Molecular dynamics-based polyfunctional group graphene oxide / graphite composite model construction and function regulation and control method

Abstract

The invention relates to the technical field of crossing of nanometer material interface engineering and calculation material science, in particular to a molecular dynamics-based multifunctional group graphene oxide / graphite composite model construction and function regulation and control method. According to the invention, a polyfunctional group graphene oxide / graphite-surfactant-water three-phase interface model is innovatively constructed, and a graphene oxide / graphite composite interface modeling and regulating method is utilized; quantitative regulation and control of oxygen-containing functional groups, the combination ratio of polyfunctional groups and accurate regulation and control of the interface structure, the adsorption performance, the stability and the interface bonding strength are explored through molecular dynamics simulation. According to the method, by optimizing functional group distribution, a virtual screening platform capable of quantizing the interface synergistic effect is formed, blindness and resource waste of actual experiments are reduced, the material research and development process is accelerated, and research and development cost is reduced.

Description

Technical Field

[0001] The present invention relates to the interdisciplinary technical field of nanomaterial interface engineering and computational materials science, and in particular to a molecular dynamics-based multi-functional graphene oxide / graphite composite model construction and function regulation method. Background Art

[0002] As high-end equipment in nuclear power and aerospace industries moves towards extreme operating conditions such as high temperature and ultra-high pressure, the problem of lubrication failure exposed during multi-pass drawing of ultra-fine metal wires has become a key constraint. Existing lubrication systems experience interfacial bonding collapse and dynamic lubrication film fracture under extreme friction, leading to extremely high wire breakage rates and poor surface quality, severely restricting the independent supply of high-precision wire. Therefore, the development of new drawing graphite emulsions with strong interfacial bonding and high-temperature stability is a key breakthrough to overcome the bottleneck problem of extreme manufacturing and ensure the security of the high-end equipment industry chain.

[0003] The lubrication properties of wire drawing graphite emulsions depend on the dispersion stability of the graphite particles in the aqueous carrier fluid and the quality of the interfacial film formation. Traditional systems struggle to meet process requirements during the extreme drawing of ultrafine wires due to weak van der Waals interactions between graphite particles, resulting in poor dispersion stability and insufficient interfacial bonding. Graphene oxide (GO), with its abundant surface oxygen-containing functional groups, high aspect ratio, and lamellar structure, can construct a three-dimensional network within the matrix. Surface modification and functionalization can further optimize dispersion stability and interfacial adhesion. Compounding GO with graphite significantly enhances the interactions between graphite particles and at the graphite-metal interface. Its unique interfacial properties (such as high thermal conductivity, superlubricity, and mechanical strengthening effects) offer innovative potential for metal lubrication.

[0004] Although studies have shown that the addition of GO can improve the dispersion stability and interfacial bonding strength of graphite, there is still a lack of systematic research on the quantitative regulation of oxygen-containing functional groups, the combination ratio of multiple functional groups, and their influence on friction and lubrication performance. Molecular dynamics simulation technology, as a core tool in modern computational materials science, can accurately track the dynamic adsorption process in the graphene oxide / graphite solution system by constructing atomic-level precision models and solving Newton's equations of motion. At the same time, the interface design and performance regulation of this system also have bottlenecks such as insufficient interface modeling accuracy, weak dynamic regulation capabilities, and poor experimental-computational correlation, which lead to problems such as large deviations in interface performance prediction, difficulties in multi-objective collaborative optimization, and poor adaptability to actual working conditions.

[0005] Therefore, there is an urgent need to develop a molecular dynamics-driven method for the coordinated regulation of graphene oxide / graphite composite functions, which can not only achieve precise design of the lubrication system, but also solve the problems of quantitative regulation of oxygen-containing functional groups and combination ratio of multiple functional groups. This is of great significance for the development of new drawing graphite emulsions suitable for extreme working conditions. Summary of the Invention

[0006] To achieve one of the above purposes, the present invention provides a method for constructing a multi-functional graphene oxide / graphite composite model and regulating its functions based on molecular dynamics. In view of the limitations of a single graphite system, the present invention constructs a graphene oxide / graphite-surfactant-water three-phase composite interface model, and realizes multi-dimensional precise regulation of interface functions through the synergy of molecular dynamics simulation functions. Compared with traditional experimental means, this technology adopts a strategy of combining molecular dynamics simulation with experimental characterization, which can not only analyze the evolution process of the graphene oxide / graphite interface at the atomic level, but also significantly reduce the cost of experimental trial and error, and at the same time can deeply understand the microscopic dynamic changes in the dispersion process. In order to solve the problems that traditional experiments are difficult to accurately determine data parameters, the experimental cost is high, the time period is long, the data analysis is difficult, and the existing problems of insufficient interface modeling accuracy, lack of multi-functional group synergistic regulation, and poor experimental-calculation correlation in the research of graphene oxide / graphite composite systems. The technical solution of the present invention is achieved as follows: The present invention provides a molecular dynamics-based method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function, comprising the following steps: Step 1: Import the graphite unit cell into Materials Studio software, construct water molecules and surfactant molecules, and perform geometry optimization; Step 2: Establish graphite / graphene oxide substrate model, surfactant molecular cluster model and water molecule solvent model; Step 3: Integrate to form a graphene oxide / graphite-surfactant-water three-phase interface model and perform energy minimization calculation; Step 4: Based on the COMPASSⅡ reaction force field, set appropriate simulation parameters and steps, and use the isothermal and isobaric ensemble (NPT) for molecular dynamics simulation; Step 5: Obtain dynamic information of the interface model; The graphene oxide surface is modified with oxygen-containing functional groups; the distribution density of the functional groups is 8 to 12 at% based on the total number of carbon atoms; the carbon atom counting method is as follows: after cutting along the (0 0 1) crystal plane of the graphite unit cell, the model size is expanded using the supercell construction (Supercell) function, and the minimum side length of the model in the x and y directions is greater than 2 times the truncation radius (Rcut), meeting the periodic boundary conditions of the medium precision simulation requirements of the graphite unit cell, and counting the number of carbon atoms.

[0007] On the basis of the above technical solution, the present invention can also be improved as follows: Preferably, the oxygen-containing functional group includes a combination of two or more of hydroxyl, carboxyl, epoxy, and sulfonic acid groups.

