Method for evaluating adhesive solid surface bonding properties based on molecular dynamics simulation
By constructing a molecular dynamics simulation model, the problems of time-consuming and blind evaluation of adhesive bonding performance in existing technologies have been solved, and rapid and accurate evaluation and prediction of bonding performance have been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG UNIV
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-05
AI Technical Summary
Existing technologies rely on macroscopic physical experiments to evaluate the bonding performance of adhesives to solid surfaces. These experiments are time-consuming, fail to reveal the interfacial interaction mechanism in depth, and cannot predict performance during the design phase.
By constructing a molecular dynamics simulation model of the adhesive and the solid surface, structural optimization and molecular dynamics equilibrium simulation are performed, and interfacial interaction energy and shear simulation are calculated to evaluate the bonding performance.
It enables rapid evaluation of the adhesion performance between adhesives and solid surfaces without the need for physical samples, and can quantitatively reveal interfacial adhesion and cohesion at the molecular scale, accurately predict fracture behavior and failure modes, and reduce the blind spots in the research and development process.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of molecular dynamics simulation technology, specifically a method for evaluating the bonding performance of adhesives on solid surfaces based on molecular dynamics simulation. Background Technology
[0002] Adhesives, as a core link in modern manufacturing, are widely used in aerospace, new energy vehicles, electronic packaging, biomedicine, and green building. Adhesives achieve reliable bonding of dissimilar materials through interfacial adhesion, and their bonding performance directly determines the mechanical integrity, durability, and functional reliability of the overall structure. Therefore, accurately and efficiently predicting and optimizing the bonding performance of adhesives to specific solid surfaces in the early stages of material development and engineering selection is of great significance for shortening the development cycle, reducing trial-and-error costs, and achieving high-performance customized bonding solutions.
[0003] Currently, the evaluation of adhesive performance in industry and academia heavily relies on macroscopic physical experimental methods. Standardized adhesive specimens are typically prepared according to specifications such as ASTM D1002 (tensile shear), ISO 4587 (tensile strength), or ASTM D3167 (floating roll peel), and data on adhesive strength, modulus, and failure modes are obtained using universal testing machines. However, this traditional model, which relies on physical testing, has many limitations when it comes to the efficient development of advanced materials. From a research and development process perspective, evaluating each new adhesive formulation or substrate surface treatment process requires a series of lengthy steps, including sample preparation, curing, environmental aging, and mechanical testing, often taking weeks or even months. This inefficient trial-and-error approach clearly cannot meet the demands of rapid iterative research and development. The test results show that macroscopic experiments can only provide the final fracture load and macroscopic failure modes such as interface failure and cohesive failure, but cannot reveal in depth the atomic or molecular-scale interaction mechanisms in the interface region, such as the distribution of van der Waals forces, the interpenetration behavior of molecular chains, and the evolution process of interface defects. Furthermore, it is difficult to quantitatively distinguish the contribution of the interfacial adhesion force between the adhesive and the solid surface and the intermolecular cohesive force of the adhesive itself to the overall bonding performance. This makes it difficult for the experimental results to effectively guide the molecular design of adhesives or the modification of solid surfaces. More importantly, the current traditional model of manufacturing first and then testing and evaluating is essentially a performance verification of existing materials. It cannot predict the performance of adhesive molecules that have not yet been synthesized or untreated solid surfaces during the design stage, making the research and development process significantly less intuitive. Summary of the Invention
[0004] The purpose of this invention is to provide a method for evaluating the bonding performance of adhesives on solid surfaces based on molecular dynamics simulation, in order to solve the above-mentioned problems.
[0005] The technical solution of this invention is: A method for evaluating the bonding performance of adhesives on solid surfaces based on molecular dynamics simulation includes the following steps: An initial model of the adhesive bonding system to a solid surface is constructed, and the structure of the initial model is optimized to obtain an optimized model of the adhesive bonding system with minimal energy. Molecular dynamics equilibrium simulations were performed on the optimized model of the adhesive bonding system to obtain the final configuration of the adhesive bonding system after the molecular dynamics simulation. The interfacial interaction energy between the adhesive and the solid surface was obtained based on the molecular dynamics simulation results. E interface ; A bilayer initialization model containing only adhesives was constructed, and molecular dynamics equilibrium simulations were performed on the constructed bilayer initialization model containing only adhesives to obtain the interaction energy between the two sets of adhesive simulation systems. E cohesive ; Shear simulation was performed on the final configuration of the adhesive bonding system to obtain the adhesive fracture surface after the shear simulation. according to E interface , E cohesive In addition to the fracture surface of the adhesive, the bonding performance of the adhesive on the solid surface is comprehensively evaluated.
