Vertical carbon nanotube array / diamond-like carbon film composite adhesive material, preparation method and application

Abstract

The application provides a preparation method of a vertical carbon nanotube array / diamond-like carbon film composite adhesive material, and the preparation method comprises the following steps: uniformly covering a transfer medium on a target flexible substrate and heating to form a semi-cured state; turning over a vertical carbon nanotube array on a silicon substrate and applying pressure to make the vertical carbon nanotube array adhere to the surface of the semi-cured transfer medium, and fully combining the transfer medium and the vertical carbon nanotube array by heating and solidification; peeling the vertical carbon nanotube array from the silicon substrate to obtain a vertical carbon nanotube array with a transferred top end; and depositing a diamond-like carbon film on the surface of the vertical carbon nanotube array by using a radio frequency plasma deposition technology, so as to obtain the vertical carbon nanotube array / diamond-like carbon film composite adhesive material. The vertical carbon nanotube array is improved in adhesive characteristics by using the excellent mechanical properties of the diamond-like carbon, the contact area of the top end of the vertical carbon nanotube array and the surface to be adhered can be increased, and the method has the advantages of simplicity and easy operation.

Description

Technical Field

[0001] This invention relates to the field of novel biomimetic adhesive materials, specifically to a vertical carbon nanotube array / diamond-like film composite adhesive material, its preparation method, and its application. Background Technology

[0002] Geckos' exceptional adhesive crawling ability stems from the dense micro-nano hierarchical structure of setae covering the undersides of their toes. When this highly adhesive micro-nano hierarchical structure comes into close contact with a surface, it generates weak van der Waals forces that converge into a macroscopic adhesive force, giving the gecko's adhesive system superior properties such as strong adhesion, easy detachment, and repeatable adhesion. The adhesive force generated between this structure and the contact surface is considered a non-directional and saturable van der Waals force, belonging to dry adhesion. In recent years, the research and development of biomimetic dry adhesive materials based on this dry adhesion mechanism has received increasing attention.

[0003] Carbon nanotubes are seamless, hollow, helical tubular nanostructures formed by coiling graphene sheets at a specific helical angle. They possess excellent physicochemical properties, especially a Young's modulus as high as 1 TPa, a flexural modulus of 0.91-1.24 TPa, a tensile strength 100 times that of steel, while having a density only 1 / 6 that of steel, and an elongation at break of 15%-30%. These superior structural and physicochemical properties, along with their adaptability to various space environments, make carbon nanotubes an important component in the preparation of biomimetic adhesive materials. Vertically oriented carbon nanotube bristle arrays exhibit a finer structure, are inherently non-adhesive, possess good mechanical properties, and have a high theoretical adhesion strength (exceeding 500 N / cm²). 2 With advantages such as 50 times the adhesion strength of gecko feet and the ability to be mass-produced, it is expected to replace polymer adhesive materials.

[0004] A search of existing technologies revealed patent number ZL201310284325.2, which discloses an adhesive material and its preparation method for a gecko-like foot-like adhesive array. This material is composed of a silicone elastomer main component (component A), a crosslinking agent component (component B), and carbon nanotubes. The carbon nanotubes are mixed in a certain proportion and cured at a suitable temperature (70–100°C) to form a composite material. The silicone elastomer main component (component A) is Dow Corning 184 component A, and the crosslinking agent component B is a mixture of Dow Corning 184 component B and Dow Corning 186 component B. Tangential adhesion can reach 4 N / cm², and normal adhesion can reach 1 N / cm². However, from a microscopic perspective, the contact area between the tip of the vertical carbon nanotube array and the area to be adhered is still limited. Compared with the bristles of a gecko's foot, the vertical carbon nanotube array needs improvement in terms of adhesion performance and material strength. Furthermore, systematic research on how to improve adhesion performance with a fixed array density is lacking. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a vertical carbon nanotube array / diamond-like carbon film composite adhesive material and its preparation method. The method utilizes the diamond-like carbon film to increase the contact area between the top of the vertical carbon nanotube array and the material to be adhered, while leveraging the excellent mechanical properties of diamond-like carbon to improve the adhesion performance of the vertical carbon nanotube array.

[0006] The objective of this invention is achieved through the following solution:

[0007] The first aspect of this invention provides a method for preparing a vertical carbon nanotube array / diamond-like film composite adhesive material, characterized in that the material consists of a vertical carbon nanotube array and a diamond-like film on its surface.

[0008] The preparation method includes the following steps:

[0009] Step 1: Evenly cover the target substrate with the transfer medium;

[0010] Step 2: After high-temperature pre-oxidation treatment, the vertical carbon nanotube array on the silicon substrate is flipped and placed on the target substrate, and normal pressure is applied to make it adhere to the surface of the semi-cured transfer medium.

