How to create an analysis model

Abstract

To provide a method for considering actual condensation reaction based on physical adsorption between silica and a silane coupling agent, for generating an analysis model.SOLUTION: There is provided a method for generating an analysis model having an interface structure in which silica and a silane coupling agent are condensed. The method is configured so that the computer executes: a first step S6 for executing molecular kinetic calculation in which the silica model and the silane coupling agent model are objects, for calculating a state in which the silica model and the silane coupling agent model are physically adsorbed; and a second step S7 for, after the first step S6, on the basis of a distance between the silica model and the silane coupling agent model, generating an interface structure in which the silica model and the silane coupling agent model are condensed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for creating an analytical model. [Background technology]

[0002] A method for calculating the correlation properties between silica and a silane coupling agent is proposed in the following Non-Patent Document 1. In this method, a model is created in which a silane coupling agent is bonded to a silanol group present on the surface of silica. [Prior art documents] [Patent documents]

[0003] [Non-Patent Document 1] Sanjib C. Chowdhury and John W. Gillespie, "Silica-silane coupling dynamics agent interphase properties using molecular simulations", J Mater Sci (2017), 52:12981-12998, July 27, 2017 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above method, arbitrary silanol groups are selected from among the multiple silanol groups on the silica surface and bonded to a silane coupling agent, which poses the problem that it is not possible to create an analytical model that takes into account the actual condensation reaction based on the physical adsorption of silica and the silane coupling agent.

[0005] The present disclosure has been devised in view of the above-described circumstances, and its main purpose is to provide a method capable of creating an analytical model taking into account the actual condensation reaction based on the physical adsorption of silica and a silane coupling agent. [Means for solving the problem]

[0006] The present disclosure provides a method for creating an analytical model having an interfacial structure in which silica and a silane coupling agent are condensed, the method comprising the steps of inputting a silica model that models the silica into a computer, and inputting a silane coupling agent model that models the silane coupling agent into the computer, wherein the computer executes a first step of performing molecular dynamics calculations on the silica model and the silane coupling agent model to calculate a state in which the silica model and the silane coupling agent model are physically adsorbed, and a second step of creating the interfacial structure in which the silica model and the silane coupling agent model are condensed, based on the distance between the silica model and the silane coupling agent model, after the first step. [Effects of the Invention]

[0007] By adopting the above steps, the analytical model creation method of the present disclosure makes it possible to create an analytical model having an interfacial structure in which silica and a silane coupling agent are condensed, taking into account the actual condensation reaction based on the physical adsorption of silica and a silane coupling agent. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a computer for executing the analysis model creation method of the present embodiment. [Figure 2] 10 is a flowchart illustrating a processing procedure of a method for creating an analysis model. [Figure 3] FIG. 1 is a conceptual diagram showing a cell in which a silica model is placed. [Figure 4] FIG. 1 is a conceptual diagram showing a cell in which a silica model and a silane coupling agent model are placed. [Figure 5] 1 is a conceptual diagram of a silica model and a silane coupling agent model. FIG. [Figure 6] FIG. 1 is a conceptual diagram showing a cell to which a silica model and a silane coupling agent model are physically adsorbed. [Figure 7] 10 is a flowchart showing the processing procedure of the first step. [Figure 8] 10 is a flowchart showing the processing procedure of a second step. [Figure 9] FIG. 1 is a conceptual diagram showing a silica model and a silane coupling agent model on which a siloxane bond model is created. [Figure 10] FIG. 1 is a conceptual diagram illustrating an analytical model. [Figure 11] 1 is a graph showing the relationship between the number of siloxane bond models and the number of times the first step, the second step, and the third step are repeated. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be understood that the drawings include exaggerated representations and representations that differ from the dimensional ratios of actual structures in order to facilitate understanding of the contents of the disclosure. Furthermore, identical or common elements are designated by the same reference numerals throughout the embodiments, and redundant explanations will be omitted. Furthermore, the specific configurations shown in the embodiments and drawings are intended to facilitate understanding of the contents of the present disclosure, and the present disclosure is not limited to the specific configurations shown in the drawings.

[0010] In the analytical model creation method of this embodiment (hereinafter, sometimes simply referred to as the "creation method"), an analytical model having an interface structure in which silica and a silane coupling agent are condensed is created. The creation method of this embodiment uses a computer.