[0006] Furthermore, the method for constructing the initialization model of the adhesive-solid surface bonding system includes: An initial model for the adhesive and an initial model for the solid surface are constructed separately; the initial model for the solid surface includes a lower surface solid initial model and an upper surface solid initial model. The Build Layers function is used to assemble the initial model of the upper solid surface as the first layer, the initial model of the adhesive as the second layer, and the initial model of the lower solid surface as the third layer, resulting in an initial model of the adhesive bonding system consisting of the initial model of the lower solid surface, the initial model of the adhesive, and the initial model of the upper solid surface.
[0007] Furthermore, the method for constructing the initial model of the adhesive is as follows: Based on the molecular types that make up the adhesive, the Sketch function of Materials Studio software is used to construct adhesive molecules with different structures, and geometric optimization is performed to obtain the final optimized molecular topological parameters of bond length, bond angle and dihedral angle. Then, the Amorphous Cell Construction module is used to construct an initial model of the adhesive with reasonable structure and composition. The initial model of the adhesive was constructed as a cubic lattice model with a length of 29.478 Å, a width of 34.038 Å, and a height of not less than 15 Å.
[0008] Furthermore, the solid surface is a non-metal such as glass, a metal such as iron or aluminum, or a metal oxide; when the solid surface is a silica surface such as glass, its contact surface with the adhesive needs to be hydroxylated. The initial model of the solid surface is a cubic lattice model with a length of 29.478 Å, a width of 34.038 Å, and a height of 16.619 Å.
[0009] When the solid surface is iron or other metal surfaces, the initial model of the lower solid surface is constructed in the same way as the initial model of the upper solid surface, as follows: The lattice file Fe.msi was exported from the Structures database in Materials Studio software, and then the final initial model of the solid surface was constructed using the Supercell function in the Symmetry section of the Build function.
[0010] When the solid surface is a silica surface such as glass, its contact surface with the adhesive needs to be hydroxylated. The method for constructing the initial model of the lower glass surface is as follows:
[0011] Export the silicon dioxide lattice file SiO2_quartz.msi from the Structures database in Materials Studio software, and then adjust the lattice orientation using the Redefine Lattice function in Symmetry of the Build function. The Redefine Lattice parameters are set as A: 210, B: 010, and C: 001. Use the Cleave Surface function in the Build feature to construct a 16 Å thick silicon dioxide cubic lattice model; An initial model of silica was constructed using the Supercell function in Symmetry within the Build function, with supercell parameters U = 6 and V = 4. By selecting the upper surface of the silica model and using the hydrogenation function, hydroxyl groups are constructed at the interface between the adhesive and the glass. The initial model of the lower surface glass was constructed by adding a vacuum layer with a thickness of 0.4948 Å using the Build Vacuum Slab function in Crystals. The supercell parameters U were set to 6 and V to 4.
[0012] When the solid surface is a glass surface, the method for constructing the initial glass model of the upper surface is the same as that described in claim 5, and the method for constructing the hydroxyl surface is as follows: The silicon atoms closest to the bottom surface in the silica surface model were removed, and hydrogen was added to their adjacent oxygen atoms to finally construct the initial glass configuration of the top surface.
[0013] Furthermore, the method for structural optimization includes: using a COMPASS force field, selecting the Steep algorithm, and setting a maximum number of iterations of 5000.
[0014] Furthermore, the method for constructing the two-layer initialization model containing only adhesive includes: Using the Build Layers function, both the first and second layers are selected as the initial adhesive model, and an initial simulation system containing two adhesive models is assembled. The Move function moves the initial model of two adhesive layers to eliminate the vacuum layer between the two sets of adhesives. The Rebuild Crystal function was used to adjust the model size along the z-axis of the initial model, resulting in a two-layer initialization model containing only adhesive.
[0015] Furthermore, the formula for calculating the interfacial interaction energy between the adhesive and the solid surface is as follows: E interface = ( E A-B - E A -E B ) / 2; where; E A-B The total energy of the adhesive solid surface bonding system; E A The total energy of the solid configuration of the upper and lower surfaces; E B Let be the total energy of the adhesive; the formula for calculating the interaction energy between the two simulated adhesive systems is: E cohesive =E ab - E a -E b ,in, E ab The total energy of the simulated system; E a , E b The total energy for each of the two adhesive groups is represented separately.
[0016] Furthermore, the method for molecular dynamics equilibrium simulation includes the following steps: Molecular dynamics simulations were performed using the Forcite module in Modules. The ensemble was set to NVT, the thermostat to Nose, the simulation temperature to 298.15 K, the electrostatic interaction force was set to the Ewald method, the van der Waals force was set to Atombased, and the cutoff radius was 1.25 nm. The time step was 0.2 fs, the simulation time was 300 ps, and the changes in energy and simulated temperature were recorded.
[0017] Furthermore, the shearing simulation method is as follows: Lattice reconstruction of the final configuration of the adhesive bonding system; Fix all atoms in the solid structure such as glass on the lower surface, restricting their movement in three dimensions; Shear simulations were performed with a shear rate of 0.1 Å / ps to 0.2 Å / ps, a simulation temperature of 298.15 K, and a simulation time of 200 ps to 300 ps.
