano hierarchical structure is obtained on the metal layer covered by the inverted trapezoidal microstructure on the inner wall of the substrate by chemical immersion.

[0099] Specifically, the substrate is placed in a silver nitrate solution with a concentration of 0.01 mol / L, reacted for 5 minutes, taken out, rinsed with deionized water and dried in the air, and a dendritic micro-nano hierarchical structure is obtained on the metal layer on the side of the inverted trapezoidal structure.

[0100] Then, low surface energy modification was performed: the substrate with the micro-nano structure obtained on the metal layer on the side of the inverted trapezoidal structure was placed in a mixed solution of stearic acid and ethanol with a stearic acid concentration of 0.01 mol / L for 60 minutes for hydrophobic modification. It was then rinsed with deionized water and dried to obtain a micro-nano hierarchical structure with superhydrophobicity on the inner surface of the micron-scale inverted trapezoid.

[0101] e. Spin-coat molten wax on the substrate treated in step d. After cooling to room temperature, the solid wax fills the micrometer-sized pores between the inverted trapezoidal structures.

[0102] f. Spin-coat positive photoresist, pre-design the photoresist pattern, and perform conventional UV lithography. After the photolithography is completed, immediately place it in the developer corresponding to the positive photoresist for development, rinse with deionized water, and dry.

[0103] The above-mentioned photolithographic pattern can be any one of square, rectangle, diamond, circle, triangle and the like.

[0104] g. Expelling the solid wax in the micron-sized pores to obtain a substrate with a super-hydrophobic surface structure; specifically, ultrasonic vibration can be used to completely expel the wax in the micron-sized pores.

[0105] The steps are as follows: placing the substrate after the second UV lithography in an ultrasonic cleaner; setting the ultrasonic cleaning temperature to 65°C and the time to 30 minutes; starting the ultrasonic cleaner, the wax inside the microstructure gradually melts, and is discharged with water due to the action of ultrasonic vibration.

[0106] h. Assemble the base to obtain an easy-to-release concrete test mold with super-hydrophobic properties.

[0107] The main body of the substrate can be a plastic substrate, a steel substrate, etc.

[0108] The super-hydrophobic surface obtained in this embodiment has the following advantages:

[0109] (1) The superhydrophobic surface has low adhesion, which reduces the bonding between the concrete and the inner wall of the test mold, making it easy for the concrete to separate from the inner wall of the concrete test mold, facilitating the complete and intact demoulding of the concrete.

[0110] (2) The superhydrophobic surface has self-cleaning properties, which can reduce the residual concrete adhering to the inner wall of the concrete test mold, thereby keeping the inner wall of the mold clean, reducing daily maintenance and cleaning work, and thus improving work efficiency.

[0111] (3) The rough structure of the superhydrophobic surface contains an air layer, which reduces the contact area between the external medium and the concrete test template surface, thereby reducing the friction between the external medium and the concrete test template surface, and can reduce the damage to the inner wall of the concrete test template when pouring concrete.

[0112] (4) The rough structure of the superhydrophobic surface contains an air layer that can effectively isolate the external corrosive medium. If the concrete mold is made of metal, the superhydrophobic surface can provide good corrosion protection for the substrate, thereby enhancing the service life of the concrete mold.

[0113] Example 2

[0114] The preparation method was the same as in Example 1, except that lubricating oil was injected into the substrate having a superhydrophobic surface structure obtained in step g of Example 1, filling the entire pore space to obtain a superslippery surface. The substrates were then assembled to obtain a test mold of an easily releasable concrete having superhydrophobic / superslippery properties.

[0115] By further injecting lubricating oil into this embodiment, the super-hydrophobic / super-slippery surface obtained has the following advantages:

[0116] (1) The lubricating oil injected into the micro-nano structure has super-slip properties, which further reduces the adhesion between the concrete and the inner wall of the concrete test mold, making it easy for the concrete to be demolded, thus not causing damage to the concrete specimen.

[0117] (2) The micro-nano structure contains lubricating oil, so there is no need to apply release agent in advance when using it, which improves work efficiency.

