Cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting thin film and its preparation method

Abstract

The application discloses a tricobalt tetraoxide super-hydrophilic / super-hydrophobic array fog-collecting film and a preparation method thereof, and specifically comprises the following steps: step 1, a tricobalt tetraoxide film is prepared on a flexible plastic substrate by adopting a sol-gel method combined with a DUV-assisted low-temperature heat treatment technology; step 2, tricobalt tetraoxide nanocluster is deposited on the surface of the tricobalt tetraoxide film by adopting a hydrothermal method, so that the tricobalt tetraoxide film with a nanocluster structure on the surface is obtained; step 3, the tricobalt tetraoxide film with the nanocluster structure on the surface is subjected to low-surface-energy modification by utilizing a molecular self-assembly technology, so that a super-hydrophobic tricobalt tetraoxide nanocluster film is obtained; and step 4, a mask plate is arranged on the surface of the super-hydrophobic tricobalt tetraoxide nanocluster film, and deep ultraviolet light is radiated, so that the tricobalt tetraoxide super-hydrophilic / super-hydrophobic array fog-collecting film is obtained. The fog-collecting film can realize efficient fog capturing and fog-collecting circulation.

Description

Technical Field

[0001] This invention belongs to the field of fog collection film technology, specifically relating to a method for preparing a cobalt tetroxide superhydrophilic / superhydrophobic array fog collection film, and also relating to a cobalt tetroxide superhydrophilic / superhydrophobic array fog collection film. Background Technology

[0002] Effectively collecting water from humid fog offers a new solution to the problem in some water-scarce areas of my country. In-depth and systematic research into the basic principles, mechanisms, and preparation methods of biomimetic fog collection has revealed that developing high-performance fog-collecting films has become a current research hotspot. Most existing fog-collecting films are superhydrophobic films controlled by factors such as surface wettability, chemical gradient, and microgeometric gradient. However, due to the slow growth rate of condensed droplets on their surface and the tendency for a water film to form on the substrate surface, thus hindering subsequent droplet condensation, their fog capture efficiency is not high. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film, which solves the problem of low fog capture efficiency of existing fog-collecting films.

[0004] Another objective of this invention is to provide a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film.

[0005] The technical solution adopted in this invention is a method for preparing a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film, which is implemented according to the following steps:

[0006] Step 1: Cobalt tetroxide thin films are prepared on flexible plastic substrates using the sol-gel method combined with DUV-assisted low-temperature heat treatment technology;

[0007] Step 2: Cobalt tetroxide nanoclusters are deposited on the surface of the cobalt tetroxide thin film using a hydrothermal method to obtain a cobalt tetroxide thin film with a nanocluster structure on the surface.

[0008] Step 3: Use molecular self-assembly technology to modify the cobalt tetroxide thin film with nanocluster structure on the surface with low surface energy to obtain superhydrophobic cobalt tetroxide nanocluster thin film.

[0009] Step 4: Place the mask on the surface of the superhydrophobic cobalt tetroxide nanocluster film and irradiate it with deep ultraviolet light to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film.

[0010] The invention is further characterized in that,

[0011] The specific process of step 1 is as follows:

[0012] Step 1.1: Dissolve cobalt acetate tetrahydrate in anhydrous methanol, seal and stir magnetically at room temperature, then add acetylacetone to obtain a clear purple solution. Seal the clear purple solution, stir at room temperature, and let it stand to age to obtain cobalt tetroxide sol.

[0013] Step 1.2: Immerse the clean flexible plastic substrate in the cobalt tetroxide sol obtained in Step 1.1, and prepare a smooth and flat sol-gel film on the surface of the flexible plastic substrate using the dip-coat method.

[0014] Step 1.3: The sol-gel film obtained in step 1.2 is placed in an oven for drying, and then the dried sol-gel film is subjected to DUV-assisted low-temperature heat treatment to obtain a cobalt tetroxide film.

[0015] In step 1.1, the concentration of cobalt tetroxide sol is 0.20 mol / L to 0.60 mol / L, and the molar ratio of cobalt acetate tetrahydrate to acetylacetone is 1:1.

[0016] In step 1.2, the flexible plastic substrate is one of polyester plastic substrate (PET), polyethylene naphthalate plastic substrate (PEN), or polyimide (PI); the lifting speed of the dip-lift method is 1 mm / s to 3 mm / s;

[0017] In step 1.3, the DUV-assisted low-temperature heat treatment process is as follows: the temperature is 50℃~200℃, the irradiation time is 60min~180min, and the ultraviolet wavelength is 180nm~265nm.