[0008] Preferably, the Step 1 is specifically as follows: Step 1-1: Obtain the graphite single crystal structure (space group P63 / mmc, lattice parameters a=2.46 Å, c=6.70 Å) from the ICSD database. Use the Visualizer module to construct water molecules and surfactant molecules, including one or more of sodium dodecylbenzenesulfonate, disodium methylene dinaphthalenesulfonate, sodium lauryl sulfate, sodium alkylsulfonate, sodium stearate, sodium lauroyl sarcosinate, and sodium ligninsulfonate. Step 1-2: Select the Energy task in the Forcite module to perform energy minimization on the initial model and use the COMPASSⅡ force field. The charge is automatically set and distributed by the force field, the accuracy is set to Medium, the electrostatic force is calculated using the Ewald summation method, the van der Waals force is calculated using the Atom-based summation method, and the Smart algorithm is selected for optimization.

[0009] Further preferably, the Step 2 is specifically as follows: Step 2-1: Cut along the (0 0 1) crystal plane of the graphite unit cell and expand the single-layer graphite model (size ≥ 2 times the Rcut value, Rcut = 12 Å); Step 2-2: Construct a single-layer graphene oxide substrate model. The modeling method is based on the Monte Carlo random algorithm. Through the rand()<$COVERAGE condition (coverage $COVERAGE=8~12 at%), the carbon atoms on the surface of the single-layer graphene are selected as grafting sites, where: functional group type: one or more combinations of hydroxyl (-OH), carboxyl (-COOH), epoxy (-O-), and sulfonic acid (-SO3H); distribution density: single-sided or double-sided grafting, the functional group density is 8~12 at% (based on the total number of carbon atoms), and the error range is ±1.5 at%; spatial repulsion constraint: the distance between adjacent functional groups is ≥3 Å to avoid site overlap; in this process, the geometric adaptation principle is followed, and the C-O bond length is 1.42~1.45 Å (based on sp 3 The bond orbital symmetry of the hybrid carbon is preferably 1.43 Å, corresponding to the minimum energy path of the CO σ bond), the bond length deviation is ≤ 0.02 Å; the CCO bond angle is 108°~112° (based on sp 3 Hybridization theory, the preferred angle is 109.5°, which is sp 3The analytical optimal solution of tetrahedral hybridization was obtained, with an angle deviation of ≤2°. The group was rotated to be perpendicular to the graphene plane by calculating the angle θ between the surface normal vector and the bond direction of the functional group, which was 85°~95°. A molecular mechanics force field (COMPASSⅡ) was used to perform 10~20 iterative geometry optimizations (step size 0.1~0.3 Å) to eliminate atomic overlap (van der Waals radius conflict threshold <0.8 Å). Mirror symmetry constraints were applied to the boundary atoms to ensure that the interlayer spacing fluctuation after grafting was ≤0.5 Å.

[0010] Step 2-3: Use the Build layer tool to combine the single-layer graphite model with the single-layer graphene oxide model to obtain a graphene oxide / graphite substrate model with ≥1 graphene oxide layer and a vacuum layer thickness of 20-50 Å. Step 2-4: Randomly combine ≥4 surfactant molecules, including two or more of sodium dodecylbenzenesulfonate, disodium methylene dinaphthalenesulfonate, sodium lauryl sulfate, sodium alkylsulfonate, sodium stearate, sodium lauroyl sarcosinate, and sodium ligninsulfonate, to obtain a surfactant molecular cluster model, and the size of the surfactant molecular cluster model is consistent with the size of the graphite substrate model; Step 2-5: Select the Construction task in the Amorphous Cell module to build a water molecule solvent model (number of molecules ≥ 500, density 0.1~0.8 g / cm 3 ), using COMPASSⅡ force field, electrostatic force (Ewald) and van der Waals force (Atom-based) calculation; Step 2-6: Select the Energy task in the Forcite module to perform energy minimization on the initial model and use the COMPASSⅡ force field. The charge is automatically assigned by the force field, the precision is set to Medium, the electrostatic force is calculated using the Ewald summation method, the van der Waals force is calculated using the Atom-based summation method, and the Smart algorithm is used for optimization. Step 2-7: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the initial model. Set the calculation accuracy to Medium. Use the Ewald summation method for electrostatic force calculation and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field.

[0011] More preferably, Step 2.2 is specifically as follows: graft double kinds of oxygen-containing functional groups onto the carbon atoms on the surface of single-layer graphite; based on the Monte Carlo random algorithm, set a random seed to ensure the repeatability of the results, traverse each carbon atom on the graphene surface and select grafting sites according to the condition rand()<COVERAGE; for each selected site, check whether its distance from the already selected sites is ≥3 Å for spatial repulsion check, if the distance is insufficient, skip this site to avoid site duplication; the functional group ratio adopts any one of the following methods: ① the ratio of hydroxyl (-OH) to carboxyl (-COOH) is 6:4; ② the ratio of hydroxyl (-OH) to epoxy (-O-) is 5:5; ③ the ratio of hydroxyl (-OH) to sulfonic acid group (-SO3H) is 7:3; ④ the ratio of carboxyl (-COOH) to epoxy (-O-) is 3:7; ⑤ the ratio of carboxyl (-COOH) to sulfonic acid group (-SO3H) is 8:2; ⑥ the ratio of epoxy (-O-) to sulfonic acid group (-SO3H) is 9:1; graft three kinds of oxygen-containing functional groups onto the carbon atoms on the surface of single-layer graphite; adopt any one of the following methods: ① the ratio of hydroxyl (-OH) to carboxyl (-COOH) to epoxy (-O-) is 5:3:2; ② the ratio of carboxyl (-COOH) to epoxy (-O-) to sulfonic acid group (-SO3H) is 4:4:2; ③ the ratio of hydroxyl (-OH) to carboxyl (-COOH) to sulfonic acid group (-SO3H) is 6:2:2; among them, the ratio of hydroxyl (-OH) to carboxyl (-COOH) to epoxy (-O-) is preferably 5:3:2.

