Construction method and application of a dissipative particle dynamics force field and a coarse-grained model with topological structure

Abstract

The present invention discloses a method for constructing a dissipative particle dynamics force field and a coarse-grained model with topological structure, and its application. The method of the present invention comprises the following steps: (1) dividing structural units into segments, identifying properties and mapping them into different coarse-grained beads; (2) automatically fitting the DPD force field parameters to the molecular structures of the corresponding segments selected in step (1); (3) constructing a coarse-grained model with a polymer topological structure. The construction method of the present invention improves the accuracy of the DPD force field, promotes the development of the DPD force field, and has important guiding significance for studying the influence of the microstructure of the self-assembly process of polymer systems in solution.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer self-assembly, and particularly relates to an automated construction method and application of a dissipative particle dynamics force field and a coarse-grained model with topological structure. Background Art

[0002] Polymer self-assembly has wide applications. To explore the polymer self-assembly process, its structural characteristics and kinetic properties, researchers have used numerous experimental techniques. However, since the scale of polymer self-assembly behavior is in the nanometer range, current experimental techniques are difficult to obtain detailed information on the formation and disassembly processes of self-assemblies, and are even less able to further explore the microscopic kinetic processes and the influence of microstructures during the self-assembly process. Dissipative particle dynamics (DPD) simulation has been proven to be a powerful tool for reflecting polymer self-assembly behavior and the structure-property relationship of self-assemblies at the mesoscopic scale, and can to a certain extent make up for the deficiencies of experimental detection techniques. For example, DPD simulation has been successfully used to explore the formation kinetics of polymer micelles and the influence mechanism of morphology transformation.

[0003] However, since the minimum unit of DPD simulation is a coarse-grained bead composed of multiple atoms, how to appropriately divide polymer coarse-grained segments seriously affects the properties of the polymer coarse-grained model. At the same time, DPD simulation only considers the conservative force between coarse-grained beads, and the conservative force is determined by the repulsive force parameters of different polymer coarse-grained segments. There are different calculation methods for repulsive force parameters, so a single calculation method cannot well fit all divided segments. The artificial calculation process often introduces errors. Therefore, there are often large deviations in the fitting of DPD force field parameters by different workers, and there has been no DPD force field parameter fitting and automatic fitting simulation method so far. In addition, the special topological structure of polymers often affects their self-assembly behavior and properties, but currently many studies on coarse-grained models rarely pay attention to the topological structure of polymer coarse-grained models, making it impossible for polymer self-assembly DPD simulation to reflect the real situation. Summary of the Invention

[0004] To solve the drawbacks and deficiencies of the prior art, the purpose of the present invention is to provide a simple and reliable method for fitting a dissipative particle dynamics force field and constructing a coarse-grained model with polymer topological structure for simulation.

[0005] The method of the present invention first divides polymers through a coarse-grained segment division method, and then obtains corresponding coarse-grained divided segments and polymers with topological structure. Further, the corresponding DPD repulsive force parameters are automatically fitted, and the corresponding DPD force field fitting parameters are obtained based on the properties of the coarse-grained divided segments.

[0006] The method of the present invention can automatically fit the dissipative particle dynamics force field parameters and realize the fitting of the topological properties of the polymer coarse-grained structure, establish a general DPD force field, and provide guidance for the microstructure morphological transformation of the polymer self-assembly DPD simulation.

