A biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant, its preparation method and application

Abstract

This invention provides a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant, its preparation method, and its application. The method involves adding 1-hexadecyl-3-methylimidazole bromide and molybdenum disulfide to deionized water to obtain a molybdenum disulfide dispersion. Carbon nanotubes are then added to the molybdenum disulfide dispersion and ultrasonically dispersed. The mixture is then transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 150-180°C to obtain an initial suspension. After centrifugation to remove unpeeled molybdenum disulfide nanosheets, the supernatant is collected and freeze-dried to obtain the biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant. The preparation method of this invention is simple, requiring no additional impurity removal steps. The solvents used in the entire process are green, environmentally friendly, and pollution-free. The process is easy to control. The prepared carbon quantum dot / molybdenum disulfide composite lubricant exhibits a short break-in period and long-lasting lubrication effect in water, oil, and other liquid environments.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, and relates to composite materials and their preparation methods. Specifically, it relates to a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive, its preparation method, and its application. Background Technology

[0002] During the long-term operation of mechanical friction pairs, traditional liquid lubrication systems often struggle to maintain a stable interfacial lubrication state, leading to increased friction coefficients and intensified wear. To improve lubrication performance, researchers typically introduce solid lubricants (such as molybdenum disulfide, graphene, and carbon nanotubes) as functional additives, utilizing their low-shear layered structure, high load-bearing capacity, and excellent friction-reducing and anti-wear properties. However, these nano-solid lubricants are prone to agglomeration and sedimentation in liquid media, exhibiting poor dispersion stability and making it difficult to continuously form a complete lubricating film at the friction interface. Simultaneously, solid particles are easily washed out of the friction zone under shear forces, resulting in a gradual decline in lubrication effectiveness and hindering the achievement of long-term stable lubrication.

[0003] The moss system in nature offers new inspiration for lubrication design. The moss surface is composed of dense, elongated fibers and hierarchical porous microstructures, forming a complex capillary network. The microfibers distribute local pressure at the contact interface, dispersing stress concentration and thus reducing friction. The pore network traps and stores liquid moisture, releasing it controllably under external pressure through capillary action and pore compression, forming a thin, uniform lubricating film and reducing shear resistance. This capillary structure and pressure response mechanism endow moss with the ability to provide sustained lubrication under varying humidity levels or high loads. Applying this biomimetic concept to tribological material design allows for efficient and controllable lubrication performance through the construction of multidimensional porous structures. However, existing biomimetic lubricating materials still have the following shortcomings: they mostly mimic macroscopic structural morphology, lacking synergistic regulation at the microscopic chemical level; the bonding force between components in the composite system is weak, leading to easy destruction of the lubricating film under shear; and under complex working conditions, interfacial stability and lubrication durability remain limited. Summary of the Invention

[0004] The purpose of this invention is to provide a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive, its preparation method, and its application. This invention constructs a composite system with a multidimensional interconnected structure and dynamic adaptive lubrication function. The prepared carbon quantum dot / molybdenum disulfide composite lubricant additive can quickly form a stable, durable, and low-friction lubrication interface in media such as water and oil, achieving a short break-in period and excellent long-term lubrication performance.

[0005] This invention is achieved through the following technical solution: This invention provides the application of a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive in lubricating materials.

[0006] The present invention also provides a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive, wherein the structure of the biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive is that carbon nanotubes with a particle size of 5-10 nm are grown on molybdenum disulfide nanosheets with a lateral size of 100-300 nm.

[0007] This invention also provides a method for preparing a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant, comprising the following steps: Step 1: Weigh 200-400 mg of 1-hexadecyl-3-methylimidazole bromide and 500 mg of molybdenum disulfide and add them to 50 mL of deionized water. Then, perform ultrasonic dispersion to obtain a molybdenum disulfide dispersion. Step 2: Weigh 300-500 mg of carbon nanotubes and add them to the molybdenum disulfide dispersion prepared in Step 1. After ultrasonic dispersion, transfer the dispersion to a high-pressure reactor and carry out a hydrothermal reaction at 150-180℃ to obtain an initial suspension. After centrifugation to remove unpeeled molybdenum disulfide nanosheets, take the supernatant and freeze-dry it to obtain a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite material.

