Method for constructing transparent conductive super-hydrophobic self-cleaning coating on surface

Abstract

The present application relates to the field of paint, disclose a kind of method for constructing transparent conductive super-hydrophobic self-cleaning coating on surface.The present application first constructs un-cured hydrophobic layer on the surface of wood using oil phase impregnation solution containing carnauba wax, tung oil, then immediately drop silver nanowire dispersion liquid, constructs transparent conductive hydrophobic coating with micro-nano rough surface;Finally, with heptadecafluorodecyltrimethoxysilane, super-hydrophobic modification is carried out, and transparent conductive super-hydrophobic self-cleaning coating is successfully constructed on the surface of wood.The present application uses carnauba wax / tung oil layer as base layer, and further modifies micron-level structure by adding silver nanowire, to obtain conductivity while further obtaining micro-nano rough structure.Tung oil in the coating of the present application will penetrate into the wood, and self-oxidation reaction will occur with oxygen in the air, forming a relatively dense crosslinking polymer network structure, which can enhance the bonding force between the coating and the wood.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of paint, in particular to a method for constructing a transparent conductive super-hydrophobic self-cleaning coating on a surface. BACKGROUND

[0002] With the continuous improvement of people's living taste and aesthetic level, the demand for photo frames with special decorative design is increasing. For example, decorating LED lights on wooden photo frames can make the photos or glass mirrors placed in them shine. However, wood material itself is insulating and non-conductive, so many wires need to be arranged on its surface, thereby reducing the aesthetic appearance of the photo frame. In addition, the inherent hydrophilic property of wood also easily causes the photo frame to corrode, age, and be unstable in size. Therefore, it is necessary to modify the wood to be super-hydrophobic, so as to effectively isolate the direct contact with water, thereby improving the stability and durability of the wood while giving it self-cleaning property.

[0003] As an environmentally friendly low-surface-energy material, Brazil palm wax will spontaneously form numerous micron-sized crystal grains when crystallizing on the surface of wood, i.e., form a micron-sized rough structure layer, which also creates conditions for further constructing a super-hydrophobic coating on the surface of wood. However, the applicant found in the previous experiments that Brazil palm wax is hard and brittle, and has poor adhesion to the surface of wood. At the same time, the hydrophobicity of the ordinary Brazil palm wax hydrophobic layer cannot meet the demand of super-hydrophobicity (hydrophobicity: contact angle greater than 90° and less than 150°; super-hydrophobicity: contact angle greater than 150° and rolling angle less than 10°).

[0004] Silver nanowires are widely used to manufacture transparent electrodes due to their high conductivity, low cost, and simple preparation method. However, there is no report on the application of silver nanowires to construct a transparent conductive super-hydrophobic self-cleaning coating on the surface of wood. In theory, the introduction of silver nanowires into the transparent super-hydrophobic self-cleaning coating can give the coating conductivity, but it is not known whether the introduction of silver nanowires will destroy the transparency and super-hydrophobicity of the coating, so further exploration and research are needed to determine its feasibility. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a method for constructing a transparent conductive super-hydrophobic self-cleaning coating on a surface. The present application first constructs an uncured hydrophobic layer on the surface of wood using an oil phase impregnating solution containing Brazil palm wax and tung oil, then immediately drops and coats a silver nanowire dispersion liquid to construct a transparent conductive hydrophobic coating with a micro-nano rough surface; finally, the transparent conductive super-hydrophobic self-cleaning coating is successfully constructed on the surface of wood by super-hydrophobic modification with heptadecafluorodecyltrimethoxysilane.

[0006] The specific technical scheme of the present application is as follows: a method for constructing a transparent conductive super-hydrophobic self-cleaning coating on a surface, comprising the following steps:

[0007] S1: roughen the surface of the wood.

[0008] S2: immerse the wood obtained in S1 in an oil phase impregnation solution containing Brazil palm wax, tung oil and ethyl acetate at 75-85℃, and take out to obtain wood with an uncured hydrophobic layer on the surface.

[0009] S3: immediately drop silver nanowire dispersion on the surface of the transparent hydrophobic coating in an environment with a temperature 50-60℃ lower than the oil phase impregnation solution when the uncured hydrophobic layer is not cooled, and the uncured hydrophobic layer is rapidly cured into a micron-level rough surface, and the silver nanowires are adhered to the surface of the cured hydrophobic layer to form a transparent conductive hydrophobic coating with a micro-nano rough surface.

[0010] S4: drop a dilute solution of heptadecafluorodecyltrimethoxysilane on the surface of the transparent conductive hydrophobic coating, and stand still, so that the heptadecafluorodecyltrimethoxysilane modifies the surface of the transparent conductive hydrophobic coating to be super-hydrophobic, and the tung oil penetrates into the wood and crosslinks, forming a transparent conductive super-hydrophobic self-cleaning coating.

