Method for analyzing atomic oxygen erosion resistance of Ti3C2Tx / polyimide film through molecular dynamics

Abstract

The invention discloses a method for analyzing atomic oxygen erosion resistance of a Ti3C2Tx / polyimide film through molecular dynamics, which comprises the following steps: firstly, establishing a polyimide film model through a polyimide monomer model by using molecular dynamics modeling software, establishing a Ti3C2Tx film model through a Ti3C2Tx monomer model, and establishing a Ti3C2Tx film model through a Ti3C2Tx film model; then a layered structure Ti3C2Tx / polyimide film model and a layered-coating structure Ti3C2Tx / polyimide film model are constructed, and then the models are subjected to structure optimization; the method comprises the following steps of: firstly extending in a Z direction by using molecular dynamics simulation software, then carrying out relaxation, and finally carrying out simulation calculation on an atomic oxygen erosion model through molecular dynamics simulation based on a ReaxFF force field to obtain a dynamic evolution condition of the model in an atomic oxygen erosion process. And the component composition of the model at the end of erosion and the mass change of the model in the erosion process are counted to obtain the atomic oxygen erosion mechanism of the Ti3C2Tx / polyimide film model with the layered structure and the Ti3C2Tx / polyimide film model with the layered-coating structure.

Description

Technical Field

[0001] The present invention belongs to the field of nanocomposite materials, and is specifically a molecular dynamics analysis Ti3C2T x / Method for resisting polyimide film to attack by proton oxygen Background Art

[0002] In low-Earth orbit, spacecraft face intense attack from atomic oxygen, which can destroy the chemical structure of materials, leading to quality degradation and mechanical property degradation, posing a serious threat to spacecraft safety. Polyimide, a material with excellent mechanical properties and thermal stability, is widely used in spacecraft surface thermal control and battery substrates. However, polyimide is susceptible to oxidative degradation in atomic oxygen environments, which in turn affects its long-term stability.

[0003] Ti3C2T x As a new type of two-dimensional material, it has shown strong antioxidant potential due to its excellent chemical stability and adjustable surface functional groups. x It is an ideal material resistant to atomic oxygen corrosion. However, its research focuses mainly on electromagnetic interference shielding and sensing, and there is a lack of reports on its application in atomic oxygen corrosion.

[0004] The study of the anti-proton oxygen corrosion performance of polyimide composite films using molecular dynamics simulation has become one of the research hotspots. The literature "ACS Applied Materials & Interfaces, 2017, 9 (14): 12802-12811" explored the anti-proton oxygen corrosion mechanism of carbon nanotube (CNT) / polyimide and graphene (Gr) / polyimide composite films through molecular dynamics simulation. However, there is currently no research on the anti-proton oxygen corrosion mechanism of Ti3C2T x / The research on the protection mechanism of polyimide membranes against atomic oxygen corrosion in low-Earth orbit environment limits the optimal design of new anti-atomic oxygen composite materials. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a molecular dynamics analysis of Ti3C2T x / Method for resisting polyimide film to attack by proton oxygen

[0006] The technical solution of the present invention to solve the technical problem is to provide a molecular dynamics analysis of Ti3C2T x / A method for resisting proton oxygen corrosion on a polyimide film, characterized in that the method comprises the following steps:

[0007] Step 1: Use molecular dynamics modeling software to build a polyimide film model through the polyimide monomer model and the Ti3C2Tx Monomer model establishment Ti3C2T x membrane model;

[0008] Step 2: Use molecular dynamics modeling software to simulate the polyimide film model and Ti3C2T x Membrane model for structural optimization;

[0009] Step 3: Using molecular dynamics modeling software, Ti3C2T x Monomer model establishment Ti3C2T x model, and then the polyimide monomer model and Ti3C2T x The model is assembled to construct a layered structure Ti3C2T x / polyimide film model; then through the layered structure Ti3C2T x / polyimide film model and Ti3C2T obtained in step 2 x Membrane model, construction of layered-coating structure Ti3C2T x / polyimide film model;

[0010] Step 4: Using molecular dynamics modeling software, the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide membrane model for structural optimization;

[0011] Step 5: Using molecular dynamics simulation software, the polyimide film model obtained in step 2 and the Ti3C2T x Membrane model, layered structure Ti3C2T obtained in step 4 x / polyimide film model and layered-coating structure Ti3C2T obtained in step 4 x / The Z direction in the polyimide film model is extended to reserve space for subsequent atomic oxygen injection;

[0012] Step 6: Using molecular dynamics simulation software, the polyimide film model obtained in step 5, the Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide film model for relaxation;

[0013] Step 7: Use the ReaxFF force field without Ti element to perform molecular dynamics simulation of atomic oxygen corrosion on the polyimide film model obtained in step 6, and use the ReaxFF force field with Ti element to simulate the Ti3C2T xThe molecular dynamics simulation of atomic oxygen corrosion was performed on the film model to obtain the simulation results of the two models respectively; then, by comparing the simulation results of the two models, the polyimide film model and the Ti3C2T x Atomic oxygen erosion mechanism of membrane model;