[0011] Step 3: After heat treatment, the vertical carbon nanotube array is peeled off from the silicon substrate to obtain the top-transferred vertical carbon nanotube array.

[0012] Step 4: Deposit a diamond-like carbon film on the surface of the vertical carbon nanotube array using ionochemical vapor deposition to obtain a vertical carbon nanotube array / diamond-like carbon film composite adhesive material.

[0013] Preferably, the transfer medium in step one is polydimethylsiloxane (PDMS) or polyurethane, and the transfer medium is in a semi-cured state.

[0014] Preferably, the semi-cured transfer medium is formed by heating and curing on a hot plate at 60-70°C for 1-2 hours.

[0015] Preferably, the high-temperature pre-oxidation treatment conditions in step two are 450–550°C in air, and the high-temperature pre-oxidation treatment time is 5–15 min.

[0016] Preferably, the normal pressure in step two is 0.2–0.8 N / cm. 2 .

[0017] Preferably, the heat treatment temperature in step three is 60-70°C, and the heat treatment curing time is 2-6 hours.

[0018] Preferably, the peeling principle utilizes the fact that the bonding force between the vertical carbon nanotube array / transfer medium is greater than the bonding force between it and the silicon substrate, so that the vertical carbon nanotube array slowly detaches from the original silicon substrate.

[0019] Preferably, the evaporation power of the iontophoresis chemical vapor deposition process in step four is 500-700W, and the deposition time of the iontophoresis chemical vapor deposition process is 2-10min.

[0020] Preferably, the thickness of the vertical carbon nanotube array / diamond-like film in step four is 10–50 nm.

[0021] The second aspect of the present invention provides a vertical carbon nanotube array / diamond-like film composite adhesive material, which is prepared by a method for preparing a vertical carbon nanotube array / diamond-like film composite adhesive material.

[0022] The third aspect of this invention provides an application of a vertical carbon nanotube array / diamond-like film composite adhesive material in the field of biomimetic adhesion, specifically for vertical climbing on the ground and for the adhesion and grasping of space debris.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The vertical carbon nanotube array / diamond-like film composite adhesive material prepared by the present invention has a relatively flat top, which can better contact the material to be adhered. At the same time, the excellent mechanical properties of diamond-like material can be utilized to further improve the adhesion performance, and the viscosity-pressure ratio can reach 1.65.

[0025] 2. The present invention deposits a diamond-like film with a nanometer-thickness on the top of a vertical carbon nanotube array, which can increase the specific surface area of ​​the top and partially fill the gaps in the vertical carbon nanotube array, thereby improving its mechanical properties.

[0026] 3. Both carbon nanotubes and diamond-like carbon are constructed from carbon elements and have similar atomic hybridization. Stronger van der Waals forces are more likely to form at the interface where the two are in atomic contact, and interface separation is less likely to occur when the vertical carbon nanotube array deforms. Attached Figure Description

[0027] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0028] Figure 1 This is a flowchart of the preparation process for vertical carbon nanotube array / diamond-like film composite adhesive materials;

[0029] Figure 2 These are SEM images of the side and top of the vertical carbon nanotube array transferred at the top in Example 1;

[0030] Figure 3 This is a SEM image of the top of the vertical carbon nanotube array / diamond-like film composite adhesive material in Example 1; Detailed Implementation

[0031] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0032] Example 1:

[0033] like Figure 1 The diagram shows the fabrication process of a vertical carbon nanotube array / diamond-like film composite adhesive material. The specific steps are as follows:

[0034] Step 1: Thoroughly mix the PDMS base components and curing agent (Sylgard 184 Silicon Elastomer, Dow Corning) in a liquid mixture at a weight ratio of 10:1, and degas using a vacuum pump under reduced pressure. Then, heat the liquid PDMS mixture on a hot plate at 65°C for 2 hours to form a semi-cured PDMS solution. Use a spin coater to evenly coat the PDMS solution onto the target substrate surface at a spin speed of 5000 rpm for approximately 30 seconds.

[0035] Step 2: Place the vertical carbon nanotube array on the silicon substrate in a tube furnace, heat it to 500℃ under atmospheric conditions and treat it for 10 minutes for thermal oxidation treatment. Then, invert it and place it on the target substrate surface coated with semi-cured PDMS solution, and apply approximately 0.5 N / cm to the vertical carbon nanotube array. 2 The normal pressure ensures that the top of the vertical carbon nanotube array is completely attached to the PDMS surface, while preventing the vertical carbon nanotube array from completely entering the adhesive.