[0012] More preferably, Step 3 is specifically as follows: Step 3-1: Combine the graphene oxide / graphite substrate model, surfactant molecular cluster model and water molecule solvent model into a graphene oxide / graphite-surfactant-water three-phase interface model through the Build layer tool, and set the thickness of the vacuum layer of the interface model to 30 Å to 60 Å; Step 3-2: Select the Geometry optimization task in the Forcite module to perform geometric optimization operations on the interface model, set the calculation accuracy to Medium, use the Ewald summation method for electrostatic force calculation, use the Atom-based summation method for van der Waals force calculation, use the COMPASSⅡ force field, and the charges are automatically set and distributed by the force field.

[0013] More preferably, Step 4 is specifically as follows: perform molecular dynamics simulation using the isothermal isobaric ensemble (NPT), the simulation time is ≥100 ps, the temperature is ≥298 K, the Nose temperature control method, and the time step is 1 fs.

[0014] Further preferably, the Step 5 specifically includes: obtaining data such as adsorption configuration, interface formation energy, radial distribution function, interaction energy, interfacial tension, and concentration distribution of each component along the Z axis.

[0015] The beneficial effects of the present invention are: 1) This invention innovatively introduces an interface modeling method for a graphene oxide / graphite composite model to form a graphene oxide / graphite-surfactant-water three-phase interface composite system. Combined with molecular dynamics simulation, this method achieves synergistic optimization of key properties such as adsorption, stability, and wettability. This solves the problem of large deviations in the prediction of interface properties in traditional single-phase systems and provides atomic-level theoretical support for the design of high-performance composite materials.

[0016] 2) Molecular dynamics simulation is used to calculate detailed information about the adsorption process, accurately, quickly, and effectively determining the type and amount of oxygen-containing functional group modification on graphene oxide. This enables precise control of the interfacial structure and properties of the graphene oxide / graphite composite system, providing an efficient virtual screening platform for the development of new composite materials.

[0017] 3) The present invention has the advantages of simple operation, low cost, and high precision, which reduces the cost of experimental trial and error, accelerates the development of new materials, and promotes the development of materials science towards a more refined and intelligent direction. It further promotes the innovative application of graphite-based materials in coatings, energy storage, composite materials and other fields, and promotes technological progress and innovative development in the field of materials science. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a flow chart of the method for preparing graphene oxide / graphite composite drawing graphite emulsion based on molecular dynamics interface optimization in the present invention; Figure 2 The initial model and final model diagrams of Example 1 and Comparative Example 1; Figure 3 The hydrogen bonds formed between the surfactant and water in the three-phase interface model before and after adsorption in Example 1 and Comparative Example 1: (a) the number of hydrogen bonds; (b) the hydrogen bond angle; (c) the hydrogen bond length; Figure 4 is the interface formation energy of the three-phase interface model before and after adsorption of Example 1 and Comparative Example 1; Figure 5It is the interfacial tension of the three-phase interface model before and after adsorption of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0021] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. Furthermore, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0022] In this document, the terms “contain”, “include” or “include” are open expressions, that is, they include the contents specified in the present invention but do not exclude other contents.

[0023] As used herein, the terms "optionally," "optionally," or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0024] The following is a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Example 1 This embodiment provides a molecular dynamics-based method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function, comprising the following steps: Step 1-1: Obtain the graphite single crystal structure (space group P63 / mmc, lattice parameters a=2.46 Å, c=6.70 Å) from the ICSD database and use the Visualizer module to construct water molecules and disodium methylene dinaphthalene sulfonate + sodium lignin sulfonate surfactant molecules respectively; Step1-2: Select the Energy task in the Forcite module to perform energy minimization on the initial model, and use the COMPASS II force field. The charges are automatically assigned by the force field. Set the accuracy to Medium. The Ewald summation method is used for electrostatic force calculation, and the Atom-based summation method is used for van der Waals force calculation. The Smart algorithm is selected for geometric optimization; Step2: Establish a graphite / graphene oxide substrate model, a surfactant molecular cluster model, and a water molecule solvent model; Step2-1: Cut along the (0 0 1) crystal plane of the graphite unit cell to expand the single-layer graphite model (size ≥ 2 times the Rcut value, Rcut = 12 Å); Based on the Monte Carlo random algorithm, set a random seed to ensure the repeatability of the results. Traverse each carbon atom on the graphene surface and select grafting sites according to the condition rand()<COVERAGE; For each selected site, check whether its distance from the already selected sites is ≥ 3 Å for spatial exclusion check. If the distance is insufficient, skip this site to avoid duplicate sites; Randomly distribute hydroxyl groups (-OH), carboxyl groups (-COOH), and epoxy groups (-O-) with a ratio of 5:3:2 on the lower surface of the single-layer graphite model, and the total density of functional groups is 12 at%, to construct a single-layer graphene oxide model; Step2-2: Use the Build layer tool to combine the single-layer graphite model and the single-layer graphene oxide model. The C-O bond length is 1.45 Å, and the bond length deviation ≤ 0.02 Å; The C-C-O bond angle is 110°, and the angle deviation ≤ 2°; By calculating that the included angle θ between the surface normal vector and the functional group bond direction is 90°, rotate the group to make it perpendicular to the graphene plane; Use the molecular mechanics force field for iterative geometric optimization to eliminate atomic overlap; And apply mirror symmetry constraints to the boundary atoms to ensure that the layer spacing fluctuation after grafting ≤ 0.5 Å, to obtain the graphene oxide / graphite substrate model, with 2 layers of graphene oxide and 2 layers of graphite, and the vacuum layer thickness is 40 Å; Step2-3: Combine 4 sodium methylene dinaphthalene disulfonate + 4 sodium lignosulfonate surfactant molecules to obtain a surfactant molecular cluster model, and the size of the surfactant molecular cluster model is the same as that of the graphite substrate model; Step2-4: Step2-3: Select the Construction task in the Amorphous Cell module to construct 1500 water molecule solvent models with a density of \(0.8g / cm^3\) 3 ), use the COMPASS II force field, and calculate electrostatic force (Ewald) and van der Waals force (Atom-based); Step 2-5: Select the Energy task in the Forcite module to perform energy minimization on the initial model and use the COMPASSⅡ force field. The charge is automatically assigned by the force field, the precision is set to Medium, the electrostatic force is calculated using the Ewald summation method, the van der Waals force is calculated using the Atom-based summation method, and the Smart algorithm is used for optimization. Step 2-6: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the initial model. Set the calculation accuracy to Medium, use the Ewald summation method for electrostatic force calculation, and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field. Step 3: Integrate to form a graphene oxide / graphite-surfactant-water three-phase interface model and perform energy minimization calculation; Step 3-1: Use the Build layer tool to combine the graphene oxide / graphite substrate model, surfactant molecule cluster model, and water molecule solvent model into a graphene oxide / graphite-surfactant-water three-phase interface model. The vacuum layer thickness of the interface model is set to 60 Å. Step 3-2: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the interface model. Set the calculation accuracy to Medium, use the Ewald summation method for electrostatic force calculation, and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field. Step 4: Based on the COMPASSⅡ reaction force field, set appropriate simulation parameters and steps, and use the isothermal isobaric ensemble (NPT) for molecular dynamics simulation. The molecular dynamics simulation is performed using the isothermal isobaric ensemble (NPT) with a simulation time of 150 ps, ​​a temperature of 298 K, the Nose temperature control method, and a step size of 1 fs. Step 5: Obtain the kinetic information of the interface model, including adsorption configuration, interface formation energy, radial distribution function, interaction energy, interfacial tension, concentration distribution of each component along the Z axis, and other data, as shown in Table 1.

