Preparation method and application of super-hydrophobic photo-thermal anti-icing material based on flexible double-size polymer

Abstract

The invention discloses a preparation method and application of a flexible double-size polymer-based super-hydrophobic photo-thermal anti-icing material, and belongs to the technical field of active photo-thermal deicing materials. The preparation method comprises the following steps: firstly, adding a polydimethylsiloxane curing agent into a polydimethylsiloxane solution, mixing and curing to prepare a flexible polydimethylsiloxane solid; and then preparing a regular polygonal micro-nano structure on the flexible polydimethylsiloxane solid by using an ultraviolet laser precision processing system, and depositing candle ash nanoparticles in the micro-nano structure through candle flame. And finally, strengthening a nano structure on the surface through a hydrolysis reaction of tetraethoxysilane and an ammonia water solution, and reducing the surface energy through heptadecafluorodecyl tripropoxysilane, so as to obtain the flexible anti-icing and deicing material with the photothermal effect and the multi-layer structure. The preparation process is simple, the raw materials are cheap, active deicing and defrosting of materials under various environmental conditions can be achieved, and self-cleaning can be achieved in daily life.

Description

Technical Field

[0001] The present invention belongs to the technical field of active photothermal deicing materials, and relates to a preparation method and application of a flexible dual-size polymer-based superhydrophobic photothermal anti-icing material. Background Art

[0002] Icing is a natural phenomenon in low-temperature environments, which can have a serious impact on aviation, transportation, and power facilities, threatening human safety and social and economic stability. Currently, mechanical deicing, electrothermal deicing, and spraying antifreeze are the main deicing methods, but they have problems such as high energy consumption, high cost, and environmental pollution. Superhydrophobic surfaces have a high water contact angle and a low contact angle hysteresis, which can delay icing and reduce ice adhesion. However, in low-temperature and high-humidity environments, superhydrophobic surfaces will lose their properties and freeze. Therefore, researchers have developed photothermal ice-repellent surfaces, which combine superhydrophobicity and photothermal conversion and can remain ice-free for a long time in low-temperature and high-humidity environments.

[0003] Photothermal materials are the key to photothermal ice-repellent surfaces, which are divided into carbon-based, plasmonic, and semiconductor materials. By spraying a superhydrophobic aqueous solution onto a solid substrate, a photothermal ice-repellent surface can be rapidly prepared. However, this method is complex in processing, high in cost, and may cause environmental pollution. In addition, the micro-nano structure of the surface is complex to process, which may affect its application on key working components and mechanical durability. Designing a photothermal ice-repellent surface with mechanical durability is crucial. At the same time, a photothermal ice-repellent surface with high flexibility and mechanical durability can adapt to complex components and rapidly empower and maintain large working components in a modular manner. Such a flexible surface is suitable for complex curved surfaces such as high-altitude transmission lines, 5G signal towers, and aircraft, which is of great significance for the development of anti-icing surfaces. Summary of the Invention

[0004] Aiming at the problems of high cost of existing deicing methods and poor flexibility and mechanical durability of photothermal deicing materials, the present invention proposes a preparation method and application of a flexible dual-size polymer-based superhydrophobic photothermal anti-icing material, and obtains a photothermal ice-repellent surface that can adapt to complex components.

[0005] A preparation method of a flexible dual-size polymer-based superhydrophobic photothermal anti-icing material is as follows:

[0006] Step 1: Prepare a flexible polydimethylsiloxane solid, specifically:

[0007] First, mix liquid polydimethylsiloxane and a polydimethylsiloxane curing agent with a mass ratio of 10:1, and stir evenly to obtain a dispersion;

[0008] Then, pour the dispersion into a polyethylene mold, and evacuate it in a vacuum dryer for 2-4 h to remove air bubbles;

[0009] Finally, place the mold containing the dispersion liquid in an oven for drying and curing, and obtain a flexible polydimethylsiloxane solid after peeling off the mold.

[0010] The stirring time is 60 - 90 min, the stirring temperature is 20 - 50 °C, and the stirring rate is 200 - 400 r / min.

[0011] The curing temperature is 50 - 100 °C, and the curing time is 2 - 4 h.