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] A method for fitting the dissipative particle dynamics force field and constructing a coarse-grained model with a polymer topological structure includes the following steps:

[0009] (1) Division and property identification of coarse-grained segments: First, use the Sketch tool of Materials Studio software to construct the all-atom structure of the corresponding polymer structural unit; then divide the polymer structural unit into segments, map to obtain different coarse-grained beads, and determine them as hydrophilic segments, hydrophobic segments or potential energy segments according to the hydrophilic-hydrophobic properties and functional group characteristics of the divided segments;

[0010] (2) Automatic fitting of DPD force field parameters: The divided segments obtained in step (1) are automatically executed by Perl script for the following steps:

[0011] i) Construction of the model box;

[0012] ii) Geometric optimization;

[0013] iii) Annealing;

[0014] iv) Short-time relaxation (NVT1);

[0015] v) Long-time relaxation (NPT);

[0016] vi) Long-time production (NVT2);

[0017] vii) Interaction properties between divided segments: The interaction force between hydrophilic segments is dominated by hydrophilic interaction, the interaction force between hydrophobic segments and hydrophilic segments or potential energy segments is dominated by binding energy, the interaction force between potential energy segments and hydrophilic segments or potential energy segments is dominated by affinity energy, and the interaction force between hydrophobic segments is dominated by affinity energy;

[0018] viii) Automatically calculate the corresponding force field parameters;

[0019] Among them, in the process of automatic fitting of DPD force field parameters, the interaction force parameters between each coarse-grained bead are obtained by using a specific repulsive force calculation formula according to the properties of the divided segments in step (1). The relationship between the interaction force parameters between coarse-grained beads and the repulsive force parameters between divided segments is as follows:

[0020] a ij =a ii+3.27*χ ij

[0021] In the formula, a ii is the interaction force parameter between the same type of coarse-grained beads, and a ij is the interaction force parameter between different types of coarse-grained beads, and χ ij is the repulsive force action parameter (Flory-Huggins parameter) between different partition segments; the repulsive force action parameter between different partition segments is dominated by the nature of the interaction between the partition segments and is calculated using the corresponding repulsive force action parameter calculation formula. The repulsive force action parameter calculation formulas dominated by affinity energy action, binding energy action, and hydrophilic action are as follows:

[0022]

[0023]

[0024]

[0025] In the formula, is the affinity energy density between the partition segment molecules, V r is the volume of the coarse-grained beads, is the volume fraction when the partition segment molecules interact, and χ i , χ j are the water solubility parameters of the partition segment molecules;

[0026] (3) Construct a coarse-grained model with a polymer topological structure: First, after constructing the corresponding polymerization chirality and polymerization sites for the different coarse-grained beads obtained in step (1) using the Repeat Unit in the Build module, use the Build Polymers tool to construct a full-atom model with a topological structure; then use the Coarse Grain tool to obtain the corresponding polymer coarse-grained model with a topological structure;

[0027] Among them, there is no sequential order between step (2) and step (3). Step (2) can be carried out first and then step (3), or step (3) can be carried out first and then step (2), or steps (2) and (3) can be carried out simultaneously.

[0028] Preferably, the method for dividing the polymer structure unit partition segments in step (1) is: Under the condition of ensuring the integrity of the functional groups, divide the polymer structure unit according to a straight chain of 3 heavy atoms, a branched chain of 4 heavy atoms, a straight chain of 4 heavy atoms, or a rigid structure of 2 heavy atoms; among them, the radius of the coarse-grained beads mapped by the straight chain of 3 heavy atoms, the branched chain of 4 heavy atoms, or the straight chain of 4 heavy atoms The radius of the coarse-grained beads mapped by the rigid structure segment of 2 heavy atoms The rigid structure includes polymer end - group fragments or a ring structure remapped into multiple molecular fragments.

[0029] Preferably, the method for distinguishing the molecular structural properties of the divided fragments in step (1) is as follows: First, determine whether the molecular structure contains special functional groups such as strong hydrophilic groups (amine groups, hydroxyl groups), aromatic functional groups (benzene rings, naphthalene rings), charged functional groups (carboxyl groups, ammonium groups), etc., and determine their hydrophilic - hydrophobic properties based on these functional groups; for the divided fragments without special functional groups, calculate their LogP parameters using the open - source online calculation software XLOGP3 provided by the Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences to determine their hydrophilic - hydrophobic properties. If there is no strong hydrophilic / hydrophobic interaction, they are uniformly classified as potential energy property types.