[0014] Step 8: Use the ReaxFF force field without Ti element to analyze the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion of the polyimide / polyimide film model was performed. In the molecular dynamics simulation of the two composite film models, only Ti3C2T was considered. x The physical barrier of the material to atomic oxygen corrosion and the effect of extending the atomic oxygen corrosion trajectory are used to obtain the simulation results of the two composite film models respectively; then, the simulation results of the two composite film models are compared with the simulation results of the polyimide film model obtained in step 7, and the Ti3C2T x The atomic oxygen corrosion mechanism of the film model leads to the layered structure of Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / Atomic oxygen corrosion mechanism of polyimide film model.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention constructs two Ti3C2T x / polyimide film model, and the atomic oxygen erosion model was simulated and calculated using the molecular dynamics simulation method based on the ReaxFF force field, and the dynamic evolution of the model during the atomic oxygen erosion process was obtained. The component composition of the model at the end of the erosion and the mass change of the model during the erosion process were statistically analyzed, thereby revealing the Ti3C2T x The mechanism of anti-oxidant oxygen corrosion of polyimide membrane provides a theoretical basis for optimizing the preparation process of composite membrane and improving its corrosion resistance.

[0017] (2) The present invention significantly reduces the time cost of experimental research by using molecular dynamics simulation instead of traditional experiments.

[0018] (3) The present invention develops two composite membrane models with different structures, namely, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide film model, which enables the study of the effects of different structures on the resistance to atomic oxygen erosion and reveals the mechanism of atomic oxygen erosion.

[0019] (4) Ti3C2T constructed by the present invention xMembrane model, layered structure Ti3C2T x / polyimide film model, layered-coating structure Ti3C2T x / The polyimide film model can maintain its original stable structure during the atomic oxygen erosion process without causing significant mass loss. x The film model can physically block the erosion effect of atomic oxygen, and can also adsorb atomic oxygen to form a titanium oxide passivation layer to effectively prevent further erosion by atomic oxygen. x / polyimide film model and layered-coating structure Ti3C2T x Ti3C2T / Polyimide Film Model x It not only fully consumes atomic oxygen but also effectively prolongs the erosion path of atomic oxygen, making it exhibit excellent resistance to atomic oxygen erosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram of a polyimide film model established in Example 1 of the present invention;

[0021] Figure 2 This is a simulation snapshot of the atomic oxygen corrosion polyimide film model process in Example 1 of the present invention;

[0022] Figure 3 This is a component statistics diagram at the end of molecular dynamics simulation of the polyimide film model of Example 1 of the present invention;

[0023] Figure 4 Ti3C2T established in Example 1 of the present invention x Diagram of membrane model;

[0024] Figure 5 The atomic oxygen erosion of Ti3C2T in Example 1 of the present invention x Simulation snapshots of membrane model processes;

[0025] Figure 6 Ti3C2T in Example 1 of the present invention x Component statistics at the end of the molecular dynamics simulation of the membrane model;

[0026] Figure 7 The layered structure Ti3C2T established in Example 1 of the present invention x / polyimide film model diagram;

[0027] Figure 8 The atomic oxygen eroded layered structure Ti3C2T in Example 1 of the present invention x / Simulation snapshot of the polyimide film model process;

[0028] Figure 9 The layered structure Ti3C2T of Example 1 of the present inventionx / Component statistics at the end of molecular dynamics simulation of polyimide membrane model;

[0029] Figure 10 The layered coating structure Ti3C2T established in Example 1 of the present invention x / polyimide film model diagram;

[0030] Figure 11 The atomic oxygen erosion layered-coating structure Ti3C2T of Example 1 of the present invention x / Simulation snapshot of the polyimide film model process;

[0031] Figure 12 The layered coating structure Ti3C2T of Example 1 of the present invention x / Component statistics at the end of molecular dynamics simulation of polyimide membrane model;

[0032] Figure 13 The polyimide film model of Example 1 of the present invention, Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / Comparison of mass changes of polyimide film model during atomic oxygen erosion process. DETAILED DESCRIPTION

[0033] The specific embodiments of the present invention are given below. The specific embodiments are only used to further illustrate the present invention and do not limit the scope of protection of the present invention.

[0034] The present invention provides a molecular dynamics analysis of Ti3C2T x / A method for resisting proton oxygen corrosion of a polyimide film (hereinafter referred to as the method), characterized in that the method comprises the following steps:

[0035] Step 1: Use molecular dynamics modeling software to build a polyimide film model through the polyimide monomer model and the Ti3C2T x The monomer model was established with the molecular formula of Ti 3n C 2n T xn Ti3C2T x Membrane model; where n≥10;

[0036] Preferably, in steps 1 to 4, the molecular dynamics modeling software is Materials Studio software.

[0037] Preferably, in step 1, the polyimide film model is constructed from 200 to 300 polyimide monomer models. In this embodiment, the polyimide film model is constructed from 200 to 300 polyimide monomer models using the Construction function in the Amorphous Cell module of Materials Studio software.

[0038] Preferably, in step 1, Ti3C2T x The specific membrane model is: Ti3C2T x The monomer model was imported into the molecular dynamics modeling software to analyze the Ti3C2T x The monomer model was expanded to obtain a molecular formula of Ti 3n C 2n T xn Ti3C2T x Film model, where n≥10. In this embodiment, Ti3C2T x Import the monomer model into Materials Studio software and use the Supercell function to analyze the Ti3C2T x The monomer model was expanded to obtain Ti3C2T x Film model. Ti3C2T x The monomer model is an existing technology, and the reference is "The Journal of Physical Chemistry C, 2019, 123(2): 1099-109".