[0011] In the above steps of the present application:

[0012] In S1, the wood is first roughened on the surface, and the above treatment can make the surface of the wood appear as a torn fiber, and this primary rough surface is conducive to the construction of a subsequent super-hydrophobic surface.

[0013] In S2, after the wood is immersed in the oil phase impregnation solution and taken out, a layer of uncured hydrophobic layer can be formed on the surface of the wood, which plays a role in preliminary hydrophobic modification, and provides a basis for subsequent further drop of silver nanowire dispersion to construct a micro-nano rough surface.

[0014] In S3, the silver nanowire dispersion is immediately dropped on the surface of the transparent hydrophobic coating in an environment with a temperature 50-60℃ lower than the oil phase impregnation solution when the uncured hydrophobic layer is not cooled. The present application finds that if the uncured hydrophobic layer is cured by cooling within a certain temperature difference range, a micron-level rough surface can be formed, and the present application further finds that the size of the temperature difference for cooling and curing is crucial to whether a micron-level rough surface can be formed. If the temperature difference is too small, the uncured hydrophobic layer cannot be crystallized into a micron-level rough surface within a proper time; if the temperature difference is too large, the crystallization rate of the hydrophobic layer is too fast. It is ultimately found that the above temperature range is relatively ideal.

[0015] After the silver nanowire dispersion is dropped, the present application uses the high viscosity of the uncured hydrophobic layer when it is completely cured to adhere the silver nanowires. On the one hand, the silver nanowires can be introduced into the coating and form a conductive network, thereby endowing the coating with conductivity; on the other hand, after the silver nanowires are attached, a micro-nano surface (a nano-level rough surface brought by the silver nanowires) can be further constructed on the basis of the original micron-level rough surface, thereby further improving the hydrophobicity of the coating.

[0016] In S4, the low surface energy heptadecafluorodecyltrimethoxysilane diluent solution is dropped on the surface of the transparent conductive hydrophobic coating layer to further enhance the hydrophobicity of the coating layer to reach the super-hydrophobicity standard. During the standing process, the tung oil acid in the tung oil infiltrated into the wood reacts with oxygen in the air to form a relatively dense cross-linked polymer network structure, which can enhance the bonding force between the coating layer and the wood to solve the problem of poor bonding force between the pure carnauba wax coating layer and the wood.

[0017] Preferably, in S1, the surface of the wood is polished with 350-450 mesh sandpaper, washed with deionized water and ethanol under ultrasonic conditions for 1-10 min, and dried at 50-70 DEG C.

[0018] Preferably, in S2, the ratio of the carnauba wax, tung oil and ethyl acetate is 0.5g-2g:3g-5g:40g-50g.

[0019] Preferably, in S2, the immersion time is 20-40s.

[0020] Preferably, in S3, the concentration of the silver nanowire dispersion liquid is 0.2-0.5mg / mL; and the dropping amount of the silver nanowire dispersion liquid on the unit area of the transparent hydrophobic coating layer is 2-8ml / 30cm 2 .

[0021] It is found that the higher the concentration and dropping amount of the silver nanowire dispersion liquid, the more conducive to the construction of the conductive network. However, when the concentration and dropping amount reach a certain limit, although the conductivity of the coating layer is excellent, the silver nanowires in the coating layer will be seriously aggregated, resulting in blackening, thereby affecting the color of the coating layer. Therefore, the conductivity and transparency of the coating layer are relatively contradictory, and the concentration and dropping amount of the silver nanowire dispersion liquid need to be controlled within a reasonable range to meet the requirements of conductivity and transparency at the same time.

[0022] Preferably, in S3, the length of the silver nanowire is 40-100um.

[0023] It is found that the higher the length of the silver nanowire, the more conducive to the construction of the conductive network. When the length of the silver nanowire increases, the network density decreases at a square rate, and the conductive network formed has a smaller node density than the short silver nanowire, and the sheet resistance is also smaller. Therefore, compared with the short silver nanowire, the long silver nanowire can achieve the same conductivity at a lower addition amount. However, in the present application, the silver nanowire that is too long will be not conducive to the formation of the micro-nano surface structure, thereby affecting the hydrophobicity of the coating layer, and therefore the length of the silver nanowire needs to be reasonably controlled.

[0024] As preferred, in S3, the preparation method of the silver nanowire dispersion liquid is: mixing polyvinylpyrrolidone (PVP) and ethylene glycol, dissolving by heating and stirring, adding silver nitrate after cooling, stirring until clear, adding ethylene glycol solution of ferric chloride, stirring, heating and reacting, cooling, centrifuging and washing to obtain silver nanowires, and then preparing a silver nanowire dispersion liquid with ethanol as a solvent.