[0012] Step 2: Use an ultraviolet laser precision machining system to construct micro - nano structures on the surface of the flexible polydimethylsiloxane solid. After rinsing and drying, a flexible polydimethylsiloxane solid with a micron - structured surface is obtained;

[0013] The parameters of the ultraviolet laser precision machining system are determined according to the preset area - occupancy fraction of the micro - structure on the entire surface. The machining power is 10 - 50%, and the machining pulse number is 10 - 100;

[0014] The micron - structured morphology on the surface of the flexible polydimethylsiloxane solid is a concave regular polygon, the side length of the structure is 100 - 600 μm, and the structure area fraction is 10% - 50%;

[0015] Rinse successively with acetone, ethanol, and deionized water, and dry in a nitrogen gas stream;

[0016] Step 3: Deposit candle soot inside the micron - structures to obtain a flexible polydimethylsiloxane solid with active photothermal performance;

[0017] Specifically:

[0018] Place the side of the flexible polydimethylsiloxane solid with micron - structures facing down on the burning candle flame, deposit candle soot inside the micron - structures, and remove the candle soot on the surface of the micron - structures after deposition to obtain a flexible polydimethylsiloxane solid with active photothermal performance;

[0019] The height of the flexible polydimethylsiloxane solid surface from the candle flame is 1 - 3 cm, and the deposition time is 10 - 50 s.

[0020] Step 4: Modify the surface of the flexible polydimethylsiloxane solid with active photothermal performance to obtain a flexible dual - scale polymer - based superhydrophobic photothermal anti - icing material;

[0021] The specific process is as follows:

[0022] The photothermal flexible polydimethylsiloxane solid and open glass containers filled with tetraethoxysilane and ammonia water solution are placed in a vacuum dryer and evacuated and maintained to form a silica coating on the surface of the microstructures; after taking out, it is placed in a dryer with an open glass container filled with 1H,1H,2H,2H-perfluorodecyltriethoxysilane to perform surface modification on the silica coating, and a flexible dual-scale polymer-based superhydrophobic photothermal anti-icing material is obtained.

[0023] The volume of tetraethoxysilane is 2 - 5 ml, the volume of ammonia water solution is 2 - 5 ml, the concentration is 25%, and the vacuum holding time is 12 - 24 h;

[0024] The volume of 1H,1H,2H,2H-perfluorodecyltriethoxysilane is 1 - 5 ml, the fluorination temperature is 50 - 100 °C, and the fluorination time is 3 - 4 h.

[0025] The flexible dual-scale polymer-based superhydrophobic photothermal anti-icing material uses a flexible polydimethylsiloxane solid as the substrate, and there are multiple layers of structures on the substrate, specifically referring to the concave microstructures, the candle soot deposited inside the microstructures, and the modified silica coating on the overall surface; the microstructures are regular polygon pits with a size of 100 - 600 μm.

[0026] The superhydrophobic photothermal anti-icing material has superhydrophobicity, photothermal properties, and high wear resistance. The microstructures and extremely low surface energy endow the material surface with superhydrophobicity, enabling water droplets to only contact the tip parts of the surface structures, maintaining the Cassie state, endowing the material with superhydrophobic performance, and the water contact angle reaching more than 150°, achieving the purpose of anti-icing. The candle soot inside the microstructures enables the material to have good photothermal properties, and the material temperature can reach 84 °C under the vertical irradiation of a standard sunlight intensity, achieving the purpose of photothermal de-icing and defrosting; the microstructures play a protective role for the internal candle soot nanoparticles, enhancing the wear resistance and mechanical stability of the material.

[0027] The superhydrophobic photothermal anti-icing material is applicable to anti-icing, de-icing, and defrosting of complex curved surfaces such as high-altitude transmission lines, 5G signal towers, and aircraft.

[0028] When the superhydrophobic photothermal anti-icing material is used for de-icing or defrosting, in a low-temperature environment and under the irradiation of one sunlight, the ice layer on the material surface completely melts within 1341 seconds, and the frost on the material surface completely melts within 157 seconds.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention provides a preparation method of an active photothermal de-icing flexible anti-icing material with superhydrophobic performance.