[0039] Step 2: Use molecular dynamics modeling software to simulate the polyimide film model and Ti3C2T x The membrane model is structurally optimized to make the simulation process closer to the actual value;

[0040] Preferably, in step 2, the polyimide film model uses COMPASS force field; Ti3C2T x The membrane model uses a general force field.

[0041] Step 3: Using molecular dynamics modeling software, Ti3C2T x Monomer model establishment Ti3C2T x model, and then the polyimide monomer model and Ti3C2T x The model is assembled to construct a layered structure Ti3C2T x / polyimide film model; then through the layered structure Ti3C2T x / polyimide film model and Ti3C2T obtained in step 1 x Membrane model, construction of layered-coating structure Ti3C2T x / polyimide film model;

[0042] Preferably, in step 3, Ti3C2T x The monomer model was imported into the molecular dynamics modeling software to analyze the Ti3C2T x The monomer model was expanded to obtain a molecular formula of Ti 3m C 2m T xm Ti3C2T x Model, where m = 1 to 9; then remove Ti3C2T x The periodicity of the model is constructed and an empty box is built to hold the Ti3C2T x The model is filled in the corresponding position according to the layered structure, and Ti3C2T x The coordinates of the model; finally, the polyimide monomer model is filled into the box to complete the assembly and obtain the layered structure Ti3C2T x / polyimide film model. In this embodiment, Ti3C2T x Import the monomer model into Materials Studio software and use the Supercell function to analyze the Ti3C2T x The monomer model was expanded to obtain a molecular formula of Ti 15 C 12 T 5x Ti3C2T x model, and then remove Ti3C2T through the Nonperiodic function x The periodicity of the model is constructed and an empty box is built to hold the Ti3C2T x The model is filled in the corresponding position according to the layered structure, and the Fix Cartesian position command is used to fix the Ti3C2T x The coordinates of the model; finally, the polyimide monomer model is filled into the box using the Packing function in the Amorphous Cell module to complete the assembly and obtain the layered structure Ti3C2T x / Polyimide film model.

[0043] Preferably, in step 3, 1 to 2 layered structures Ti3C2T x / polyimide film model as the matrix model, the Ti3C2T x The film model is used as the coating model, and the coating model is assembled with the substrate model to obtain the layered-coating structure Ti3C2T x / polyimide film model. In this embodiment, 1 to 2 layered structures of Ti3C2T x / polyimide film model as the matrix model, the Ti3C2T xThe film model is used as the coating model, and the coating model and the substrate model are assembled using the Build Layer function in Materials Studio software to obtain the layered-coating structure Ti3C2T x / Polyimide film model.

[0044] Step 4: Using molecular dynamics modeling software, the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / The polyimide film model is structurally optimized to make the simulation process closer to the actual value;

[0045] Preferably, in step 4, the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide membrane models all use a general force field.

[0046] Step 5: Using molecular dynamics simulation software, the polyimide film model obtained in step 2 and the Ti3C2T x Membrane model, layered structure Ti3C2T obtained in step 4 x / polyimide film model and layered-coating structure Ti3C2T obtained in step 4 x / The Z direction in the polyimide film model is extended to reserve space for subsequent atomic oxygen injection;

[0047] Preferably, in steps 5 to 8, the molecular dynamics simulation software is LAMMPS software.

[0048] Preferably, in step 5, the Z direction is extended to 1500 to 2500 angstroms (preferably 2000 angstroms).

[0049] Step 6: Using molecular dynamics simulation software, the polyimide film model obtained in step 5, the Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / The polyimide film model is relaxed to make the simulation process closer to the actual value;

[0050] Preferably, in step 6, the Langevin method is used to perform relaxation in a canonical ensemble (NVT, N-fixed number of atoms, V-fixed volume, T-fixed temperature) to simulate an environmental steady state. In the canonical ensemble, the temperature is 300K to simulate room temperature.

[0051] Preferably, in step 6, the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2Tx / polyimide film model was relaxed to 300K by gradually increasing the temperature for at least 3 times (preferably 3 to 10 times). This is because the layered structure of Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / The polyimide film model is large in size and contains a large number of atomic oxygen atoms, and the multiple relaxation method can effectively avoid atomic overlap.

[0052] Step 7: Use the ReaxFF force field without Ti element to perform molecular dynamics simulation of atomic oxygen corrosion on the polyimide film model obtained in step 6, and use the ReaxFF force field with Ti element to simulate the Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion was performed on the film model to obtain the simulation results of the two models respectively; then, by comparing the simulation results of the two models, the polyimide film model and the Ti3C2T x Atomic oxygen erosion mechanism of membrane model;

[0053] Preferably, in step 7, the simulation results are: polyimide film model and Ti3C2T x The dynamic behavior evolution and mass change law of the film model during the atomic oxygen erosion process, and the polyimide film model and Ti3C2T at the end of the molecular dynamics simulation x The components of the membrane model were statistically analyzed to obtain the component distribution characteristics of the two models at the end of the simulation.