[0026] Example 2 The interface modeling and molecular dynamics-driven functional synergistic regulation method of graphene oxide / graphite composite model comprises the following steps: Step1-1: Obtain the graphite single crystal structure (space group P63 / mmc, lattice parameters a = 2.46 Å, c = 6.70 Å) from the ICSD database, and use the Visualizer module to construct water molecules and sodium dodecylbenzenesulfonate + sodium lignosulfonate surfactant molecules respectively; Step1-2: Select the Energy task in the Forcite module to perform energy minimization on the initial model, and use the COMPASSⅡ force field. Among them, the charges are automatically assigned by the force field. Set the accuracy to Medium. The Ewald summation method is used for electrostatic force calculation, and the Atom-based summation method is used for van der Waals force calculation. The Smart algorithm is selected for geometric optimization; Step2: Establish a graphite / graphene oxide substrate model, a surfactant molecular cluster model, and a water molecule solvent model; Step2-1: Cut along the (0 0 1) crystal plane of the graphite unit cell to expand the single-layer graphite model (size ≥ 2 times the Rcut value, Rcut = 12 Å); Based on the Monte Carlo random algorithm, set the random seed to ensure the repeatability of the results. Traverse each carbon atom on the graphene surface and select the grafting site according to the condition rand()<COVERAGE; For each selected site, check whether its distance from the already selected sites is ≥ 3 Å for spatial repulsion check. If the distance is insufficient, skip this site to avoid site duplication; Randomly distribute carboxyl groups (-COOH), epoxy groups (-O-), and sulfonic acid groups (-SO3H) with a ratio of 4:4:2 on the lower surface of the single-layer graphite model, and the total functional group density is 8 at%, to construct a single-layer graphene oxide model; Step2-2: Use the Build layer tool to combine the single-layer graphite model and the single-layer graphene oxide model. The C-O bond length is 1.45 Å, and the bond length deviation ≤ 0.02 Å; The C-C-O bond angle is 110°, and the angle deviation ≤ 2°; By calculating that the included angle θ between the surface normal vector and the functional group bond direction is 90°, rotate the group to make it perpendicular to the graphene plane; Use the molecular mechanics force field for iterative geometric optimization to eliminate atomic overlap; And apply mirror symmetry constraints to the boundary atoms to ensure that the layer spacing fluctuation after grafting ≤ 0.5 Å, to obtain the graphene oxide / graphite substrate model, with 2 layers of graphite, 2 layers of graphene oxide, 2 layers of graphite, and a vacuum layer thickness of 30 Å; Step2-3: Combine 4 sodium dodecylbenzenesulfonate + 4 sodium lignosulfonate surfactant molecules to obtain a surfactant molecular cluster model, and the size of the surfactant molecular cluster model is the same as that of the graphite substrate model; Step 2-4: Step 2-3: Select the Construction task in the Amorphous Cell module to build a solvent model of 1000 water molecules with a density of 0.1 g / cm 3 ), using COMPASSⅡ force field, electrostatic force (Ewald) and van der Waals force (Atom-based) calculation; Step 2-5: Select the Energy task in the Forcite module to perform energy minimization on the initial model and use the COMPASSⅡ force field. The charge is automatically assigned by the force field, the precision is set to Medium, the electrostatic force is calculated using the Ewald summation method, the van der Waals force is calculated using the Atom-based summation method, and the Smart algorithm is used for optimization. Step 2-6: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the initial model. Set the calculation accuracy to Medium, use the Ewald summation method for electrostatic force calculation, and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field. Step 3: Integrate to form a graphene oxide / graphite-surfactant-water three-phase interface model and perform energy minimization calculation; Step 3-1: Use the Build layer tool to combine the graphene oxide / graphite substrate model, surfactant molecule cluster model, and water molecule solvent model into a graphene oxide / graphite-surfactant-water three-phase interface model. The vacuum layer thickness of the interface model is set to 30 Å. Step 3-2: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the interface model. Set the calculation accuracy to Medium, use the Ewald summation method for electrostatic force calculation, and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field. Step 4: Based on the COMPASSⅡ reaction force field, set appropriate simulation parameters and steps, and use the isothermal isobaric ensemble (NPT) for molecular dynamics simulation. The molecular dynamics simulation is performed using the isothermal isobaric ensemble (NPT) with a simulation time of 200 ps, ​​a temperature of 318 K, the Nose temperature control method, and a step size of 1 fs. Step 5: Obtain the kinetic information of the interface model, including adsorption configuration, interface formation energy, radial distribution function, interaction energy, interfacial tension, concentration distribution of each component along the Z axis, and other data, as shown in Table 1.

