A super-slippery device based on surface modification and a preparation method thereof

Abstract

The application discloses a kind of structural super-slippery devices based on surface modification and preparation method thereof, the structural super-slippery devices based on surface modification, comprising: three-dimensional substrate and two-dimensional material layer on three-dimensional substrate;Two-dimensional material layer includes single crystal interface, the force position of two-dimensional material layer is the middle region of two-dimensional material layer;The contact surface of three-dimensional substrate and two-dimensional material layer includes multiple nanostructures, the size of nanostructure is much smaller than the size of two-dimensional material layer, and in the movable range of two-dimensional material layer, two-dimensional material layer is covered simultaneously with several nanostructures.The technical scheme of the application overcomes the technical problem that structural super-slippery is invalid due to the existence of dangling bond at the edge of two-dimensional material, reduces the requirement of roughness for structural super-slippery, and forms stable structural super-slippery.

Description

Technical Field

[0001] This invention relates to the field of friction control, and in particular to a surface-modified structural superlubricating device and its preparation method. Background Technology

[0002] Friction and wear are two fundamental physical phenomena coupled together in nature, causing enormous energy waste, environmental pollution, and component failures in mechanical systems, and making it difficult to overcome many key technologies. Especially in the microscopic world, due to scale effects, interfacial friction and wear can lead to device failure. Therefore, to solve these problems, a new revolutionary technology is needed to reduce or even eliminate friction and wear from their essential physical properties, rather than introducing other indirect materials as friction pairs.

[0003] Structural superlubricity (SSL), a state of near-zero friction and wear between two contacting solid surfaces, has brought a glimmer of hope for a revolutionary solution to friction and wear problems. Recently, structural superlubricity has been achieved between two-dimensional interfaces (such as graphite with a single-crystal surface) and planar three-dimensional materials, greatly expanding its application range. However, due to the presence of edges in two-dimensional materials, these edges have a certain probability of wear compared to planar three-dimensional materials, causing the structural superlubricity state to fail.

[0004] Existing technologies typically employ a method of depositing a stress-shrinkage film at the edge of a two-dimensional interface. The shrinkage of the film causes the edge of the two-dimensional interface to warp, thereby overcoming the wear phenomenon caused by the edge effect. However, this method requires pre-processing of the two-dimensional interface, which is relatively complex, and the edge warping height is not fixed, which may still lead to the failure of the structure in a super-slippery state. Summary of the Invention

[0005] This invention provides a surface-modified structural superlubricating device and its fabrication method to solve the problem that wear occurs at the edges of two-dimensional materials and on flat three-dimensional materials in existing structural superlubricants, causing the structural superlubricating state to fail.

[0006] In a first aspect, the present invention provides a surface-modified structural superlubricating device, comprising: a three-dimensional substrate and a two-dimensional material layer located on the three-dimensional substrate;

[0007] The two-dimensional material layer includes a single crystal interface, and the stress location of the two-dimensional material layer is the middle region of the two-dimensional material layer.

[0008] The contact surface between the three-dimensional substrate and the two-dimensional material layer includes multiple nanostructures. The size of the nanostructures is much smaller than the size of the two-dimensional material layer, and within the movable range of the two-dimensional material layer, the two-dimensional material layer is simultaneously covered with several of the nanostructures.

[0009] Optionally, each of the nanostructures is in point contact with the two-dimensional material layer, and the protrusions of all the nanostructures facing the two-dimensional material layer are located on the same horizontal plane.

[0010] Optionally, each nanostructure is in surface contact with the two-dimensional material layer, all the nanostructures facing the two-dimensional material layer are located on the same horizontal plane, and the nanostructures facing the two-dimensional material layer satisfy atomic-level flatness.

[0011] Optionally, the nanostructure array is arranged on the three-dimensional substrate.

[0012] Optionally, the cross-sectional shape of the nanostructure can be spherical, hemispherical, arc-shaped, triangular, trapezoidal, rectangular, or irregular.

[0013] Optionally, the height H of the nanostructure can be in the range of 5nm ≤ H ≤ 10nm.

[0014] Optionally, the spacing L between any two adjacent nanostructures can be in the range of 200nm ≤ L ≤ 400nm.

[0015] Optionally, the two-dimensional material layer includes graphite, graphene, molybdenum disulfide, tungsten diselenide, tungsten disulfide, or black phosphorus.

[0016] Optionally, the three-dimensional substrate includes one or a combination of Si, SiC, SOI, sapphire, mica, graphene, and molybdenum disulfide.