[0054] Preferably, step 7 specifically comprises: using a ReaxFF force field without Ti elements to perform molecular dynamics simulation of atomic oxygen corrosion on the polyimide film model obtained in step 6, and using a ReaxFF force field containing Ti elements to simulate the Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion was performed on the film model to obtain the polyimide film model and Ti3C2T x The dynamic behavior evolution and mass change law of the film model during the atomic oxygen erosion process, and the polyimide film model and Ti3C2T at the end of the molecular dynamics simulation x The components of the film model were statistically analyzed to obtain the component distribution characteristics of the two models at the end of the simulation. Then, by comparing the different behavioral evolution and mass loss differences of the two models during the atomic oxygen erosion process, and combining the component distribution characteristics of each model at the end of the simulation, the two types of materials (i.e., polyimide and Ti3C2T x ) Differences in atomic oxygen corrosion kinetics, the polyimide film model and Ti3C2T x Atomic oxygen corrosion mechanism of the membrane model.

[0055] Preferably, in step 7, the force field is a set of mathematical functions and parameters that describe the interactions between atoms and molecules, and is used to calculate the total energy of the system and the forces on the atoms. Molecular dynamics simulation relies on the potential energy functions (such as bond length, bond angle, dihedral angle, van der Waals force and electrostatic force, etc.) provided by the force field to drive the movement of atoms. The reaction force field (ReaxFF) is a type of force field suitable for describing the reaction process. Both ReaxFF force fields are prior art. The reference for the ReaxFF force field without Ti element is Journal of Physical Chemistry A, 2014, 118 (15) and the reference for the ReaxFF force field with Ti element is Langmuir, 2013, 29 (25): 7838-7846.

[0056] Step 8: Use the ReaxFF force field without Ti element to analyze the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide film model was used to simulate atomic oxygen corrosion. In these two composite film models (i.e., layered Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide film model) in molecular dynamics simulations, only Ti3C2T x The physical barrier of the material to atomic oxygen corrosion and the effect of extending the atomic oxygen corrosion trajectory are used to obtain the simulation results of the two composite film models respectively; then, the simulation results of the two composite film models are compared with the simulation results of the polyimide film model obtained in step 7, and the Ti3C2T x The atomic oxygen corrosion mechanism of the film model leads to the layered structure of Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / Atomic oxygen corrosion mechanism of polyimide film model.

[0057] Preferably, in step 8, the simulation result is: layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide film model in the process of atomic oxygen corrosion dynamic behavior evolution and mass change law; at the end of the molecular dynamics simulation, the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x The components of the polyimide / polyimide membrane model were statistically analyzed to obtain the component distribution characteristics of the two composite membrane models at the end of the simulation.

[0058] Preferably, step 8 is specifically: using the ReaxFF force field without Ti element to perform the multi-layered Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion of the polyimide / polyimide film model was performed. In the molecular dynamics simulation of the two composite film models, only Ti3C2T was considered. x The physical barrier of the material to atomic oxygen corrosion and the effect of extending the atomic oxygen corrosion trajectory are used to obtain the dynamic behavior evolution and mass change law of the two composite film models during the atomic oxygen corrosion process. At the same time, the components of the two composite film models at the end of the molecular dynamics simulation are statistically analyzed to obtain the component distribution characteristics of the two composite film models at the end of the simulation. The different behavior evolution and mass loss differences of the two composite film models and the polyimide film model obtained in step 7 during the atomic oxygen corrosion process are compared, and the component distribution characteristics of the two composite film models at the end of the simulation and the Ti3C2T x The atomic oxygen corrosion mechanism of the film model is systematically analyzed, and the difference in atomic oxygen corrosion kinetics of the two composite film models is obtained, and the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / Atomic oxygen corrosion mechanism of polyimide film model.

[0059] Preferably, in step 7 and step 8, the polyimide film model, Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x In the polyimide film model, an oxygen atom was inserted every 1000-2000 steps (preferably 2000 steps), for a total simulation time of 800,000-1,200,000 steps (i.e., 80-120 ps, ​​where ps stands for picoseconds) (preferably 1,000,000 steps (i.e., 100 ps)). Step in molecular dynamics simulations refers to the number of steps.

[0060] Preferably, in steps 7 and 8, the ReaxFF force field calculates the destruction and connection of the current structure by evaluating the relationship between bond distance and bond order, and bond order and bond energy, so as to describe the chemical reaction process; the bond order expression is as follows:

[0061]

[0062] In formula (1), is the bond order between atoms i and j, is the bond order contribution of the σ bond, is the bond order contribution value of the π bond, The bond order contribution value of the double-π bond;

[0063] Based on bond order, polyimide film model, Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / The energy calculation formula of the polyimide film model during atomic oxygen corrosion is as follows:

[0064] E system =E bond +E triple +E C2 +E val +E pen +E tors +E lp +E coa +E conj +E over +E unde

[0065] +E Hbond +E vdW +E coulomb (2)

[0067] In formula (2), E system is the total energy of the system; E bond 、E triple 、E C2 They are bond energy term, triple bond energy correction term, and triple bond energy penalty term; E val 、E pen They are the bond angle energy term and the bond angle energy penalty term; E tors 、E lp 、E coa 、E conj They are the torsion angle energy term, the lone pair electron energy term, the three-body conjugation effect energy, and the four-body conjugation effect energy; E over 、E under are the over-coordination and under-coordination energy correction terms respectively; E Hbond 、E vdW 、E coulomb They are non-bonding hydrogen bond term, van der Waals term, and Coulomb term.

[0068] Preferably, in steps 7 and 8, the visualization software ovito is used to observe the dynamic behavior evolution of the model during the atomic oxygen erosion process to obtain simulation snapshots.

[0069] Preferably, in steps 7 and 8, the fix reax / c / species command of the LAMMPS software is used to perform statistical analysis of the components of the model at the end of the molecular dynamics simulation.