[0025] As preferred, the usage ratio of the polyvinylpyrrolidone, ethylene glycol, silver nitrate and ferric chloride is 0.1-0.3g: 15-30mL: 0.1-0.3g: 2-5g.

[0026] As preferred, the molecular weight of the polyvinylpyrrolidone is 300000-400000.

[0027] As preferred, the concentration of ferric chloride in the ethylene glycol solution of ferric chloride is 550-650μM.

[0028] As preferred, the preparation method of the silver nanowire dispersion liquid specifically comprises: adding polyvinylpyrrolidone and ethylene glycol into a 250ml three-necked flask, stirring at 350-600rpm under heating conditions at 50-70℃ for 5-15h, adding silver nitrate after cooling to room temperature, stirring at 350-600rpm until clear and transparent, then adding a ferric chloride solution, stirring at 350-600rpm for 1-5min, and finally putting the three-necked flask into an oil bath pot heated to 120-140℃ for reaction for 4-7h. The centrifugation rate is 2000-8000rpm, and the centrifugation time is 5-10min; the washing method is deionized water washing for 2-4 times and ethanol washing for 2-4 times.

[0029] As preferred, in S4, the solvent of the heptadecafluorodecyltrimethoxysilane dilution liquid is ethanol; and the usage ratio of heptadecafluorodecyltrimethoxysilane and ethanol in the heptadecafluorodecyltrimethoxysilane dilution liquid is 0.5-1.5mL: 5-10mL.

[0030] As preferred, in S4, the unit area drop coating amount of the heptadecafluorodecyltrimethoxysilane dilution liquid on the surface of the transparent conductive hydrophobic coating is 0.1-0.3ml / 30cm 2 .

[0031] As preferred, in S4, the standing time is 7-8 days.

[0032] Compared with the prior art, the application has the following beneficial effects:

[0033] (1) The present application takes the Brazil palm wax / tung oil layer as the base layer, and further modifies the micron-level structure by adding silver nanowires, so as to obtain the conductive and micro-nano rough structure, and then the surface is modified to be super-hydrophobic, so as to obtain the transparent conductive super-hydrophobic coating.

[0034] (2) In the present application, the tung oil penetrates into the wood, the tung oil acid in the tung oil reacts with oxygen in the air to form a relatively dense cross-linked polymer network structure, which can enhance the bonding force between the coating and the wood, so as to solve the problem of poor bonding force between the pure Brazil palm wax coating and the wood. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The preparation flow chart of the transparent conductive super-hydrophobic self-cleaning coating constructed on the wood surface of the present application;

[0036] Figure 2 The electron microscope picture of the raw wood with the magnification of 200 times;

[0037] Figure 3 The electron microscope picture of the wood surface with the Brazil palm wax / tung oil layer with the magnification of 200 times;

[0038] Figure 4 The electron microscope picture of the transparent conductive super-hydrophobic self-cleaning coating in Example 1 with the magnification of 200 times;

[0039] Figure 5 The transmission electron microscope picture of the silver nanowires prepared in Example 1;

[0040] Figure 6 The digital photo of the circuit connected in Example 1;

[0041] Figure 7 The contact angle picture of Example 1;

[0042] Figure 8 The contact angle picture of Comparative Example 1;

[0043] Figure 9 The digital photo of the raw wood (a), Example 1 (b) and Example 4 (c);

[0044] Figure 10 The self-cleaning performance chart of the raw wood (a-c) and the transparent conductive super-hydrophobic coating (d-f) prepared in Example 1. DETAILED DESCRIPTION

[0045] The present application will be further described below in combination with examples.

[0046] General examples

[0047] A method for constructing a transparent conductive super-hydrophobic self-cleaning coating on a surface, comprising the following steps:

[0048] S1: sand the wood surface with 350-450 mesh sandpaper, wash with deionized water and ethanol under ultrasonic condition for 1-10 min, and dry at 50-70℃.

[0049] In the above S1, the wood is first subjected to surface roughening treatment, and after the above treatment, the wood surface is in a torn fibrous state, which is conducive to the construction of the subsequent super-hydrophobic self-cleaning coating. S2: immerse the wood obtained in S1 in an oil phase impregnating solution at 75-85℃ for 20-40 s, and after taking out, obtain wood with an uncured hydrophobic layer on the surface. The amount ratio of carnauba wax, tung oil and ethyl acetate in the oil phase impregnating solution is 0.5 g-2 g: 3 g-5 g: 40 g-50 g.

[0050] In the above S2, after the wood is immersed in the oil phase impregnating solution and taken out, a layer of uncured hydrophobic layer is formed on the wood surface, which plays a preliminary hydrophobic modification role, and at the same time provides a basis for the subsequent further drop-coating of silver nanowire dispersion to construct a micro-nano rough surface.