[0018] The specific process of step 2 is as follows:

[0019] Step 2.1: Using cobalt chloride hexahydrate as the cobalt source and urea as the alkali source, fully dissolve it in deionized water to obtain cobalt tetroxide hydrothermal reaction solution;

[0020] Step 2.2: Place the cobalt tetroxide film obtained in Step 1 at a 45° angle with its surface facing down into a polytetrafluoroethylene (PTFE) liner, and pour the cobalt tetroxide reaction solution obtained in Step 2.1 into the PTFE liner. Place the PTFE liner into a hydrothermal reactor for reaction, and cool it to room temperature with the furnace. After the reaction is complete, take out the sample.

[0021] Step 2.3: Wash the excess cobalt tetroxide nanoparticles adhering to the sample surface alternately with deionized water and anhydrous ethanol. Dry and anneal the washed sample to obtain a cobalt tetroxide thin film with a nanocluster structure on the surface.

[0022] In step 2.1, the concentration of the cobalt tetroxide hydrothermal reaction solution is 0.02 mol / L to 0.05 mol / L, and the molar ratio of cobalt chloride hexahydrate to urea is 1:5;

[0023] In step 2.2, the reaction temperature in the hydrothermal reactor is 95℃, and the reaction time is 4h to 12h.

[0024] In step 2.3, the drying temperature is 60℃~80℃ and the drying time is 10min~30min.

[0025] The specific process of step 3 is as follows: the cobalt tetroxide thin film with nanocluster structure on the surface obtained in step 2 is immersed in a low surface energy modifier solution for modification, and after being taken out, it is washed with anhydrous ethanol to remove the residual modifier on the surface. After drying, a superhydrophobic cobalt tetroxide nanocluster thin film is obtained.

[0026] The concentration of the low surface energy modifier solution is 20 g / L to 50 g / L. The low surface energy modifier is one of octadecyltrimethyloxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, hexadecyltrimethyloxysilane, and tri-(1H,1H-pentadecylfluorooctoxy)-tert-butoxysilane. The solvent is anhydrous ethanol. The immersion modification time is 10 min to 40 min. The drying temperature is 25℃ to 80℃ and the time is 10 min to 40 min.

[0027] The specific process of step 4 is as follows: cover the surface of the superhydrophobic cobalt tetroxide nanocluster film obtained in step 3 with a mask template with a specific pattern, and then irradiate the unmasked area with deep ultraviolet light at room temperature to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film.

[0028] The ultraviolet light wavelength is 180nm~265nm, and the irradiation time is 3h~4h.

[0029] Another technical solution adopted in this invention is a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film, which is prepared by the above-mentioned method.

[0030] The beneficial effects of this invention are as follows: The preparation method of the cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film of this invention firstly uses the sol-gel method combined with DUV-assisted low-temperature heat treatment technology to prepare a cobalt tetroxide film on a flexible plastic substrate. Then, a dense cobalt tetroxide nanoclusters are further deposited on its surface using a hydrothermal method. After that, the surface energy is modified to be low using molecular self-assembly technology. Then, an array with regularly alternating superhydrophilic and superhydrophobic regions is constructed using deep ultraviolet irradiation-assisted masking technology. Finally, by effectively controlling its curvature gradient, efficient fog capture and fog collection circulation can be achieved. Attached Figure Description

[0031] Figure 1 This is a SEM image of a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film prepared on a PET plastic substrate by the method of this invention;

[0032] Figure 2 This is a characterization diagram of the unbent droplet movement on the surface of the cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film prepared on a PET substrate by the method of the present invention;

[0033] Figure 3 This is a characterization diagram of droplet movement when the surface of the cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film prepared on a PET substrate by the method of the present invention is bent at 150°.

[0034] Figure 4 This is a characterization diagram of droplet movement when the surface of the cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film prepared on a PET substrate by the method of the present invention is bent at 120°.

[0035] Figure 5 This is a characterization diagram of droplet movement when the surface of the cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film prepared on a PET substrate by the method of the present invention is bent at 90°.

[0036] Figure 6 This is a characterization diagram of droplet movement when the surface of the cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film prepared on a PET substrate by the method of the present invention is bent at 60°.

