A flexible anti-icing cross-scale structure and a method of making the same

Abstract

This invention relates to a flexible, anti-icing, multi-scale structure and its preparation method. The structure's substrate is a flexible, conductive, porous material. A spiderweb-like structure is formed on the surface of the substrate, exhibiting a hydrophilic state. A multi-scale micro / nano composite structure is formed around the spiderweb-like structure on the substrate surface, exhibiting a hydrophobic state. The method includes: Step 1: Using the flexible, conductive, porous structure as an electroplating cathode, electroplating is performed in an electrolyte solution to grow an adjustable multi-scale micro / nano composite structure on the conductive porous framework, exhibiting a hydrophobic state; Step 2: The porous structure obtained in Step 1 is directly written using a femtosecond laser to create a spiderweb-like structure, with the spiderweb network exhibiting a hydrophilic state. The structure of this invention is flexible, anti-icing, and capable of capturing and collecting droplets in low-temperature environments.

Description

Technical Field

[0001] This invention belongs to the field of anti-icing surface preparation technology, specifically relating to a flexible anti-icing multi-scale structure and its preparation method. Background Technology

[0002] People in arid regions, facing increasingly severe water resource situations, need to collect and reuse water to meet their needs. Among these efforts, the fabrication of permeable structures with wetting properties to collect droplets from the environment for daily life, agriculture, and industry has become an important way to alleviate water resource pressure. However, when the ambient temperature is below freezing, captured droplets easily condense into ice on the structure's surface. This not only reduces water collection efficiency but can also cause structural damage or even render the entire water collection system ineffective. Most existing anti-icing surfaces are single hydrophobic surfaces or coatings, but their design often focuses on anti-icing while neglecting the rapid capture and directional transport of droplets. Therefore, proposing a structure and manufacturing method that can both resist icing and collect droplets in low-temperature environments is particularly important, as it can provide new ideas for water resource utilization in extreme environments. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies by proposing a flexible anti-icing multi-scale structure and its preparation method that can both resist icing and guide droplet capture and aggregation. One of the above-mentioned objectives of this invention is achieved through the following technical solution: A flexible anti-icing multi-scale structure is disclosed, wherein the substrate of the flexible anti-icing multi-scale structure is made of a flexible conductive porous material, and a spider web-like structure is formed on the surface of the substrate, wherein the spider web-like structure is hydrophilic; a multi-scale micro-nano composite structure is adopted on the surface of the substrate around the spider web-like structure, wherein the multi-scale micro-nano composite structure is hydrophobic.

[0004] The second objective of this invention is achieved through the following technical solution: A method for preparing the above-mentioned flexible anti-icing multi-scale structure includes the following steps: Step 1: The flexible conductive porous structure is used as the electroplating cathode and placed in an electrolyte solution for electroplating treatment, so that an adjustable cross-scale micro-nano composite structure can be grown on the conductive porous framework, exhibiting a hydrophobic state. Step 2: The porous structure obtained in Step 1 is processed by direct writing using a femtosecond laser to create a spider web-like structure, with the spider web network exhibiting a hydrophilic state.

[0005] Moreover, in step one, the flexible conductive porous structure adopts a metal-organic framework or foam metal, and the pores of the flexible conductive porous structure are at the micron level.

[0006] Moreover, in step one, the electrolyte solution contains copper ions, gold ions, silver ions, or platinum ions.

[0007] Moreover, in step one, the electroplating process current density is 0.33-1.32 A / dm2, and the energizing time is 30-180 s.

[0008] Furthermore, in step one, the electroplating apparatus for electroplating includes an electrolytic cell, a digital source meter, wires, an electroplating cathode, and an electroplating anode. The electrolyte is placed in the electrolytic cell, and a metal element with the same metal ions as those contained in the electrolyte is selected as the electroplating anode. A conductive porous structure is used as the electroplating cathode, and the digital source meter is connected to the cathode and anode with wires. By controlling the current density and the energizing time, metal nano- to micron particles with adjustable morphology and size are electroplated on the surface of the conductive porous structure framework, forming a cross-scale hydrophobic structure with the pores and framework of the porous structure.