[0017] Secondly, the present invention provides a method for fabricating a surface-modified superlubricated device, comprising:

[0018] Surface modification is performed on the three-dimensional substrate to form multiple nanostructures. The size of the nanostructures is much smaller than the size of the two-dimensional material layer, and the two-dimensional material layer is covered with several nanostructures at the same time when it moves.

[0019] Provide a two-dimensional material layer with a single-crystal interface;

[0020] The two-dimensional material layer is transferred to one side surface of the three-dimensional substrate where the nanostructure is formed, and a force is applied toward the middle region of the two-dimensional material layer.

[0021] Optionally, multiple nanostructures arranged in an array are formed on the flat surface of the three-dimensional substrate, including:

[0022] An array of micro / nano structures is deposited on the flat surface of the three-dimensional substrate;

[0023] The array of micro-nano structures deposited on the three-dimensional substrate is subjected to plasma etching to reduce the size of the micro-nano structures in the array to a predetermined size;

[0024] Using the micro-nano structure array as a mask, an ion beam etching process is employed to form multiple nanostructures arranged in an array on the flat surface of the three-dimensional substrate.

[0025] The micro-nano structure array is removed by plasma etching.

[0026] The technical solution of this invention involves setting multiple nanostructures at the contact surface between a two-dimensional material layer and a single-crystal interface in a three-dimensional substrate. The size of the nanostructures is much smaller than the size of the two-dimensional material layer, and within the movable range of the two-dimensional material layer, the two-dimensional material layer is simultaneously covered with several of the nanostructures. This allows the two-dimensional material layer and the three-dimensional substrate with nanostructures to form a local contact. When the middle region of the two-dimensional material layer is subjected to external force, the two-dimensional material layer experiences a reaction force from the nanostructures, causing its edges to warp. This eliminates the interaction between the edge of the two-dimensional material layer and the three-dimensional substrate, overcoming the problem in existing structural superlubricity where friction is generated when the edge of the two-dimensional material layer contacts the three-dimensional substrate due to the dangling bonds at the edge of the two-dimensional material layer and the interfacial chemical bonds of the three-dimensional substrate, leading to the failure of the structural superlubricity. This invention forms a stable structural superlubricity, providing a new method for the widespread realization of structural superlubricity technology.

[0027] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a surface-modified superlubricating device provided in an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of the two-dimensional material layer sliding of a surface-modified superlubricated device provided in an embodiment of the present invention.

[0031] Figure 3Atomic force microscopy morphology comparison of a three-dimensional substrate with a nanostructure and a traditional flat three-dimensional substrate for a surface-modified superlubricated device provided in an embodiment of the present invention;

[0032] Figure 4 A comparison chart of friction test results between a surface-modified superlubricating device and a traditional flat three-dimensional substrate superlubricating device provided in the embodiments of the present invention;

[0033] Figure 5 This is a schematic diagram of another surface-modified superlubricating device provided in an embodiment of the present invention;

[0034] Figure 6 A flowchart illustrating a method for fabricating a structurally superlubricating device according to an embodiment of the present invention;

[0035] Figure 7 This is a schematic diagram of the process structure for fabricating a structurally superlubricating device provided in an embodiment of the present invention;

[0036] Figure 8 A flowchart illustrating another method for fabricating a superlubricating device according to an embodiment of the present invention;

[0037] Figure 9 A schematic diagram of the process structure for forming nanostructures on a flat surface of a three-dimensional substrate;

[0038] Figure 10 This is a scanning electron microscope image showing the morphology of the micro / nano structure array during oxygen plasma etching. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0041] This embodiment provides a structurally superlubricating device. Figure 1This is a schematic diagram of a surface-modified superlubricating device provided as an embodiment of the present invention. Figure 1 As shown, the superlubricating device includes a three-dimensional substrate 1 and a two-dimensional material layer 2 located on the three-dimensional substrate 1; the two-dimensional material layer 2 includes a single crystal interface, and the force-bearing location of the two-dimensional material layer 2 is the middle region of the two-dimensional material layer 2; the contact surface between the three-dimensional substrate 1 and the two-dimensional material layer 2 includes multiple nanostructures 3, the size of the nanostructures 3 is much smaller than the size of the two-dimensional material layer 2, and within the movable range of the two-dimensional material layer 2, the two-dimensional material layer 2 is simultaneously covered with several nanostructures 3.