[0011] [computer] FIG. 1 is a perspective view showing a computer 1 for executing the analytical model creation method of this embodiment. The computer 1 includes a main body 1a, a keyboard 1b, a mouse 1c, and a display device 1d. The main body 1a is provided with a central processing unit (CPU), ROM, working memory, storage devices such as magnetic disks, and disk drive devices 1a1 and 1a2. The storage device stores in advance a processing procedure (program) for executing the creation method of this embodiment.

[0012] [Silane coupling agents] The silane coupling agent is not particularly limited as long as it can condense with silica (for example, form a siloxane bond). Examples of silane coupling agents include bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) polysulfide, and bis(2-triethoxysilylethyl) polysulfide. The silane coupling agent used in this embodiment is bis(3-triethoxysilylpropyl) disulfide, but is not particularly limited. In addition, the silane coupling agent may have a novel structure that does not currently exist.

[0013] [How to create an analysis model] Next, a creation method of this embodiment will be described. Fig. 2 is a flowchart for explaining the processing steps of the analysis model creation method of this embodiment. Fig. 3 is a conceptual diagram showing a cell 4 in which a silica model 2 is arranged. Fig. 4 is a conceptual diagram showing a cell 4 in which a silica model 2 and a silane coupling agent model 3 are arranged. Fig. 5 is a conceptual diagram of the silica model 2 and the silane coupling agent model 3. In Fig. 5, a portion of the silica model 2 and one silane coupling agent model 3 are representatively shown, and the silica model 2 is colored.

[0014] [Enter silica model] In the production method of this embodiment, first, a silica model 2, which is a model of silica, is input into a computer 1 (shown in FIG. 1) (step S1). As shown in FIGS. 3 to 5, the silica model 2 of this embodiment is configured as an all-atom model, but is not limited to this, and may be, for example, a coarse-grained model.

[0015] As shown in FIG. 5, the silica model 2 of this embodiment is configured to include a plurality of particle models 5 and bond models 6 that bond the particle models 5, 5 together.

[0016] The particle model 5 of this embodiment includes a silicon particle model 5si and an oxygen particle model 5o, which respectively model silicon atoms and oxygen atoms contained in silica. The silica model 2 of this embodiment has a silanol group model 7, which models silanol groups contained in silica. This silanol group model 7 is configured to include an oxygen particle model 5o and a hydrogen particle model 5h, which models hydrogen atoms.

[0017] In the particle models 5 of this embodiment (silicon particle model 5si, oxygen particle model 5o, and hydrogen particle model 5h), parameters such as mass, diameter, charge, and initial coordinates are defined. As a result, the particle models 5 are treated as mass points in the equation of motion in molecular dynamics calculations.

[0018] The bond model 6 is used to constrain the particle models 5, 5. A potential (not shown) that generates an interaction (including repulsive and attractive forces) is defined between adjacent particle models 5, 5 via the bond model 6. These potentials include, for example, a bond potential, a bond angle potential, and a bond dihedral angle potential. Such potentials can be appropriately defined based on the description in, for example, a patent document (JP 2018-032077 A). This defines a silica model 2. The silica model 2 is stored in a computer 1 (shown in FIG. 1).

[0019] [Enter the silane coupling agent model] Next, in the production method of this embodiment, a silane coupling agent model 3, which is a model of a silane coupling agent, is input into a computer 1 (shown in FIG. 1) (step S2). As shown in FIG. 5, the silane coupling agent model 3 of this embodiment is configured as an all-atom model, similar to the silica model 2, but may also be configured as a coarse-grained model.

[0020] The silane coupling agent model 3 of this embodiment is configured to include a plurality of particle models 9 and bond models 10 that bond the particle models 9, 9 together.

[0021] The particle model 9 of this embodiment is a model of the carbon atom, oxygen atom, hydrogen atom, sulfur atom, and silicon atom contained in the silane coupling agent. Therefore, the particle model 9 includes a carbon particle model 9c, an oxygen particle model 9o, a hydrogen particle model 9h, a sulfur particle model 9s, and a silicon particle model 9si. The particle model 9 and the bond model 10 (interaction) are set in the same manner as the particle model 5 and the bond model 6 of the silica model 2.

[0022] The silane coupling agent model 3 of this embodiment has a silanol group model 8 that models a silanol group contained in a silane coupling agent (a silane coupling agent in which an alkoxy group is hydrolyzed). This silanol group model 8 is configured to include an oxygen particle model 9o and a hydrogen particle model 9h. The silane coupling agent model 3 is stored in a computer 1 (shown in FIG. 1).

[0023] Cell Input Next, in the creation method of this embodiment, a cell 4 (shown in FIG. 3), which is a virtual space, is input to the computer 1 (shown in FIG. 1) (step S3). The cell 4 of this embodiment is defined as a calculation target space for molecular dynamics calculation.