[0037] Figure 7 This is a graph showing the relationship between the surface contact angle and the number of friction cycles of a superhydrophobic cobalt tetroxide nanocluster film prepared on a PEN plastic substrate using the method of this invention. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0039] The method for preparing the cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting thin film of the present invention is implemented according to the following steps:

[0040] Step 1: Cobalt tetroxide thin films are prepared on flexible plastic substrates using the sol-gel method combined with DUV-assisted low-temperature heat treatment technology;

[0041] The specific process of step 1 is as follows:

[0042] Step 1.1: Dissolve cobalt acetate tetrahydrate in anhydrous methanol, seal and stir magnetically at room temperature, then add acetylacetone to obtain a clear purple solution. Seal the clear purple solution, stir at room temperature, and let it stand to age to obtain cobalt tetroxide sol.

[0043] The concentration of cobalt tetroxide sol was 0.20 mol / L to 0.60 mol / L, and the molar ratio of cobalt acetate tetrahydrate to acetylacetone was 1:1.

[0044] Step 1.2: Immerse the clean flexible plastic substrate in the cobalt tetroxide sol obtained in Step 1.1, and prepare a smooth and flat sol-gel film on the surface of the flexible plastic substrate using the dip-coat method.

[0045] The flexible plastic substrate is made of one of the following: polyester plastic substrate (PET), polyethylene naphthalate plastic substrate (PEN), or polyimide (PI).

[0046] The lifting speed of the dip-lifting method is 1 mm / s to 3 mm / s;

[0047] Step 1.3: Place the sol-gel film obtained in step 1.2 in an oven and dry it at 80°C for 30 minutes. Then, subject the dried sol-gel film to DUV-assisted low-temperature heat treatment to obtain a cobalt tetroxide film.

[0048] The process of DUV (deep ultraviolet) assisted low-temperature heat treatment is as follows: temperature is 50℃~200℃, irradiation time is 60min~180min, and ultraviolet wavelength is 180nm~265nm.

[0049] Step 2: Cobalt tetroxide nanoclusters are deposited on the surface of the cobalt tetroxide thin film using a hydrothermal method to obtain a cobalt tetroxide thin film with a nanocluster structure on the surface.

[0050] The specific process is as follows:

[0051] Step 2.1: Using cobalt chloride hexahydrate as the cobalt source and urea as the alkali source, fully dissolve it in deionized water to obtain cobalt tetroxide hydrothermal reaction solution;

[0052] The concentration of the cobalt tetroxide hydrothermal reaction solution is 0.02 mol / L to 0.05 mol / L, and the molar ratio of cobalt chloride hexahydrate to urea is 1:5.

[0053] Step 2.2: Place the cobalt tetroxide film obtained in Step 1 at a 45° angle with its surface facing down into a polytetrafluoroethylene (PTFE) liner, and pour the cobalt tetroxide reaction solution obtained in Step 2.1 into the PTFE liner. Place the PTFE liner into a hydrothermal reactor for reaction, and cool it to room temperature with the furnace. After the reaction is complete, take out the sample.

[0054] The reaction temperature in the hydrothermal reactor is 95℃, and the reaction time is 4h to 12h.

[0055] Step 2.3: Wash the excess cobalt tetroxide nanopowder adhering to the sample surface alternately with deionized water and anhydrous ethanol, and dry the washed sample to obtain a cobalt tetroxide thin film with a nano-cluster structure on the surface.

[0056] The drying temperature is 60℃~80℃, and the drying time is 10min~30min;

[0057] Step 3: Use molecular self-assembly technology to modify the surface of cobalt tetroxide thin film with nanocluster structure to a low surface energy, so as to obtain superhydrophobic cobalt tetroxide nanocluster thin film;

[0058] The specific process is as follows:

[0059] The cobalt tetroxide thin film with nanocluster structure on the surface obtained in step 2 was immersed in a low surface energy modifier solution with a concentration of 20 g / L to 50 g / L for 10 min to 40 min. After taking it out, it was washed with anhydrous ethanol to remove the residual modifier on the surface. After drying at 25℃ to 80℃ for 10 min to 40 min, a superhydrophobic cobalt tetroxide nanocluster thin film was obtained.

[0060] Among them, the low surface energy modifier is one of octadecyltrimethyloxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, hexadecyltrimethyloxysilane, and tri-(1H,1H-pentadecafluorooctoxy)-tert-butoxysilane, and the solvent is anhydrous ethanol;

[0061] Step 4: Place the mask on the surface of the superhydrophobic cobalt tetroxide nanocluster film and irradiate it with deep ultraviolet light to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film.

[0062] The specific process is as follows:

[0063] A mask with a stripe size of 1 mm × 4 cm is used to cover the surface of the superhydrophobic cobalt tetroxide nanocluster film obtained in step 3. The unmasked area is then irradiated with deep ultraviolet light at room temperature to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film. The surface of the obtained cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film is bent under external force.