[0042] Wherein, the two-dimensional material layer 2 refers to a material in which electrons can move freely only at the nanoscale in two dimensions. The two-dimensional material layer 2 may include one or more layers. The two-dimensional material layer 2 may have a single crystal interface. In an example embodiment, the two-dimensional material layer 2 may include graphite, graphene, molybdenum disulfide, tungsten diselenide, tungsten disulfide, or black phosphorus. The three-dimensional substrate 1 is a structure that can have macroscopic dimensions in all three dimensions. In an example embodiment, the three-dimensional substrate 1 may include one or a combination of Si, SiC, SOI, sapphire, mica, graphene, and molybdenum disulfide.

[0043] Specifically, Figure 2 This is a schematic diagram of the two-dimensional material layer sliding of a surface-modified superlubricated device according to an embodiment of the present invention, in conjunction with reference to the reference. Figure 1 and Figure 2The contact surface between the three-dimensional substrate 1 and the two-dimensional material layer 2 includes multiple nanostructures 3. Within the movable range of the two-dimensional material layer 2, the two-dimensional material layer 2 is simultaneously covered with several nanostructures 3, so that the two-dimensional material layer 2 and the three-dimensional substrate 1 with nanostructures 3 form a local contact. On the one hand, this reduces the contact area between the three-dimensional substrate 1 and the two-dimensional material layer 2. At the same time, when an external force is applied to the middle region of the two-dimensional material layer 2, the two-dimensional material layer 2 can slide relative to the three-dimensional substrate 1. Moreover, the two-dimensional material layer 2 is subjected to the reaction force of the nanostructures 3, and its edge warps upward. This makes the edge of the two-dimensional material layer 2 move away from the three-dimensional substrate 1 when it slides relative to the three-dimensional substrate 1, eliminating or reducing the friction caused by the dangling bonds at the edge of the two-dimensional material layer 2 and the interfacial chemical bonds of the three-dimensional substrate 1, thereby achieving stable structural superlubricity. In this device, nanostructures 3 can be arrayed on a three-dimensional substrate 1, and the size of nanostructures 3 is much smaller than that of two-dimensional material layer 2. When two-dimensional material layer 2 slides relative to three-dimensional substrate 1, several nanostructures 3 will be covered by two-dimensional material layer 2 at the same time. This allows two-dimensional material layer 2 to produce edge warping under the reaction force of nanostructures 3. Regardless of which direction two-dimensional material layer 2 slides relative to three-dimensional substrate 1, it can prevent friction caused by contact between the edge dangling bonds of two-dimensional material layer 2 and the interface chemical bonds of three-dimensional substrate 1. This allows the surface-modified structure superlubricating device to have high stability.

[0044] It should be noted that, Figure 1 and Figure 2 The diagram only shows a triangular cross-sectional shape of the nanostructure 3 on the three-dimensional substrate 1. In the embodiments of the present invention, the nanostructure 3 on the three-dimensional substrate 1 can also have other morphologies. In an exemplary embodiment, the cross-sectional shape of the nanostructure 3 can be spherical, hemispherical, arc-shaped, triangular, trapezoidal, rectangular, or irregular.

[0045] In one exemplary embodiment, Figure 3 Comparison of atomic force microscopy morphology of a three-dimensional substrate for a surface-modified superlubricated device and a traditional flat three-dimensional substrate, provided in this embodiment of the invention, in conjunction with reference. Figure 1-3 As shown, the surface morphology of the flat three-dimensional substrate 01 and the three-dimensional substrate 1 with nanostructure 3 were characterized by atomic force microscopy. It can be seen that the flat three-dimensional substrate 01 has a very flat surface (e.g., Figure 3 a) The surface of the three-dimensional substrate 1 with nanostructure 3 has periodic, highly uniform nanostructure 3 (e.g. Figure 3b) Therefore, when the two-dimensional material layer 2 and the flat three-dimensional substrate 01 are in close contact, and the two-dimensional material layer 2 and the flat three-dimensional substrate 01 slide relative to each other, the dangling bonds at the edge of the two-dimensional material layer 2 combine with the interfacial chemical bonds of the flat three-dimensional substrate 01, resulting in wear and causing the super-lubricating state of the structure to fail. However, when the three-dimensional substrate 1 with nanostructure 3 comes into contact with the two-dimensional material layer 2, because the surface of the three-dimensional substrate 1 has nanostructure 3, and within the movable range of the two-dimensional material layer 2, the two-dimensional material layer 2 is simultaneously covered with several nanostructures 3, which will support the two-dimensional material layer 2, so that the two-dimensional material layer 2 only forms local contact with the nanostructure 3. Thus, when the two-dimensional material layer 2 is subjected to external force in the middle region and slides relative to the three-dimensional substrate 1, the two-dimensional material layer 2 is subjected to the reaction force of the nanostructure 3, and its edge warps upward. This can reduce or eliminate the friction caused by the dangling bonds at the edge of the two-dimensional material layer 2 and the interfacial chemical bonds of the three-dimensional substrate, thereby achieving stable super-lubricating structure. This allows the surface-modified super-lubricating structure to be reused indefinitely, thereby improving the service life of the super-lubricating structure.