[0009] Furthermore, in step two, the femtosecond laser processing apparatus includes a femtosecond laser, a grating, an attenuator, an optical shutter, a mirror, a focusing lens, a computer, and a translation stage. After the femtosecond laser pulse is emitted from the laser, it passes through the grating and the attenuator in sequence, and then the optical shutter controls the switching of the laser. The pulse is introduced into the focusing lens used for processing via the mirror. The sample to be processed is placed on the translation stage. The femtosecond laser is used to directly write a spider web-like hydrophilic structure on the surface of the electroplated substrate.

[0010] Furthermore, in step two, the laser flux range is 0.8-1.5 J / cm2.

[0011] The advantages and positive effects of this invention are as follows: 1. This invention provides a flexible anti-icing multi-scale structure, which is a biomimetic spider web hydrophilic-multi-scale micro-nano composite hydrophobic heterostructure. This structure is composed of a biomimetic spider web hydrophilic patterned structure and hydrophobic nano-micro metal particles, and has the ability to be flexible, anti-icing, and capture and collect droplets in low-temperature environments.

[0012] 2. This invention provides a method for preparing a flexible anti-icing multi-scale structure, which combines electroplating and femtosecond laser direct writing, and has the advantages of being maskless, flexible in processing, and having an adjustable processing structure. Attached Figure Description

[0013] Figure 1 This is a flowchart of the preparation method of the flexible anti-icing multi-scale structure of the present invention; In the figure: (b) the electroplating process of metal nano- and micro-particles, and (c) the process of femtosecond laser direct writing to fabricate a hydrophilic biomimetic spider web region; Figure 2 This is a schematic diagram of the femtosecond laser processing device used in this invention; Among them, 1-femtosecond laser; 2-grating; 3-attenuator; 4-optical shutter; 5-reflector; 6-focusing lens; 7-sample to be processed; 8-computer; 9-translation stage; Figure 3 These are morphology diagrams of electroplated copper particles in embodiments of the present invention; Figure 4 This is a schematic diagram of a biomimetic spider web collecting water in an embodiment of the present invention. Detailed Implementation

[0014] The structure of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that these embodiments are descriptive and not limiting.

[0015] A flexible anti-icing multi-scale structure is disclosed, the invention of which is as follows: the substrate of the flexible anti-icing multi-scale structure is made of flexible conductive porous material, and a spider web-like structure is formed on the surface of the substrate, wherein the spider web network is hydrophilic; a multi-scale micro-nano composite structure is adopted on the surface of the substrate around the spider web-like structure, wherein the multi-scale micro-nano composite structure is hydrophobic.

[0016] For a method of fabricating the flexible anti-icing multi-scale structure described above, please refer to [link / reference needed]. Figures 1-4 Its inventive point is: including the following steps: Step 1: The flexible conductive porous structure is used as the electroplating cathode and placed in an electrolyte solution for electroplating treatment, so that an adjustable cross-scale micro-nano composite structure can be grown on the conductive porous framework, exhibiting a hydrophobic state. Step 2: The porous structure obtained in Step 1 is processed by direct writing using a femtosecond laser to create a spider web-like structure, with the spider web network exhibiting a hydrophilic state.

[0017] After electroplating, a nano-to-micron composite structure of metal particles is generated on the surface of the conductive porous framework. This multi-scale structure, composed of micron-pores and dendritic rough nano-to-micron metal particles, is hydrophobic. Subsequent femtosecond laser direct writing fabrication of the spiderweb-like region patterns and removes the hydrophobic particles from the structure generated during electroplating. By controlling the laser parameters in step two, a hydrophilic spiderweb structure is generated. This method allows for the fabrication of a biomimetic spiderweb-like multi-scale hydrophilic-hydrophobic heterostructure. This structure can rapidly capture and guide water droplets from the environment, like a natural spiderweb, collecting them along the spiderweb lines from sparse to dense. Furthermore, this spiderweb-like multi-scale hydrophilic-hydrophobic heterostructure can effectively delay the freezing process of droplets.