[0051] S3: prepare silver nanowire dispersion: mix 0.1-0.3 g of polyvinylpyrrolidone (PVP, molecular weight 300000-400000) and 15-30 mL of ethylene glycol, and stir at 350-600 rpm under heating conditions at 50-70℃ for 5-15 h, then add 0.1-0.3 g of silver nitrate after cooling to room temperature, and stir at 350-600 rpm until clear and transparent, add 2-5 g of 550-650 μM iron chloride in ethylene glycol solution, and stir at 350-600 rpm for 1-5 min, heat to 120-140℃ in an oil bath, and react for 4-7 h, cool, centrifuge (2000-8000 rpm, 5-10 min), wash with deionized water 2-4 times, and wash with ethanol 2-4 times, to obtain silver nanowires with a length of 40-100 μm, and prepare a silver nanowire dispersion with a concentration of 0.2-0.5 mg / mL using ethanol as the solvent; immediately drop-coat the silver nanowire dispersion on the surface of the transparent hydrophobic coating layer in an environment with a temperature 50-60℃ lower than that of the oil phase impregnating solution while the uncured hydrophobic layer is not cooled, and the uncured hydrophobic layer is rapidly cooled and solidified into a micron-level rough surface, and at the same time, the silver nanowires adhere to the surface of the solidified hydrophobic layer, to form a transparent conductive hydrophobic coating layer with a micro-nano rough surface. The drop-coating amount of the silver nanowire dispersion on the surface of the transparent hydrophobic coating layer per unit area is 2-8 ml / 30 cm 2 .

[0052] In the above S3, the present application immediately drops the silver nanowire dispersion liquid on the surface of the transparent hydrophobic coating layer in an environment with a temperature 50-60℃ lower than the oil phase impregnating liquid when the uncured hydrophobic layer is not cooled. The present application finds that if the uncured hydrophobic layer is cooled and cured in a certain temperature difference range, a micron-level rough surface can be formed. The present application further finds that the temperature difference in cooling and curing is crucial to whether a micron-level rough surface can be formed. If the temperature difference is too small, the uncured hydrophobic layer cannot be cured and crystallized into a micron-level rough surface in a proper time. If the temperature difference is too large, the uncured hydrophobic layer is cured and crystallized too fast. It is finally found that the above temperature range is relatively ideal. After the silver nanowire dispersion liquid is dropped, the present application uses the high viscosity of the uncured hydrophobic layer when it is completely cured to adhere the silver nanowires. On the one hand, the silver nanowires can be introduced into the coating layer and form a conductive network, thereby imparting conductivity to the coating layer. On the other hand, after the silver nanowires are attached, a micro-nano surface (a nano-level rough surface brought by the silver nanowires) can be further constructed on the basis of the original micron-level rough surface, thereby further improving the hydrophobicity of the coating layer. S4: a dilute solution of heptadecafluorodecyltrimethoxysilane is dropped on the surface of the transparent conductive hydrophobic coating layer, and is left to stand for 7-8 days. The heptadecafluorodecyltrimethoxysilane modifies the surface of the transparent conductive hydrophobic coating layer to be super-hydrophobic, and at the same time, the tung oil penetrates into the wood and crosslinks to form a transparent conductive super-hydrophobic self-cleaning coating layer. The solvent of the dilute solution of heptadecafluorodecyltrimethoxysilane is ethanol. The ratio of the amount of heptadecafluorodecyltrimethoxysilane to the amount of ethanol in the dilute solution of heptadecafluorodecyltrimethoxysilane is 0.5-1.5 mL: 5-10 mL. The unit area drop amount of the dilute solution of heptadecafluorodecyltrimethoxysilane on the surface of the transparent conductive hydrophobic coating layer is 0.1-0.3 ml / 30 cm 2 .

[0053] In the above S4, the present application drops the dilute solution of heptadecafluorodecyltrimethoxysilane with low surface energy on the surface of the transparent conductive hydrophobic coating layer to further improve the hydrophobicity of the coating layer to reach the super-hydrophobic standard. During the standing process, the tung oil acid in the tung oil that penetrates into the wood reacts with oxygen in the air to form a relatively dense crosslinked polymer network structure, which can enhance the bonding force between the coating layer and the wood, thereby solving the problem of poor bonding force between the pure Brazil palm wax coating layer and the wood.

[0054] Example 1

[0055] As Figure 1 shown in the preparation flow chart of the present application for constructing a transparent conductive super-hydrophobic self-cleaning coating layer on the surface of wood, the present application specifically comprises the following steps:

[0056] (1) The wood is pretreated, and the wood block (pine wood, 3 cm x 3 cm x 1 cm) is polished with 400 mesh sandpaper, then washed with deionized water and ethanol under ultrasonic conditions for 5 min each, and dried at 60℃ for standby.