[0118] (3) The prepared micron-scale inverted trapezoidal structure is a polymer with elasticity. After pouring concrete, it will be compressed downward by the gravity of the concrete, thereby squeezing the lubricating oil stored in the micro-nano structure to the surface of the porous structure.

[0119] (4) The obtained micron-scale inverted trapezoidal structure and the micro-nanostructure attached to the surface of the microstructure can lock the lubricating oil and reduce the loss of lubricating oil, so that the concrete test mold has good durability during use.

[0120] (5) The super-slip surface has self-cleaning properties, which can reduce the residual concrete adhering to the inner wall of the concrete test mold, thereby keeping the inner wall of the mold clean, reducing daily maintenance and cleaning work, and thus improving work efficiency.

[0121] (6) The rough structure of the super-slip surface contains lubricating oil, which can effectively isolate the external corrosive medium. If the concrete mold is made of metal, the super-hydrophobic surface can provide good corrosion protection for the substrate, thereby enhancing the service life of the concrete mold.

[0122] (7) The rough structure of the super-smooth surface contains a layer of lubricating oil, which can effectively isolate the external corrosive medium. If the concrete test mold is made of metal, the super-smooth surface can provide good corrosion protection for the substrate, thereby enhancing the service life of the concrete test mold.

[0123] (8) The rough structure of the super-slip surface contains a layer of lubricating oil, which reduces the friction between external substances and the concrete test mold surface, and can reduce the damage to the inner wall of the concrete test mold when pouring concrete.

[0124] Example 3

[0125] The preparation method is the same as that of Example 1, except that in step b, the deposited metal layer is an Al metal layer. Correspondingly, in step d, the substrate is placed in a 1 mol / L copper chloride solution (or a 2 mol / L hydrochloric acid solution), reacts for 60 seconds, then slowly removed, immediately ultrasonically cleaned with deionized water, and air-dried, thereby obtaining a micro-nanoscale stepped structure on the metal layer on the side of the inverted trapezoidal structure.

[0126] Example 4

[0127] A method for preparing an easy-to-release concrete test mold with an inner wall having super-hydrophobic properties comprises the following steps:

[0128] a. Spin-coat negative photoresist and use ultraviolet lithography to obtain a substrate with an inverted trapezoidal microstructure on the inner wall.

[0129] Step a specifically includes the following steps:

[0130] a1. Use the vertical plate or bottom plate as the base and clean it with acetone, ethanol and deionized water in sequence.

[0131] a2. Spin-coat a layer of negative photoresist on the inner wall surface of the substrate.

[0132] a3. Use an ultraviolet light source to perform the first tilted ultraviolet lithography.

[0133] a4. Rotate the UV light source 180° and perform a second tilted UV lithography.

[0134] a5. After the photolithography is completed, the substrate is immediately placed in a developer corresponding to the negative photoresist for development, and then rinsed with deionized water and dried to obtain a substrate with an inverted trapezoidal microstructure on the inner wall.

[0135] In the above steps, when performing tilted UV lithography, a UV light source and a reflective lens are used, such as Figure 1 、 Figure 3 As shown in the figure, a reflective lens is placed at an angle opposite the UV light source so that the UV light can be irradiated on the UV photoresist at an angle, completing the first UV lithography. The UV light source and the reflective lens are then rotated 180 degrees synchronously to perform the second UV lithography.

[0136] b. Vacuum evaporation deposition of metal layer

[0137] The substrate with the inverted trapezoidal microstructure is subjected to metal coating. After the coating is completed, the substrate with the inverted trapezoidal microstructure after the metal layer is evaporated is taken out.

[0138] The evaporated metal layer is a Mg, Zn, or Cu metal layer.

[0139] c. Remove the metal layer on the upper surface of the inverted trapezoidal microstructure on the inner wall of the substrate.

[0140] Specifically, a chemical etching method is used to remove the metal layer on the upper surface of the inverted trapezoidal microstructure.