[0064] The ultraviolet light wavelength is 180nm~265nm, and the irradiation time is 3h~4h.

[0065] The principle of this invention is that the superhydrophilic regions in the cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film have a strong adhesion to fog droplets, enabling them to quickly capture fog droplets in the air and cause them to coalesce into larger droplets. The superhydrophobic regions have low surface free energy and high contact angle, resulting in extremely weak adhesion to fog droplets, allowing them to quickly roll off the sample surface. The regular alternation of superhydrophilic and superhydrophobic regions not only accelerates the aggregation and growth of fog droplets, significantly improving the nucleation and capture efficiency, but also allows the droplets to quickly roll off the surface of the array fog collecting film when they reach a critical size, due to the low adhesion of the superhydrophobic regions, allowing the superhydrophilic regions to re-contact and capture the fog droplets. Furthermore, by bending the material surface with external force, the Laplace pressure difference generated on the surface increases with the degree of bending, and the rate of droplet directional movement accelerates. In the superhydrophilic region, the droplets rapidly nucleate and grow to the critical size. Under the combined action of the superhydrophobic region and the Laplace pressure difference, they move towards the center. During this process, the droplets continuously converge and grow until they fall off, repeating the cycle, thereby achieving efficient fog capture and fog collection circulation.

[0066] Example 1

[0067] Step 1: Cobalt tetroxide thin films are prepared on flexible plastic substrates using the sol-gel method combined with DUV-assisted low-temperature heat treatment technology;

[0068] The specific process of step 1 is as follows:

[0069] Step 1.1: Dissolve 5.98g of cobalt acetate tetrahydrate in 40mL of anhydrous methanol, seal and stir magnetically for 30min at room temperature, then add 2.40g of acetylacetone to obtain a clear purple solution. Seal the clear purple solution and stir at room temperature for 3h, then let it stand for 12h to obtain a purple cobalt tetroxide sol with a concentration of 0.20mol / L.

[0070] Step 1.2: Immerse the clean PET substrate in the cobalt tetroxide sol obtained in Step 1.1, and use the dip-coat method to prepare a smooth and flat sol-gel film on the surface of the PET substrate at a lifting speed of 1 mm / s.

[0071] Step 1.3: Place the sol-gel film obtained in step 1.2 in an oven and dry it at 80°C for 30 minutes. Then, subject the dried sol-gel film to DUV-assisted low-temperature heat treatment to obtain a cobalt tetroxide film.

[0072] The process of DUV-assisted low-temperature heat treatment is as follows: temperature is 50℃, irradiation time is 60min, and ultraviolet wavelength is 180nm~265nm.

[0073] Step 2: Cobalt tetroxide nanoclusters are deposited on the surface of the cobalt tetroxide thin film using a hydrothermal method to obtain a cobalt tetroxide thin film with a nanocluster structure on the surface.

[0074] The specific process is as follows:

[0075] Step 2.1: Using 0.87g of cobalt chloride hexahydrate as the cobalt source and 1.08g of urea as the alkali source, dissolve them completely in 60mL of deionized water to obtain a hydrothermal reaction solution with a concentration of 0.02mol / L cobalt tetroxide.

[0076] Step 2.2: Place the cobalt tetroxide film obtained in Step 1 at a 45° angle with the surface facing down into a 100 mL polytetrafluoroethylene (PTFE) liner. During this process, ensure that the volume of the reaction liquid does not exceed 2 / 3 of the PTFE liner's volume. Pour the cobalt tetroxide reaction solution obtained in Step 2.1 into the PTFE liner. Place the PTFE liner into a hydrothermal reactor and react at 95°C for 4 hours. Cool the reactor to room temperature. After the reaction is complete, remove the sample.

[0077] Step 2.3: Wash the excess cobalt tetroxide nanopowder adhering to the sample surface alternately with deionized water and anhydrous ethanol, and dry the washed sample to obtain a cobalt tetroxide thin film with a nano-cluster structure on the surface.

[0078] The drying temperature was 80℃, and the drying time was 10 minutes.

[0079] Step 3: Use molecular self-assembly technology to modify the cobalt tetroxide thin film with nanocluster structure on the surface with low surface energy to obtain superhydrophobic cobalt tetroxide nanocluster thin film.

[0080] The specific process is as follows:

[0081] The cobalt tetroxide thin film with nanocluster structure obtained in step 2 was immersed in an anhydrous ethanol solution of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane with a concentration of 20 g / L for 20 min. After removal, it was washed with anhydrous ethanol to remove the residual modifier on the surface. After drying at 80 °C for 10 min, a superhydrophobic cobalt tetroxide nanocluster thin film was obtained.