[0031] (1) The micro-nano structures of the flexible anti-icing material prepared by the present invention have extremely low surface energy, endowing the material with superhydrophobic performance.

[0032] (2) The flexible anti-icing material prepared by the present invention has good photothermal performance through candle soot. Under the vertical irradiation of a standard sunlight intensity, the material temperature can reach 84 °C. When the sunlight weakens, the temperature can still reach above 50 °C, improving the efficiency of active de-icing and defrosting.

[0033] (3) The flexible anti-icing material prepared by the present invention has strong environmental adaptability. Due to its flexible characteristics, it can adapt to various components, face and solve problems that occur in many environments, and can achieve active de-icing and defrosting of the material under various conditions, and can also achieve self-cleaning in daily life.

[0034] (4) The preparation method of the present invention is simple, the raw materials used are easily available, and non-toxic. While being widely used, it will not cause pollution to the environment. Description of the Drawings

[0035] Figure 1 are the contact angle photos of the materials prepared in 3 embodiments of the present invention; among them Figure 1 (a) is Example 1, Figure 1 (b) is Example 2, Figure 1 (c) is Example 3, Figure 1 (d) is the column chart of the contact angles of the three samples;

[0036] Figure 2 is the SEM photo of the material prepared in Example 1 of the present invention; among them Figure 2 (a) is the micron structure array of Example 1, Figure 2 (b) is a single micron structure of Example 1;

[0037] Figure 3 are the heating curves of the materials prepared in 3 embodiments of the present invention under 1 sun;

[0038] Figure 4 is the photo of the defrosting process of the material prepared in Example 1 of the present invention;

[0039] Figure 5 is the photo of the de-icing process of the material prepared in Example 2 of the present invention. Detailed Embodiments

[0040] The present invention will be further described in detail below in conjunction with the drawings and embodiments.

[0041] The present invention provides a preparation method of a flexible dual-size polymer-based superhydrophobic photothermal anti-icing material, and the preparation method specifically includes the following steps:

[0042] Step 1: Add a polydimethylsiloxane curing agent to a polydimethylsiloxane solution and stir evenly to obtain a dispersion. Load the dispersion into a polyethylene mold and evacuate it in a vacuum dryer to remove air bubbles; place the dispersion in an oven for curing, and carefully peel the cured solid from the mold. A flexible polydimethylsiloxane solid is obtained.

[0043] Preferably, the mass ratio of the polydimethylsiloxane curing agent to the liquid polydimethylsiloxane in the dispersion is 1:10;

[0044] Preferably, the stirring time is 60 - 90 min, the stirring temperature is 20 - 50 °C, and the stirring rate is 200 - 400 r / min.

[0045] Preferably, the evacuation time is 2 - 4 h, the curing temperature is 50 - 100 °C, and the curing time is 2 - 4 h.

[0046] Preferably, the shape of the mold is selected or designed according to the different uses of the anti-icing material.

[0047] Step 2: Use an ultraviolet laser precision machining system to construct micro-nano structures on the surface of the flexible polydimethylsiloxane solid. The processed surface of the flexible polydimethylsiloxane solid is rinsed with acetone, ethanol, and deionized water respectively, and dried in a nitrogen gas stream to obtain a flexible polydimethylsiloxane solid with micro-nano structures;

[0048] Preferably, the parameters of the ultraviolet laser precision machining system are determined according to the preset area fraction of the micro-structure on the entire surface, the machining power is 10 - 50%, and the machining pulse number is 10 - 100;

[0049] Preferably, the morphology of the ultraviolet laser precision machined micro-structure is a concave regular polygon structure, the side length of the micro-structure is 100 - 600 μm, and the area fraction of the micro-structure is 10% - 50%;

[0050] Step 3: Place the flexible polydimethylsiloxane solid with micro-nano structures on a candle flame to deposit candle soot. While depositing the candle soot, gently scrape off the candle soot on the top of the structure with a blade to obtain a flexible polydimethylsiloxane solid with active photothermal de-icing performance;

[0051] Preferably, the distance between the surface of the micro-structure and the flame is 1 - 3 cm, and the deposition time is 10 - 50 s.