[0018] Furthermore, a method for comprehensively evaluating the bonding performance of adhesives on solid surfaces includes the following steps: By comparison E interface and E cohesive The size relationship, combined with whether the adhesive fracture surface is located at the interface or inside the adhesive body, is used to determine the adhesive performance and failure mode of the adhesive: when E interface The absolute value is less than E cohesive When the absolute value of the value is 0 and the adhesive fracture surface is located at the interface, the failure mode is determined to be interface failure; when E interface The absolute value is greater than E cohesive When the absolute value of the value is obtained and the fracture surface of the adhesive is located inside the adhesive body, the failure mode is determined to be cohesive failure.
[0019] Compared with the prior art, the beneficial effects of the present invention are: This invention constructs and optimizes an initial model of the adhesive-solid surface bonding system. This allows for the acquisition of specific information such as the adhesive's adsorption configuration, interfacial interactions, and intermolecular cohesive forces on the solid surface without the need for physical sample preparation. This fundamentally eliminates the efficiency bottleneck caused by lengthy steps in traditional experimental methods, such as sample preparation, curing, and environmental aging. It can rapidly respond to the evaluation needs of new adhesive formulations or new substrate surface treatment processes. By performing molecular dynamics simulations on the optimized model and calculating the interfacial interaction energy, and simultaneously constructing a bilayer initial model containing only the adhesive to simulate and calculate the interaction energy between the two sets of adhesives, this invention can quantitatively reveal the contribution of the interfacial adhesion force between the adhesive and the solid surface, as well as the intermolecular cohesive forces of the adhesive itself, to the overall bonding performance at the molecular scale. This overcomes the technical limitations of traditional macroscopic experiments that cannot deeply analyze van der Waals force distribution, molecular chain interpenetration behavior, and interfacial defect evolution at the atomic or molecular level. Furthermore, by performing shear simulations on the final configuration after molecular dynamics simulations and obtaining the adhesive fracture surface, combined with… E interface and E cohesive Numerical comparisons can accurately predict the fracture behavior and failure modes of adhesives under stress, transforming the traditional passive evaluation mode of manufacturing first and then testing into proactive performance prediction in the design stage. This provides forward-looking guidance for adhesive molecules that have not yet been synthesized or untreated solid surfaces, significantly reducing the blind spots in the R&D process. Attached Figure Description
[0020] Figure 1 The example shows the initial model of the adhesive.
[0021] Figure 2 The initial model of the lower surface solid is shown in the example.
[0022] Figure 3 The initial model of the upper surface solid is shown in the example.
[0023] Figure 4 This is an initialization model of the glass surface adhesive bonding system for an example.
[0024] Figure 5 This is a molecular dynamics shearing simulation used in the examples.
[0025] Figure 6 This is a molecular dynamics simulation system used in the examples to calculate the strength of the adhesive itself.
[0026] Figure 7 The molecular structure models of citric acid (a), Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide (b), and water molecule (c) in the examples are shown.
[0027] Figure 8 The interaction between the adhesive and the glass surface in Example 1 E interface How it changes with temperature.
[0028] Figure 9 The adhesive's intrinsic strength in Example 1 E cohesive The effect of temperature changes.
[0029] Figure 10 This is the initial model of the iron surface in Example 2.
[0030] Figure 11 This is the initial model of the adhesive bonding system for iron surfaces in Example 2.
[0031] Figure 12 This is a molecular dynamics shearing simulation from Example 2.
[0032] Figure 13 The interaction between the adhesive and the glass surface in Example 2 E interface How it changes with temperature. Detailed Implementation
[0033] The following is combined with Figures 1 to 13 The specific embodiments of the present invention will be described in detail below.
[0034] Example 1 A method for evaluating the bonding performance of adhesives on solid surfaces based on molecular dynamics simulation includes the following steps: An initial model of the adhesive bonding system to a solid surface is constructed, and the structure of the initial model is optimized to obtain an optimized model of the adhesive bonding system with minimal energy. Molecular dynamics equilibrium simulations were performed on the optimized model of the adhesive bonding system to obtain the final configuration of the adhesive bonding system after the molecular dynamics simulation. The interfacial interaction energy between the adhesive and the solid surface was obtained based on the molecular dynamics simulation results. E interface ; A bilayer initialization model containing only adhesives was constructed, and molecular dynamics equilibrium simulations were performed on the constructed bilayer initialization model containing only adhesives to obtain the interaction energy between the two sets of adhesive simulation systems. E cohesive ; Shear simulation was performed on the final configuration of the adhesive bonding system to obtain the fracture surface of the adhesive after the shear simulation. according to E interface , E cohesiveIn addition to the fracture surface of the adhesive, the bonding performance of the adhesive on the solid surface is comprehensively evaluated.