[0030] Preferably, during the automatic fitting process of DPD force field parameters in step (2), to maintain the integrity and simulation degree of the topological structure, the ring structure is calculated as a whole, such as benzene rings, cyclohexanes, etc.

[0031] Preferably, the construction of the model box in step (2) is completed using the AmorphousCell module of Materials Studios software; in the case of divided fragments without ring structures, the component of each divided fragment is set to 100, and the water component is set to 300; in the case of divided fragments containing ring structures, the ring component is set to 100, the component of the remaining divided fragments is set to 200, and the water component is set to 600; to facilitate the rapid convergence of the simulation, the density of the model box is set to 0.8 g / cm 3 。

[0032] Preferably, during the automatic fitting process of DPD force field parameters in step (2), the molecular dynamics simulation process is completed using the Forcite module of Materials Studios software, and the simulation parameters are as follows: the simulation temperature is uniformly 310K, the pressure is uniformly 1.01 kPa, and the calculation accuracy is uniformly Ultra - Fine; among them, the geometric optimization is executed for 500 steps; the annealing simulation is executed for 5 cycles, specifically executed at 310 - 500K using the Berendsen heat bath method; the short - time NVT relaxation is 100 ps, specifically executed using the Berendsen heat bath method; the long - time NPT relaxation is 500 ps to reach equilibrium, specifically executed using the Nose heat bath and Nose pressure bath methods; the long - time NVT relaxation is 2 ns to output energy, specifically executed using the Nose heat bath.

[0033] Preferably, the a in step (2) ii The interaction force parameter between the same type of coarse - grained beads is set to 25. At this time, the fitting degree of the DPD force field parameters for the self - assembly simulation of polymers is better and closer to the experimental data.

[0034] Preferably, in step (3) during the construction of the coarse-grained model with a polymer topological structure, in order to maintain the rigidity of the ring structure, a restraining potential needs to be applied to the corresponding beads of the coarse-grained model; use the Constraints and Restraints in the Modify module of Materials Studios software to fix the bond angle and set the restraining potential to 5 kcal / mol / rad 2 。

[0035] Application of the above method for dissipative particle dynamics force field fitting and construction of a coarse-grained model with a polymer topological structure in the DPD self-assembly simulation of a polymer coarse-grained model with a topological structure

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] (1) Currently, no unified simulation method for DPD force field fitting has been found, nor has a simulation method for automatic fitting of the DPD force field been found. The present invention provides for the first time a general simulation method for automatic fitting of the DPD force field by coarse-grained fragment division. This method can conveniently and quickly obtain the DPD force field parameters by automatic fitting. At the same time, the basic DPD force field parameters can be directly obtained from the force field library in step (2). This force field has the universality of the currently imperfect force field in the field. The same coarse-grained fragments of different polymers can directly use the corresponding force field parameters to carry out self-assembly simulations of polymers

[0038] (2) The present invention provides a simulation method for realizing the topology of polymer coarse-grained structures. This method can be used for fitting the topology of all polymer coarse-grained structures; it can be used to explore the influence of microstructural changes in the self-assembly process of different polymers and the influence of stability caused by different polymer structures. The original steric hindrance and special topological structure of polymers greatly affect the self-assembly process of polymers. This method retains the original topological structure of polymers

[0039] (3) The simulation method of the present invention is fast in calculation, easy to implement, and accurate in calculation results. The corresponding polymer self-assembly process is consistent with the experimental results; it can make up for the current deficiencies in DPD force field fitting and the lack of polymer topological structures, provide a general DPD force field, and accurately fit the topology of polymer coarse-grained structures, providing guidance for the exploration of the polymer self-assembly process and the controllable construction of self-assembled structures in experiments Description of the Drawings

[0040] Figure 1 It is a mapping schematic diagram of the coarse-grained model with a topological structure of the polymer system [PPMA4-b-POPMA4-b-PhGMA4] provided by an embodiment of the present invention