[0036] Step 3: Heat and cure the bonded vertical carbon nanotube array at 70°C for 4 hours. Since the adhesion between the vertical carbon nanotube array and the cured PDMS adhesive is greater than the adhesion between it and the silicon substrate, the vertical carbon nanotube array can be peeled off from the substrate by scraping the edges with tweezers and a small blade.

[0037] Step 4: Using a radio frequency discharge plasma chemical vapor deposition process with methane as the carbon source, an evaporation power of 600W and an evaporation time of 2 minutes are used to deposit a 10-nanometer-thick diamond-like film on the top of the vertical carbon nanotube array, thus obtaining a vertical carbon nanotube array / diamond-like film composite adhesive material.

[0038] like Figure 2 , 3 The image shows the microstructure of the vertical carbon nanotube array before and after diamond-like carbon deposition. The viscosity-pressure ratio can be increased from 1.50 before deposition to 1.65.

[0039] Example 2:

[0040] like Figure 1 The diagram shows the fabrication process of a vertical carbon nanotube array / diamond-like film composite adhesive material. The specific steps are as follows:

[0041] Step 1: Thoroughly mix the PDMS base components and curing agent (Sylgard 184 Silicon Elastomer, Dow Corning) in a liquid mixture at a weight ratio of 10:1, and degas using a vacuum pump under reduced pressure. Then, heat the liquid PDMS mixture on a hot plate at 65°C for 1 hour to form a semi-cured PDMS solution. Use a spin coater to evenly coat the PDMS solution onto the target substrate surface at a spin speed of 5000 rpm for approximately 30 seconds.

[0042] Step 2: Place the vertical carbon nanotube array on the silicon substrate in a tube furnace, heat it to 450℃ under atmospheric conditions and treat it for 15 minutes for thermal oxidation. Then, invert it and place it on the target substrate surface coated with semi-cured PDMS solution, and apply approximately 0.2 N / cm to the vertical carbon nanotube array. 2 The normal pressure ensures that the top of the vertical carbon nanotube array is completely attached to the PDMS surface, while preventing the vertical carbon nanotube array from completely entering the adhesive.

[0043] Step 3: Heat and cure the bonded vertical carbon nanotube array at 70°C for 6 hours. Since the adhesion between the vertical carbon nanotube array and the cured PDMS adhesive is greater than the adhesion between it and the silicon substrate, the vertical carbon nanotube array can be peeled off from the substrate by scraping the edges with tweezers and a small blade.

[0044] Step 4: Using a radio frequency discharge plasma chemical vapor deposition process with methane as the carbon source, an evaporation power of 600W and an evaporation time of 10 minutes are used to deposit a 50-nanometer-thick diamond-like film on the top of the vertical carbon nanotube array, thus obtaining a vertical carbon nanotube array / diamond-like film composite adhesive material.

[0045] Example 3:

[0046] like Figure 1 The diagram shows the fabrication process of a vertical carbon nanotube array / diamond-like film composite adhesive material. The specific steps are as follows:

[0047] Step 1: Thoroughly mix the PDMS base components and curing agent (Sylgard 184 Silicon Elastomer, Dow Corning) in a liquid mixture at a weight ratio of 10:1, and degas using a vacuum pump under reduced pressure. Then, heat the liquid PDMS mixture on a hot plate at 65°C for 1 hour to form a semi-cured PDMS solution. Use a spin coater to evenly coat the PDMS solution onto the target substrate surface at a spin speed of 5000 rpm for approximately 30 seconds.

[0048] Step 2: Place the vertical carbon nanotube array on the silicon substrate in a tube furnace, heat it to 500℃ under atmospheric conditions and treat it for 10 minutes for thermal oxidation. Then, invert it and place it on the target substrate surface coated with semi-cured PDMS solution, and apply approximately 0.4 N / cm to the vertical carbon nanotube array. 2 The normal pressure ensures that the top of the vertical carbon nanotube array is completely attached to the PDMS surface, while preventing the vertical carbon nanotube array from completely entering the adhesive.

[0049] Step 3: Heat and cure the bonded vertical carbon nanotube array at 70°C for 6 hours. Since the adhesion between the vertical carbon nanotube array and the cured PDMS adhesive is greater than the adhesion between it and the silicon substrate, the vertical carbon nanotube array can be peeled off from the substrate by scraping the edges with tweezers and a small blade.

[0050] Step 4: Using a radio frequency discharge plasma chemical vapor deposition process with methane as the carbon source, an evaporation power of 600W and an evaporation time of 5 minutes are used to deposit a 30-nanometer-thick diamond-like film on the top of the vertical carbon nanotube array, thus obtaining a vertical carbon nanotube array / diamond-like film composite adhesive material.