[0052] Step 4: Place the prepared flexible polydimethylsiloxane solid together with open glass containers containing tetraethoxysilane and ammonia water solution in a vacuum dryer, evacuate and hold, then take out and place it in a dryer with an open glass container containing 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10 - heptadecafluorodecyltripropoxysilane, and place it in an oven to obtain a flexible anti-icing and de-icing material.

[0053] Preferably, the volume of tetraethoxysilane is 2 - 5 ml, the volume of the ammonia water solution is 2 - 5 ml, the concentration is 25%, and the vacuum holding time is 12 - 24 h;

[0054] Preferably, the volume of heptadecafluorodecyltripropoxysilane is 1 - 5 ml, the fluorination temperature is 50 - 100 °C, and the fluorination time is 3 - 4 h;

[0055] The prepared flexible anti-icing and de-icing material with photothermal effect and multi-layer structure has a microstructure of regular hexagonal pits with a size of 100 - 600 μm.

[0056] Example 1

[0057] Add 0.5 g of polydimethylsiloxane curing agent to 5 g of polydimethylsiloxane solution, and stir the mixed solution at 200 revolutions per minute with a magnetic stirrer for 60 min. Load the dispersion into a polyethylene mold, and evacuate it in a vacuum dryer for 2 h to remove air bubbles; place the dispersion in an oven at 60 °C for 2 h to cure and obtain a flexible polydimethylsiloxane solid.

[0058] Use an ultraviolet laser precision machining system to construct regular hexagonal micron structures with an area fraction of 10% on the surface of the flexible polydimethylsiloxane solid at a power of 10% and a pulse number of 10. Rinse it with acetone, ethanol, and deionized water respectively, and dry it in a nitrogen stream for 2 h to obtain a flexible polydimethylsiloxane solid with micro-nano structures;

[0059] Keep the flexible polydimethylsiloxane solid with micro-nano structures at a position 1.5 cm away from the flame height for 30 s to ensure sufficient deposition of candle soot on the surface, and gently scrape off the candle soot on the top of the structure with a blade to obtain a flexible polydimethylsiloxane solid with active photothermal de-icing performance;

[0060] Put the prepared flexible polydimethylsiloxane solid together with open glass containers containing 2 ml of tetraethoxysilane and 2 ml of ammonia water solution into a vacuum dryer, evacuate and keep for 24 h, then take it out and put it into a dryer with an open glass container containing 1 ml of heptadecafluorodecyltripropoxysilane, and place it in an oven at 90 °C for 3 h to obtain a flexible anti-icing and de-icing material.

[0061] The area fraction of the regular hexagonal micron structures in the material prepared in this example is 10%, so the material code is 10%.

[0062] As Figure 1 (a) shows that the contact angle of this material is as high as 156°, having excellent superhydrophobic effect.

[0063] Figure 2SEM photographs of the material are shown. It can be seen that the surface structure has a multi-layer structure, and the candle soot nanoparticles are mainly located inside the micron-scale wear-resistant structure. The micron-scale regular hexagonal structure constitutes the primary structure of the material surface, and the internal candle soot nanoparticles constitute the secondary structure. This can reduce the contact area with the material, allowing water droplets to only contact the tips of the surface structure of the material, thereby improving the hydrophobicity and anti-icing performance of the entire anti-icing material. In addition, the micron-scale regular hexagonal structure plays a protective role for the internal candle soot nanoparticles. Even if the surface structure of the material is worn, the candle soot nanoparticles inside the regular hexagonal structure can remain intact. This also enhances the wear resistance and mechanical stability of the material.

[0064] Figure 3 The heating curve of the material under 1 sun is shown. It can heat up by more than 50 °C within 300 seconds, and the temperature peak reaches 83.1 °C, which can effectively achieve photothermal de-icing. Figure 4 The defrosting effect diagram of the material at -15 °C under 1 sun is shown. Figure 5 The de-icing effect diagram of the material at -15 °C under 1 sun is shown. It can be seen that active de-icing and defrosting can be achieved.