[0008] Furthermore, the ultrasonic dispersion time in step 1 is 25-30 min.

[0009] Furthermore, the ultrasonic dispersion time in step 2 is 40-45 minutes.

[0010] Furthermore, the hydrothermal reaction time in step 2 is 18-24 h.

[0011] Furthermore, the centrifugation speed in step 2 is 2000~4000 rpm, and the centrifugation time is 20~30 min.

[0012] Compared with the prior art, the present invention has the following beneficial effects: This invention successfully achieved in-situ growth of carbon nanotubes (CNTs) on the surface of ultrathin MoS2 nanosheets using a one-step hydrothermal method assisted by 1-hexadecyl-3-methylimidazolium bromide, constructing a multidimensional interconnected composite structure. The combination of MoS2 and CNTs achieves complementary and synergistic performance: MoS2 provides low-shear slip channels to reduce friction, while the three-dimensional support network of CNTs prevents MoS2 sheet stacking and peeling, and enhances the rolling effect, thereby improving the structural stability and lubrication performance of the material. In this composite system, the layered structure of MoS2 can slide along the interlayer under shear force, significantly reducing friction and wear. Simultaneously, the three-dimensional support network of CNTs plays a crucial role in preventing the stacking, peeling, or sedimentation of MoS2 sheets, maintaining the stability of the lubricating film. Furthermore, the three-dimensional network structure constructed by CNTs simulates the fibrous skeleton of moss, providing structural support for the system, effectively dispersing local contact pressure, alleviating stress concentration at the friction interface, and thus significantly improving the structural stability and wear resistance of the composite material. More importantly, the ionic liquids (ILs) in the composite system can be dynamically released to the friction interface under pressure, forming a lubricating film with dynamic adsorption function, further reducing the coefficient of friction and wear. This invention, through the design and synergistic effect of a multi-dimensional composite structure, significantly improves the performance of lubricating materials under complex working conditions, giving them broad application potential and promising technological prospects in modern mechanical lubrication systems. The preparation method of this invention is simple and easy to implement, requiring no unnecessary impurity removal steps. The solvents used throughout the process are green, environmentally friendly, and pollution-free. The implementation process is easy to control, and the preparation cost is low, making it suitable for industrial production. Attached Figure Description

[0013] Figure 1 The image shows the XRD patterns of carbon nanotubes, molybdenum disulfide, and the prepared composite lubricant additive in Example 1. Figure 2 shows SEM images of molybdenum disulfide and the prepared composite lubricating additive in Example 1. Figure 2(a) is an SEM image of molybdenum disulfide observed at a scale of 5 μm, Figure 2(b) is an SEM image of the composite lubricating additive observed at a scale of 5 μm, and Figure 2(c) is an SEM image of the same composite lubricating additive observed at a scale of 2 μm. Figure 3 The friction coefficient curves of the carbon nanotube / molybdenum disulfide composite lubricant additives prepared in Examples 1-3 under pure water friction environment are shown. Figure 4 The friction coefficient curves of the carbon nanotube / molybdenum disulfide composite lubricating additives prepared in Examples 1-3 under oil friction environment are shown. Detailed Implementation

[0014] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. These descriptions are intended to explain the invention and not to limit it.

[0015] Example 1: A method for preparing a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant, comprising the following steps: Step 1: Weigh 200 mg of 1-hexadecyl-3-methylimidazole bromide and 500 mg of molybdenum disulfide and add them to 50 mL of deionized water. Then, ultrasonically disperse the mixture for 25 min to obtain a molybdenum disulfide dispersion. Step 2: Weigh 300 mg of carbon nanotubes and add them to the molybdenum disulfide dispersion prepared in Step 1. After ultrasonic dispersion for 40 min, transfer the dispersion to a high-pressure reactor and carry out hydrothermal reaction at 180℃ for 18 h to obtain an initial suspension. Centrifuge at 2000 rpm for 30 min to remove unpeeled molybdenum disulfide nanosheets, and take the supernatant. After freeze-drying, obtain a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive.