[0027] Example 3 An interfacial modeling method for graphene oxide / graphite composite model and a molecular dynamics-driven functional synergistic regulation method, which includes the following steps: Step1-1: Obtain the graphite single crystal structure (space group P63 / mmc, lattice parameters a = 2.46 Å, c = 6.70 Å) from the ICSD database. Use the Visualizer module to construct water molecules and the surfactant molecules of sodium dodecyl sulfate + sodium lauroyl sarcosinate respectively; Step1-2: Select the Energy task in the Forcite module to perform energy minimization on the initial model, and use the COMPASSⅡ force field. Among them, the charges are automatically set and assigned by the force field. Set the accuracy to Medium. The Ewald summation method is used for electrostatic force calculation, and the Atom-based summation method is used for van der Waals force calculation. The Smart algorithm is selected for geometric optimization; Step2: Establish a graphite / graphene oxide substrate model, a surfactant molecular cluster model, and a water molecule solvent model; Based on the Monte Carlo random algorithm, set a random seed to ensure the repeatability of the results. Traverse each carbon atom on the graphene surface and select grafting sites according to the condition rand()<COVERAGE; For each selected site, check whether its distance from the already selected sites is ≥3 Å for spatial repulsion check. If the distance is insufficient, skip this site to avoid site duplication; Randomly distribute hydroxyl groups (-OH), carboxyl groups (-COOH), and sulfonic acid groups (-SO3H) with a ratio of 6:2:2 on the upper and lower surfaces of the single-layer graphite model, with a functional group density of 10 at%, to construct a single-layer graphene oxide model; Step2-2: Use the Build layer tool to combine the single-layer graphite model and the single-layer graphene oxide model. The C-O bond length is 1.45 Å, and the bond length deviation ≤0.02 Å; The C-C-O bond angle is 110°, and the angle deviation ≤2°; By calculating the angle θ = 90° between the surface normal vector and the functional group bond direction, rotate the group to make it perpendicular to the graphene plane; Use the molecular mechanics force field for iterative geometric optimization to eliminate atomic overlap; And apply mirror symmetry constraints to the boundary atoms to ensure that the layer spacing fluctuation after grafting ≤0.5 Å, to obtain the graphene oxide / graphite substrate model, with 3 layers of graphite, 1 layer of graphene oxide, 2 layers of graphite, and a vacuum layer thickness of 20 Å; Step2-3: Combine 4 sodium dodecyl sulfate + 4 sodium lauroyl sarcosinate surfactant molecules to obtain a surfactant molecular cluster model, and the size of the surfactant molecular cluster model is the same as that of the graphite substrate model; Step 2-4: Select the Construction task in the Amorphous Cell module to build a solvent model of 500 water molecules with a density of 0.3 g / cm 3 ), using COMPASSⅡ force field, electrostatic force (Ewald) and van der Waals force (Atom-based) calculation; Step 2-5: Select the Energy task in the Forcite module to perform energy minimization on the initial model and use the COMPASSⅡ force field. The charge is automatically assigned by the force field, the precision is set to Medium, the electrostatic force is calculated using the Ewald summation method, the van der Waals force is calculated using the Atom-based summation method, and the Smart algorithm is used for optimization. Step 2-6: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the initial model. Set the calculation accuracy to Medium, use the Ewald summation method for electrostatic force calculation, and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field. Step 3: Integrate to form a graphene oxide / graphite-surfactant-water three-phase interface model and perform energy minimization calculation; Step 3-1: Use the Build layer tool to combine the graphene oxide / graphite substrate model, surfactant molecule cluster model, and water molecule solvent model into a graphene oxide / graphite-surfactant-water three-phase interface model. The vacuum layer thickness of the interface model is set to 50 Å. Step 3-2: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the interface model. Set the calculation accuracy to Medium, use the Ewald summation method for electrostatic force calculation, and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field. Step 4: Based on the COMPASSⅡ reaction force field, set appropriate simulation parameters and steps, and use the isothermal isobaric ensemble (NPT) for molecular dynamics simulation. The molecular dynamics simulation is performed using the isothermal isobaric ensemble (NPT) with a simulation time of 250 ps, ​​a temperature of 298 K, the Nose temperature control method, and a step size of 1 fs. Step 5: Obtain the kinetic information of the interface model, including adsorption configuration, interface formation energy, radial distribution function, interaction energy, interfacial tension, concentration distribution of each component along the Z axis, and other data, as shown in Table 1.

[0028] Example 4 This embodiment provides a molecular dynamics-based method for constructing and regulating the functions of a multifunctional graphene oxide / graphite composite model. The difference from Example 1 is that hydroxyl groups (-OH) and carboxyl groups (-COOH) are randomly distributed in a ratio of 6:4 on the lower surface of the single-layer graphite model, and the rest are the same.

[0029] Example 5 This embodiment provides a molecular dynamics-based method for constructing and regulating the functions of a multifunctional graphene oxide / graphite composite model. The difference from Example 1 is that hydroxyl groups (-OH) and epoxy groups (-O-) are randomly distributed in a ratio of 5:5 on the lower surface of the single-layer graphite model, and the rest are the same.

[0030] Example 6 This embodiment provides a molecular dynamics-based method for constructing and regulating the functions of a multifunctional graphene oxide / graphite composite model. The difference from Example 1 is that hydroxyl groups (-OH) and sulfonic acid groups (-SO3H) are randomly distributed in a ratio of 7:3 on the lower surface of the single-layer graphite model, and the rest are the same.

[0031] Example 7 This embodiment provides a molecular dynamics-based method for constructing and regulating the functions of a multifunctional graphene oxide / graphite composite model. The difference from Example 1 is that carboxyl groups (-COOH) and epoxy groups (-O-) are randomly distributed on the lower surface of the single-layer graphite model in a ratio of 3:7, and the rest are the same.

[0032] Example 8 This embodiment provides a molecular dynamics-based method for constructing and regulating the functions of a multifunctional graphene oxide / graphite composite model. The difference from Example 1 is that carboxyl groups (-COOH) and sulfonic acid groups (-SO3H) are randomly distributed on the lower surface of the single-layer graphite model in a ratio of 8:2, and the rest are the same.

[0033] Example 9 This embodiment provides a molecular dynamics-based method for constructing and regulating the functions of a multifunctional graphene oxide / graphite composite model. The difference from Example 1 is that epoxy groups (-O-) and sulfonic acid groups (-SO3H) are randomly distributed on the lower surface of the single-layer graphite model in a ratio of 9:1, and the rest are the same.