[0046] In another exemplary embodiment, Figure 4 This is a comparison chart of friction test results between a surface-modified superlubricating device provided in this invention and a traditional flat three-dimensional substrate-based superlubricating device. (Refer to reference...) Figure 1 , Figure 3 and Figure 4 As shown, when the two-dimensional material layer 2 slides relative to the three-dimensional substrate in the +X direction, the frictional force at the contact surface between the flat three-dimensional substrate 01 and the two-dimensional material layer 2 is 6 μN, while the frictional force at the contact surface between the three-dimensional substrate 1 with nanostructure 3 and the two-dimensional material layer 2 is only 0.2 μN. When the two-dimensional material layer 2 slides relative to the three-dimensional substrate in the -X direction, the frictional force at the contact surface between the flat three-dimensional substrate 01 and the two-dimensional material layer 2 is -6 μN, while the frictional force at the contact surface between the three-dimensional substrate 1 with nanostructure 3 and the two-dimensional material layer 2 is only -0.2 μN. That is, when the two-dimensional material layer 2 slides relative to the three-dimensional substrate 1, the frictional force generated by the nano-modified superlubricating device is much smaller than that generated by the traditional superlubricating device using a flat three-dimensional substrate. Therefore, the frictional force generated by the nano-modified superlubricating device during relative motion is small, forming a stable superlubricating state.

[0047] In this embodiment, multiple nanostructures are set at the contact surface between the two-dimensional material layer and the single-crystal interface in the three-dimensional substrate. The size of the nanostructures is much smaller than the size of the two-dimensional material layer, and within the movable range of the two-dimensional material layer, the two-dimensional material layer is simultaneously covered with several of the nanostructures. This allows the two-dimensional material layer and the three-dimensional substrate with nanostructures to form local contact. When the two-dimensional material layer is subjected to external force and slides relative to the three-dimensional substrate in the middle region, the two-dimensional material layer is subjected to the reaction force of the nanostructures, and its edges warp upwards. This eliminates the edge interaction between the two-dimensional material layer edge and the three-dimensional substrate, overcoming the problem of existing structural superlubricity where the friction caused by the combination of the edge dangling bonds of the two-dimensional material layer and the interface chemical bonds at the contact surface leads to the failure of the structural superlubricity. This results in a stable structural superlubricity.

[0048] Optional, continue to refer to the references Figure 1 and Figure 2 As shown, each nanostructure 3 is in point contact with the two-dimensional material layer 2. The protrusions of all nanostructures 3 facing the two-dimensional material layer 2 are located on the same horizontal plane. At this time, the maximum height of each nanostructure 3 in the vertical direction is consistent, and each nanostructure 3 has a uniform size. This allows the two-dimensional material layer 2 to contact each of the nanostructures 3 it covers when no external force is applied to it. That is, the nanostructures 3 covered by the two-dimensional material layer 2 all provide support for the two-dimensional material layer 2. Thus, when an external force is applied to the middle position of the two-dimensional material layer 2, the nanostructures 3 covered by the two-dimensional material layer 2 can have sufficient reaction force on the two-dimensional material layer 2, causing the edge of the two-dimensional material layer 2 to warp upward. This prevents the edge dangling bonds of the two-dimensional material layer 2 from combining with the interface chemical bonds of the three-dimensional substrate 1, which would generate large frictional forces, and further improves the stability of the surface-modified structure superlubricated device.

[0049] In another alternative embodiment, Figure 5 A schematic diagram of another surface-modified superlubricating device provided in an embodiment of the present invention is shown below. Figure 5 As shown, each nanostructure 3 is in surface contact with the two-dimensional material layer 2. The surfaces of all nanostructures 3 facing the two-dimensional material layer 2 are located on the same horizontal plane. At this time, the maximum height of each nanostructure 3 in the vertical direction is consistent. Under the premise that each nanostructure 3 has a uniform size, the surface of the nanostructure 3 facing the two-dimensional material layer 2 satisfies atomic-level flatness, so that when relative sliding occurs between the two-dimensional material layer 2 and the three-dimensional substrate, the friction between the two-dimensional material layer 2 and the nanostructure 3 can be minimized or eliminated.