[0024] 3, the cell 4 of this embodiment has at least one pair of surfaces 11, 11 facing each other (three pairs of surfaces 11, 11 facing each other in this embodiment). The cell 4 of this embodiment is defined as a rectangular parallelepiped or cube (a rectangular parallelepiped in this embodiment).

[0025] In this embodiment, a periodic boundary condition is defined on each face 11 of the cell 4. This allows, in the molecular dynamics calculation described below, calculation to be performed so that, for example, a part of the silane coupling agent model 3 (shown in FIG. 5) that has left one face 11a enters from the other face 11b.

[0026] The size of the cell 4 can be set appropriately depending on, for example, the total number of silica models 2 and silane coupling agent models 3 placed inside the cell 4. The cell 4 is stored in a computer 1 (shown in FIG. 1).

[0027] [Layout of silica model and silane coupling agent model] Next, in the production method of this embodiment, the silica model 2 and the silane coupling agent model 3 are placed inside the cell 4 (step S4).

[0028] In step S4 of this embodiment, first, as shown in Fig. 3, inside the cell 4, a silica model 2 is placed along at least one surface 11 constituting the cell 4. As a result, a silica model 2 that models a portion including the outer surface of the silica is set inside the cell 4. As shown in Figs. 3 and 5, silanol group models 7 (hydrogen particle models 5h and oxygen particle models 5o) are placed on the outer surface 12 side of the silica model 2 (in this example, the opposite side in the z-axis direction from the surface 11 on which the silica model 2 is placed).

[0029] Next, in step S4 of this embodiment, as shown in Fig. 4, at least one (in this example, multiple) silane coupling agent model 3 is randomly arranged inside the cell 4 in a region other than the region where the silica model 2 is arranged. The arrangement of the silica model 2 and the silane coupling agent model 3 may be performed by the computer 1 (shown in Fig. 1) or may be performed by an operator. The cell 4 in which the silica model 2 and the silane coupling agent model 3 are arranged is stored in the computer 1 (shown in Fig. 1).

[0030] [Potential definition] 5, a potential P1 is defined between adjacent particle models 5 and 9 without a bond model 6 or 10 in between (step S5). In this embodiment, a potential P1 is defined between adjacent particle models 5 and 5 of the silica model 2, between adjacent particle models 9 and 9 of the silane coupling agent model 3, and between adjacent particle models 5 and 9 of the silica model 2 and silane coupling agent model 3.

[0031] In this embodiment, an LJ potential is used as the potential P1. With this potential P1, attractive and repulsive forces can be defined between adjacent particle models (between particle models 5, 5, between particle models 9, 9, and between particle models 5, 9) without using bond models 6, 10. The LJ potential can be appropriately defined based on the description in, for example, a patent document (JP 2020-086773 A). The potential P1 is stored in a computer 1 (shown in FIG. 1).

[0032] [1st step] Next, in the creation method of this embodiment, the computer 1 (shown in Fig. 1) calculates the state in which the silica model 2 and the silane coupling agent model 3 shown in Fig. 4 and Fig. 5 are physically adsorbed (first step S6). In the first step S6, a molecular dynamics calculation is performed on the silica model 2 and the silane coupling agent model 3, thereby calculating the state in which the silica model 2 and the silane coupling agent model 3 are physically adsorbed.

[0033] In molecular dynamics calculations, for example, Newton's equations of motion are applied to the cell 4 shown in Figure 4 for a predetermined time, assuming that the silica model 2 and silane coupling agent model 3 follow classical mechanics. The movements of the particle models 5 and 9 (shown in Figure 5) at each time are tracked for each unit time step of the molecular dynamics calculations. Such structural relaxation calculations can be performed using, for example, COGNAC, which is included in the Soft Material Integrated Simulator (J-OCTA) manufactured by JSOL Corporation.

[0034] In the molecular dynamics calculation of this embodiment, the pressure (e.g., 1 atm) is kept constant in the cell 4. As a result, in the first step S6, the initial positions of the silica model 2 and the silane coupling agent model 3 are relaxed to approximate the actual molecular motion of silica and the silane coupling agent, and a state in which the silica model 2 and the silane coupling agent model 3 are physically adsorbed can be calculated. To stably calculate the physically adsorbed state, structural relaxation may be calculated with the position of the silica model 2 constrained. FIG. 6 is a conceptual diagram showing the cell 4 to which the silica model 2 and the silane coupling agent model 3 are physically adsorbed.