[0035] In some embodiments, the method for constructing an initialization model of the adhesive-solid surface bonding system includes: Construct initial models for the adhesive and solid surfaces respectively; the initial solid surface model includes a lower surface solid initial model and an upper surface solid initial model. Based on the molecular types that make up the adhesive, the Sketch function of Materials Studio software is used to construct adhesive molecules with different structures, and geometric optimization is performed to obtain the final optimized molecular topological parameters of bond length, bond angle and dihedral angle. Then, the Amorphous Cell Construction module is used to construct an initial model of the adhesive with reasonable structure and composition. The Build Layers function is used to assemble the initial model of the upper solid surface as the first layer, the initial model of the adhesive as the second layer, and the initial model of the lower solid surface as the third layer, resulting in an initial model of the adhesive bonding system consisting of the initial model of the lower solid surface, the initial model of the adhesive, and the initial model of the upper solid surface.
[0036] The initial model of the adhesive was constructed as a cubic lattice model with a length of 29.478 Å, a width of 34.038 Å, and a height of not less than 15 Å.
[0037] Specifically, the construction of the initial adhesive model in this embodiment includes the following steps: The adhesive is a Bola-type eutectic adhesive. The initial model of the adhesive includes three molecular structures: citric acid, Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide, and water. The molecular ratio of each component is: citric acid : Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide : water = 30 : 45 : 79. The three components were molecularly constructed using the Sketch Atom function of Materials Studio software, as follows: Figure 7 As shown in (a), (b), and (c), models of citric acid, Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide, and water molecules were constructed, respectively. Then, using the Amorphous Cell Construction module, an initial adhesive model containing 30 citric acid molecules, 45 Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide molecules, and 79 water molecules was constructed. The density of the initial adhesive model was 1.35 g / cm³. 3 ,like Figure 1 As shown, the initial model has a length of 29.478 Å, a width of 34.038 Å, and a height of 16.986 Å.
[0038] The solid surface is a non-metal such as glass, a metal such as iron or aluminum, or a metal oxide; when the solid surface is a glass surface, the silica surface in contact with the adhesive needs to be hydroxylated. The initial model of the solid surface is a cubic lattice model with a length of 29.478 Å, a width of 34.038 Å, and a height of 16.619 Å.
[0039] Construct an initial model of the lower surface solid.
[0040] In this embodiment, the solid surface is a glass surface, and the silica surface in contact with the adhesive needs to be hydroxylated. The specific method is as follows: Export the silica lattice file SiO2_quartz.msi from the Structures database in Materials Studio software. Then, adjust the lattice orientation using the Redefine Lattice function in the Symmetry section of the Build function. The Redefine Lattice parameters are set to A: 210, B: 010, and C: 001. Construct a 16 Å thick silica cubic lattice model using the CleaveSurface function in the Surface section of the Build function. Construct an initial silica model using the Supercell function in the Symmetry section of the Build function, with supercell parameters U = 6 and V = 4. Select the upper surface of the silica model and construct the hydroxyl groups at the adhesive-glass interface using the hydrogenation function. Add a 0.4948 Å thick vacuum layer using the Build Vacuum Slab function in the Crystals section of the Build function to construct the final initial glass model for the lower surface. Figure 2 As shown, the initial solid model of the lower surface is a cubic lattice model with dimensions of 29.478 Å × 34.038 Å × 16.619 Å.
[0041] Construct an initial model of the solid surface.
[0042] In some embodiments, the solid surface is a glass surface, and the silica surface in contact with the adhesive needs to be hydroxylated. The specific method is as follows: like Figure 3 As shown, the construction method is basically the same as that of the initial model of the lower surface solid. Finally, the silicon atom closest to the lower surface in the silica surface model is deleted, and hydrogen is added to the adjacent oxygen atom to construct the initial configuration of the upper surface solid containing the hydroxyl surface.
[0043] The initial model of the adhesive, the initial model of the upper surface solid, and the initial model of the lower surface solid are assembled to obtain the initial model of the adhesive bonding system on the glass surface.
[0044] The initial solid surface model and the initial adhesive model were assembled using the Build Layers function. The initial solid model on the upper surface was Layer 1, the initial adhesive model was Layer 2, and the initial solid model on the lower surface was Layer 3. This assembly resulted in a lower solid model / adhesive / upper solid model. Then, the Movement function was used to move the solid surface model, eliminating the vacuum layer between the adhesive and the initial solid surface model. Finally, the Rebuild Crystal function was used to adjust the z-axis dimension of the initial model to 60 Å, resulting in the final model as shown below. Figure 4 The initial model of the adhesive bonding system is shown. The simulation system size of the initial model is 29.478 Å × 34.038 Å × 60 Å.
[0045] The initial model of the adhesive system was structurally optimized to obtain an optimized model of the adhesive system that minimizes energy. The structural optimization methods included: using the COMPASS force field, employing the Steep algorithm for energy minimization, and setting a maximum of 5000 iterations.