[0050] It should be noted that when the two-dimensional material layer 2 and the nanostructure 3 are in point contact, the cross-sectional shape of the nanostructure 3 is not limited to a triangle. For example, the cross-sectional shape of the nanostructure can also be an arc or other irregular structure. Correspondingly, when the two-dimensional material layer 2 and the nanostructure 3 are in surface contact, the cross-sectional shape of the nanostructure is not limited to a rectangle. For example, the cross-sectional shape of the nanostructure can also be a trapezoid or other irregular structure.

[0051] Optionally, the height H of the nanostructure 3 can be in the range of 5nm ≤ H ≤ 10nm, preferably, the height H of the nanostructure 3 is 7nm. When the height H of the nanostructure 3 is less than 5nm, because the height H of the nanostructure 3 is too small, when the two-dimensional material layer 2 is subjected to external force and slides relative to the three-dimensional substrate 1, the reaction force of the nanostructure 3 on the two-dimensional material layer 2 is insufficient to cause its edges to warp upwards, thus failing to eliminate or reduce the frictional force generated by the interaction between the edges of the two-dimensional material layer 2 and the three-dimensional substrate 1; since the thickness of the two-dimensional material layer 2 is only at the nanoscale, when the height H of the nanostructure 3 is greater than 10nm, the height of the nanostructure 3 is too large and cannot meet the requirement of warping the two-dimensional material layer 2. By limiting the height H of the nanostructure 3 to between 5 nm and 10 nm, when the middle region of the two-dimensional material layer 2 is subjected to external force and slides relative to the three-dimensional substrate 1, the two-dimensional material layer 2 is subjected to the reaction force of the nanostructure 3, which allows its edge to be subjected to sufficient force and warp upward, thereby reducing or eliminating the friction caused by the presence of dangling bonds at the edge of the two-dimensional material layer 2, and thus achieving stable structural super-lubricity.

[0052] Optionally, in this superlubricating device, the spacing L between any two adjacent nanostructures 3 is in the range of 200nm ≤ L ≤ 400nm. Preferably, the spacing L between any two adjacent nanostructures 3 is 350nm. When the spacing L between any two adjacent nanostructures 3 is less than 200nm, the contact area between the two-dimensional material layer 2 and the three-dimensional substrate 1 with nanostructures 3 is too large due to the narrow spacing L. The effect is comparable to that of the two-dimensional material layer 2 contacting the three-dimensional substrate with an atomically flat surface. The reaction force of the nanostructures 3 on the two-dimensional material layer 2 is insufficient to cause its edges to warp upwards, thus failing to reduce or eliminate the friction caused by dangling bonds at the edges of the two-dimensional material layer 2. Similarly, when the spacing L between any two adjacent nanostructures 3 is greater than 400nm, the reaction force of the nanostructures 3 on the two-dimensional material layer 2 is also insufficient to cause its edges to warp upwards due to the large spacing L, thus failing to reduce or eliminate the friction caused by dangling bonds at the edges of the two-dimensional material layer 2. Therefore, by limiting the spacing L between any two nanostructures 3 to between 200nm and 400nm, when the middle region of the two-dimensional material layer 2 is subjected to external force and slides relative to the three-dimensional substrate 1, the two-dimensional material layer 2 is subjected to the reaction force of the nanostructure 3, causing its edge to warp upward, thereby reducing or eliminating the friction caused by the presence of dangling bonds at the edge of the two-dimensional material layer 2, and thus achieving stable structural super-lubricity.

[0053] The technical solution provided in this embodiment sets multiple nanostructures at the contact surface between the two-dimensional material layer and the single-crystal interface in a three-dimensional substrate. The size of the nanostructures is much smaller than the size of the two-dimensional material layer, and within the movable range of the two-dimensional material layer, the two-dimensional material layer is simultaneously covered with several nanostructures. This allows the two-dimensional material layer and the three-dimensional substrate with nanostructures to form local contact. When the two-dimensional material layer is subjected to external force and slides relative to the three-dimensional substrate in the middle region, the two-dimensional material layer is subjected to the reaction force of the nanostructures, and its edges warp upwards. This eliminates the edge interaction between the two-dimensional material layer edge and the three-dimensional substrate, overcoming the problem of structural superlubricity failure caused by frictional forces at the contact surface between the two-dimensional material layer edge and the three-dimensional substrate due to the combination of edge dangling bonds and interface chemical bonds. This results in a stable structural superlubricity and provides a new method for the widespread realization of structural superlubricity technology.