[0051] Example 4:

[0052] like Figure 1 The diagram shows the fabrication process of a vertical carbon nanotube array / diamond-like film composite adhesive material. The specific steps are as follows:

[0053] Step 1: Thoroughly mix the polyurethane base components and curing agent in a liquid mixture at a weight ratio of 10:1, and degas using a vacuum pump under reduced pressure. Then, heat the liquid polyurethane mixture on a hot plate at 65°C for 2 hours to form a semi-cured polyurethane solution. Use a spin coating method to evenly coat the PDMS solution onto the target substrate surface at a spin speed of 5000 rpm for approximately 30 seconds.

[0054] Step 2: Place the vertical carbon nanotube array on the silicon substrate in a tube furnace, heat it to 550℃ under atmospheric conditions and treat it for 5 minutes for thermal oxidation treatment. Then, invert it and place it on the target substrate surface coated with a semi-cured polyurethane solution, and apply approximately 0.8 N / cm to the vertical carbon nanotube array. 2 The normal pressure ensures that the top of the vertical carbon nanotube array is completely adhered to the polyurethane surface, while preventing the vertical carbon nanotube array from completely entering the adhesive.

[0055] Step 3: Heat and cure the bonded vertical carbon nanotube array at 70°C for 6 hours. Since the bonding force between the vertical carbon nanotube array and the cured polyurethane adhesive is greater than the bonding force between it and the silicon substrate, the vertical carbon nanotube array can be peeled off from the substrate by scraping the edges with tweezers and a small blade.

[0056] Step 4: Using a radio frequency discharge plasma chemical vapor deposition process with methane as the carbon source, an evaporation power of 600W and an evaporation time of 5 minutes are used to deposit a 30-nanometer-thick diamond-like film on the top of the vertical carbon nanotube array, thus obtaining a vertical carbon nanotube array / diamond-like film composite adhesive material.

[0057] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for preparing a vertical carbon nanotube array / diamond-like film composite adhesive material, characterized in that, The material consists of a vertical array of carbon nanotubes and a diamond-like film on its surface. The preparation method includes the following steps: Step 1: Evenly cover the target substrate with the transfer medium; Step 2: After high-temperature pre-oxidation treatment, the vertical carbon nanotube array on the silicon substrate is flipped and placed on the target substrate, and normal pressure is applied to make it adhere to the surface of the semi-cured transfer medium. Step 3: After heat treatment, the vertical carbon nanotube array is peeled off from the silicon substrate to obtain the top-transferred vertical carbon nanotube array. Step 4: Deposit a diamond-like carbon film on the surface of the vertical carbon nanotube array using ionization chemical vapor deposition (ICVD) to obtain a vertical carbon nanotube array / diamond-like carbon film composite adhesive material. The transfer medium in step one is polydimethylsiloxane (PDMS) or polyurethane, and the transfer medium is in a semi-cured state. The high-temperature pre-oxidation treatment conditions in step two are: treatment at 450–550°C in air, and the high-temperature pre-oxidation treatment time is 5–15 minutes.

2. The method for preparing a vertical carbon nanotube array / diamond-like film composite adhesive material according to claim 1, characterized in that, The semi-cured transfer medium is formed by heating and curing on a hot plate at 60-70°C for 1-2 hours.

3. The method for preparing a vertical carbon nanotube array / diamond-like film composite adhesive material according to claim 1, characterized in that, The normal pressure in step two is 0.2–0.8 N / cm². 2 .

4. The method for preparing a vertical carbon nanotube array / diamond-like film composite adhesive material according to claim 1, characterized in that, The heat treatment temperature in step three is 60-70°C, and the heat treatment curing time is 2-6 hours.

5. The method for preparing a vertical carbon nanotube array / diamond-like film composite adhesive material according to claim 1, characterized in that, The evaporation power of the iontophoresis chemical vapor deposition process in step four is 500-700W, and the deposition time is 2-10min.

6. The method for preparing a vertical carbon nanotube array / diamond-like film composite adhesive material according to claim 1, characterized in that, In step four, the thickness of the diamond-like carbon film is 10–50 nm.

7. A vertical carbon nanotube array / diamond-like film composite adhesive material prepared by the preparation method according to any one of claims 1 to 6.

8. An application of the vertical carbon nanotube array / diamond-like film composite adhesive material as described in claim 7, characterized in that, The material is used in the field of biomimetic adhesion, specifically for vertical climbing on the ground and for the adhesion and grasping of space debris.

Images