[0041] Figure 2Flow chart of the coarse-grained force field fragment division method and the construction method of the coarse-grained model with topological structure provided by the embodiments of the present invention;

[0042] Figure 3 Flow chart of the automatic fitting method for DPD force field parameters provided by the embodiments of the present invention;

[0043] Figure 4 For the automatic fitting process of DPD force field parameters of the polymer system [PPMA x -b-POPMA y -b-PhGMA z : Coarse-grained mapping details of the polymer system (A), construction of the calculation partition fragment interaction model box (B), change of the model box size during the annealing simulation process (C), change of the density during the long-time NPT relaxation (D), and energy output during the long-time NVT relaxation (E); among them, the schematic diagrams of (B)-(D) take the calculation of the intermolecular force between the mapped fragments C3H7 and C2H4O molecules as an example;

[0044] Figure 5 For the coarse-grained model of the polymer with topological structure [PPMA 14 -b-POPMA 10 -b-PhGMA6] based on the automatically fitted DPD force field, schematic diagrams of the morphological changes during the DPD self-assembly micelle, cross-linking process, and controlled release of the cross-linked micelle (A), density distribution schematic diagram (B). For easy observation, the water beads are hidden;

[0045] Figure 6 For the coarse-grained models of polymers with topological structures with different block ratios [PPMA x -b-POPMA y -b-PhGMA z based on the automatically fitted DPD force field, morphological diagrams of the DPD self-assembled cross-linked micelles (A), experimental data results (B), and stability evaluation (C). Detailed implementation manners

[0046] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the implementation manners of the present invention are not limited thereto.

[0047] In the embodiments of the present invention, those not specified under specific conditions are carried out according to conventional conditions or the conditions recommended by the manufacturer. The raw materials, reagents, etc. not specified for the manufacturer can all be obtained as conventional products through commercial purchase.

[0048] Example 1

[0049] (1) In this example, a typical methacrylate-based triblock polymer [PPMAx -b-POPMA y -b-PhGMA z Taking polymer systems represented by [C3H7, CO2, C3H5O, C3H6O, C2H4O, CH4O, C2H2] as an example, first, the all-atom structures of polymer repeating units (PMA, OPMA, hGMA) were constructed using the Sketch tool in Materials Studio software. The polymer repeating units were divided into segments to obtain the corresponding segments: C3H7, CO2, C3H5O, C3H6O, C2H4O, CH4O, C2H2. Among them, C2H2 (benzene ring) and CH4O (end group) were divided into segments and mapped to rigid coarse-grained beads, and their atomic radii After special functional group recognition and LogP calculation, the segments CO2, C2H4O, and CH4O were classified as hydrophilic, C2H2 was classified as hydrophobic, and the rest were potential energy properties. The above-mentioned obtained segments were respectively mapped to the corresponding coarse-grained beads, as Figure 4 shown in Figure A.

[0050] (2) Use the automated fitting method of DPD force field parameters to calculate the corresponding DPD force field parameters. The process of the automated fitting method is as Figure 3 shown. Taking the calculation of the intermolecular interaction force between the segments C3H7 and C2H4O as an example, the automated fitting method of DPD force field parameters automatically executes the molecular dynamics simulation process of modeling the model box, geometric optimization, annealing simulation, short-time NVT relaxation, long-time NPT relaxation to calculate the density, and long-time NVT relaxation to output energy. The calculation details are as follows: the temperature is unified as 310K, the pressure is unified as 1.01kPa, and the calculation accuracy is unified as Ultra-Fine; among them, the geometric optimization is executed for 500 steps; the annealing simulation is executed for 5 cycles, specifically executed with the berendsen heat bath method at 310 - 500K; the short-time NVT relaxation is 100ps, specifically executed with the berendsen heat bath method; the long-time NPT relaxation is 500ps to reach equilibrium, specifically executed with the Nose heat bath and Nose pressure bath methods; the long-time NVT relaxation is 2ns to output energy, specifically executed with the Nose heat bath. The corresponding annealing simulation results, density equilibrium results, and energy output results are respectively as Figure 4 shown in Figures B, C, and D.