[0018] The flexible conductive porous structure in step one above can be a metal-organic framework, metal foam, or other flexible conductive porous materials. The pore size of the flexible conductive porous structure is on the micrometer scale, the current density during electroplating is 0.33-1.32 A / dm², and the energizing time is 30-180 s. The electrolyte solution may contain copper ions, gold ions, silver ions, or platinum ions.

[0019] In step two above, the laser energy, scanning speed, and scanning spacing during the femtosecond laser processing are controlled to ensure a laser flux range of 0.8-1.5 J / cm². At this laser flux, all electroplated particles in the laser-processed spiderweb-shaped area are removed, and the area exhibits hydrophilicity; this biomimetic structure possesses the ability to converge and capture droplets.

[0020] After processing in steps one and two, a patterned micron-pore-hydrophilic patterned skeleton flexible multi-scale structure resembling a spider web is formed, which is flexible, anti-icing, and capable of capturing and collecting droplets in low-temperature environments.

[0021] The electroplating apparatus for achieving the electroplating process in step one above includes an electrolytic cell, a digital source meter, wires, an electroplating cathode, and an electroplating anode. An electrolyte is placed in the electrolytic cell, and a metal element with the same metal ions as those in the electrolyte is selected as the electroplating anode. A conductive porous structure is used as the electroplating cathode, and the digital source meter is connected to the cathode and anode with wires. By controlling the current density and the energizing time, metal nano- to micron-sized particles with adjustable morphology and size are electroplated onto the surface of the conductive porous structure framework, forming a multi-scale hydrophobic structure with the pores and framework of the porous structure.

[0022] The femtosecond laser processing apparatus for achieving the femtosecond laser processing in step two above includes a femtosecond laser 1, a grating 2, an attenuator 3, an optical shutter 4, a mirror 5, a focusing lens 6, a computer 8, and a translation stage 9. After the femtosecond laser pulse is emitted from the laser, it passes through the grating and the attenuator in sequence. Then, the optical shutter controls the switching of the laser. The pulse is introduced into the focusing lens used for processing via the mirror. The sample to be processed 7 is placed on the translation stage. The femtosecond laser is used to directly write a spider web-like hydrophilic structure on the surface of the electroplated substrate, thereby forming a hydrophilic-hydrophobic heterogeneous surface. This surface can quickly capture and guide supercooled water droplets in the environment to converge and collect, delaying the freezing of the droplets.

[0023] Example: Taking copper foam with a thickness of 0.5 mm and a pore size of approximately 150 μm as an example, the manufacturing steps of the flexible anti-icing multi-scale structure are as follows: Step one involves using copper foam as the electroplating cathode and placing it in an electrolytic cell with CuSO4 solution as the main electrolyte for electroplating. By controlling the current density and energizing time, hydrophobic micro / nano-scale copper particles are generated on the copper foam, such as... Figure 3 As shown; Step two, build as follows Figure 2 The femtosecond laser processing system shown uses a 100x plano-convex objective lens as the focusing lens. Through a computer-controlled program, a femtosecond laser is used to perform patterned direct-write scanning on the electroplated foam copper surface to create a spider web pattern.

[0024] The electroplating process in step one includes the following steps: (1) At room temperature, an electrolyte for copper electroplating was prepared by mixing 30g CuSO4·5H2O, 1.2ml H2SO4, 25mg NaCl and 266ml water.

[0025] (2) Add the prepared electrolyte into the electrolytic cell. The anode is a 5cm*5cm pure copper sheet, and the cathode is the above-mentioned foamed copper.

[0026] (3) The above device is powered by DC using a digital source meter. The electroplating time is 30s and the current intensity is 0.66A / dm2.

[0027] In step two, the femtosecond laser flux range is 1.2 J / cm2. The femtosecond laser 1 used in this invention has a laser center wavelength of 800 nm, a pulse width of 50 fs, a maximum repetition frequency of 1 kHz, a Gaussian intensity distribution, and a horizontally linearly polarized output laser.