[0035] [First calculation step] 7 is a flowchart showing the processing procedure of the first step S6 of this embodiment. In the first step S6 of this embodiment, first, a molecular dynamics calculation is performed based on a second temperature higher than a predetermined first temperature (first calculation step S61). The first temperature and the second temperature are temperatures set in cell 4 (shown in FIGS. 4 and 6).

[0036] The first temperature may be set as appropriate as long as it is lower than the second temperature. In this embodiment, the first temperature is set to a temperature at which silica and the silane coupling agent are condensed (for example, room temperature (290 to 310 K)).

[0037] In the first calculation step S61 of this embodiment, the molecular dynamics calculation is performed based on a second temperature higher than the first temperature, thereby allowing for greater movement of the silane coupling agent model 3 than when the molecular dynamics calculation is performed at the first temperature. This allows the position of the silane coupling agent model 3 to be moved away from the local stable point, thereby promoting physical adsorption with the silica model 2. Here, the local stable point refers to a state in which the silane coupling agent models 3 interact with each other in a manner dependent on the initial position of the silica coupling agent model, resulting in a structure in which the silane coupling agent model 3, which may be physically adsorbed to the silica model 2, cannot be physically adsorbed.

[0038] The second temperature can be set appropriately as long as it is higher than the first temperature. In this embodiment, the second temperature is preferably set to 380 to 420 K. Setting the second temperature to 380 K or higher makes it possible to move the position of the silane coupling agent model 3 away from the local stable point, thereby promoting physical adsorption in the second calculation step S62. On the other hand, setting the second temperature to 420 K or lower prevents the movement of the silane coupling agent model 3 from becoming too large, and prevents the silane coupling agent model 3 from moving too far away from the silica model 2 (which would make it impossible to calculate physical adsorption). From this perspective, the second temperature is preferably 390 K or higher and 410 K or lower.

[0039] In the first calculation step S61, it is preferable to perform the molecular dynamics calculation until the position of the silane coupling agent model 3 escapes from the local stable point. Whether or not the local stable point has been escaped can be determined as appropriate, for example, based on the potential energy change of the simulation system.

[0040] [Second calculation process] Next, in the first step S6 of this embodiment, after the first calculation step S61, a molecular dynamics calculation is performed based on the first temperature (second calculation step S62). In the second calculation step S62, after the position of the silane coupling agent model 3 moves away from the local stable point, a molecular dynamics calculation is performed based on the first temperature at which the silica and the silane coupling agent are condensed. As a result, in the second calculation step S62, the physical adsorption between the silica model 2 and the silane coupling agent model 3 can be promoted based on the actual condensation reaction between the silica and the silane coupling agent, as shown in FIG.

[0041] In the second calculation step S62 of this embodiment, it is preferable to perform molecular dynamics calculations until the silane coupling agent model 3 reaches an equilibrium state. As a result, in the first step S6, the physical adsorption between the silica model 2 and the silane coupling agent model 3 can be calculated. The cell 4 (shown in FIG. 6) in which the physical adsorption between the silica model 2 and the silane coupling agent model 3 is calculated is stored in the computer 1 (shown in FIG. 1).

[0042] [Second process] Next, in the preparation method of this embodiment, the computer 1 (shown in FIG. 1) prepares an interface structure in which the silica model 2 and the silane coupling agent model 3 are condensed based on the distance between the silica model 2 and the silane coupling agent model 3 (second step S7). The second step S7 of this embodiment is performed after the first step S6 in which the silica model 2 and the silane coupling agent model 3 are physically adsorbed.

[0043] [Calculating the distance between the silica model and the silane coupling agent model] 8 is a flowchart showing the procedure of the second step S7 of this embodiment. In the second step S7 of this embodiment, first, as shown in FIG. 5, the distance L1 between the silanol group model 7 of the silica model 2 and the silanol group model 8 of the silane coupling agent model 3 is calculated (step S71).

[0044] In this embodiment, the distance (shortest distance) L1 between the silanol group model 8 of all silane coupling agent models 3 and the silanol group model 7 of the silica model 2 is calculated. In this embodiment, for example, the distance (shortest distance) L1 between the hydrogen particle model 5h of the silanol group model 7 of the silica model 2 and the oxygen particle model 9o of the silanol group model 8 of the silane coupling agent model 3 is calculated. The distance (shortest distance) L1 is stored in the computer 1 (shown in FIG. 1).