[0070] Preferably, in steps 7 and 8, the behavior evolution includes the degree of disorder of the model and the number of small molecules missing from the model.

[0071] Preferably, in step 8, Ti3C2T has been obtained in step 7 x The atomic oxygen corrosion mechanism of the material, the selected ReaxFF force field containing Ti element can only describe the atomic oxygen and Ti3C2T x The atomic interactions between materials cannot describe the atomic interactions between atomic oxygen and polyimide models, while the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / Polyimide film models include both polyimide models and Ti3C2T x The composite material model of the model is used. Therefore, the ReaxFF force field without Ti element is used to simulate the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x Molecular dynamics simulation of atomic oxygen corrosion was performed on a polyimide film model.

[0072] Example 1:

[0073] Step 1: Use Materials Studio software to build a polyimide film model using a polyimide monomer model and a Ti3C2T x Monomer model establishment Ti3C2T x membrane model;

[0074] Prepare polyimide monomer (molecular formula C in Materials Studio software) 22 N2O5H 12 ) model, the polyimide film model is constructed by 200 polyimide monomer models through the Construction function in the Amorphous Cell module of Materials Studio software, such as Figure 1 shown.

[0075] Ti3C2T x The monomer (molecular formula is Ti3C2O2) model was imported into Materials Studio software, and the Supercell function was used to analyze the Ti3C2T x The monomer model was expanded to obtain Ti3C2T x Membrane model (molecular formula is Ti768 C 512 O 512 ),like Figure 4 shown.

[0076] Step 2: Using Materials Studio software, COMPASS force field was used to optimize the structure of the polyimide film model, and the general force field was used to optimize the Ti3C2T x Membrane model for structural optimization;

[0077] Step 3: Use Materials Studio software to x Monomer model establishment Ti3C2T x model, and then the polyimide monomer model and Ti3C2T x The model is assembled to construct a layered structure Ti3C2T x / polyimide film model; then through the layered structure Ti3C2T x / polyimide film model and Ti3C2T obtained in step 2 x Membrane model, construction of layered-coating structure Ti3C2T x / polyimide film model;

[0078] Ti3C2T x The monomer (molecular formula is Ti3C2O2) model was imported into Materials Studio software, and the Supercell function was used to analyze the Ti3C2T x The monomer model was expanded to obtain Ti3C2T x Model (molecular formula is Ti 15 C 12 O 12 ), remove Ti3C2T through Nonperiodic function x The periodicity of the model is constructed and an empty box is built to hold the Ti3C2T x The model is filled in the corresponding position according to the layered structure, and the Fix Cartesian position command is used to fix the Ti3C2T x The coordinates of the model; finally, the polyimide monomer model is filled into the box using the Packing function in the Amorphous Cell module to complete the assembly and obtain the layered structure Ti3C2T x / Polyimide film model, see Figure 7 ;

[0079] Establish two layered structures Ti3C2T x / polyimide film model as the matrix model, the Ti3C2T xThe film model is used as the coating model, and the coating model and the substrate model are assembled using the Build Layer function in Materials Studio software to obtain the layered-coating structure Ti3C2T x / Polyimide film model, see Figure 10 ;

[0080] Step 4: Using Materials Studio software, use the general force field to separate the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / The polyimide film model is structurally optimized to make the simulation process closer to the actual value;

[0081] Step 5: Using LAMMPS software, the polyimide film model obtained in step 2 and the Ti3C2T x Membrane model, layered structure Ti3C2T obtained in step 4 x / polyimide film model and layered-coating structure Ti3C2T obtained in step 4 x / The Z direction of the polyimide film model is extended to 2000 Å to reserve space for subsequent atomic oxygen injection;

[0082] Step 6: Using LAMMPS software, the polyimide film model obtained in step 5, the Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / The polyimide film model uses the Langevin method in a canonical ensemble and is relaxed six times to 300K by gradually increasing the temperature, making the simulation process closer to the actual value;

[0083] Step 7: Use the ReaxFF force field without Ti element to perform molecular dynamics simulation of atomic oxygen corrosion on the polyimide film model obtained in step 6, and use the ReaxFF force field with Ti element to simulate the Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion was performed on the film model to obtain the polyimide film model and Ti3C2T x Dynamic behavior evolution of the film model during atomic oxygen corrosion ( Figure 2 and Figure 5 ) and quality change law ( Figure 13 ), and the polyimide film model and Ti3C2T at the end of the molecular dynamics simulation x Statistical analysis of the components of the membrane model ( Figure 3 and Figure 6), and the component distribution characteristics of the two models at the end of the simulation were obtained; then, by comparing the different behavioral evolution and mass loss differences of the two models during the atomic oxygen erosion process, and combining the component distribution characteristics of each model at the end of the simulation, the differences in the atomic oxygen erosion kinetics of the two types of materials were systematically analyzed, and the polyimide film model and Ti3C2T x Atomic oxygen erosion mechanism of membrane model;

[0084] Step 8: Use the ReaxFF force field without Ti element to analyze the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion of the polyimide / polyimide film model was performed. In the molecular dynamics simulation of the two composite film models, only Ti3C2T was considered. x The physical barrier of the material to atomic oxygen corrosion and the effect of extending the atomic oxygen corrosion trajectory were used to obtain the dynamic behavior evolution of the two composite film models during the atomic oxygen corrosion process ( Figure 8 and Figure 11 ) and quality change law ( Figure 13 ); At the same time, the components of the two composite membrane models at the end of the molecular dynamics simulation were statistically analyzed ( Figure 9 and Figure 12 ), the component distribution characteristics of the two composite film models at the end of the simulation were obtained; then, by comparing the different behavioral evolutions and mass loss differences of the two composite film models and the polyimide film model obtained in step 7 during the atomic oxygen erosion process, and combining the component distribution characteristics of the two composite film models at the end of the simulation and the Ti3C2T x The atomic oxygen corrosion mechanism of the film model leads to the layered structure of Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / Atomic oxygen corrosion mechanism of polyimide film model.