[0054] Based on the same inventive concept, this invention provides a method for preparing a structural superlubricating device, which can be used to prepare a surface-modified structural superlubricating device provided in any embodiment of this invention. Figure 6 This is a flowchart illustrating a method for fabricating a structurally superlubricated device according to an embodiment of the present invention. Figure 7 This is a schematic diagram illustrating the fabrication process of the superlubricating device provided in an embodiment of the present invention. (Refer to reference...) Figure 6 and Figure 7 As shown, the method includes:

[0055] S110. Surface modification is performed on a three-dimensional substrate to form multiple nanostructures. The size of the nanostructures is much smaller than the size of the two-dimensional material layer, and several nanostructures are covered simultaneously when the two-dimensional material layer moves.

[0056] Specifically, such as Figure 7 As shown, the three-dimensional substrate 1 refers to a substrate whose size is larger than the nanometer scale in any dimension, and can be in the micrometer size range or even larger. In an example embodiment, the three-dimensional substrate 1 may include one or a combination of Si, SiC, SOI, sapphire, mica, graphene, molybdenum disulfide, or similar materials.

[0057] Multiple nanostructures 3 can be formed by surface modification on a three-dimensional substrate 1 using methods such as vapor deposition, electrochemical deposition, and self-assembly. The height H of the formed nanostructure 3 can range from 5 nm to 10 nm, and the spacing L between two adjacent nanostructures 3 can range from 200 nm to 400 nm.

[0058] S120 provides a two-dimensional material layer with a single-crystal interface.

[0059] Among them, continue to refer to Figure 7 The two-dimensional material layer 2 with a single crystal interface can be a nanofilm prepared by methods such as chemical vapor deposition, redox intercalation exfoliation, hydrothermal template assembly, and ultrasonic exfoliation. The two-dimensional material layer 2 with a single crystal interface can be a single layer or multiple layers, and its material can be, but is not limited to, graphite, graphene, molybdenum disulfide, tungsten diselenide, or black phosphorus.

[0060] S130. Transfer the two-dimensional material layer to one side surface of the three-dimensional substrate where the nanostructure is formed, and apply force toward the middle region of the two-dimensional material layer.

[0061] For details, please refer to [link / reference]. Figure 7 After preparing a two-dimensional material layer 2 with a single-crystal interface, it can be transferred to one side surface of a three-dimensional substrate 1 where a nanostructure 3 is formed, so that the two-dimensional material layer 2 with a single-crystal interface comes into contact with the nanostructure 3 of the three-dimensional substrate 1. By applying a force toward the middle region of the two-dimensional material layer 2, the two-dimensional material layer 2 can be subjected to the reaction force of the nanostructure 3, causing the edge of the two-dimensional material layer 2 to warp upward, thereby forming the structural super-lubricating device provided in any embodiment of the present invention.

[0062] In this embodiment, multiple nanostructures are formed by surface modification on a three-dimensional substrate. A two-dimensional material layer with a single-crystal interface is transferred to the side of the three-dimensional substrate where the nanostructures are formed. This allows the two-dimensional material layer with the single-crystal interface to form local contact with the nanostructures on the three-dimensional substrate. When the two-dimensional material layer is subjected to external force and slides relative to the three-dimensional substrate in the middle region, the two-dimensional material layer is subjected to the reaction force of the nanostructures, and its edges warp upwards. This eliminates the edge interaction between the two-dimensional material layer edge and the three-dimensional substrate, overcoming the frictional force caused by the combination of edge dangling bonds and interface chemical bonds at the contact surface between the two-dimensional material layer edge and the three-dimensional substrate in existing structural superlubricity, thereby forming a stable structural superlubricity.

[0063] In an optional embodiment, the method for forming an array of multiple nanostructures on a flat surface of a three-dimensional substrate can specifically be a self-assembled micro / nanostructure array deposition method. Figure 8 This is a flowchart illustrating another method for fabricating a superlubricated device according to an embodiment of the present invention. Figure 9 This is a schematic diagram illustrating the formation of nanostructures on a flat surface of a three-dimensional substrate. (Refer to reference.) Figure 8 and Figure 9 As shown, the specific method for fabricating this superlubricating device includes:

[0064] S210, Depositing an array of micro / nano structures on a flat surface of a three-dimensional substrate.