[0045] [Create a siloxane model] Next, in the second step S7 of this embodiment, a siloxane bond model 15 is created (step S72). In step S72, the siloxane bond model is created when it is determined that the distance L1 between the silanol group model 7 of the silica model 2 and the silanol group model 8 of the silane coupling agent model 3 is within a predetermined second threshold. FIG. 9 is a conceptual diagram showing the silica model 2 and the silane coupling agent model 3 on which the siloxane bond model 15 has been created. In FIG. 9, the silica model 2 is colored, as in FIG. 5.

[0046] The siloxane bond model 15 of this embodiment is a model of a siloxane bond (Si-O-Si) generated by condensation of silica and a silane coupling agent. Therefore, in this embodiment, the siloxane bond model 15 shown in FIG. 9 can be created by calculating the bond between the silica model 2 and the silane coupling agent model 3.

[0047] The second threshold value can be set appropriately. Condensation between silica and the silane coupling agent generates siloxane bonds through hydrogen bonds between the silica and the silane coupling agent (hydrogen bonds between silanol groups). Therefore, the second threshold value in this embodiment is preferably set based on the distance of the hydrogen bonds between the silica and the silane coupling agent (for example, 1.5 to 2.5 Å).

[0048] 5, in step S72 of the present embodiment, it is determined whether the distance (shortest distance) L1 between the silanol group model 8 of all silane coupling agent models 3 and the silanol group model 7 of the silica model 2 is within a second threshold value. Then, in step S72, a siloxane bond model 15 (shown in FIG. 9) is created for pairs of the silanol group model 8 of the silane coupling agent model 3 and the silanol group model 7 of the silica model 2, for which the distance L1 is within the second threshold value.

[0049] As shown in Figure 9, in step S72 of this embodiment, a siloxane bond model 15 is created by combining a silicon particle model 5si of the silica model 2 with a silicon particle model 9si and an oxygen particle model 9o of the silane coupling agent model 3.

[0050] In step S72 of this embodiment, the hydrogen particle model 5h is cleaved from the silanol group model 7 of the silica model 2 shown in Fig. 5 by creating the siloxane bond model 15. Furthermore, the hydrogen particle model 9h and the oxygen particle model 9o are cleaved from the silanol group model 8 of the silane coupling agent model 3.

[0051] In the second step S7 of this embodiment, an analytical model 20 having an interface structure 21 in which silica and a silane coupling agent are condensed is created by creating a siloxane bond model 15. Fig. 10 is a conceptual diagram showing the analytical model 20. The analytical model 20 is stored in the computer 1 (shown in Fig. 1).

[0052] As described above, in the preparation method of this embodiment, a molecular dynamics calculation is performed in the first step S6, and a state in which the silica model 2 and the silane coupling agent model 3 are physically adsorbed can be calculated based on the interaction between the silica and the silane coupling agent (shown in FIG. 6). Furthermore, in the second step S7, an interface structure 21 (shown in FIG. 10) in which the silica model 2 and the silane coupling agent model 3 are condensed is prepared based on the distance L1 (shown in FIG. 5) between the silica model 2 and the silane coupling agent model 3 that are physically adsorbed to each other. As described above, in the preparation method of this embodiment, it is possible to prepare an analytical model 20 having an interface structure in which the silica and the silane coupling agent are condensed, taking into account the actual condensation reaction based on the physical adsorption of the silica and the silane coupling agent.

[0053] [Create a water molecule model] Next, in the second step S7 of this embodiment, as shown in Fig. 9, a water molecule model 22 is created as a by-product of the siloxane bond model 15 (step S73). In the condensation reaction between silica and a silane coupling agent, water molecules are generated as a by-product of the siloxane bond. Therefore, in step S73 of this embodiment, a water molecule model 22 is created by modeling the by-product water molecules.

[0054] In step S73 of this embodiment, the hydrogen particle model 5h cleaved from the silanol group model 7 of the silica model 2 is bonded to the silanol group model 8 (hydrogen particle model 9h and oxygen particle model 9o) cleaved from the silane coupling agent model 3. This creates a water molecule model 22 that includes one hydrogen particle model 9h and two oxygen particle models 5o and 9o. Therefore, in the second step S7 of this embodiment, it is possible to reproduce the actual condensation reaction between silica and the silane coupling agent. The water molecule model 22 is stored in the computer 1 (shown in FIG. 1).