[0082] Step 4: Place the mask on the surface of the superhydrophobic cobalt tetroxide nanocluster film and irradiate it with deep ultraviolet light to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film.

[0083] The specific process is as follows:

[0084] A mask with a grid size of 50μm×50μm was used to cover the surface of the superhydrophobic cobalt tetroxide nanocluster film obtained in step 3. The unmasked area was then irradiated with ultraviolet light with a wavelength of 180nm~265nm for 4 hours at room temperature to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film.

[0085] Depend on Figure 1 It can be seen that the surface morphology of the cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film is a nanocluster structure.

[0086] Example 2

[0087] Step 1: Cobalt tetroxide thin films are prepared on flexible plastic substrates using the sol-gel method combined with DUV-assisted low-temperature heat treatment technology;

[0088] The specific process of step 1 is as follows:

[0089] Step 1.1: Dissolve 11.95g of cobalt acetate tetrahydrate in 40mL of anhydrous methanol, seal and stir magnetically at room temperature for 30min, then add 4.80g of acetylacetone to obtain a clear purple solution. Seal the clear purple solution and stir at room temperature for 4h, then let it stand for 12h to obtain a purple cobalt tetroxide sol with a concentration of 0.40mol / L.

[0090] Step 1.2: Immerse the clean PET substrate in the cobalt tetroxide sol obtained in Step 1.1, and use the dip-coat method to prepare a smooth and flat sol-gel film on the surface of the PET substrate at a lifting speed of 2 mm / s.

[0091] Step 1.3: Place the sol-gel film obtained in step 1.2 in an oven and dry it at 80°C for 30 minutes. Then, subject the dried sol-gel film to DUV-assisted low-temperature heat treatment to obtain a cobalt tetroxide film.

[0092] The process of DUV-assisted low-temperature heat treatment is as follows: temperature is 150℃, irradiation time is 120min, and ultraviolet wavelength is 180nm~265nm.

[0093] Step 2: Cobalt tetroxide nanoclusters are deposited on the surface of the cobalt tetroxide thin film using a hydrothermal method to obtain a cobalt tetroxide thin film with a nanocluster structure on the surface.

[0094] The specific process is as follows:

[0095] Step 2.1: Using 1.30g of cobalt chloride hexahydrate as the cobalt source and 1.62g of urea as the alkali source, dissolve them completely in 60mL of deionized water to obtain a hydrothermal reaction solution with a concentration of 0.03mol / L cobalt tetroxide.

[0096] Step 2.2: Place the cobalt tetroxide film obtained in Step 1 at a 45° angle with the surface facing down into a 100 mL polytetrafluoroethylene (PTFE) liner. During this process, ensure that the volume of the reaction liquid does not exceed 2 / 3 of the PTFE liner's volume. Pour the cobalt tetroxide reaction solution obtained in Step 2.1 into the PTFE liner. Place the PTFE liner into a hydrothermal reactor and react at 95°C for 6 hours. Cool the reactor to room temperature. After the reaction is complete, remove the sample.

[0097] Step 2.3: Wash the excess cobalt tetroxide nanopowder adhering to the sample surface alternately with deionized water and anhydrous ethanol, and dry the washed sample to obtain a cobalt tetroxide thin film with a nano-cluster structure on the surface.

[0098] The drying temperature was 80℃, and the drying time was 10 minutes.

[0099] Step 3: Use molecular self-assembly technology to modify the cobalt tetroxide thin film with nanocluster structure on the surface with low surface energy to obtain superhydrophobic cobalt tetroxide nanocluster thin film.

[0100] The specific process is as follows:

[0101] The cobalt tetroxide thin film with nanocluster structure obtained in step 2 was immersed in an anhydrous ethanol solution of 50 g / L octadecyltrimethyloxysilane for 10 min for modification. After removal, it was washed with anhydrous ethanol to remove the residual modifier on the surface. After drying at 80 °C for 10 min, a superhydrophobic cobalt tetroxide nanocluster thin film was obtained.

[0102] Step 4: Place the mask on the surface of the superhydrophobic cobalt tetroxide nanocluster film and irradiate it with deep ultraviolet light to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film.

[0103] The specific process is as follows:

[0104] A mask with a grid size of 50μm×50μm was used to cover the surface of the superhydrophobic cobalt tetroxide nanocluster film obtained in step 3. The unmasked area was then irradiated with ultraviolet light with a wavelength of 180nm~265nm for 3 hours at room temperature to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film.