[0016] X-ray diffraction (XRD) analysis was performed on the carbon nanotubes, molybdenum disulfide, and their composite lubricant additives in Example 1 to observe the crystal information and elemental composition of the samples, such as... Figure 1 The diagram shows all the characteristic peaks of the composite material. The characteristic peaks in the 10–80° range indicate the presence of a 2H-MoS2 hexagonal phase structure. No additional peaks, such as those of molybdenum oxide, are observed, confirming the pure phase of MoS2. The (002) peak at 14.3° is significantly shifted to the right, reflecting an increase in interlayer spacing. This indicates that interlayer materials (ILs) open the MoS2 interlayers. The diffraction peak at 25.8° corresponds to the (002) crystal plane of CNTs, indicating that the CNTs retain a graphitized structure. This suggests the presence of molybdenum disulfide and carbon nanotubes in the composite.

[0017] The morphology of molybdenum disulfide and its composite lubricant additive in Example 1 was observed by SEM, as shown in Figure 2. Figure 2(a) shows that the unexfoliated MoS2 exhibits a small interlayer spacing and a tightly packed morphology. This high-density stacking structure restricts the slippage and expansion between the layers, making it difficult to fully utilize its low-shear properties during friction. Figures 2(b) and 2(c) show that the carbon nanotube / molybdenum disulfide composite lubricant additive exhibits a moss-like structure, where slender tubular CNTs grow on the surface of the MoS2 sheets, forming a composite structure. Microscopically, this loose structure enhances interlayer slippage and load dispersion capabilities.

[0018] Example 2: A method for preparing a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant, comprising the following steps: Step 1: Weigh 300 mg of 1-hexadecyl-3-methylimidazole bromide and 500 mg of molybdenum disulfide and add them to 50 mL of deionized water. Then, ultrasonically disperse the mixture for 30 min to obtain a molybdenum disulfide dispersion. Step 2: Weigh 400 mg of carbon nanotubes and add them to the molybdenum disulfide dispersion prepared in Step 1. After ultrasonic dispersion for 42 min, transfer the dispersion to a high-pressure reactor and carry out hydrothermal reaction at 150 °C for 24 h to obtain an initial suspension. Centrifuge at 4000 rpm for 20 min to remove unpeeled molybdenum disulfide nanosheets, and take the supernatant. After freeze-drying, obtain a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive.

[0019] Example 3: A method for preparing a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant, comprising the following steps: Step 1: Weigh 400 mg of 1-hexadecyl-3-methylimidazole bromide and 500 mg of molybdenum disulfide and add them to 50 mL of deionized water. Then, ultrasonically disperse the mixture for 28 min to obtain a molybdenum disulfide dispersion. Step 2: Weigh 500 mg of carbon nanotubes and add them to the molybdenum disulfide dispersion prepared in Step 1. After ultrasonic dispersion for 45 min, transfer the dispersion to a high-pressure reactor and carry out hydrothermal reaction at 170℃ for 20 h to obtain an initial suspension. Centrifuge at 3000 rpm for 25 min to remove unpeeled molybdenum disulfide nanosheets, and take the supernatant. After freeze-drying, obtain a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive.

[0020] The composite lubricating additives prepared in Examples 1-3 were freeze-dried and then dispersed in pure water and PAO10 base oil to prepare suspensions with different concentrations (1.0 wt%, 2.0 wt%, and 3.0 wt%). The change in the coefficient of friction of the carbon nanotube / molybdenum disulfide composite lubricating additive over time was tested. Figure 3 As shown, in a pure water environment, the average friction coefficients of the carbon nanotube / molybdenum disulfide composite lubricating additives prepared in Examples 1-3 were 0.129, 0.105, and 0.087, respectively. Figure 4As shown, in PAO10 base oil, the average friction coefficients of the carbon nanotube / molybdenum disulfide composite lubricant additives prepared in Examples 1-3 were 0.061, 0.058, and 0.041, respectively. This is because the two-dimensional layered structure of molybdenum disulfide provides low-shear slip channels, effectively reducing interlaminar shear strength during sliding friction. The carbon nanotubes exert a rolling effect at the interface, simultaneously dispersing contact stress, thus significantly reducing friction and wear. The carbon nanotubes, molybdenum disulfide, and 1-hexadecyl-3-methylimidazolium bromide ionic liquid synergistically construct a continuous and dense lubricating film. This synergistic mechanism achieves a dual friction-reducing effect from both sliding and rolling friction. This composite lubricant additive possesses excellent lubrication performance and can effectively reduce friction and wear.