[0051] After the calculation, the interaction properties between the segments are automatically identified to use the corresponding repulsive force parameter calculation formula. The interaction properties between the segments are divided into: the interaction force between hydrophilic segments and hydrophilic segments is dominated by hydrophilic interaction, the interaction force between hydrophobic segments and hydrophilic segments or potential energy segments is dominated by binding energy, the interaction force between potential energy segments and hydrophilic segments or potential energy segments is dominated by affinity energy, and the interaction force between hydrophobic segments and hydrophobic segments is dominated by affinity energy; the repulsive force parameter calculation formulas dominated by affinity energy, binding energy, and hydrophilic interaction are as follows:

[0052]

[0053]

[0054]

[0055] In the formula, χ ij is the repulsive force interaction parameter (Flory-Huggins parameter) between different partition segments, is the affinity energy density between the molecules of the partition segment, V r is the volume of the coarse-grained bead, is the volume fraction when the molecules of the partition segment interact, χ i and χ j are the water solubility parameters of the molecules of the partition segment;

[0056] Finally, the interaction force parameter between the coarse-grained beads is automatically calculated using the following formula,

[0057] a ij = a ii + 3.27 * χ ij

[0058] In the formula, a ii is the interaction force parameter between the same type of coarse-grained beads, a ij is the interaction force parameter between different types of coarse-grained beads. a ii is set to 25. At this time, the fitting degree of the DPD force field parameters for the self-assembly simulation of polymers is better and closer to the experimental data.

[0059] The corresponding DPD force field parameters calculated using the automated fitting method for the DPD force field parameters are summarized in Table 1 below. Among them, the ES and NNH coarse-grained beads are the partition segments of the cross-linking agent DTP, both of which do not have a ring structure. NNH is dominated by hydrophilic interaction, and ES is dominated by potential energy.

[0060] Table 1 DPD Force Field Parameter Table

[0061]

[0062] (3) After constructing the corresponding polymerization chirality and polymerization sites of different polymer repeating units and their divided fragments obtained in step (1) using RepeatUnit in the Build module, use the Build Polymers tool to construct an all-atom model with a topological structure. Then, use the Coarse Grain tool to map the divided fragments into corresponding coarse-grained beads to obtain a corresponding polymer coarse-grained model with a topological structure. Finally, use the Constraints and Restraints in the Modify module of Materials Studios software to fix the bond angle of C2H2 (benzene ring) and set the restraining potential to 5 kcal / mol / rad 2 。

[0063] (4) The DPD self-assembly simulation of the polymer coarse-grained model with a topological structure [PPMA x -b-POPMA y -b-PhGMA z is carried out using the Mesocite module of Materials Studio software, and the DPD force field parameters obtained by the automatic fitting method are adopted. The size of the model box is , and this size can effectively avoid the influence brought by the periodic boundary structure. The elastic constant C, the integration step Δt, and the dissipative force parameter γ are 4.0, 0.05, and 4.5 respectively, and the number of simulation steps is 150,000. The self-assembled structure of the polymer micelles after simulation is shown in Figure 5 A, and the density distribution of the polymer micelles is shown in Figure 5 B.

[0064] In this example, the automated construction method based on the dissipative particle dynamics force field and the coarse-grained model with a topological structure is successfully applied to study the microscopic kinetic behavior of the self-assembly process of polymer crosslinked micelles.