[0065] Example 2

[0066] Add 0.5 g of polydimethylsiloxane curing agent to 5 g of polydimethylsiloxane solution, and stir the mixed solution at 400 revolutions per minute with a magnetic stirrer for 90 min. Pour the dispersion into a polyethylene mold, and evacuate it in a vacuum dryer for 3 h to remove air bubbles; put the dispersion in an oven at 50 °C and cure it for 4 h to obtain a flexible polydimethylsiloxane solid.

[0067] Use an ultraviolet laser precision machining system to construct a regular hexagonal micron-scale structure with an area fraction of 20% on the surface of the flexible polydimethylsiloxane solid at a power of 10% and a pulse number of 100. Rinse it with acetone, ethanol, and deionized water respectively, and dry it in a nitrogen gas stream for 2 h to obtain a flexible polydimethylsiloxane solid with a micro-nano structure;

[0068] Keep the flexible polydimethylsiloxane solid with a micro-nano structure at a position 1 cm away from the flame height for 10 s to ensure sufficient deposition of candle soot on the surface, and gently scrape off the candle soot on the top of the structure with a blade to obtain a flexible polydimethylsiloxane solid with active photothermal de-icing performance;

[0069] Put the prepared flexible polydimethylsiloxane solid together with open glass containers containing 2 ml of tetraethoxysilane and 2 ml of ammonia water solution into a vacuum dryer, evacuate and keep it for 36 h, then take it out and put it into a dryer with an open glass container containing 1 ml of 1,1,2,2,3,3,4,4,5,5,6,6,7,7,7-heptadecafluorodecyltripropoxysilane, and place it in an oven at 50 °C for 4 h to obtain a flexible anti-icing and de-icing material.

[0070] The area fraction of the regular hexagonal micron structure in the material prepared in this example is 20%, so the material code is 20%.

[0071] As Figure 1 shown in (b), the contact angle of this material is as high as 151.93°, showing excellent superhydrophobic effect. Figure 3 is the heating curve of this material under 1 sun. It can heat up to above 50 °C within 300 seconds, and the temperature peak reaches 78.8 °C, which can effectively achieve photothermal de-icing.

[0072] Example 3

[0073] Add 0.5 g of polydimethylsiloxane curing agent to 5 g of polydimethylsiloxane solution, and stir the mixed solution at 200 revolutions per minute with a magnetic stirrer for 60 min. Load the dispersion into a polyethylene mold, and evacuate it in a vacuum dryer for 4 h to remove air bubbles; place the dispersion in an oven at 100 °C and cure for 2 h to obtain a flexible polydimethylsiloxane solid.

[0074] Use an ultraviolet laser precision machining system to construct a regular hexagonal micron structure with an area fraction of 30% on the surface of the flexible polydimethylsiloxane solid at a power of 50% and a pulse number of 10. Rinse it with acetone, ethanol and deionized water respectively, and dry it in a nitrogen stream for 2 h to obtain a flexible polydimethylsiloxane solid with micro-nano structure;

[0075] Keep the flexible polydimethylsiloxane solid with micro-nano structure at a position 3 cm away from the flame height for 50 s to ensure that the candle soot is fully deposited on the surface, and gently scrape off the candle soot on the top of the structure with a blade to obtain a flexible polydimethylsiloxane solid with active photothermal de-icing performance;

[0076] Put the prepared flexible polydimethylsiloxane solid together with open glass containers containing 5 ml of tetraethoxysilane and 5 ml of ammonia water solution into a vacuum dryer and evacuate for 12 h, then take it out and put it into a dryer with an open glass container containing 5 ml of heptadecafluorodecyltripropoxysilane, and place it in an oven at 100 °C for 3 h to obtain a flexible anti-icing and de-icing material.

[0077] The area fraction of the regular hexagonal micron structure in the material prepared in this example is 30%, so the material code is 30%.

[0078] As Figure 1 shown in (c), the contact angle of this material is as high as 151.42°, showing excellent superhydrophobic effect. Figure 3 is the heating curve of this material under 1 sun. It can heat up by more than 40 °C within 300 seconds, and the temperature peak reaches 77.4 °C, which can effectively achieve photothermal de-icing.