[0046] The method for molecular dynamics equilibrium simulation includes the following steps: Molecular dynamics simulations were performed using the Forcite module in Modules. The ensemble was set to NVT, the thermostat to Nose, the simulation temperature to 298.15 K, the electrostatic interaction force was set to the Ewald method, the van der Waals force was set to Atombased, and the cutoff radius was 1.25 nm. The time step was 0.2 fs, the simulation time was 300 ps, and the changes in energy and simulated temperature were recorded.
[0047] The formula for calculating the interfacial interaction energy between adhesives and solid surfaces is as follows: E interface = ( E A-B -E A -E B ) / 2; where; E A-B The total energy of the adhesive solid surface bonding system; E A The total energy of the solid configuration of the upper and lower surfaces; E B Let be the total energy of the adhesive; the formula for calculating the interaction energy between the two simulated adhesive systems is: E cohesive =E ab -E a-E b ,in, E ab The total energy of the simulated system; E a , E b The total energy for each of the two adhesive groups is represented separately.
[0048] Methods for constructing a two-layer initialization model containing only adhesives include: Using the Build Layers function, both the first and second layers are selected as the initial adhesive model, and an initial simulation system containing two adhesive models is assembled. The Move function moves the initial model of two adhesive layers to eliminate the vacuum layer between the two sets of adhesives. By using the Rebuild Crystal function to adjust the model size along the z-axis in the initial model, a two-layer initialization model containing only adhesive was obtained, resulting in the final model shown below. Figure 6 The adhesive initialization model is shown. The simulation system size of the initialization model is 29.478 Å × 34.038 Å × 60 Å.
[0049] The shearing simulation method is as follows: The Rebuild Crystal function in Build's Crystals is used to reconstruct the lattice structure of the final adhesive bonding system. The Constraints function in the Modify module is used to fix all atoms in the solid configuration of the lower surface, restricting their movement in three dimensions; Shearing simulation was performed using the Forcite module in Modules, with a shear rate of 0.1 Å / ps, NVT selected as the ensemble, Nose selected as the thermostat, 298.15 K as the simulation temperature, and 300 ps as the simulation time.
[0050] After the shear simulation is completed, the adhesion performance of the adhesive on the glass surface can be evaluated based on the fracture surface of the adhesive.
[0051] A comprehensive method for evaluating the bonding performance of adhesives on solid surfaces includes the following steps: By comparison E interface and E cohesive The size relationship, combined with whether the adhesive fracture surface is located at the interface or inside the adhesive body, is used to determine the adhesive performance and failure mode of the adhesive: when E interface The absolute value is less than E cohesiveWhen the absolute value of the value is 0 and the adhesive fracture surface is located at the interface, the failure mode is determined to be interface failure; when E interface The absolute value is greater than E cohesive When the absolute value of the value is obtained and the fracture surface of the adhesive is located inside the adhesive body, the failure mode is determined to be cohesive failure.
[0052] The adhesion performance of this Bola-type eutectic adhesive to glass surfaces is affected by the interaction energy between the adhesive and the glass surface. E interface The interaction of the adhesive itself E cohesive The combined effects of these factors. Molecular dynamics simulations revealed that at 298.15 K, E interface It is -383.2 kcal / mol. E cohesive The strength is -860.3 kcal / mol, indicating a relatively weak interfacial interaction between the adhesive and the glass. The adhesive's own strength is much greater than its interaction force with the glass surface. In molecular dynamics shear simulations, such as... Figure 5 As shown, the adhesive matrix remained stable during the shearing process without any obvious breakage, but the adhesive showed obvious peeling on the glass surface. This indicates that under external tensile force, the bonding strength of the adhesive on the glass surface is mainly affected by the interfacial interaction between the adhesive and the glass. Under strong tensile force, the adhesive is very easy to peel off from the glass surface.
[0053] This method can accurately assess the impact of adhesive structure and composition on its bonding performance. By adjusting the number of water molecules in the adhesive, significant differences in adhesive performance were observed in this example. When the number of citric acid molecules and Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide molecules remained constant in the adhesive simulation system, and the number of water molecules was 0, at 298.15 K, E interface At a concentration of 383.2 kcal / mol, the adhesive exhibits a significant repulsive effect on the glass surface, preventing it from adhering properly. When the number of water molecules in the simulated adhesive system is 200, at 298.15 K, E interface The efficiency was -371.3 kJ / mol, which slightly reduced the interfacial interaction between the adhesive and the glass surface compared to the adhesive system with 79 water molecules.