[0065] Example 2

[0066] To verify the simulation degree of the polymer coarse-grained model with a topological structure and the automated fitting method of DPD force field parameters for the experimental system, nine polymer coarse-grained models with topological structures [PPMA x -b-POPMA y -b-PhGMA z with different block ratios and DPD self-assembled crosslinked micelle models ( Figure 6 A) were constructed respectively according to the steps of Example 1 above, and the kinetics and thermodynamic stability of different crosslinked micelles were further characterized ( Figure 6 B). The results show that the polymer hOP8 [PPMA6-b-POPMA 10 -b-PhGMA 14With excellent kinetic and thermodynamic stabilities, polymer hOP2 has good kinetic stability, while polymer hOP7 has good thermodynamic stability. The corresponding polymers were prepared by ATRP polymerization method. Experiments show that ( Figure 6 C), hOP8 exhibits excellent anti-protein stability. Thanks to good thermodynamic / kinetic stabilities, hOP7 / hOP2 also exhibits good anti-protein stability. Therefore, the automated fitting method for the coarse-grained model of polymers with topological structures and DPD force field parameters is very important for studying the DPD self-assembly process of polymers, greatly improving the simulation accuracy of coarse-grained simulations.

[0067] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent substitution methods and are all included in the protection scope of the present invention.

Claims

1. A method for fitting a dissipative particle dynamics force field and constructing a coarse-grained model with a polymer topological structure, characterized in that, It includes the following steps: (1) Division and property identification of coarse-grained segments: First, use the Sketch tool of Materials Studio software to construct the all-atom structure of the corresponding polymer structural unit; then divide the polymer structural unit into segments, map to obtain different coarse-grained beads, and determine them as hydrophilic segments, hydrophobic segments or potential energy segments according to the hydrophilic-hydrophobic properties and functional group characteristics of the divided segments; (2) Automatic fitting of DPD force field parameters: Use Perl script to automatically execute the following steps for the divided segments obtained in step (1): i) Construction of model box; ii) Geometric optimization; iii) Annealing; iv) Short-time relaxation; v) Long-time relaxation; vi) Long-time output; vii) Interaction properties between divided segments: The interaction force between hydrophilic segments is dominated by hydrophilic interaction, the interaction force between hydrophobic segments and hydrophilic segments or potential energy segments is dominated by binding energy, the interaction force between potential energy segments and hydrophilic segments or potential energy segments is dominated by affinity energy, and the interaction force between hydrophobic segments is dominated by affinity energy; viii) Automatically calculate the corresponding force field parameters; Among them, in the process of automatic fitting of DPD force field parameters, the interaction force parameters between each coarse-grained bead are obtained by using the repulsive force calculation formula according to the segment properties in step (1). The relationship between the interaction force parameters between coarse-grained beads and the repulsive force parameters between divided segments is as follows: a ij = a ii + 3.27 * X ij where a ii is the interaction force parameter between the same type of coarse-grained beads, and a ij is the interaction force parameter between different types of coarse-grained beads, and X ij is the repulsive force interaction parameter (Flory-Huggins parameter) between different partition segments; the repulsive force interaction parameter between different partition segments is dominated by the nature of the interaction between the partition segments and is calculated using the corresponding repulsive force interaction parameter calculation formula. The repulsive force interaction parameter calculation formulas dominated by affinity energy interaction, binding energy interaction, and hydrophilic interaction are as follows: In the formula, is the affinity energy density between divided segments, V r is the volume of the coarse-grained bead, is the volume fraction when divided segment molecules interact, X i and x j are the aqueous solubility parameters of the divided segment molecules; (3) Construct a coarse-grained model with a polymer topological structure: First, use the Repeat Unit in the Build module to construct the corresponding polymerization chirality and polymerization sites for the different coarse-grained beads obtained in step (1), and then use the Build Polymers tool to construct an all-atom model with a topological structure; then use the Coarse Grain tool to obtain the corresponding polymer coarse-grained model with a topological structure; There is no sequence priority between step (2) and step (3).