[0065] Specifically, such as Figure 9As shown, the micro / nanostructure array on the flat surface of the three-dimensional substrate can be formed by self-assembly. For example, before depositing the micro / nanostructure array on the flat surface of the three-dimensional substrate, the three-dimensional substrate can be ultrasonically cleaned and hydrophilically treated. Specifically, acetone ultrasonic cleaning can be used to remove contaminants such as grease from the surface of the three-dimensional substrate 1, alcohol ultrasonic cleaning can be used to remove the residual acetone on the surface of the three-dimensional substrate 1 after ultrasonic cleaning in acetone, and finally deionized water cleaning can be used to remove the residual alcohol on the surface of the three-dimensional substrate 1 after ultrasonic cleaning in alcohol, thereby obtaining a three-dimensional substrate 1 with a clean surface; oxygen plasma bombardment is then used to obtain the clean surface. A flat surface of a three-dimensional substrate 1 is used to inject oxygen plasma into the surface of the substrate 1, forming oxygen dangling bonds. These dangling bonds can combine with hydrogen ions or hydroxide ions in water, thus making the surface of the three-dimensional substrate 1 hydrophilic. After immersing the hydrophilic three-dimensional substrate 1 in deionized water, a diluted solution of micro / nanostructures is dropped onto one side of the flat surface of the three-dimensional substrate 1, allowing the micro / nanostructures to self-assemble into a micro / nanostructure array on one side of the flat surface of the three-dimensional substrate 1. Finally, the deionized water is evaporated, allowing the micro / nanostructure array to deposit on the flat surface of the three-dimensional substrate 1. The diluted solution of the micro / nanostructures can be a mixture of polystyrene solution, alcohol, and deionized water in a predetermined ratio.

[0066] S220: A micro / nano structure array is deposited on a three-dimensional substrate using plasma etching to reduce the size of the micro / nano structures in the array to a preset size.

[0067] Plasma etching refers to the technique of using plasma to corrode or strip the surface of a material. In this scheme, plasma etching can be, but is not limited to, using oxygen plasma etching. The etching amount of the micro-nano structure array of the three-dimensional substrate is related to the etching time and the plasma flow rate during etching.

[0068] For details, please refer to [link / reference]. Figure 9 After etching the micro-nano structure array on the three-dimensional substrate with plasma for a certain period of time, the size of the micro-nano structure in the micro-nano structure array is reduced to a preset size, and there is a certain spacing between two adjacent micro-nano structures. At this time, the size of the micro-nano structure can be the spacing between the nanostructures 3 formed laterally, and the spacing between two adjacent micro-nano structures can be the lateral dimension of the nanostructures 3 formed laterally.

[0069] For example, scanning electron microscopy characterization was performed during the oxygen plasma etching of micro / nanostructure arrays, with reference to... Figure 10 As shown in Figure a, when the micro-nanostructures in the micro-nanostructure array are not etched by oxygen plasma, the micro-nanostructures in the self-assembled micro-nanostructure array are tightly packed; Reference Figure 10As shown in b, after 3 minutes of oxygen plasma etching, the size of the micro / nanostructure decreases from 200 nm to 150 nm, with a certain gap between adjacent micro / nanostructures; Reference Figure 10 As shown in Figure c, when the oxygen plasma etching time is further extended to 4 minutes, the size of the micro / nanostructure decreases to 100 nm, and the spacing between two adjacent micro / nanostructures further increases. Therefore, by limiting the etching time of the oxygen plasma, micro / nanostructures of corresponding sizes can be obtained, thereby enabling the limitation of the spacing and lateral dimensions between the subsequently formed nanostructures 3.

[0070] S230: Using a micro-nano structure array as a mask, multiple nanostructures are arranged in an array on a flat surface of a three-dimensional substrate by employing an ion beam etching process.

[0071] Ion beam etching refers to the process where, when directional high-energy ions bombard a solid target, energy is transferred from the incident ions to the atoms on the solid surface. If the binding energy between the atoms on the solid surface is lower than the energy of the incident ions, the atoms on the solid surface will be removed or eliminated from the surface. Thus, when forming nanostructure 3 using ion beam etching, a three-dimensional substrate 1 can be used as the solid target. Due to the presence of the micro / nanostructure array, when directional high-energy ions bombard the three-dimensional substrate 1, atoms on the surface of the three-dimensional substrate 1 in the region between two adjacent micro / nanostructures can be removed. This creates a depression in the region between two adjacent micro / nanostructures in the three-dimensional substrate 1, while the area covered by the micro / nanostructures will be relatively convex. The convex position is the formed nanostructure 3. Since the micro / nanostructures in the micro / nanostructure array are arranged in an array, the nanostructures formed using the micro / nanostructure array as a mask will also be arranged in an array. It should be noted that by changing the energy of the high-energy ions during ion beam etching, the direction of impact on the three-dimensional substrate 1, and the shape of the micro-nano structure, nanostructures 3 with different morphologies can be obtained. For example, the cross-sectional shape of the nanostructure 3 can be spherical, hemispherical, arc-shaped, triangular, trapezoidal, rectangular, or irregular.

[0072] S240: Plasma etching is used to remove the micro-nano structure array.