[0034] Comparative Example 1 This comparative example provides a method for interface modeling of a graphite model and molecular dynamics-driven functional synergistic regulation, which includes the following steps: Step 1-1: Obtain the graphite single crystal structure (space group P63 / mmc, lattice parameters a=2.46 Å, c=6.70 Å) from the ICSD database and use the Visualizer module to construct water molecules and disodium methylene dinaphthalene sulfonate + sodium lignin sulfonate surfactant molecules respectively; Step 1-2: Select the Energy task in the Forcite module to perform energy minimization on the initial model and use the COMPASSⅡ force field. The charge is automatically assigned by the force field, the precision is set to Medium, the electrostatic force is calculated using the Ewald summation method, the van der Waals force is calculated using the Atom-based summation method, and the Smart algorithm is used for geometry optimization. Step 2: Establish graphite / graphene oxide substrate model, surfactant molecular cluster model and water molecule solvent model; Step 2-1: Cut along the (0 0 1) crystal plane of the graphite unit cell, expand the single-layer graphite model (size ≥ 2 times the Rcut value, Rcut = 12 Å), and construct a pure graphite substrate model; Step 2-2: Use the Build layer tool to combine the single-layer graphite model to obtain a graphene oxide / graphite substrate model with 4 graphite layers and a vacuum layer thickness of 40 Å; Step 2-3: Combine 4 disodium methylene dinaphthalene sulfonate + 4 sodium lignin sulfonate surfactant molecules to obtain a surfactant molecular cluster model, and the size of the surfactant molecular cluster model is consistent with the size of the graphite substrate model; Step 2-4: Select the Construction task in the Amorphous Cell module to build a solvent model of 1500 water molecules with a density of 0.8 g / cm 3 ), using COMPASSⅡ force field, electrostatic force (Ewald) and van der Waals force (Atom-based) calculation; Step 2-5: Select the Energy task in the Forcite module to perform energy minimization on the initial model and use the COMPASSⅡ force field. The charge is automatically assigned by the force field, the precision is set to Medium, the electrostatic force is calculated using the Ewald summation method, the van der Waals force is calculated using the Atom-based summation method, and the Smart algorithm is used for optimization. Step 2-6: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the initial model. Set the calculation accuracy to Medium, use the Ewald summation method for electrostatic force calculation, and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field. Step 3: Integrate to form a graphite-surfactant-water three-phase interface model and perform energy minimization calculation; Step 3-1: Use the Build layer tool to combine the graphite substrate model, surfactant molecule cluster model, and water molecule solvent model into a graphite-surfactant-water three-phase interface model. The vacuum layer thickness of the interface model is set to 60Å. Step 3-2: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the interface model. Set the calculation accuracy to Medium, use the Ewald summation method for electrostatic force calculation, and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field. Step 4: Based on the COMPASSⅡ reaction force field, set appropriate simulation parameters and steps, and use the isothermal isobaric ensemble (NPT) for molecular dynamics simulation. The molecular dynamics simulation is performed using the isothermal isobaric ensemble (NPT) with a simulation time of 150 ps, ​​a temperature of 298 K, the Nose temperature control method, and a step size of 1 fs. Step 5: Obtain the kinetic information of the interface model, including adsorption configuration, interface formation energy, radial distribution function, interaction energy, interfacial tension, concentration distribution of each component along the Z axis, and other data, as shown in Table 1.

[0035] Table 1 Comparison of kinetic information of interface models constructed by the embodiments of the present invention and the comparative examples

[0036] Depend on Figure 3 The simulations show that in the different three-phase interface systems composed of graphite and graphite / graphene oxide in Example 1, the number of hydrogen bonds formed between water molecules and surfactants in graphite oxide is greater than that in graphite itself, indicating that graphite oxide has greater hydrophilicity, which is related to its surface oxygen functional groups. Furthermore, the distribution of hydrogen bond angles in the graphite / graphene oxide system is mostly concentrated between 120° and 150°, indicating that hydrogen bonds are more flexible, more conducive to dispersion, and help promote dispersion. This system has a longer dynamic range of bond lengths and angles, which is more conducive to dispersion in water.

[0037] Depend on Figure 4It can be seen that: simulation shows that the three-phase interface formation energy of the graphite / graphene oxide-surfactant-water system of Example 1 is -1110.723 kacl / mol, and the three-phase interface formation energy of the graphite-surfactant-water system of Comparative Example 1 is -1020.415 kacl / mol. The higher the absolute value of the interface formation energy, the lower the system energy and the stronger the thermodynamic stability, indicating that the oxygen-containing functional groups of graphene oxide enhance the interfacial interaction through chemical adsorption, making the interfacial bonding more stable.

[0038] Depend on Figure 5 Simulations show that the surface tension of the three-phase interface of the graphite / graphene oxide-surfactant-water system in Example 1 is 1292.576 mN / m, while that of the graphite-surfactant-water system in Comparative Example 1 is 1818.128 mN / m. Lower interfacial tension indicates better interfacial compatibility, leading to more efficient adsorption and dispersion of surfactant molecules between graphite sheets, which facilitates the formation of a stable composite structure. The introduction of oxygen-containing functional groups from graphene oxide enhances interfacial hydrophilicity, improves the wettability of the composite, and effectively reduces interfacial energy.

[0039] The present invention also forms a virtual screening platform for quantifiable interfacial synergistic effects by optimizing the functional group distribution and ratio on the graphene oxide surface. As shown in Table 1, in Example 1, when the ratio of (-OH): (-COOH): (-O-) is 5:3:2, the bond angle distribution between the O atoms of the surfactant and the H atoms in water is 120°~150°, the average interfacial binding energy is -1110.723 kacl / mol, and the average interfacial tension of the three-phase interface is 1292.576 mN / m, indicating that this ratio has the best comprehensive performance, can improve dispersion stability, interfacial bonding strength and lubricating film continuity, is suitable for most conventional drawing working conditions, and can effectively reduce wire breakage.