[0105] Depend on Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 It can be seen that when the surface is curved to 90°, the droplets on the surface are the largest and the distribution is the most dense.

[0106] Example 3

[0107] Step 1: Cobalt tetroxide thin films are prepared on flexible plastic substrates using the sol-gel method combined with DUV-assisted low-temperature heat treatment technology;

[0108] The specific process of step 1 is as follows:

[0109] Step 1.1: Dissolve 8.96g of cobalt acetate tetrahydrate in 40mL of anhydrous methanol, seal and stir magnetically for 30min at room temperature, then add 3.60g of acetylacetone to obtain a clear purple solution. Seal the clear purple solution and stir at room temperature for 3h, then let it stand for 12h to obtain a purple cobalt tetroxide sol with a concentration of 0.30mol / L.

[0110] Step 1.2: Immerse the clean PET substrate in the cobalt tetroxide sol obtained in Step 1.1, and use the dip-coat method to prepare a smooth and flat sol-gel film on the surface of the PET substrate at a lifting speed of 1 mm / s.

[0111] Step 1.3: Place the sol-gel film obtained in step 1.2 in an oven and dry it at 80°C for 30 minutes. Then, subject the dried sol-gel film to DUV-assisted low-temperature heat treatment to obtain a cobalt tetroxide film.

[0112] The process of DUV-assisted low-temperature heat treatment is as follows: temperature is 100℃, irradiation time is 90min, and ultraviolet wavelength is 180nm~265nm.

[0113] Step 2: Cobalt tetroxide nanoclusters are deposited on the surface of the cobalt tetroxide thin film using a hydrothermal method to obtain a cobalt tetroxide thin film with a nanocluster structure on the surface.

[0114] The specific process is as follows:

[0115] Step 2.1: Using 1.74g of cobalt chloride hexahydrate as the cobalt source and 2.16g of urea as the alkali source, dissolve them fully in 60mL of deionized water to obtain a hydrothermal reaction solution with a concentration of 0.04mol / L cobalt tetroxide.

[0116] Step 2.2: Place the cobalt tetroxide film obtained in Step 1 at a 45° angle with the surface facing down into a 100 mL polytetrafluoroethylene (PTFE) liner. During this process, ensure that the volume of the reaction liquid does not exceed 2 / 3 of the PTFE liner's volume. Pour the cobalt tetroxide reaction solution obtained in Step 2.1 into the PTFE liner. Place the PTFE liner into a hydrothermal reactor and react at 95°C for 8 hours. Cool the reactor to room temperature. After the reaction is complete, remove the sample.

[0117] Step 2.3: Wash the excess cobalt tetroxide nanopowder adhering to the sample surface alternately with deionized water and anhydrous ethanol, and dry the washed sample to obtain a cobalt tetroxide thin film with a nano-cluster structure on the surface.

[0118] The drying temperature was 80℃, and the drying time was 20 minutes.

[0119] Step 3: Use molecular self-assembly technology to modify the cobalt tetroxide thin film with nanocluster structure on the surface with low surface energy to obtain superhydrophobic cobalt tetroxide nanocluster thin film.

[0120] The specific process is as follows:

[0121] The cobalt tetroxide thin film with nanocluster structure on the surface obtained in step 2 was immersed in an anhydrous ethanol solution of octadecyltrimethyloxysilane with a concentration of 30 g / L for 15 min for modification. After being taken out, it was washed with anhydrous ethanol to remove the residual modifier on the surface. After drying at 80°C for 20 min, a superhydrophobic cobalt tetroxide nanocluster thin film was obtained.

[0122] Step 4: Place the mask on the surface of the superhydrophobic cobalt tetroxide nanocluster film and irradiate it with deep ultraviolet light to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film.

[0123] The specific process is as follows:

[0124] A mask with a grid size of 50μm×50μm was used to cover the surface of the superhydrophobic cobalt tetroxide nanocluster film obtained in step 3. The unmasked area was then irradiated with ultraviolet light with a wavelength of 180nm~265nm for 4 hours at room temperature to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film.

[0125] Depend on Figure 7 It can be seen that as the number of rubbing cycles increases, the contact angle of the film surface decreases slowly. After 10 rubbing cycles, the contact angle remains at 141.2°, indicating hydrophobicity.