2. The method for fitting a dissipative particle dynamics force field and constructing a coarse-grained model with a polymer topological structure according to claim 1, characterized in that The method for dividing the polymer structural unit into segments in step (1) is as follows: Under the condition of ensuring the integrity of functional groups, the polymer structural unit is divided into segments according to a straight chain of 3 heavy atoms, a branched chain of 4 heavy atoms, a straight chain of 4 heavy atoms, or a rigid structure of 2 heavy atoms; among them, the radius of the coarse-grained bead obtained by mapping the segment of a straight chain of 3 heavy atoms, a branched chain of 4 heavy atoms, or a straight chain of 4 heavy atoms The radius of the coarse-grained bead obtained by mapping the segment of a rigid structure of 2 heavy atoms The rigid structure includes a polymer end-group segment or a ring structure re-mapped into multiple molecular segments.

3. A method for dissipative particle dynamics force field fitting and construction of a coarse-grained model with a polymer topological structure according to claim 1, characterized in that, The method for identifying the molecular structure properties of the divided segments in step (1) is as follows: First, judge whether the molecular structure contains special functional groups, and determine its hydrophilic-hydrophobic properties according to these functional groups; for the divided segments without special functional groups, calculate their LogP parameters using the open-source online calculation software XLOGP3 provided by the Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences to determine the hydrophilic-hydrophobic properties. If there is no strong hydrophilic / hydrophobic interaction, they are uniformly classified as potential energy property categories.

4. A dissipative particle dynamics force field fitting and coarse-grained model construction method with a polymer topological structure according to claim 1, characterized in that In the process of automatic fitting of DPD force field parameters in step (2), the ring structure is calculated as a whole.

5. A dissipative particle dynamics force field fitting and coarse-grained model construction method with a polymer topological structure according to claim 1, characterized in that, The model box construction described in step (2) is completed using the Amorphous Cell module of Materials Studios software; in the case of dividing fragments without ring structures, the component of each divided fragment is set to 100, and the water component is set to 300; in the case of dividing fragments with ring structures, the ring component is set to 100, the components of the remaining divided fragments are set to 200, and the water component is set to 600; the density of the model box is set to 0.8 g / cm 3 .

6. The method for dissipative particle dynamics force field fitting and constructing a coarse-grained model with a polymer topological structure according to claim 1, wherein In step (3), during the process of constructing a coarse-grained model with a polymer topological structure, for the coarse-grained beads obtained by mapping the ring structure, the Constraints and Restraints in the Modify module of Materials Studios software are used to fix the bond angle and set the restraining potential to 5 kcal / mol / rad 2 .

7. A method for dissipative particle dynamics force field fitting and construction of a coarse-grained model with a polymer topological structure according to claim 1, characterized in that In the process of automatic fitting of DPD force field parameters in step (2), the molecular dynamics simulation process is completed using the Forcite module of Materials Studios software, and the simulation parameters are as follows: the simulation temperature is uniformly 310 K, the pressure is uniformly 1.01 kPa, and the calculation accuracy is uniformly Ultra-Fine; among them, the geometric optimization is performed for 500 steps; the annealing simulation is performed for 5 cycles, specifically executed at 310 - 500 K using the Berendsen heat bath method; the short-time NVT relaxation is 100 ps, specifically executed using the Berendsen heat bath method; the long-time NPT relaxation is 500 ps to reach equilibrium, specifically executed using the Nose heat bath and Nose pressure bath methods; the long-time NVT relaxation is 2 ns to output energy, specifically executed using the Nose heat bath.

8. A dissipative particle dynamics force field fitting and coarse-grained model construction method with a polymer topological structure according to claim 1, characterized in that The a described in step (2) ii Set 25 for the interaction force parameter between the same kind of coarsened beads.

9. Application of the method for fitting a dissipative particle dynamics force field and constructing a coarse-grained model with a polymer topological structure according to any one of claims 1 to 8 in the DPD self-assembly simulation of a coarse-grained model of a polymer with a topological structure.

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