[0021] Example 4: A method for preparing a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant, comprising the following steps: Step 1: Weigh 300 mg of 1-hexadecyl-3-methylimidazole bromide and 500 mg of molybdenum disulfide and add them to 50 mL of deionized water. Then, ultrasonically disperse the mixture for 26 min to obtain a molybdenum disulfide dispersion. Step 2: Weigh 400 mg of carbon nanotubes and add them to the molybdenum disulfide dispersion prepared in Step 1. After ultrasonic dispersion for 44 min, transfer the dispersion to a high-pressure reactor and carry out hydrothermal reaction at 180℃ for 22 h to obtain an initial suspension. Centrifuge at 2500 rpm for 22 min to remove unpeeled molybdenum disulfide nanosheets, and take the supernatant. After freeze-drying, obtain a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive.

[0022] Example 5: A method for preparing a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant, comprising the following steps: Step 1: Weigh 300 mg of 1-hexadecyl-3-methylimidazole bromide and 500 mg of molybdenum disulfide and add them to 50 mL of deionized water. Then, ultrasonically disperse the mixture for 30 min to obtain a molybdenum disulfide dispersion. Step 2: Weigh 400 mg of carbon nanotubes and add them to the molybdenum disulfide dispersion prepared in Step 1. After ultrasonic dispersion for 43 min, transfer the dispersion to a high-pressure reactor and carry out hydrothermal reaction at 165℃ for 24 h to obtain an initial suspension. Centrifuge at 3500 rpm for 28 min to remove unpeeled molybdenum disulfide nanosheets, and take the supernatant. After freeze-drying, obtain a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive.

Claims

1. Application of a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive in lubricating materials.

2. The biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive as described in claim 1, characterized in that, The biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive has a structure in which carbon nanotubes with a particle size of 5-10 nm are grown on molybdenum disulfide nanosheets with a lateral size of 100-300 nm.

3. The preparation method of the biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive as described in claim 1, characterized in that, Includes the following steps: Step 1: Weigh 200-400 mg of 1-hexadecyl-3-methylimidazole bromide and 500 mg of molybdenum disulfide and add them to 50 mL of deionized water, then disperse them by ultrasonication to obtain a molybdenum disulfide dispersion. Step 2: Weigh 300-500 mg of carbon nanotubes and add them to the molybdenum disulfide dispersion prepared in Step 1. After ultrasonic dispersion, transfer the dispersion to a high-pressure reactor and carry out a hydrothermal reaction at 150-180℃ to obtain an initial suspension. After centrifugation to remove unpeeled molybdenum disulfide nanosheets, take the supernatant and freeze-dry it to obtain a biomimetic moss-structured carbon nanotube / molybdenum disulfide composite material.

4. The preparation method of the biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive according to claim 3, characterized in that, The ultrasonic dispersion time in step 1 is 25~30 min.

5. The preparation method of the biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive according to claim 3, characterized in that, The ultrasonic dispersion time in step 2 is 40~45 min.

6. The preparation method of the biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive according to claim 3, characterized in that, The hydrothermal reaction in step 2 takes 18-24 hours.

7. The preparation method of the biomimetic moss-structured carbon nanotube / molybdenum disulfide composite lubricant additive according to claim 3, characterized in that, The centrifugation speed in step 2 is 2000~4000 rpm, and the centrifugation time is 20~30 min.

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