[0085] Preferably, in step 7 and step 8, the polyimide film model, Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x In the polyimide film model, one atomic oxygen was inserted every 2000 steps, and the simulation lasted for a total of 1,000,000 steps (i.e., 100 ps).

[0086] Preferably, in steps 7 and 8, the fix reax / c / species command of the LAMMPS software is used to perform statistical analysis of the components of the model at the end of the molecular dynamics simulation.

[0087] Depend on Figure 1It can be seen that the present invention uses molecular dynamics simulation software to prepare a polyimide membrane model, and the polyimide membrane model has a compact structure.

[0088] Depend on Figure 2 It can be seen that during the atomic oxygen erosion process, a large number of chemical bonds in the polyimide film model are broken, the stable structure is lost, and a large number of atoms escape from the model, causing a large amount of mass loss. In addition, the erosion behavior of atomic oxygen not only occurs on the surface of the material, but also gradually penetrates into the interior of the material as the erosion time goes by.

[0089] Depend on Figure 3 It can be seen that atomic oxygen corrodes the polyimide film model to generate a large number of small molecular products, such as carbon monoxide (CO) and water (H2O), and the carbon chain of the polyimide monomer in the polyimide film model will also gradually decompose, causing the polyimide film model to lose its stable structure. Figure 2 In the atomic oxygen environment, a large number of chemical bonds in the polyimide film model are destroyed, causing some atoms to escape in the form of small molecules, indicating that the polyimide film model has poor atomic oxygen durability.

[0090] Depend on Figure 4 It can be seen that the Ti3C2T prepared by the molecular dynamics simulation software in the present invention x The membrane model is a double-layer flat plate structure.

[0091] Depend on Figure 5 It can be seen that atomic oxygen has a great influence on Ti3C2T x The membrane model produces a smaller erosion effect than Figure 2 , Ti3C2T x The film model has fewer missing atoms, and Ti3C2T x The membrane model can not only physically block the corrosion effect of atomic oxygen, but also adsorb atomic oxygen to form a titanium oxide passivation layer to effectively block further corrosion by atomic oxygen, demonstrating its excellent resistance to atomic oxygen corrosion.

[0092] Depend on Figure 6 It can be seen that atomic oxygen corrodes Ti3C2T x The products of the membrane model are few and mainly oxygen, indicating that Ti3C2T x The membrane model is only prone to losing surface oxygen atoms; combined Figure 5 ,contrast Figure 3 , Ti3C2T x The membrane model exhibits excellent durability in atomic oxygen environment by physically isolating the atomic oxygen corrosion effect and adsorbing atomic oxygen to generate titanium oxide.

[0093] Depend on Figure 7It can be seen that the present invention successfully prepared Ti3C2T with distinct layered structural characteristics using molecular dynamics simulation software. x / Polyimide film model.

[0094] Depend on Figure 8 It can be seen that compared with Figure 2 , atomic oxygen on layered structure Ti3C2T x / polyimide film model produces a smaller erosion effect, in which the layered structure Ti3C2T x The polyimide film model does not lose large fragment molecules. This is mainly attributed to the layered structure of Ti3C2T x Ti3C2T / Polyimide Film Model x The atomic oxygen is fully consumed and the erosion path of the atomic oxygen is effectively prolonged.

[0095] Depend on Figure 9 It can be seen that atomic oxygen corrodes the layered structure of Ti3C2T x The products of the polyimide membrane model are mostly small molecules such as carbon monoxide (CO) and water (H2O). Figure 3 By comparison, we can see that the layered structure Ti3C2T x / Only a small portion of the carbon chain in the polyimide film model is degraded, and most of the remaining carbon chains are C6-C 10 There are fragments, layered structure Ti3C2T x / The anti-oxidation corrosion performance of the polyimide film model is better than that of the polyimide film model; Figure 8 As well as the above-mentioned Ti3C2T x Atomic oxygen corrosion mechanism of film model, layered structure Ti3C2T x Ti3C2T / polyimide film model x It can react with atomic oxygen to generate titanium oxide, realizing the effective consumption of atomic oxygen. Its layered structure prolongs the diffusion path of atomic oxygen, which slows down the erosion effect of atomic oxygen. x / polyimide film models exhibit excellent durability in atomic oxygen environments.

[0096] Depend on Figure 10 It can be seen that the present invention successfully prepared Ti3C2T with distinct layered-coating structural characteristics using molecular dynamics simulation software. x / Polyimide film model.

[0097] Depend on Figure 11 It can be seen that compared with Figure 2 , atomic oxygen erosion layered-coating structure Ti3C2T x / polyimide film model, the reaction is slow, and the model will only lose volatile small molecules. The layered-coating structure surface model can isolate most of the erosion effects, and the internal Ti3C2T x The atomic oxygen is fully consumed and the erosion path of the atomic oxygen is effectively prolonged.