[0028] After the above two steps, a multi-scale hydrophilic-hydrophobic heterostructure of the biomimetic spider web can be obtained. A schematic diagram of the biomimetic spider web's water collection is shown below. Figure 4 As shown. Because copper particles are deposited in the mesh portion of the spiderweb-like structure, forming a composite structure of micron-sized pores and a framework-nanoparticle structure, this portion is hydrophobic. The portion processed by femtosecond laser removes the copper nanoparticle structure, and due to the higher laser flux, the laser-processed spiderweb network portion becomes hydrophilic. This makes the hydrophilic portion more likely to capture tiny droplets from the air, and these droplets easily move along... Figure 4 The droplets move in the direction of their motion and converge at the center of the grid, thus completing the droplet collection. Because hydrophilic and hydrophobic heterostructures exist simultaneously on the same surface, and the hydrophobic and hydrophilic structures are interwoven with the hydrophobic structures occupying a large area, this heterostructure has anti-icing capabilities.

[0029] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A flexible anti-icing multi-scale structure, characterized in that: The substrate of the flexible anti-icing multi-scale structure is made of a flexible conductive porous material. A spider web-like structure is formed on the surface of the substrate, and the spider web-like structure is hydrophilic. A multi-scale micro-nano composite structure is adopted on the surface of the substrate around the spider web-like structure, and the multi-scale micro-nano composite structure is hydrophobic.

2. A method for preparing a flexible anti-icing multi-scale structure as described in claim 1, characterized in that: Includes the following steps: Step 1: The flexible conductive porous structure is used as the electroplating cathode and placed in an electrolyte solution for electroplating treatment, so that an adjustable cross-scale micro-nano composite structure can be grown on the conductive porous framework, exhibiting a hydrophobic state. Step 2: The porous structure obtained in Step 1 is processed by direct writing using a femtosecond laser to create a spider web-like structure, with the spider web network exhibiting a hydrophilic state.

3. The method for preparing the flexible anti-icing multi-scale structure according to claim 1 as described in claim 2, characterized in that: In step one, the flexible conductive porous structure adopts a metal-organic framework or foam metal, and the pores of the flexible conductive porous structure are at the micron level.

4. The method for preparing the flexible anti-icing multi-scale structure according to claim 1 as described in claim 2, characterized in that: In step one, the electrolyte solution contains copper ions, gold ions, silver ions, or platinum ions.

5. The method for preparing the flexible anti-icing multi-scale structure according to claim 1 as described in claim 2, characterized in that: In step one, the electroplating apparatus for electroplating includes an electrolytic cell, a digital source meter, wires, an electroplating cathode, and an electroplating anode; The electrolyte is placed in an electrolytic cell. A metal element with the same metal ions as those in the electrolyte is selected as the electroplating anode, and a conductive porous structure is used as the electroplating cathode. The digital source meter is connected to the cathode and anode with wires. By controlling the current density and the energizing time, metal nano- to micron particles with adjustable morphology and size are electroplated on the surface of the conductive porous structure framework, forming a cross-scale hydrophobic structure with the pores and framework of the porous structure.

6. The method for preparing the flexible anti-icing multi-scale structure according to claim 1 as described in claim 2, characterized in that: In step one, the current density during electroplating is 0.33-1.32 A / dm2, and the energizing time is 30-180 s.

7. The method for preparing the flexible anti-icing multi-scale structure according to claim 1 as described in claim 2, characterized in that: In step two, the femtosecond laser processing apparatus includes a femtosecond laser, a grating, an attenuator, an optical shutter, a mirror, a focusing lens, a computer, and a translation stage. After the femtosecond laser pulse is emitted from the laser, it passes through the grating and the attenuator in sequence. Then, the optical shutter controls the switching of the laser. The pulse is introduced into the focusing lens used for processing via the mirror. The sample to be processed is placed on the translation stage. The femtosecond laser is used to directly write a spider web-like hydrophilic structure on the surface of the electroplated substrate.

8. The method for preparing the flexible anti-icing multi-scale structure according to claim 1 as described in claim 2, characterized in that: In step two, the laser flux range is 0.8-1.5 J / cm2.

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