[0054] Furthermore, by setting different temperatures and constructing different solid surface models, the bonding performance and temperature resistance of adhesives at different interfaces can be accurately evaluated, providing a reference for the selection and use of adhesives in different environments. Figure 8 The illustrated adhesive simulation system contains 30 citric acid molecules, 45 Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide molecules, and 200 water molecules. E interface The effect of temperature variation. (Through...) Figure 8 It can be observed that the adhesive in this embodiment exhibits good glass interface bonding performance at lower temperatures, specifically at 223.15 K. E interface The concentration was -433.3 kcal / mol. As temperature increased, the interaction between the adhesive and the glass surface decreased rapidly; at 273.15 K, E interface The concentration drops to -371.2 kcal / mol, and within the temperature range of 273.15 K to 323.15 K, the interaction energy between the adhesive and the glass surface remains essentially unchanged. For example... Figure 9 The illustrated adhesive simulation system contains 30 citric acid molecules, 45 Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide molecules, and 200 water molecules. E cohesive The effect of temperature variation. (Through...) Figure 9 It can be observed that the adhesive strength in this embodiment is also significantly affected by temperature; within the temperature range of 273.15K to 323.15K, the adhesive strength continuously increases with increasing temperature. At 323.15K, E cohesive It reached its maximum value of -1146 kcal / mol.
[0055] Example 2 The difference from Example 1 is that the solid surface in this example is an iron surface, which is used to evaluate the bonding performance of the adhesive on the iron surface.
[0056] In this embodiment, the solid surface is an iron surface. The initial model of the lower solid surface is the same as that of the upper solid surface. The construction method for both is based on the iron lattice model, and the specific construction is as follows: The lattice file Fe.msi was exported from the Structures database in Materials Studio software. Then, the initial model of the final solid surface was constructed using the Supercell function within the Symmetry module of the Build function. The supercell parameters were set to A:11, B:12, and C:5. Figure 10 As shown, the initial solid model of the lower surface is a cubic lattice model of 31.530Å × 34.397Å × 14.332Å.
[0057] The initial model of the adhesive, the initial model of the upper surface solid, and the initial model of the lower surface solid are assembled to obtain the initial model of the adhesive bonding system on the iron surface.
[0058] The Build Layers function is used to assemble the initial solid surface model and the initial adhesive model. The initial solid model for the upper surface is Layer 1, the initial adhesive model is Layer 2, and the initial solid model for the lower surface is Layer 3. The initial models of the iron surface and adhesive were assembled using the Build Layers function. The initial model of the upper solid surface was Layer 1, the initial model of the adhesive was Layer 2, and the initial model of the lower solid surface was Layer 3. The Matching parameter was set to Layer 2. This assembly resulted in the lower solid surface initial model / adhesive / upper solid initial model. Then, the Movement function was used to move the solid surface model to eliminate the vacuum layer between the adhesive and the initial solid surface model. Finally, the Rebuild Crystal function was used to adjust the model size in the z-axis direction of the initial model to 60 Å, resulting in the final model as shown below. Figure 11 The initial model of the adhesive bonding system is shown. The simulation system size of the initial model is 29.478 Å × 34.038 Å × 60 Å.
[0059] The initial model was structurally optimized to obtain an optimized model of the solid surface adhesive bonding system that minimizes energy.
[0060] The force field used is the COMPASS force field, and the energy minimization process uses the Steep algorithm with a maximum number of iterations of 5000.
[0061] Molecular dynamics simulation analysis was performed on the optimized model of the adhesive bonding system on the solid surface to obtain the final adsorption configuration of the adhesive on the solid surface and the interaction force between the adhesive and the solid surface.
[0062] The molecular dynamics simulation methods are as follows: Molecular dynamics simulations were performed using the Forcite module in Modules. The ensemble was set to NVT, the thermostat to Nose, and the simulation temperature to 298.15 K. The electrostatic interaction force was set to the Ewald method, the van der Waals force was set to Atom-based, and the cutoff radius was 1.25 nm. The molecular dynamics simulation was performed using equilibrium molecular dynamics, with a time step of 0.2 fs and a simulation time of 300 ps. The energy and simulation temperature changes of the optimized model were recorded.
[0063] Molecular dynamics simulations were performed on a model system containing an initial configuration of two layers of adhesive to obtain the intermolecular forces within the adhesive, which were then used to evaluate the strength of the adhesive itself.
[0064] Methods for molecular dynamics simulations include: An initial molecular dynamics simulation model was constructed to calculate the strength of the adhesive itself.
[0065] The method for constructing a molecular dynamics simulation model to calculate the strength of the adhesive itself includes: using the Build Layers function to select both Layer 1 and Layer 2 as the initial adhesive models to assemble an initial simulation system containing two adhesive models; then using the Move function to move the two adhesive initial models to eliminate the vacuum layer between the two sets of adhesives; finally, using the Rebuild Crystal function to adjust the model size in the z-axis direction of the initial model to 60 Å, resulting in the final simulation system as shown below. Figure 6 The adhesive initialization model is shown. The simulation system size of the initialization model is 29.478 Å × 34.038 Å × 60 Å.
[0066] Molecular dynamics simulations were performed on the initial model of the adhesive. The interaction forces between the two sets of adhesives were obtained based on the simulation results, which were used to evaluate the strength of the adhesive itself.