[0098] Depend on Figure 12 It can be seen that atomic oxygen corrosion leads to a layered-coating structure of Ti3C2T x / polyimide film model generates carbon monoxide as the main product, Figure 3 By comparison, the layered-coating structure Ti3C2T x / The polyimide film model has excellent anti-oxidation corrosion resistance; combined Figure 11 As well as the above-mentioned Ti3C2T x Atomic oxygen corrosion mechanism of film model, layered-coating structure Ti3C2T x / Polyimide film model relies on the surface Ti3C2T x The coating passivation barrier and the internal retardation of atomic oxygen in the substrate show excellent durability in atomic oxygen environment.

[0099] Depend on Figure 13 It can be seen that the mass of the polyimide film model gradually decreases during the atomic oxygen erosion process. At the end of the simulation, the mass loss of the polyimide film model is as high as 30%, indicating that the polyimide has poor environmental durability. x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide film model The three models have no obvious weight reduction, among which the layered structure Ti3C2T x Ti3C2T / polyimide film model x It can react with atomic oxygen to generate titanium oxide, realizing the effective consumption of atomic oxygen. Its layered structure prolongs the diffusion path of atomic oxygen, which slows down the erosion effect of atomic oxygen. x / polyimide film model exhibits excellent durability in atomic oxygen environment; layered-coating structure Ti3C2T x / Polyimide film model relies on the surface Ti3C2T x The coating passivation barrier and the internal retardation of atomic oxygen in the substrate show excellent durability in atomic oxygen environment.

[0100] Figures 1-13 In the figure, grey atoms represent carbon (C), white atoms represent hydrogen (H), red atoms represent oxygen (O), blue atoms represent nitrogen (N), silver atoms represent titanium (Ti), and green atoms represent atomic oxygen (AO).

[0101] Any matters not described in the present invention are applicable to the prior art.

Claims

1. A molecular dynamics analysis of Ti3C2T x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: The method comprises the following steps: Step 1: Use molecular dynamics modeling software to build a polyimide film model through the polyimide monomer model and the Ti3C2T x Monomer model establishment Ti3C2T x membrane model; Step 2: Use molecular dynamics modeling software to simulate the polyimide film model and Ti3C2T x Membrane model for structural optimization; Step 3: Using molecular dynamics modeling software, Ti3C2T x Monomer model establishment Ti3C2T x model, and then the polyimide monomer model and Ti3C2T x The model is assembled to construct a layered structure Ti3C2T x / polyimide film model; then through the layered structure Ti3C2T x / polyimide film model and Ti3C2T obtained in step 2 x Membrane model, construction of layered-coating structure Ti3C2T x / polyimide film model; Step 4: Using molecular dynamics modeling software, the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide membrane model for structural optimization; Step 5: Using molecular dynamics simulation software, the polyimide film model obtained in step 2 and the Ti3C2T x Membrane model, layered structure Ti3C2T obtained in step 4 x / polyimide film model and layered-coating structure Ti3C2T obtained in step 4 x / The Z direction in the polyimide film model is extended to reserve space for subsequent atomic oxygen injection; Step 6: Using molecular dynamics simulation software, the polyimide film model obtained in step 5, the Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide film model for relaxation; Step 7: Use the ReaxFF force field without Ti element to perform molecular dynamics simulation of atomic oxygen corrosion on the polyimide film model obtained in step 6, and use the ReaxFF force field with Ti element to simulate the Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion was performed on the film model to obtain the simulation results of the two models respectively; then, by comparing the simulation results of the two models, the polyimide film model and the Ti3C2T x Atomic oxygen erosion mechanism of membrane model; Step 8: Use the ReaxFF force field without Ti element to analyze the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion of the polyimide / polyimide film model was performed. In the molecular dynamics simulation of the two composite film models, only Ti3C2T was considered. x The physical barrier of the material to atomic oxygen corrosion and the effect of extending the atomic oxygen corrosion trajectory are used to obtain the simulation results of the two composite film models respectively; then, the simulation results of the two composite film models are compared with the simulation results of the polyimide film model obtained in step 7, and the Ti3C2T x The atomic oxygen corrosion mechanism of the film model leads to the layered structure of Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / Atomic oxygen corrosion mechanism of polyimide film model.

2. Molecular dynamics analysis of Ti3C2T according to claim 1 x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: In step 1, a polyimide film model is constructed from 200 to 300 polyimide monomer models; In step 1, Ti3C2T x The specific membrane model is: Ti3C2T x The monomer model was imported into the molecular dynamics modeling software to analyze the Ti3C2T x The monomer model was expanded to obtain a molecular formula of Ti 3n C 2n T xn Ti3C2T x Membrane model, where n ≥ 10.

3. Molecular dynamics analysis of Ti3C2T according to claim 1 x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: In step 2, the polyimide film model uses the COMPASS force field; Ti3C2T x The membrane model uses a general force field; In step 4, the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / polyimide membrane models all use a general force field.