[0040] In Example 2, when the ratio of (-COOH): (-O-): (-SO3H) is 4:4:2, the bond angle distribution between the O atoms of the surfactant and the H atoms in water is 120°~140°, the average interfacial binding energy is -1211.737 kacl / mol, and the average interfacial tension of the three-phase interface is 923.2436 mN / m. This shows that graphene oxide can balance interfacial chemical adsorption, interlayer slip efficiency and stability, has good adaptability, and can overcome the problem of lubrication failure under extreme conditions such as high temperature / high speed.

[0041] In Example 3, when the ratio of (-OH): (-COOH): (-SO3H) is 6:2:2, the bond angle distribution between the O atoms of the surfactant and the H atoms in water is 115°~135°, the average interfacial binding energy is -1288.979 kacl / mol, and the average interfacial tension of the three-phase interface is 1310.569 mN / m, indicating that the hydroxyl group dominates the dispersibility, the carboxyl group enhances the binding force, and the sulfonic acid group improves the adaptability to extreme environments. It is suitable for extreme environmental scenarios such as high load and high shear environments or extreme temperature change environments that have extremely high requirements on material performance.

[0042] In Example 4, when the ratio of (-OH): (-COOH) is 6:4, the bond angle distribution between the O atoms of the surfactant and the H atoms in water is 130°~150°, the average interfacial binding energy is -1080.316 kacl / mol, and the average interfacial tension of the three-phase interface is 1429.921 mN / m, indicating that a high hydroxyl ratio increases hydrophilicity, and the carboxyl group strengthens the interfacial bonding force between the lubricating film and the metal surface through chemical adsorption. However, there is a problem of insufficient interfacial bonding force, and it can be applied to fields such as light load and medium speed mechanical lubrication.

[0043] In Example 5, when the ratio of (-OH): (-O-) is 5:5, the bond angle distribution between the O atoms of the surfactant and the H atoms in water is 135°~155°, the average interfacial binding energy is -1069.944 kacl / mol, and the average interfacial tension of the three-phase interface is 1522.088 mN / m, indicating that the hydroxyl group maintains basic dispersibility and prevents graphite sedimentation, while the epoxy group expands the spacing between graphite layers and improves the flexibility and continuity of the lubricating film. This can overcome the problems of local wear and increased friction resistance caused by the discontinuity of the lubricating film in medium-load and medium-speed mechanical lubrication scenarios that require good flexibility and continuity, such as the lubrication of micro-bearings in precision instruments and electronic equipment.

[0044] In Example 6, when the ratio of (-OH): (-SO3H) is 7:3, the bond angle distribution between the O atoms of the surfactant and the H atoms in water is 125°~145°, the average interfacial binding energy is -1073.938 kacl / mol, and the average interfacial tension of the three-phase interface is 1623.99 mN / m. This shows that the hydroxyl groups ensure dispersion stability, the sulfonic acid groups enhance hydrophilicity, and avoid solution agglomeration. It is suitable for water-based lubricants and environments requiring high hydrophilicity, such as food processing equipment and underwater machinery lubrication, and can overcome the problems of solution agglomeration and lubrication failure caused by insufficient hydrophilicity.

[0045] In Example 7, when the ratio of (-COOH): (-O-) is 3:7, the bond angle distribution between the O atoms of the surfactant and the H atoms in water is 120°~140°, the average interfacial binding energy is -1056.869 kacl / mol, and the average interfacial tension of the three-phase interface is 1715.902 mN / m, indicating that the carboxyl group provides edge active sites to promote bonding with the metal surface, and the epoxy group reduces friction resistance through interlayer slip, thereby improving lubrication efficiency. It can be used in precision machinery and micro-scale lubrication scenarios, such as micro-bearings and nano-machinery lubrication, to overcome the problem of low lubrication efficiency caused by high friction resistance.

[0046] In Example 8, when the ratio of (-COOH): (-SO3H) is 8:2, the bond angle distribution between the O atoms of the surfactant and the H atoms in water is 115°~135°, the average interfacial binding energy is -1090.008 kacl / mol, and the average interfacial tension of the three-phase interface is 1332.82 mN / m, indicating that the carboxyl group dominates the interfacial binding, reduces friction and wear, and the sulfonic acid group assists in improving the high-temperature stability and inhibiting the decomposition of the lubricating film. It is suitable for high-temperature and high-humidity environments and strong oxidizing environments, such as lubrication of machinery and chemical equipment in tropical regions, and can overcome the problems of lubricating film decomposition and lubrication failure caused by high temperature.

[0047] In Example 9, when the ratio of (-O-): (-SO3H) is 9:1, the bond angle distribution between the O atoms of the surfactant and the H atoms in water is 125°~145°, the average interfacial binding energy is -1085.662 kacl / mol, and the average interfacial tension of the three-phase interface is 1491.388 mN / m. The epoxy group maintains the stability of the interlayer structure and avoids the strength loss caused by excessive oxidation. The sulfonic acid group introduces a trace amount of active reaction sites to adapt to special process requirements. It is suitable for special process scenarios with high requirements for structural stability, such as electronic device manufacturing and high vacuum environment lubrication, and can overcome the problems of strength loss and lubricating film failure caused by excessive oxidation.

[0048] In summary, this invention achieves precise control of graphene oxide's performance by optimizing the distribution and ratio of functional groups on its surface, providing strong technical support for its widespread application in various fields. In practical applications, the appropriate functional group ratio can be selected based on specific operating requirements and performance goals, fully leveraging the performance advantages of graphene oxide and solving technical challenges in related fields. This method has important theoretical significance and practical application value.

[0049] The embodiments described above are some embodiments of the present invention, rather than all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

Claims

1. A molecular dynamics-based multifunctional graphene oxide / graphite composite model construction and function regulation method, characterized in that: The steps include: Step 1: Import the graphite unit cell into Materials Studio software, construct water molecules and surfactant molecules, and perform geometry optimization; Step 2: Establish graphite / graphene oxide substrate model, surfactant molecular cluster model and water molecule solvent model; Step 3: Integrate to form a graphene oxide / graphite-surfactant-water three-phase interface model and perform energy minimization calculation; Step 4: Based on the COMPASSⅡ reaction force field, set appropriate simulation parameters and steps, and use the isothermal and isobaric ensemble to perform molecular dynamics simulation; Step 5: Obtain dynamic information of the interface model; The graphene oxide surface is modified with oxygen-containing functional groups; the distribution density of the functional groups is 8 to 12 at% based on the total number of carbon atoms; the total number of carbon atoms is calculated by expanding the model size by supercell construction function and satisfying the periodic boundary conditions of medium precision simulation.