[0055] [Delete water molecule model] Next, in the second step S7 of this embodiment, the water molecule model 22 (shown in FIG. 9) is deleted (step S74). In step S74 of this embodiment, the water molecule model 22 (shown in FIG. 9) created in step S73 is deleted in cell 4 shown in FIG. 10. As a result, in the creation method of this embodiment, it is possible to create an analytical model 20 in which water molecules have been deleted from the interface structure in which silica and a silane coupling agent are condensed. The analytical model 20 in which the water molecule model 22 has been deleted is stored in the computer 1 (shown in FIG. 1).

[0056] [3rd step] Next, in the creation method of this embodiment, after the second step S7, the computer 1 (shown in FIG. 1) calculates structural relaxation based on the molecular dynamics method for the interface structure 21 (third step S8). In the third step S8 of this embodiment, similar to the first step S6, the molecular dynamics calculation is performed in the cell 4 shown in FIG. 10 while the pressure (for example, 1 atm) is kept constant.

[0057] In this embodiment, molecular dynamics calculations are performed until the silica model 2, the silane coupling agent model 3, and the siloxane bond model 15 (shown in FIG. 9) reach an equilibrium state. This allows for the creation of an analytical model 20 that stabilizes an interface structure 21 in which the silica model 2, including the siloxane bond model 15, and the silane coupling agent model 3 are condensed. In this embodiment, the water molecule model 22 is deleted, which prevents an increase in the number of calculation targets, allowing the silica model 2 and the silane coupling agent model 3 to reach an equilibrium state more quickly.

[0058] The temperature for the molecular dynamics calculation in the third step S8 can be set as appropriate. In the third step S8, the molecular dynamics calculation is preferably performed based on the first temperature. This prevents the movement of the silane coupling agent model 3 from becoming excessively large, making it possible to calculate the equilibrium state. The analytical model 20 having the relaxed interface structure 21 is stored in the computer 1.

[0059] [Determine whether the number of condensed elements is greater than or equal to the first threshold] 2, in the production method of this embodiment, it is determined whether the number of siloxane bond models 15 (shown in FIG. 9) formed by condensation of silica models 2 and silane coupling agent models 3 is equal to or greater than a predetermined first threshold (step S9). The first threshold can be set appropriately based on, for example, the number of silane coupling agent models 3 (silanol group models 8) and the desired interface structure required for analysis of the silane coupling agent. In this embodiment, the first threshold is set to, for example, 30 to 50.

[0060] If it is determined in step S9 that the number of condensed molecules is equal to or greater than the first threshold value ("Yes" in step S9), the next step S10 is performed. On the other hand, if it is determined in step S9 that the number of condensed molecules is less than the first threshold value ("No" in step S9), the first step S6, the second step S7, and the third step S8 are performed.

[0061] Thus, in the preparation method of this embodiment, the first step S6, the second step S7, and the third step S8 are repeated until the number of condensed molecules reaches or exceeds the first threshold, thereby reliably calculating an analytical model 20 (shown in FIG. 10) having an interface structure 21 with the desired number of condensations. Furthermore, in this embodiment, in the first step S6, the second step S7, and the third step S8, which are performed again, the physical adsorption and new condensation of the silane coupling agent model 3 can be calculated taking into account the influence of the silane coupling agent model 3 that has already condensed on the silica model 2. Therefore, in the preparation method of this embodiment, the analytical model 20 can be prepared taking into account the actual condensation reaction that gradually progresses while being influenced by the silane coupling agent that has already condensed.

[0062] The silane coupling agent model 3 that did not condense with the silica model 2 (that did not bond via the siloxane bond model 15) does not constitute the interface structure 21 of the analytical model 20. Therefore, the silane coupling agent model 3 that did not condense may be deleted.

[0063] [Evaluating the condensation reaction] Next, in the creation method of this embodiment, it is determined whether the interface structure 21 (shown in FIG. 10) of the analytical model 20 is good or bad (step S10). In step S10, for example, it is determined whether the interface structure 21 is good or bad based on the position where the silica model 2 and the silane coupling agent model 3 are condensed (the position where the siloxane bond model 15 (shown in FIG. 9) is created). Furthermore, the determination of the quality of the interface structure may be made by the computer 1 (shown in FIG. 1) or by an operator.

[0064] In step S10, if it is determined that the interfacial structure of the analytical model 20 is good ("Yes" in step S10), a product (e.g., a rubber product such as a tire) using silica and a silane coupling agent is manufactured (step S11). In step S11, a new simulation is performed using the analytical model 20, and a product (e.g., a rubber product) may be manufactured based on the analysis results of the simulation. This makes it possible to manufacture a product with desired performance.