Claims

1. A flexible dual-size polymer-based super-hydrophobic photothermal anti-icing material, characterized in that: The substrate is a flexible polydimethylsiloxane solid with a multilayer structure, specifically a concave micron structure, candle soot deposited inside the micron structure, and a modified silicon dioxide coating on the overall surface; the micron structure is a regular polygonal pit of 100 to 600 μm.

2. The flexible dual-size polymer-based super-hydrophobic photothermal anti-icing material according to claim 1, characterized in that: The micron structure and low surface energy make the material surface super hydrophobic, so that water droplets only contact the tip part of the surface structure, maintaining the Cassie state, and the water contact angle reaches more than 150°, achieving the purpose of anti-icing; the candle ash inside the micron structure makes the material have good photothermal properties. Under a standard sunlight intensity vertical irradiation, the material temperature can reach 84°C, and when the sunlight is weakened, the material temperature can reach more than 50°C, achieving the purpose of photothermal deicing and defrosting; the micron structure protects the internal candle ash nanoparticles and enhances the wear resistance and mechanical stability of the material.

3. A flexible dual-size polymer-based super-hydrophobic photothermal anti-icing material according to claim 1 or 2, characterized in that: In a low temperature environment, under the irradiation of one sunlight, the ice on the surface of the material completely melted within 1341 seconds, and the frost on the surface of the material completely melted within 157 seconds.

4. A flexible dual-size polymer-based super-hydrophobic photothermal anti-icing material, characterized in that: Suitable for anti-icing, de-icing and defrosting of complex curved surfaces on high-altitude transmission lines, 5G signal towers and aircraft.

5. A method for preparing a flexible dual-size polymer-based super-hydrophobic photothermal anti-icing material, characterized in that: The specific steps are as follows: Step 1, preparing a flexible polydimethylsiloxane solid, constructing a micron structure on the surface of the flexible polydimethylsiloxane solid using an ultraviolet laser precision processing system, and obtaining a flexible polydimethylsiloxane solid having a micron structure on the surface after rinsing and drying; The parameters of the UV laser precision processing system are determined according to the area ratio of the preset microstructure to the entire surface, the processing power is 10-50%, and the number of processing pulses is 10-100; The microstructure morphology of the flexible polydimethylsiloxane solid surface is a concave regular polygon, the side length of the structure is 100-600 μm, and the structure area fraction is 10%-50%; Step 2, depositing candle soot inside the microstructure to obtain a flexible polydimethylsiloxane solid with active photothermal properties; Specifically: The flexible polydimethylsiloxane solid surface with the micron-structure side facing downward is placed on the flame of a burning candle, and candle soot is deposited inside the micro-nanostructure. After the deposition is completed, the candle soot on the surface of the micron-structure is removed to obtain a flexible polydimethylsiloxane solid with active photothermal properties; Step three, surface modification of the flexible polydimethylsiloxane solid with active photothermal properties is performed to obtain a flexible dual-size polymer-based superhydrophobic photothermal anti-icing material.

6. The method for preparing a flexible dual-size polymer-based super-hydrophobic photothermal anti-icing material according to claim 5, characterized in that: The specific process of preparing flexible polydimethylsiloxane solid is: First, liquid polydimethylsiloxane and polydimethylsiloxane curing agent are mixed in a mass ratio of 10:1, and stirred to obtain a dispersion; Then, the dispersion was loaded into a polyethylene mold and evacuated in a vacuum dryer for 2 to 4 h to remove air bubbles; Finally, the mold containing the dispersion is placed in an oven for drying and curing, and the flexible polydimethylsiloxane solid is obtained after the mold is peeled off.

7. The method for preparing a flexible dual-size polymer-based super-hydrophobic photothermal anti-icing material according to claim 5, characterized in that: The specific process of the surface modification is: The photothermal flexible polydimethylsiloxane solid is placed in a vacuum desiccator together with an open glass container respectively filled with tetraethoxysilane and an ammonia solution, and a vacuum is drawn to form a silica coating on the surface of the microstructure; after being taken out, it is placed in a dryer with an open glass container filled with heptadecafluorodecyltripropoxysilane to modify the surface of the silica coating, thereby obtaining a flexible dual-size polymer-based superhydrophobic photothermal anti-icing material.

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