[0126] Example 4

[0127] Step 1: Cobalt tetroxide thin films are prepared on flexible plastic substrates using the sol-gel method combined with DUV-assisted low-temperature heat treatment technology;

[0128] The specific process of step 1 is as follows:

[0129] Step 1.1: Dissolve 17.93g of cobalt acetate tetrahydrate in 40mL of anhydrous methanol, seal and stir magnetically at room temperature for 30min, then add 7.20g of acetylacetone to obtain a clear purple solution. Seal the clear purple solution and stir at room temperature for 5h, then let it stand for 12h to obtain a purple cobalt tetroxide sol with a concentration of 0.60mol / L.

[0130] Step 1.2: Immerse the clean PEN substrate in the cobalt tetroxide sol obtained in Step 1.1, and use the dip-coat method to prepare a smooth and flat sol-gel film on the PET substrate surface at a coating speed of 3 mm / s.

[0131] Step 1.3: Place the sol-gel film obtained in step 1.2 in an oven and dry it at 80°C for 30 minutes. Then, subject the dried sol-gel film to DUV-assisted low-temperature heat treatment to obtain a cobalt tetroxide film.

[0132] The process of DUV-assisted low-temperature heat treatment is as follows: temperature is 200℃, irradiation time is 180min, and ultraviolet wavelength is 180nm~265nm.

[0133] Step 2: Cobalt tetroxide nanoclusters are deposited on the surface of the cobalt tetroxide thin film using a hydrothermal method to obtain a cobalt tetroxide thin film with a nanocluster structure on the surface.

[0134] The specific process is as follows:

[0135] Step 2.1: Using 2.17g of cobalt chloride hexahydrate as the cobalt source and 2.70g of urea as the alkali source, dissolve them completely in 60mL of deionized water to obtain a hydrothermal reaction solution with a concentration of 0.05mol / L cobalt tetroxide.

[0136] Step 2.2: Place the cobalt tetroxide film obtained in Step 1 at a 45° angle with the surface facing down into a 100 mL polytetrafluoroethylene (PTFE) liner. During this process, ensure that the volume of the reaction liquid does not exceed 2 / 3 of the PTFE liner's volume. Pour the cobalt tetroxide reaction solution obtained in Step 2.1 into the PTFE liner. Place the PTFE liner into a hydrothermal reactor and react at 95°C for 12 hours. Cool the reactor to room temperature. After the reaction is complete, remove the sample.

[0137] Step 2.3: Wash the excess cobalt tetroxide nanopowder adhering to the sample surface alternately with deionized water and anhydrous ethanol, and dry the washed sample to obtain a cobalt tetroxide thin film with a nano-cluster structure on the surface.

[0138] The drying temperature was 60℃, and the drying time was 30 minutes.

[0139] Step 3: Use molecular self-assembly technology to modify the cobalt tetroxide thin film with nanocluster structure on the surface with low surface energy to obtain superhydrophobic cobalt tetroxide nanocluster thin film.

[0140] The specific process is as follows:

[0141] The cobalt tetroxide thin film with nanocluster structure obtained in step 2 was immersed in an anhydrous ethanol solution of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane with a concentration of 50 g / L for 40 min. After removal, it was washed with anhydrous ethanol to remove the residual modifier on the surface. After drying at 25 °C for 40 min, a superhydrophobic cobalt tetroxide nanocluster thin film was obtained.

[0142] Step 4: Place the mask on the surface of the superhydrophobic cobalt tetroxide nanocluster film and irradiate it with deep ultraviolet light to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog-collecting film.

[0143] The specific process is as follows:

[0144] A mask with an aperture size of r = 5 mm was used to cover the surface of the superhydrophobic cobalt tetroxide nanocluster film obtained in step 3. The unmasked area was then irradiated with ultraviolet light with a wavelength of 180 nm to 265 nm for 3 hours at room temperature to obtain a cobalt tetroxide superhydrophilic / superhydrophobic array fog collecting film.