[0065] On the other hand, if it is determined in step S10 that the interfacial structure of the analytical model 20 is not satisfactory ("No" in step S10), the silane coupling agent is changed (step S12), and steps S1 to S10 are performed again. In step S12, the silane coupling agent is changed to one with a different chemical structure. This makes it possible, with the creation method of this embodiment, to create an analytical model 20 having a desired interfacial structure 21, manufacture a product with desired performance, and the like. The changed silane coupling agent may have a new structure that does not currently exist.

[0066] [Method for creating an analysis model (second embodiment)] In the second step S7 of the above-described embodiments, step S73 of creating a water molecule model 22 (shown in FIG. 9) is performed, but the present invention is not limited to this. For example, the oxygen particle model 5o cleaved from the silanol group model 7 of the silica model 2 and the silanol group model 8 (hydrogen particle model 9h and oxygen particle model 9o) cleaved from the silane coupling agent model 3 may be deleted. This omits step S73 of creating the water molecule model 22 and step S74 of deleting the water molecule model 22 shown in FIG. 8, thereby shortening the calculation time required to create the analytical model 20.

[0067] [Method for creating an analysis model (third embodiment)] In the second step S7 in the above-described embodiments, step S74 of deleting the water molecule model 22 (shown in FIG. 9 ) is performed, but the present invention is not limited to this. For example, step S74 of deleting the water molecule model 22 may be omitted. As a result, the creation method of this embodiment makes it possible to create an analytical model 20 that includes a water molecule model 22 created as a by-product of the siloxane bond model 15. Such an analytical model makes it possible to analyze the influence of water molecules on siloxane bonds, etc.

[0068] [Method for creating an analysis model (fourth embodiment)] In the creation methods of the above-described embodiments, an analytical model 20 having an interface structure 21 in which the silica model 2 and the silane coupling agent model 3 are condensed is created, but the present invention is not limited to this. For example, not only the condensation between the silica model 2 and the silane coupling agent model 3 but also the condensation between the silane coupling agent models 3, 3 themselves may be calculated.

[0069] Although particularly preferred embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the illustrated embodiments and can be modified and implemented in various forms. [Example]

[0070] Based on the processing procedure shown in FIG. 2, analytical models having an interface structure in which silica and a silane coupling agent were condensed were created (Examples 1 and 2).

[0071] In Examples 1 and 2, a first step was carried out in which a molecular dynamics calculation was carried out on a silica model and a silane coupling agent model to calculate the state in which the silica model and the silane coupling agent model were physically adsorbed. In the first step, a first calculation step was carried out in which a molecular dynamics calculation was carried out based on a second temperature higher than the first temperature, based on the procedure shown in Figure 7. Furthermore, after the first calculation step, a second calculation step was carried out in which a molecular dynamics calculation was carried out based on the first temperature, based on the procedure shown in Figure 8.

[0072] In Example 1 and Example 2, the second step was carried out to create an interface structure in which the silica model and the silane coupling agent model were condensed based on the distance between the silica model and the silane coupling agent model.In the second step, when the distance between the silanol group model of the silica model and the silane coupling agent model of the silane coupling agent model was determined to be within a second threshold, a siloxane bond model was created that bonded the silica model and the silane coupling agent model.Then, in Example 1 and Example 2, the third step was carried out to calculate the structural relaxation based on molecular dynamics for the surface structure.

[0073] In Example 1, the first, second, and third steps were each performed once. On the other hand, in Example 2, the first, second, and third steps were repeatedly performed until the number of condensed molecules reached or exceeded the first threshold. The common specifications are as follows: Silane coupling agent: Bis(3-triethoxysilylpropyl) disulfide Silane coupling agent model ratio: 0.8 / 1.0 nm 2 1st temperature: 300K Second temperature: 400K First threshold: 40 Second threshold: 2Å

[0074] As a result of the test, in Examples 1 and 2, an analytical model was created that had an interface structure in which silica and a silane coupling agent were condensed, taking into account the actual condensation reaction based on the physical adsorption of silica and a silane coupling agent.

[0075] Figure 11 is a graph showing the relationship between the number of siloxane bond models and the number of repetitions of steps 1, 2, and 3. As shown in Figure 11, in Example 2, the number of condensed models increased as the number of repetitions increased. Therefore, in Example 2, an analytical model was created taking into account the actual condensation reaction that gradually progresses while being influenced by the already condensed silane coupling agent.

[0076] [Note] The present disclosure includes the following aspects.