[0067] The molecular dynamics simulation methods are as follows: Molecular dynamics simulations were performed using the Forcite module in Modules. The ensemble was set to NVT, the thermostat to Nose, and the simulation temperature to 298.15 K. The electrostatic interaction force was set to the Ewald method, the van der Waals force was set to Atom-based, and the cutoff radius was 1.25 nm. The molecular dynamics simulation was performed using equilibrium molecular dynamics, with a time step of 0.2 fs and a simulation time of 300 ps. The energy and simulation temperature changes of the optimized model were recorded.
[0068] The formula for calculating the interfacial interaction energy between adhesives and solid surfaces is as follows: E interface = ( E A-B -E A -E B ) / 2; where; E A-B The total energy of the adhesive solid surface bonding system; E A The total energy of the solid configuration of the upper and lower surfaces; E B Let be the total energy of the adhesive; the formula for calculating the interaction energy between the two simulated adhesive systems is: E cohesive =E ab-E a -E b ,in, E ab The total energy of the simulated system; E a , E b The total energy for each of the two adhesive groups is represented separately.
[0069] Molecular dynamics shear simulations were performed on the adhesive bonding system. Based on the adhesive's own fracture and the adhesive residue on the solid surface, combined with the interaction energy between the adhesive and the glass surface... E interface The interaction of the adhesive itself E cohesive Evaluate the adhesive properties.
[0070] Molecular dynamics shear simulation was performed on the adhesive bonding system.
[0071] The methods for molecular dynamics shearing simulation are as follows: The Rebuild Crystal function in Build's Crystals was used to reconstruct the final configuration of the adhesive bonding system after the kinetic simulation. The lattice parameters were a: 100 Å, b: 100 Å, c: 52.53 Å. The Constraints function in the Modify module is used to fix all atoms in the solid configuration of the lower surface, restricting their movement in three dimensions; Shear simulation was performed using the Forcite module in Modules, with a shear rate of 0.1 Å / ps, NVT selected as the ensemble, Nose as the thermostat, 298.15 K as the simulation temperature, and 300 ps as the simulation time. After the shear simulation is completed, the adhesion performance of the adhesive on the iron surface can be evaluated based on the fracture surface of the adhesive.
[0072] Based on the adhesive's own fracture and the amount of adhesive residue on the solid surface, combined with the interaction energy between the adhesive and the iron surface... E interface The interaction of the adhesive itself E cohesive Evaluate the adhesive properties.
[0073] The adhesion performance of this Bola-type eutectic adhesive to iron surfaces is affected by the interaction energy between the adhesive and the iron surface. E interface The interaction of the adhesive itself E cohesiveThe combined effects of these factors. Molecular dynamics simulations revealed that at 298.15 K, E interface It is -1559.2 kcal / mol. E cohesive The strength is -865.9 kcal / mol, indicating a relatively strong interfacial interaction between the adhesive and iron. The adhesive's own strength is much less than its interaction force with the iron surface. In molecular dynamics shear simulations, such as... Figure 12 As shown, the adhesive exhibited a clear fracture surface during the shearing process, and a large amount of adhesive residue remained on the iron surface. This indicates that under external tensile force, the bonding strength of the adhesive on the iron surface is mainly limited by the strength of the adhesive itself. Under strong tensile force, the adhesive itself is easily broken, leading to bonding failure.
[0074] This method can accurately assess the impact of adhesive structure and composition on its bonding performance. By adjusting the number of water molecules in the adhesive, significant differences in adhesive performance were observed in this example. When the number of citric acid molecules and Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide molecules remained constant in the adhesive simulation system, and the number of water molecules was 0, at 298.15 K, E interface At a concentration of 485.1 kcal / mol, the adhesive exhibits a significant repulsive effect on iron, preventing it from adhering properly to the iron surface. When the number of water molecules in the simulated adhesive system is 200, at 298.15 K, E interface The efficiency was -1508.9 kJ / mol, which slightly reduced the interfacial interaction between the adhesive and the glass surface compared to the adhesive system with 79 water molecules.
[0075] In addition, by setting different temperatures and constructing different solid surface models, the bonding performance and temperature resistance of adhesives at different interfaces can be accurately evaluated, providing a reference for the selection and use of adhesives in different environments. Figure 13 This is a simulated adhesive system containing 30 citric acid molecules, 45 Bola-type -N,N,N',N'-tetramethylethylenediamine dioxide molecules, and 200 water molecules. E interface The effect of temperature variation: Within the temperature range of 223.15K to 323.15K, the adhesive performance on the iron surface is relatively stable. E interface The fluctuation range is less than 2.2%. Within the range of 248.15K to 273.15K, the adhesive exhibits strong interaction energy on the iron surface.