Claims

1. A method for fabricating a tri-cobalt-tetroxide superhydrophilic / superhydrophobic array fog-collecting film, characterized in that, The method is implemented according to the following steps: Step 1: a cobaltosic oxide film is prepared on a flexible plastic substrate by a sol-gel method combined with a DUV-assisted low-temperature heat treatment technology; The specific process of step 1 is as follows: Step 1.1: dissolve cobalt acetate tetrahydrate in anhydrous methanol, and then seal and stir magnetically at room temperature; then add acetylacetone to obtain a purple clear solution; seal the purple clear solution, stir and stand at room temperature, and obtain a cobaltosic oxide sol after aging; Step 1.2: immerse a clean flexible plastic substrate in the cobaltosic oxide sol obtained in step 1.1, and prepare a smooth sol-gel film on the surface of the flexible plastic substrate by an immersion-drawing method; Step 1.3: dry the sol-gel film obtained in step 1.2 in an oven, and then perform a DUV-assisted low-temperature heat treatment on the dried sol-gel film to obtain a cobaltosic oxide film; Step 2: deposit cobaltosic oxide nanoclusters on the surface of the cobaltosic oxide film by a hydrothermal method to obtain a cobaltosic oxide film with a nanocluster structure on the surface; The specific process of step 2 is as follows: Step 2.1: dissolve cobalt chloride hexahydrate as a cobalt source and urea as an alkali source in deionized water to obtain a cobaltosic oxide hydrothermal reaction solution; Step 2.2: place the cobaltosic oxide film obtained in step 1 in a polytetrafluoroethylene liner with the surface downwardly inclined at an angle of 45°, and pour the cobaltosic oxide reaction solution obtained in step 2.1 into the polytetrafluoroethylene liner; then place the polytetrafluoroethylene liner in a hydrothermal kettle for reaction, and cool to room temperature with the furnace; after the reaction is completed, take out the sample; Step 2.3: wash the sample surface with deionized water and anhydrous ethanol alternately to remove the excess cobaltosic oxide nanometer powder attached to the surface, dry the washed sample, and obtain a cobaltosic oxide film with a nanocluster structure on the surface; Step 3: modify the cobaltosic oxide film with a nanocluster structure on the surface by a molecular self-assembly technology to obtain a super-hydrophobic cobaltosic oxide nanocluster film; The specific process of step 3 is as follows: immerse the cobaltosic oxide film with a nanocluster structure on the surface obtained in step 2 in a low-surface-energy modifier solution for modification, wash the surface with anhydrous ethanol to remove the residual modifier, and dry to obtain a super-hydrophobic cobaltosic oxide nanocluster film; The low-surface-energy modifier is one of octadecyltrimethylsiloxy, 1H, 1H, 2H, 2H-perfluorodecyltrimethoxysilane, hexadecyltrimethylsiloxy, and tris-(1H, 1H-pentadecafluorooctyloxy)-tert-butoxysilane; Step 4: place a mask plate on the surface of the super-hydrophobic cobaltosic oxide nanocluster film, and irradiate with deep ultraviolet light to obtain a cobaltosic oxide super-hydrophilic / super-hydrophobic array fog-collecting film; The specific process of step 4 is as follows: cover a mask plate with a specific pattern on the surface of the super-hydrophobic cobaltosic oxide nanocluster film obtained in step 3, and irradiate the unmasked area with deep ultraviolet light at room temperature to obtain a cobaltosic oxide super-hydrophilic / super-hydrophobic array fog-collecting film; The obtained cobaltosic oxide super-hydrophilic / super-hydrophobic array fog-collecting film is in a curved state under the action of external force.

2. The method of claim 1, wherein the method of fabricating a tri-cobalt-tetroxide superhydrophilic / superhydrophobic array fog-harvesting film is characterized by, In step 1.1, the concentration of the tricobalt tetraoxide sol is 0.20 mol / L-0.60 mol / L, and the molar ratio of cobalt acetate tetrahydrate to acetylacetone is 1:1; In step 1.2, the flexible plastic substrate is one of PET plastic substrate, PEN plastic substrate or PI; the pulling speed of the dip-drawing method is 1 mm / s-3 mm / s; In step 1.3, the process of DUV-assisted low-temperature heat treatment is: the temperature is 50℃-200℃, the irradiation time is 60 min-180 min, and the wavelength of the ultraviolet light is 180 nm-265 nm.

3. The method of claim 1, wherein the method is characterized by: In step 2.1, the concentration of the tricobalt tetraoxide hydrothermal reaction solution is 0.02 mol / L-0.05 mol / L, and the molar ratio of cobalt chloride hexahydrate to urea is 1:5; In step 2.2, the reaction temperature in the hydrothermal kettle is 95℃, and the reaction time is 4 h-12 h; In step 2.3, the drying temperature is 60℃-80℃, and the drying time is 10 min-30 min.

4. The method of claim 1, wherein the method is characterized by: The concentration of the low surface energy modifier solution is 20 g / L-50 g / L, the solvent is anhydrous ethanol, the soaking modification time is 10 min-40 min, the drying temperature is 25℃-80℃, and the time is 10 min-40 min.

5. The method of claim 1, wherein the method is characterized by: The wavelength of the ultraviolet light is 180 nm-265 nm, and the irradiation time is 3 h-4 h.

6. A tri-cobalt-tetroxide superhydrophilic / superhydrophobic array fog collection film characterized by, The preparation method is obtained by using any one of claims 1-5.

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