[0077] [Disclosure 1] A method for creating an analytical model having an interface structure in which silica and a silane coupling agent are condensed, comprising: inputting a silica model obtained by modeling the silica into a computer; and inputting a silane coupling agent model obtained by modeling the silane coupling agent into the computer, The computer a first step of calculating a state in which the silica model and the silane coupling agent model are physically adsorbed by performing a molecular dynamics calculation on the silica model and the silane coupling agent model; After the first step, a second step is carried out in which the interface structure in which the silica model and the silane coupling agent model are condensed is created based on the distance between the silica model and the silane coupling agent model. How to create an analytical model. [Disclosure 2] The analytical model creation method described in Disclosure 1 further includes, after the second step, a third step in which the computer calculates structural relaxation based on molecular dynamics for the interface structure. [Disclosure 3] The analytical model creation method according to Disclosure 2, wherein the first step, the second step, and the third step are repeated until the number of condensed elements becomes equal to or greater than a predetermined first threshold value. [Disclosure 4] the first step includes a first calculation step of performing the molecular dynamics calculation based on a second temperature higher than a predetermined first temperature; The method for creating an analytical model according to any one of Disclosures 1 to 3, further comprising, after the first calculation step, a second calculation step of performing the molecular dynamics calculation based on the first temperature. [Disclosure 5] the silica model is an all-atom model having a silanol group model that models a silanol group contained in the silica, the silane coupling agent model is an all-atom model having a silanol group model that models a silanol group contained in the silane coupling agent, The analytical model creation method described in any one of Disclosures 1 to 4, wherein the second step includes a step of creating a siloxane bond model that bonds the silica model and the silane coupling agent model when it is determined that the distance between the silanol group model of the silica model and the silane coupling agent model is within a predetermined second threshold. [Disclosure 6] The analytical model creating method according to the present disclosure 5, wherein the second threshold is set based on the distance of a hydrogen bond between the silica and the silane coupling agent. [Disclosure 7] The second step is a step of creating a water molecule model as a by-product of the siloxane bond model; and deleting the water molecule model. [Explanation of symbols]

[0078] S6 1st process S7 2nd process

Claims

1. A method for creating an analytical model having an interface structure in which silica and a silane coupling agent are condensed, comprising: inputting a silica model obtained by modeling the silica into a computer; and inputting a silane coupling agent model obtained by modeling the silane coupling agent into the computer, the silica model is an all-atom model having a silanol group model that models a silanol group contained in the silica, The all-atom model of the silica model includes a silicon particle model that models silicon atoms contained in the silica, the silane coupling agent model is an all-atom model having a silanol group model that models a silanol group contained in the silane coupling agent, the all-atom model of the silane coupling agent model includes a silicon particle model and an oxygen particle model that respectively model silicon atoms and oxygen atoms contained in the silane coupling agent, The computer a first step of calculating a state in which the silica model and the silane coupling agent model are physically adsorbed by performing a molecular dynamics calculation on the silica model and the silane coupling agent model; After the first step, a second step is carried out in which the interface structure in which the silica model and the silane coupling agent model are condensed is created based on the distance between the silica model and the silane coupling agent model; the second step includes a step of creating a siloxane bond model that bonds the silica model and the silane coupling agent model when it is determined that the distance between the silanol group model of the silica model and the silane coupling agent model is within a predetermined second threshold, and a step of creating a water molecule model as a by-product of the siloxane bond model; In the step of creating the siloxane bond model, the silicon particle model of the silica model is combined with the silicon particle model and the oxygen particle model of the silane coupling agent model to create the siloxane bond model; In the step of creating the water molecule model, a hydrogen particle model cleaved from the silanol group model of the silica model is bonded to the silanol group model cleaved from the silane coupling agent model. How to create an analytical model.

2. A method for creating an analytical model as described in claim 1, wherein the second threshold is set based on the distance of the hydrogen bond between the silica and the silane coupling agent.

3. A method for creating an analytical model as described in claim 1 or 2, wherein the second step includes a step of deleting the water molecule model.

4. A method for creating an analytical model described in any one of claims 1 to 3, further comprising a third step in which, after the second step, the computer calculates structural relaxation based on molecular dynamics for the interfacial structure.

5. A method for creating an analytical model as described in claim 4, wherein the first step, the second step, and the third step are repeated until the number of condensed particles becomes equal to or greater than a predetermined first threshold value.

6. The first step includes a first calculation step of performing the molecular dynamics calculation based on a second temperature higher than a predetermined first temperature; 6. The analytical model creation method according to claim 1, further comprising, after the first calculation step, a second calculation step of performing the molecular dynamics calculation based on the first temperature.

Images