4. Molecular dynamics analysis of Ti3C2T according to claim 1 x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: In step 3, Ti3C2T x The monomer model was imported into the molecular dynamics modeling software to analyze the Ti3C2T x The monomer model was expanded to obtain a molecular formula of Ti 3m C 2m T xm Ti3C2T x Model, where m = 1 to 9; then remove Ti3C2T x The periodicity of the model is constructed and an empty box is built to hold the Ti3C2T x The model is filled in the corresponding position according to the layered structure, and Ti3C2T x The coordinates of the model; finally, the polyimide monomer model is filled into the box to complete the assembly and obtain the layered structure Ti3C2T x / polyimide film model; In step 3, 1 to 2 layered structures of Ti3C2T are established. x / polyimide film model as the matrix model, the Ti3C2T x The film model is used as the coating model, and the coating model is assembled with the substrate model to obtain the layered-coating structure Ti3C2T x / Polyimide film model.

5. The molecular dynamics analysis of Ti3C2T according to claim 1 x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: In step 5, the Z direction is extended to 1500 to 2500 angstroms.

6. The molecular dynamics analysis of Ti3C2T according to claim 1 x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: In step 6, the Langevin method is used to relax the canonical ensemble to simulate the stable state of the environment; in the canonical ensemble, the temperature is 300K; In step 6, the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x The polyimide film model was relaxed to 300 K at least three times by gradually increasing the temperature.

7. The molecular dynamics analysis of Ti3C2T according to claim 1 x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: Step 7 is as follows: using the ReaxFF force field without Ti element to perform molecular dynamics simulation of atomic oxygen corrosion on the polyimide film model obtained in step 6, and using the ReaxFF force field with Ti element to simulate the Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion was performed on the film model to obtain the polyimide film model and Ti3C2T x The dynamic behavior evolution and mass change law of the film model during the atomic oxygen erosion process, and the polyimide film model and Ti3C2T at the end of the molecular dynamics simulation x The components of the membrane model were statistically analyzed to obtain the component distribution characteristics of the two models at the end of the simulation; Then, by comparing the different behavioral evolution and mass loss differences of the two models during the atomic oxygen erosion process, and combining the component distribution characteristics of each model at the end of the simulation, the differences in the atomic oxygen erosion kinetics of the two types of materials were systematically analyzed, and the polyimide film model and Ti3C2T x Atomic oxygen corrosion mechanism of the membrane model.

8. The molecular dynamics analysis of Ti3C2T according to claim 1 x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: Step 8 is to use the ReaxFF force field without Ti element to simulate the layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x The molecular dynamics simulation of atomic oxygen corrosion of the polyimide / polyimide film model was performed. In the molecular dynamics simulation of the two composite film models, only Ti3C2T was considered. x The material's physical barrier to atomic oxygen corrosion and its role in extending the atomic oxygen corrosion trajectory were used to obtain the dynamic behavior evolution and mass change rules of the two composite film models during the atomic oxygen corrosion process. At the same time, a statistical analysis was performed on the components of the two composite film models at the end of the molecular dynamics simulation to obtain the component distribution characteristics of the two composite film models at the end of the simulation. Then, by comparing the different behavioral evolution and mass loss differences of the two composite film models and the polyimide film model obtained in step 7 during the atomic oxygen erosion process, and combining the component distribution characteristics of the two composite film models at the end of the simulation and the Ti3C2T x The atomic oxygen corrosion mechanism of the film model leads to the layered structure of Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / Atomic oxygen corrosion mechanism of polyimide film model.

9. The molecular dynamics analysis of Ti3C2T according to claim 1 x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: In steps 7 and 8, the polyimide film model, Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / In the polyimide film model, one atomic oxygen was inserted every 1000–2000 steps, and the simulation lasted a total of 800,000–1,200,000 steps; In steps 7 and 8, the ReaxFF force field calculates the destruction and connection of the current structure by evaluating the relationship between bond distance and bond order, and bond order and bond energy, thereby describing the chemical reaction process; the bond order expression is as follows: In formula (1), is the bond order between atoms i and j, is the bond order contribution of the σ bond, is the bond order contribution value of the π bond, The bond order contribution value of the double-π bond; Based on bond order, polyimide film model, Ti3C2T x Membrane model, layered structure Ti3C2T x / polyimide film model and layered-coating structure Ti3C2T x / The energy calculation formula of the polyimide film model during atomic oxygen corrosion is as follows: AND system =And bond +E triple +E C2 +E val +E pen +E tors +E lp +E coa +E conj +E over +E under +E Hbond +E vdW +E coulomb (2) In formula (2), E system is the total energy of the system; E bond 、E triple 、E C2 They are bond energy term, triple bond energy correction term, and triple bond energy penalty term; E val 、E pen They are the bond angle energy term and the bond angle energy penalty term; E tors 、E lp 、E coa 、E conj They are torsion angle energy term, lone pair electron energy term, three-body conjugation effect energy, and four-body conjugation effect energy; E over 、E under are the over-coordination and under-coordination energy correction terms respectively; E Hbond 、E vdW 、E coulomb They are non-bonding hydrogen bond term, van der Waals term, and Coulomb term; In steps 7 and 8, the visualization software Ovito was used to observe the dynamic behavior evolution of the model during the atomic oxygen erosion process and obtain simulation snapshots; In steps 7 and 8, the behavioral evolution includes the degree of disorder in the model and the number of small molecules missing from the model.

10. The molecular dynamics analysis of Ti3C2T according to claim 1 x / A method for preventing a polyimide film from being corroded by proton oxygen, characterized in that: In steps 1 to 4, the molecular dynamics modeling software is Materials Studio software; In steps 5 to 8, the molecular dynamics simulation software is LAMMPS software.

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