2. The method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function according to claim 1, wherein: The oxygen-containing functional group includes a combination of two or more of a hydroxyl group, a carboxyl group, an epoxy group, and a sulfonic acid group.

3. The method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function according to claim 1, wherein: The Step 2 specifically includes: Step 2-1: Cut along the (0 0 1) crystal plane of the graphite unit cell to expand the single-layer graphite model; Step 2-2: Construct a single-layer graphene oxide substrate model based on the Monte Carlo random algorithm. Using the rand() < $COVERAGE condition, where coverage $COVERAGE = 8-12 at%, the surface carbon atoms of the single-layer graphene are selected as grafting sites, and oxygen-containing functional groups are grafted onto one or both sides. Step 2-3: Use the Build layer tool to combine the single-layer graphite model with the single-layer graphene oxide model to obtain a graphene oxide / graphite substrate model with ≥1 graphene oxide layer and a vacuum layer thickness of 20-50 Å. Step 2-4: Randomly combine ≥4 surfactant molecules, including two or more of sodium dodecylbenzenesulfonate, disodium methylene dinaphthalenesulfonate, sodium lauryl sulfate, sodium alkylsulfonate, sodium stearate, sodium lauroyl sarcosinate, and sodium ligninsulfonate, to obtain a surfactant molecular cluster model, and the size of the surfactant molecular cluster model is consistent with the size of the graphite substrate model; Step 2-5: Select the Construction task in the Amorphous Cell module to build a water molecule solvent model, using the COMPASSⅡ force field, electrostatic force and van der Waals force calculations; Step 2-6: Select the Energy task in the Forcite module to perform energy minimization on the initial model and use the COMPASSⅡ force field. The charge is automatically assigned by the force field, the precision is set to Medium, the electrostatic force is calculated using the Ewald summation method, the van der Waals force is calculated using the Atom-based summation method, and the Smart algorithm is used for optimization. Step 2-7: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the initial model. Set the calculation accuracy to Medium. Use the Ewald summation method for electrostatic force calculation and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field.

4. The method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function according to claim 3, wherein: The Step 2.2 specifically includes: grafting two oxygen-containing functional groups onto carbon atoms on the surface of monolayer graphene; setting a random seed based on the Monte Carlo random algorithm to ensure the repeatability of the results, traversing each carbon atom on the graphene surface and selecting a grafting site according to the condition rand() < COVERAGE; for each selected site, checking whether its distance to the selected site is ≥3 Å is used for spatial repulsion check. If the distance is insufficient, the site is skipped to avoid site duplication. The functional group ratio adopts any of the following methods: ① the ratio of hydroxyl: carboxyl is 6:4; ② the ratio of hydroxyl: epoxy is 5:5; ③ the ratio of hydroxyl: sulfonic acid is 7:3; ④ the ratio of carboxyl: epoxy is 3:7; ⑤ the ratio of carboxyl: sulfonic acid is 8:2; ⑥ the ratio of epoxy: sulfonic acid is 9:1; three oxygen-containing functional groups are grafted onto the carbon atoms on the surface of monolayer graphite; any of the following methods is used: ① the ratio of hydroxyl: carboxyl: epoxy is 5:3:2; ② the ratio of carboxyl: epoxy: sulfonic acid is 4:4:2; ③ the ratio of hydroxyl: carboxyl: sulfonic acid is 6:2:

2.

5. The method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function according to claim 3, wherein: The Step 2.2 specifically includes: grafting three oxygen-containing functional groups onto carbon atoms on the surface of the monolayer graphite in the following manner: ① The ratio of hydroxyl: carboxyl: epoxy is 5:3:

2.

6. The method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function according to claim 1, wherein: In the Step 2.2 process, the C-O bond length is 1.42~1.45 Å, and the bond length deviation is ≤0.02 Å; the C-O bond angle is 108°~112°, and the angle deviation is ≤2°; by calculating the angle θ=85°~95° between the surface normal vector and the bond direction of the functional group, the group is rotated so that it is perpendicular to the graphene plane; the molecular mechanics force field is used for iterative geometry optimization to eliminate atomic overlap; and mirror symmetry constraints are applied to the boundary atoms to ensure that the interlayer spacing fluctuation after grafting is ≤0.5 Å.

7. The method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function according to claim 1, wherein: The Step 1 specifically includes: Step 1-1: Obtain the graphite single crystal structure from the ICSD database and use the Visualizer module to construct water molecules and surfactant molecules respectively; Step 1-2: Select the Energy task in the Forcite module to perform energy minimization on the initial model and use the COMPASSⅡ force field. The charge is automatically set and distributed by the force field, the accuracy is set to Medium, the electrostatic force is calculated using the Ewald summation method, the van der Waals force is calculated using the Atom-based summation method, and the Smart algorithm is selected for optimization.

8. The method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function according to claim 1, wherein: The Step 3 specifically includes: Step 3-1: Use the Build layer tool to combine the graphene oxide / graphite substrate model, surfactant molecule cluster model, and water molecule solvent model into a graphene oxide / graphite-surfactant-water three-phase interface model. Set the vacuum layer thickness of the interface model to 30Å~60Å. Step 3-2: Select the Geometry Optimization task in the Forcite module to perform geometry optimization on the interface model. Set the calculation accuracy to Medium. Use the Ewald summation method for electrostatic force calculation and the Atom-based summation method for van der Waals force calculation. Use the COMPASSⅡ force field, and the charge is automatically set and distributed by the force field.

9. The method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function according to claim 1, wherein: The Step 4 specifically includes: performing molecular dynamics simulation, with a simulation time ≥100 ps, ​​a temperature ≥298 K, a Nose temperature control method, and a step size of 1 fs.

10. The method for constructing a multifunctional graphene oxide / graphite composite model and regulating its function according to claim 1, wherein: The Step 5 specifically includes: obtaining adsorption configuration, interface formation energy, radial distribution function, interaction energy, interfacial tension, and concentration distribution data of each component along the Z axis.

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