[0057] (2) 0.2 g PVP-K60 and 25 ml ethylene glycol were added into a 250 ml three-necked flask, stirred at 500 rpm for 12 h under heating at 60°C, and then 0.25 g silver nitrate was added after cooling to room temperature, stirred at 500 rpm until clear and transparent, followed by adding 3.5 g of a 600 μM iron chloride solution, stirred at 500 rpm for 2 min, and finally the three-necked flask was placed in an oil bath heated to 130°C for reaction for 5 h. After the reaction was completed, it was cooled to room temperature, centrifuged at a speed of 4000 rpm for 10 min, washed with deionized water for 3 times and ethanol for 3 times. After washing, silver nanowires were obtained, and finally the silver nanowires were prepared into a solution for storage with ethanol as the solvent.

[0058] (3) 1 g of carnauba wax and 4 g of tung oil were added into 45 g of ethyl acetate, dissolved by stirring at a speed of 500 rpm at 80°C, and then the wood block was vertically immersed in the solution, and after 30 s, it was pulled out of the solution to obtain a preliminarily modified wood block.

[0059] (4) 4 ml of the prepared silver nanowire dispersion solution with a concentration of 0.4 mg / ml was uniformly drop-coated on the surface of the modified wood block obtained in step (3) at an ambient temperature of 25°C.

[0060] (5) 1 ml of FAS-17 was diluted in 10 ml of ethanol, and 0.1 ml of the diluted solution was uniformly drop-coated on the surface of the wood block obtained in step (4), and after 8 days, a wood material with a transparent conductive super-hydrophobic self-cleaning coating was obtained.

[0061] Example 2

[0062] As Figure 1 shown in the preparation flow chart of the present application for constructing a transparent conductive super-hydrophobic self-cleaning coating on the surface of wood, it specifically comprises the following steps:

[0063] (1) The wood was pretreated, and the wood block (pine wood, 3 cm x 3 cm x 1 cm) was polished with 400 mesh sandpaper, and then washed with deionized water and ethanol under ultrasonic conditions for 5 min each, and dried at 60°C for standby use.

[0064] (2) 0.2 g PVP-K60 and 25 ml ethylene glycol were added into a 250 ml three-necked flask, stirred at 500 rpm for 12 h under heating at 60°C, and then 0.25 g silver nitrate was added after cooling to room temperature, stirred at 500 rpm until clear and transparent, followed by adding 3.5 g of a 600 μM iron chloride solution, stirred at 500 rpm for 2 min, and finally the three-necked flask was placed in an oil bath heated to 130°C for reaction for 5 h. After the reaction was completed, it was cooled to room temperature, centrifuged at a speed of 4000 rpm for 10 min, washed with deionized water for 3 times and ethanol for 3 times. After washing, silver nanowires were obtained, and finally the silver nanowires were prepared into a solution for storage with ethanol as the solvent.

[0065] (3) 1 g of carnauba wax and 4 g of tung oil were added into 45 g of ethyl acetate, dissolved by stirring at a speed of 500 rpm at 80°C, and then the wood block was vertically immersed in the solution, and after 30 s, it was pulled out of the solution to obtain a preliminarily modified wood block.

[0066] (4) 3 ml of the prepared silver nanowire dispersion solution with a concentration of 0.4 mg / ml was uniformly drop-coated on the surface of the modified wood block obtained in step (3) at an ambient temperature of 25°C.

[0067] (5) 1 ml of FAS-17 was diluted in 10 ml of ethanol, and 0.1 ml of the diluted solution was uniformly drop-coated on the surface of the wood block obtained in step (4), and after 8 days, a wood material with a transparent conductive super-hydrophobic self-cleaning coating was obtained.

[0068] Example 3

[0069] As Figure 1 shown in the preparation flow chart of the present application for constructing a transparent conductive super-hydrophobic self-cleaning coating on the surface of wood, it specifically comprises the following steps:

[0070] (1) The wood was pretreated, and the wood block (pine wood, 3 cm x 3 cm x 1 cm) was polished with 400 mesh sandpaper, and then washed with deionized water and ethanol under ultrasonic conditions for 5 min each, and dried at 60°C for standby use.

[0071] (2) 0.2 g PVP-K60 and 25 ml ethylene glycol were added into a 250 ml three-necked flask, stirred at 500 rpm for 12 h under heating at 60°C, and then 0.25 g silver nitrate was added after cooling to room temperature, stirred at 500 rpm until clear and transparent, followed by adding 3.5 g of a 600 μM iron chloride solution, stirred at 500 rpm for 2 min, and finally the three-necked flask was placed in an oil bath heated to 130°C for reaction for 5 h. After the reaction was completed, it was cooled to room temperature, centrifuged at a speed of 4000 rpm for 10 min, washed with deionized water for 3 times and ethanol for 3 times. After washing, silver nanowires were obtained, and finally the silver nanowires were prepared into a solution for storage with ethanol as the solvent.