[0076] The above-disclosed embodiments are merely preferred embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation, characterized in that, Includes the following steps: An initial model of the adhesive bonding system to a solid surface is constructed, and the structure of the initial model is optimized to obtain an optimized model of the adhesive bonding system with minimal energy. Molecular dynamics equilibrium simulations were performed on the optimized model of the adhesive bonding system to obtain the final configuration of the adhesive bonding system after the molecular dynamics simulation. The interfacial interaction energy between the adhesive and the solid surface was obtained based on the molecular dynamics simulation results. E interface ; A bilayer initialization model containing only adhesives was constructed, and molecular dynamics equilibrium simulations were performed on the constructed bilayer initialization model containing only adhesives to obtain the interaction energy between the two sets of adhesive simulation systems. E cohesive ; Shear simulation was performed on the final configuration of the adhesive bonding system to obtain the adhesive fracture surface after the shear simulation. according to E interface , E cohesive In addition to the fracture surface of the adhesive, the bonding performance of the adhesive on the solid surface is comprehensively evaluated.
2. The method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation according to claim 1, characterized in that, The method for constructing the initialization model of the adhesive-solid surface bonding system includes: An initial model for the adhesive and an initial model for the solid surface are constructed separately; the initial model for the solid surface includes a lower surface solid initial model and an upper surface solid initial model. The initial model of the upper surface solid is assembled as the first layer, the initial model of the adhesive is assembled as the second layer, and the initial model of the lower surface solid is assembled as the third layer to obtain the initial model of the adhesive bonding system consisting of the initial model of the lower surface solid, the initial model of the adhesive, and the initial model of the upper surface solid.
3. The method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation according to claim 2, characterized in that, The method for constructing the initial model of the adhesive is as follows: Based on the molecular types that make up the adhesive, adhesive molecules with different structures are constructed, and geometric optimization is performed to obtain the final optimized bond lengths, bond angles, and dihedral angle molecular topological parameters. Then, an initial model of an adhesive with reasonable structure and composition is constructed. The initial model of the adhesive was constructed as a cubic lattice model with a length of 29.478 Å, a width of 34.038 Å, and a height of not less than 15 Å.
4. The method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation according to claim 2, characterized in that, The solid surface is a non-metal, a metal, or a metal oxide; when the solid surface is a silica surface, its contact surface with the adhesive is hydroxylated. The initial model of the solid surface is a cubic lattice model with a length of 29.478 Å, a width of 34.038 Å, and a height of 16.619 Å.
5. The method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation according to claim 1, characterized in that, The structural optimization method includes: using the COMPASS force field, selecting the Steep algorithm, and setting the maximum number of iterations to 5000.
6. The method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation according to claim 1, characterized in that, The method for constructing the two-layer initialization model containing only adhesive includes: Both the first and second layers are selected as the initial adhesive models, and an initial simulation system containing two adhesive models is assembled. Move the initial model of the two adhesive layers to eliminate the vacuum layer between the two sets of adhesives; Adjust the model size along the z-axis in the initial model to obtain a two-layer initialization model containing only the adhesive.
7. The method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation according to claim 1, characterized in that, The formula for calculating the interfacial interaction energy between adhesives and solid surfaces is as follows: E interface = ( E A-B -E A - E B ) / 2; where; E A-B The total energy of the adhesive solid surface bonding system; E A The total energy of the solid configuration of the upper and lower surfaces; E B Let be the total energy of the adhesive; the formula for calculating the interaction energy between the two simulated adhesive systems is: E cohesive =E ab -E a - E b ,in, E ab This represents the total energy of the simulated system. E a , E b The total energy of each of the two adhesive groups is represented separately.
8. The method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation according to claim 1, characterized in that, The method for simulating molecular dynamics equilibrium includes the following steps: Molecular dynamics simulations were performed using the Forcite module in Modules. The ensemble was set to NVT, the thermostat to Nose, the simulation temperature to 298.15 K, the electrostatic interaction force was set to the Ewald method, the van der Waals force was set to Atom based, and the cutoff radius was 1.25 nm. The time step was 0.2 fs, the simulation time was 300 ps, and the changes in energy and simulated temperature were recorded.
9. The method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation according to claim 1, characterized in that, The shearing simulation method is as follows: Lattice reconstruction of the final configuration of the adhesive bonding system; Fix all atoms in the solid configuration of the lower surface to restrict their movement in three dimensions; Shear simulations were performed with a shear rate of 0.1 Å / ps to 0.2 Å / ps, a simulation temperature of 298.15 K, and a simulation time of 200 ps to 300 ps.
10. The method for evaluating the solid surface bonding performance of adhesives based on molecular dynamics simulation according to claim 1, characterized in that, A comprehensive method for evaluating the bonding performance of adhesives on solid surfaces includes the following steps: By comparison E interface and E cohesive The size relationship, combined with whether the adhesive fracture surface is located at the interface or inside the adhesive body, is used to determine the adhesive performance and failure mode of the adhesive: when E interface The absolute value is less than E cohesive When the absolute value of the value is 0 and the adhesive fracture surface is located at the interface, the failure mode is determined to be interface failure; when E interface The absolute value is greater than E cohesive When the absolute value of the value is determined and the fracture surface of the adhesive is located inside the adhesive body, the failure mode is determined to be cohesive failure.