[0141] Prepare a 6 mol / L nitric acid solution. Place the substrate horizontally with the inverted trapezoidal structure facing downward and slowly move it horizontally downward. Once the substrate is in contact with the nitric acid solution, keep it still to ensure that the metal layer on the upper surface of the inverted trapezoidal microstructure is exposed to the solution while the metal layers on the side are shielded from it. After 5 seconds, rinse with deionized water and dry.

[0142] d. A micro-nano hierarchical structure is obtained on the metal layer covered by the inverted trapezoidal microstructure on the inner wall of the substrate by chemical immersion.

[0143] Specifically, the substrate is placed in a silver nitrate solution with a concentration of 0.01 mol / L, reacted for 5 minutes, taken out, rinsed with deionized water and dried in the air, and a dendritic micro-nano hierarchical structure is obtained on the metal layer on the side of the inverted trapezoidal structure.

[0144] Then, low surface energy modification was performed: the substrate with the micro-nano structure obtained on the metal layer on the side of the inverted trapezoidal structure was placed in a mixed solution of stearic acid and ethanol with a stearic acid concentration of 0.01 mol / L for 60 minutes for hydrophobic modification. It was then rinsed with deionized water and dried to obtain a micro-nano hierarchical structure with superhydrophobicity on the inner surface of the micron-scale inverted trapezoid.

[0145] e. Spin-coat molten wax on the substrate treated in step d. After cooling to room temperature, the solid wax fills the micrometer-sized pores between the inverted trapezoidal structures.

[0146] f. Aluminum is deposited by vacuum evaporation and then anodized to obtain a porous metal aluminum surface.

[0147] The steps for vacuum evaporation deposition of aluminum are as follows:

[0148] Fix the substrate on the substrate table and place the aluminum target in the evaporation boat; then set the parameters and start the coating operation; after the coating is completed, take out the aluminum-coated substrate.

[0149] The anodizing steps are as follows:

[0150] The aluminum-plated substrate was anodized in a phosphoric acid solution with a concentration of 0.25 mol / L, with the aluminum-plated substrate as the anode and the stainless steel as the cathode, and the distance between the two electrodes was set to 20 mm; the anodization voltage was set to 120 V, and the anodization operation was started at an initial temperature of 50°C; after the anodization time lasted for 1 minute, the anodized aluminum-plated substrate was removed, rinsed with deionized water and dried in air to obtain anodized aluminum with a porous structure.

[0151] After the anodic oxidation treatment, the substrate is placed in an ethanol solution of 0.01 mol / L stearic acid (or silane) for 60 minutes for hydrophobic modification.

[0152] g. Expelling the solid wax from the micron-sized pores to obtain a substrate having a super-hydrophobic surface structure. Specifically, ultrasonic vibration can be used to completely expel the wax from the micron-sized pores.

[0153] The steps are as follows: placing the substrate after the second UV lithography in an ultrasonic cleaner; setting the ultrasonic cleaning temperature to 65°C and the time to 30 minutes; starting the ultrasonic cleaner, the wax inside the microstructure gradually melts, and is discharged with water due to the action of ultrasonic vibration.

[0154] h. Assemble the base to obtain an easy-to-release concrete test mold with super-hydrophobic properties.

[0155] Example 5

[0156] The preparation method was the same as in Example 4, except that lubricating oil was injected into the substrate having a superhydrophobic surface structure obtained in step g of Example 4, filling the entire pore space to obtain a superslippery surface. The substrates were then assembled to obtain a test mold of an easily releasable concrete having superhydrophobic / superslippery properties.