[0072] (3) 1 g of carnauba wax and 4 g of tung oil were added into 45 g of ethyl acetate, dissolved by stirring at a speed of 500 rpm at 80°C, and then the wood block was vertically immersed in the solution, and after 30 s, it was pulled out of the solution to obtain a preliminarily modified wood block.

[0073] (4) 2 ml of the prepared silver nanowire dispersion solution with a concentration of 0.4 mg / ml was uniformly drop-coated on the surface of the modified wood block obtained in step (3) at an ambient temperature of 25°C.

[0074] (5) 1 ml of FAS-17 was diluted in 10 ml of ethanol, and 0.1 ml of the diluted solution was uniformly drop-coated on the surface of the wood block obtained in step (4), and after 8 days, a wood material with a transparent conductive super-hydrophobic self-cleaning coating was obtained.

[0075] Example 4

[0076] As Figure 1 shown in the preparation flow chart of the present application for constructing a transparent conductive super-hydrophobic self-cleaning coating on the surface of wood, it specifically comprises the following steps:

[0077] (1) The wood was pretreated, and the wood block (pine wood, 3 cm x 3 cm x 1 cm) was polished with 400 mesh sandpaper, and then washed with deionized water and ethanol under ultrasonic conditions for 5 min each, and dried at 60°C for standby use.

[0078] (2) 0.2 g PVP-K60 and 25 ml ethylene glycol were added into a 250 ml three-necked flask, stirred at 500 rpm for 12 h under heating at 60 °C, 0.25 g silver nitrate was added after cooling to room temperature, stirred at 500 rpm until clear and transparent, then 3.5 g of iron chloride solution with a concentration of 600 μΜ was added, stirred at 500 rpm for 2 min, finally the three-necked flask was placed in an oil bath heated to 130 °C for reaction for 5 h. After the reaction was completed, it was cooled to room temperature, centrifuged at a speed of 4000 rpm for 10 min, washed with deionized water for 3 times and ethanol for 3 times. After washing, silver nanowires were obtained, and finally the silver nanowires were prepared into a solution for storage with ethanol as the solvent.

[0079] (3) 1 g of carnauba wax and 4 g of tung oil were added into 45 g of ethyl acetate, dissolved by stirring at a speed of 500 rpm at 80 °C, then the wood block was vertically immersed in the solution, and after 30 s it was pulled out of the solution to obtain a preliminarily modified wood block.

[0080] (4) 8 ml of prepared silver nanowire dispersion solution with a concentration of 0.4 mg / ml was uniformly drop-coated on the surface of the modified wood block obtained in step (3) at an ambient temperature of 25 °C.

[0081] (5) 1 ml of FAS-17 was diluted in 10 ml of ethanol, and 0.1 ml of the diluted solution was uniformly drop-coated on the surface of the wood block obtained in step (4), and after 8 days, a wood material with a transparent conductive super-hydrophobic self-cleaning coating was obtained.

[0082] Comparative Example 1

[0083] (1) The wood was pretreated, and the wood block (pine wood, 3 cm x 3 cm x 1 cm) was polished with 400 mesh sandpaper, then washed with deionized water and ethanol under ultrasonic conditions for 5 min each, and dried at 60 °C for standby use.

[0084] (2) 0.2 g PVP-K60 and 25 ml ethylene glycol were added into a 250 ml three-necked flask, stirred at 500 rpm for 12 h under heating at 60 °C, 0.25 g silver nitrate was added after cooling to room temperature, stirred at 500 rpm until clear and transparent, then 3.5 g of iron chloride solution with a concentration of 600 μΜ was added, stirred at 500 rpm for 2 min, finally the three-necked flask was placed in an oil bath heated to 130 °C for reaction for 5 h. After the reaction was completed, it was cooled to room temperature, centrifuged at a speed of 4000 rpm for 10 min, washed with deionized water for 3 times and ethanol for 3 times. After washing, silver nanowires were obtained, and finally the silver nanowires were prepared into a solution for storage with ethanol as the solvent.

[0085] (3) Take 4 ml of the prepared silver nanowire dispersion solution with a concentration of 0.4 mg / ml, and uniformly drop coat the wood block surface at an ambient temperature of 25°C.

[0086] (4) Dilute 1 ml of FAS-17 in 10 ml of ethanol, and uniformly drop coat 0.1 mL of the diluted solution on the wood block surface obtained in step (3).