[0073] Specifically, after forming an array of nanostructures 3 on a three-dimensional substrate 1 using a micro / nanostructure array as a mask, it is necessary to remove the micro / nanostructures covering the nanostructures 3 and continue referencing... Figure 9The micro / nanostructure array can be further etched using oxygen plasma to reduce its size until the micro / nanostructures disappear or their size becomes negligible. After removing the micro / nanostructure array, the three-dimensional substrate can be ultrasonically cleaned to remove any remaining micro / nanostructures. Specifically, acetone can be used to ultrasonically clean the organic matter on the nanostructure 3, followed by the removal of residual acetone using alcohol. Finally, deionized water can be used to clean the residual alcohol from the nanostructure, resulting in a uniformly distributed nanostructure 3 with consistent peak heights.

[0074] S250 provides a two-dimensional material layer with a single-crystal interface.

[0075] S260. Transfer the two-dimensional material layer to one side of the three-dimensional substrate where a nanostructure has been formed, and apply a force toward the middle region of the two-dimensional material layer.

[0076] In this embodiment, after depositing a micro-nano structure array on a flat surface of a three-dimensional substrate, a micro-nano structure array mask is obtained by plasma etching of the micro-nano structure array. Using the micro-nano structure array as a mask, an ion beam is used to etch the three-dimensional substrate to form an array of nanostructures on the three-dimensional substrate. This makes the size and arrangement of the formed nanostructures controllable and the preparation method simple.

[0077] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A surface-modified superlubricated device, characterized in that, include: A three-dimensional substrate and a two-dimensional material layer located on the three-dimensional substrate; The two-dimensional material layer includes a single crystal interface, and the stress location of the two-dimensional material layer is the middle region of the two-dimensional material layer. The contact surface between the three-dimensional substrate and the two-dimensional material layer includes multiple nanostructures. The size of the nanostructures is much smaller than the size of the two-dimensional material layer, and within the movable range of the two-dimensional material layer, the two-dimensional material layer is simultaneously covered with several of the nanostructures.

2. The superlubricating device according to claim 1, characterized in that, Each nanostructure is in point contact with the two-dimensional material layer, and the protrusions of all nanostructures facing the two-dimensional material layer are located on the same horizontal plane.

3. The superlubricating device according to claim 1, characterized in that, Each nanostructure is in surface contact with the two-dimensional material layer, all the surfaces of the nanostructures facing the two-dimensional material layer are on the same horizontal plane, and the surfaces of the nanostructures facing the two-dimensional material layer satisfy atomic-level flatness.

4. The superlubricating device according to claim 1, characterized in that, The nanostructure array is arranged on the three-dimensional substrate.

5. The superlubricating device according to claim 1, characterized in that, The cross-sectional shape of the nanostructure is arc-shaped, triangular, trapezoidal, rectangular, or other irregular shapes.

6. The superlubricating device according to claim 1, characterized in that, The height H of the nanostructure has a range of values: 5nm ≤ H ≤ 10nm.

7. The superlubricating device according to claim 1, characterized in that, The spacing L between any two adjacent nanostructures can be in the range of 200nm ≤ L ≤ 400nm.

8. The superlubricating device according to claim 1, characterized in that, The two-dimensional material layer includes graphene, molybdenum disulfide, tungsten diselenide, tungsten disulfide, or black phosphorus.

9. The superlubricating device according to claim 1, characterized in that, The three-dimensional substrate includes one or a combination of Si, SiC, SOI, sapphire, and mica.

10. A method for fabricating a structurally superlubricated device, characterized in that, include: Surface modification is performed on a three-dimensional substrate to form multiple nanostructures; Provide a two-dimensional material layer with a single-crystal interface; The size of the nanostructure is much smaller than the size of the two-dimensional material layer, and the two-dimensional material layer covers several nanostructures at the same time when it moves. The two-dimensional material layer is transferred to one side surface of the three-dimensional substrate where the nanostructure is formed, and a force is applied toward the middle region of the two-dimensional material layer.

11. The method for preparing the structurally superlubricated device according to claim 10, characterized in that, Multiple nanostructures arranged in an array are formed on the flat surface of the three-dimensional substrate, including: An array of micro / nano structures is deposited on the flat surface of the three-dimensional substrate; The array of micro-nano structures deposited on the three-dimensional substrate is subjected to plasma etching to reduce the size of the micro-nano structures in the array to a predetermined size; Using the micro-nano structure array as a mask, an ion beam etching process is employed to form multiple nanostructures arranged in an array on the flat surface of the three-dimensional substrate. The micro-nano structure array is removed by plasma etching.

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