Claims

1. A method for preparing an easy-to-release concrete test mold with a super-hydrophobic inner wall, the easy-to-release concrete test mold comprising four vertical plates and a bottom plate, wherein the inner walls of the vertical plates and the bottom plate are each provided with a super-hydrophobic surface structure, wherein the super-hydrophobic surface structure is a micro-nano structure; characterized in that: The preparation method comprises the following steps: a. Spin-coating a negative photoresist and performing ultraviolet lithography to obtain a substrate having an inner wall with an inverted trapezoidal microstructure; b. Vacuum evaporation deposition of metal layer The substrate having the inverted trapezoidal microstructure is subjected to metal coating; after the coating is completed, the substrate having the inverted trapezoidal microstructure after the metal layer is evaporated is taken out; c. removing the metal layer on the upper surface of the inverted trapezoidal microstructure on the inner wall of the substrate; d. A micro-nano hierarchical structure is obtained on the metal layer covered by the inverted trapezoidal microstructure on the inner wall of the substrate by chemical immersion; e. Spin-coating molten wax on the substrate treated in step d. After cooling to room temperature, the solid wax fills the micrometer-sized pores between the inverted trapezoidal structures. f. Spin-coat positive photoresist and perform UV lithography; g. Expelling the solid wax from the micron-sized pores to obtain a substrate with a super-hydrophobic surface structure; h. Assemble the base to obtain an easy-to-release concrete test mold with super-hydrophobic properties.

2. The method for preparing a test mold of an easy-to-release concrete with an inner wall having super-hydrophobic properties according to claim 1, wherein: Step a specifically includes the following steps: a1. Use the vertical plate or bottom plate as the base and clean it with acetone, ethanol and deionized water in sequence; a2. Spin-coating a layer of negative photoresist on the inner wall surface of the substrate; a3. Performing the first tilted UV lithography using a UV light source; a4. Rotate the UV light source 180° and perform a second tilted UV lithography; a5. After the photolithography is completed, the substrate is immediately placed in a developer compatible with the negative photoresist for development, and then rinsed with deionized water and dried to obtain a substrate with an inverted trapezoidal microstructure on the inner wall.

3. The method for preparing an easy-to-release concrete test mold with an inner wall having super-hydrophobic properties according to claim 2, wherein: When performing tilted UV lithography, a UV light source and a reflective lens are used. A reflective lens is placed at an angle opposite the UV light source so that the UV light can be irradiated onto the UV photoresist at an angle, completing the first UV lithography. The UV light source and the reflective lens are then rotated 180° synchronously to perform the second UV lithography.

4. The method for preparing a test mold of easy-to-release concrete with an inner wall having super-hydrophobic properties according to claim 1, wherein: In step b: the evaporated metal layer is a Mg, Zn, Cu or Al metal layer.

5. The method for preparing a test mold of easy-to-release concrete with an inner wall having super-hydrophobic properties according to claim 1, wherein: In step c: removing the metal layer on the upper surface of the inverted trapezoidal microstructure by chemical etching; Prepare a nitric acid solution first, then place the substrate horizontally with the side of the inverted trapezoidal structure facing downward and slowly move it horizontally downward. When the substrate just contacts the nitric acid solution, keep it still to ensure that the metal layer on the upper surface of the inverted trapezoidal micron-scale structure can contact the nitric acid solution, while the metal layer on the side is not exposed to the nitric acid solution. After the reaction was complete, the samples were rinsed with deionized water and dried.

6. The method for preparing a test mold of easy-to-release concrete with an inner wall having super-hydrophobic properties according to claim 1, wherein: In step d: placing the substrate in a silver nitrate solution or a copper chloride solution, taking it out after the reaction, rinsing it with deionized water and drying it in air, thereby obtaining a micro-nano structure on the metal layer on the side of the inverted trapezoidal structure.

7. The method for preparing an easy-to-release concrete test mold with an inner wall having super-hydrophobic properties according to claim 6, wherein: It also includes a low surface energy modification step: placing the substrate with a micro-nano structure obtained on the metal layer on the side of the inverted trapezoidal structure in a mixed solution of stearic acid and ethanol for hydrophobic modification, and then rinsing with deionized water and drying, thereby obtaining a micro-nano structure with super hydrophobicity on the inner surface of the micron-scale inverted trapezoid.

8. The method for preparing an easy-to-release concrete test mold with an inner wall having super-hydrophobic properties according to claim 1, wherein: In step g: the wax in the micron-sized pores is completely expelled by ultrasonic vibration.

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