[0087] Performance test and characterization

[0088] Table 1: Contact angle and sheet resistance test results of different wood

[0089] Contact angle (°) Sheet resistance (Ω / sq) Lumber 53.1 - Carnauba wax / tung oil layer 139.1 - Example 1 154.3 4.3 Example 2 154.5 43.9 Example 3 153.8 457.2 Example 4 154.7 2.6 Comparative Example 1 146.7 6.3

[0090] Table 1 is the contact angle and sheet resistance parameters of the original wood, the wood block with a carnauba wax / tung oil layer obtained after preliminary modification, and Example 1, Example 2, Example 3, Example 4 and Comparative Example 1. Figure 7 The contact angle pictures of Example 1 and Comparative Example 1 are shown in Figures Figure 7 and Figure 8 and Figure 8 respectively. The contact angle pictures of Example 1 and Comparative Example 1 are shown in Figures The contact angle of the sample is measured by a contact angle measuring instrument, and the volume of the water droplet is 4 μL. At least three points on the surface of each wood block are measured for the contact angle, and the final result is the average value. The sheet resistance of the wood block is measured by a four-probe measuring instrument, and at least three positions on the surface of each wood block are measured for the sheet resistance, and the final result is the average value. The adhesion of the coating is judged by comparing the change of the sheet resistance after the coating surface is torn by a transparent tape. According to Table 1, the contact angle of the wood block with a carnauba wax / tung oil layer after preliminary modification reaches 139.1°, which is because the carnauba wax spontaneously forms micron-level crystals on the surface of the wood block, and the carnauba wax is a low surface energy material. The contact angles of Examples 1-4 are all greater than 150°, while the contact angle of Comparative Example 1 is only 146.7°. This is because Comparative Example 1 does not use the carnauba wax / tung oil layer as the base layer, and the lack of micron-level base layer makes the roughness of the wood block surface much worse than that of Examples 1-4, so the modification effect is poor and does not achieve super-hydrophobic effect. In addition, through the tape tearing experiment, the sample of Comparative Example 1 loses conductivity after being torn once, while the sample of Example 1 has a sheet resistance of 4.7 Ω / sq after the same treatment, and there is no great change. Therefore, the carnauba wax / tung oil layer not only increases the roughness of the coating, but also plays an adhesive role, greatly increasing the adhesion of the coating on the wood surface.

[0091] As can be seen from the sheet resistance values ​​of Examples 1-4, the sheet resistance of the coating gradually decreases with increasing amounts of silver nanowire dispersion. However, the aggregation of silver nanowires becomes increasingly severe with increasing amounts of silver nanowire dispersion. The amount of silver nanowire dispersion used in Example 4 is twice that of Example 1, but the sheet resistance values ​​are similar, showing no significant difference. Figure 9 (like Figure 9 As shown in the digital photographs of the log (a), Example 1 (b), and Example 4 (c), it can be seen that the sample of Example 4 exhibits more agglomeration on its surface and is significantly darkened. Although the surface color of the sample of Example 1 is darker than that of the log, it basically retains the color and texture of the log and does not show obvious agglomeration. From the above analysis, it can be seen that the performance is optimal when the amount of silver nanowire solution used is 4 ml, i.e., Example 1 has the best performance. The above experimental results show that if the concentration and drop volume of the silver nanowire dispersion reach a certain limit, although the coating has excellent conductivity, it will lead to severe aggregation of silver nanowires in the coating, resulting in blackening and affecting the color of the coating. Therefore, the conductivity and transparency of the coating are relatively contradictory; the concentration and drop volume of the silver nanowire dispersion need to be controlled within a reasonable range to simultaneously meet the requirements of conductivity and transparency.

[0092] like Figure 2 The image shown is an electron microscope image of the log at 200x magnification. The surface of the wood block, after being rubbed with sandpaper, exhibits a torn fibrous structure. This primary roughness is conducive to the formation of a superhydrophobic surface. Figure 3 The image shown is an electron microscope image at 200x magnification after obtaining the cured hydrophobic layer in step (3) of Example 1. It shows numerous micron-sized crystal structures formed by carnauba wax, completely covering the original wood tissue, creating favorable conditions for further construction of a superhydrophobic coating. Figure 4 The image shown is an electron microscope image of the conductive superhydrophobic coating of Example 1 at a magnification of 200x. It can be seen that the silver nanowires are distributed on the carnauba wax crystals and overlap to form a conductive network. Furthermore, the micron-scale crystal structure is modified to form a micro-nano rough surface.

[0093] like Figure 5 The image shown is a transmission electron microscope (TEM) image of the silver nanowires prepared in Example 1. The study found that the higher the aspect ratio of the silver nanowires (AgNWs), the better the photoelectric properties of the prepared transparent conductive superhydrophobic coating. As the length of the silver nanowires increases, the network density decreases at a quadratic rate, resulting in a conductive network with a lower node density and therefore a lower sheet resistance compared to shorter wires. However, considering that this invention also requires the construction of a superhydrophobic coating, and that excessively long silver nanowires are detrimental to the formation of micro / nano surface structures, thus affecting the hydrophobicity of the coating, the length of the silver nanowires needs to be reasonably controlled. Through further research... Figure 5From the observation, it can be seen that the longest silver nanowire is close to 100 μm, and the length of most silver nanowires is between 40-100 μm, so it is reasonable to control in the above range.

[0094] As shown in Fig. 1, the LED light in the figure is bright, which indicates that the sample of Example 1 has conductivity. Figure 6 As shown in Fig. 1, the LED light in the figure is bright, which indicates that the sample of Example 1 has conductivity.

[0095] As shown in Fig. 1, the LED light in the figure is bright, which indicates that the sample of Example 1 has conductivity. Figure 10 Fig. 4 shows the self-cleaning performance of the raw wood (a-c) and the transparent conductive super-hydrophobic coating (d-f) prepared in Example 1. As can be seen from the figures (a-c), after dropping water droplets, the soil on the surface of the wood block is not completely removed and is wetted by the water droplets, because the surface of the raw wood contains a large number of hydrophilic groups, and the soil containing water is adhered to the surface of the wood, making the surface of the wood block dirtier. As can be seen from the figures (d-f), after dropping water droplets, the soil on the super-hydrophobic surface is completely removed, because the super-hydrophobic surface has extremely low adhesion to water, and has excellent self-cleaning performance.

[0096] The raw materials and equipment used in the present application are conventional raw materials and equipment in the art unless otherwise specified; the methods used in the present application are conventional methods in the art unless otherwise specified.

[0097] The above description is only the preferred embodiment of the present application, and does not limit the present application in any way, and any simple modification, change and equivalent transformation of the above embodiment according to the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A method for fabricating a transparent conductive superhydrophobic self-cleaning coating on a surface, characterized in that The method comprises the following steps: S1: roughening the surface of the wood; S2: immersing the wood obtained in S1 in an oil phase impregnation solution containing carnauba wax, tung oil and ethyl acetate at 75-85℃, and taking out to obtain wood with an uncured hydrophobic layer on the surface; S3: immediately dropping a silver nanowire dispersion liquid on the surface of the transparent hydrophobic coating in an environment with a temperature 50-60℃ lower than that of the oil phase impregnation solution, and the uncured hydrophobic layer is rapidly cured into a micron-level rough surface, and the silver nanowire is adhered to the surface of the cured hydrophobic layer to form a transparent conductive hydrophobic coating with a micro-nano rough surface; S4: dropping a heptadecafluorodecyltrimethoxysilane dilution liquid on the surface of the transparent conductive hydrophobic coating, and standing to form a transparent conductive super-hydrophobic self-cleaning coating.

2. The method of claim 1, wherein: In S2, the amount ratio of the carnauba wax, tung oil and ethyl acetate is 0.5g-2g:3g-5g:40g-50g.

3. The method of claim 1, wherein: In S3, the length of the silver nanowire is 40-100μm.

4. The method according to claim 1 or 3, characterized in that: In S3, The concentration of the silver nanowire dispersion liquid is 0.2-0.5mg / mL; The drop-coating amount of the silver nanowire dispersion liquid on the surface of the transparent hydrophobic coating layer is 2-8 ml / 30 cm 2 .

5. The method of claim 1, wherein: In S3, the preparation method of the silver nanowire dispersion liquid is as follows: mixing polyvinylpyrrolidone and ethylene glycol, dissolving by heating and stirring, adding silver nitrate after cooling, stirring until clear, adding an ethylene glycol solution of ferric chloride, stirring, heating and reacting, cooling, centrifuging and washing to obtain silver nanowires, and preparing a silver nanowire dispersion liquid with ethanol as the solvent.

6. The method of claim 5, wherein: The amount ratio of the polyvinylpyrrolidone, ethylene glycol, silver nitrate and ferric chloride is 0.1-0.3g:15-30mL:0.1-0.3g:2-5g.

7. The method of claim 5, wherein: The molecular weight of the polyvinylpyrrolidone is 300000-400000.

8. The method of claim 1, wherein: In S4, The solvent of the heptadecafluorodecyltrimethoxysilane dilution liquid is ethanol; The amount ratio of heptadecafluorodecyltrimethoxysilane and ethanol in the heptadecafluorodecyltrimethoxysilane dilution liquid is 0.5-1.5mL:5-10mL.

9. The method of claim 1 or 8, wherein: In S4, the unit area drop coating amount of the heptadecafluorodecyltrimethoxysilane dilution solution on the surface of the transparent conductive hydrophobic coating is 0.1-0.3 ml / 30 cm 2 .

10. The method of claim 1, wherein: In S4, the standing time is 7-8 days.

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