[SY-K4] Large-scale coarse-grained molecular dynamics simulations on fracture processes of lamellar structure in crystalline polymers
Understanding the fracture processes of crystalline polymers such as polyethylene by molecular theory is one of the big challenges, which contributes to the increase in the toughness of polymeric materials in industry. To reveal the fracture process, coarse-grained molecular dynamics simulation is effective; however the fracture processes of the most fundamental crystal structure, lamellar structure consisting of amorphous and crystalline layers, in polyethylene has not been revealed. The reason is the difficulty of the construction of the lamellar structure due to the small simulation size in the order of 104 beads. Thus, we propose a crystallization method for the large-scale lamellar structure in the order of 106 beads and perform the fracture simulation.
In the fracture process of the lamellar structure by coarse-grained molecular dynamics simulation, mechanical properties are consistent with the experiment, confirming the validity of the simulation results. We also reveal that the movement of chain ends from amorphous layers to crystalline layers causes the deformation and void generation in the amorphous region, indicating that the chain ends act as defect [1, 2]. In the large scale simulations, the buckling of crystalline layer and its fragmentations are observed, which can be compared directly with the experimental observation by electronic microscope. Our large-scale coarse-grained molecular dynamics simulations are useful to reveal the fracture process of polymers at molecular level. We develop the above molecular technology which can reveal the fracture processes of polymeric materials at the molecular level and successfully apply it to the fracture process of double network gels [3].
[1] Y. Higuchi et al., Macromolecules 50, 3690-3702 (2017).
[2] Y. Higuchi, Polym. J. in press (2018).
[3] Y. Higuchi et al., Macromolecules in press (2018).
In the fracture process of the lamellar structure by coarse-grained molecular dynamics simulation, mechanical properties are consistent with the experiment, confirming the validity of the simulation results. We also reveal that the movement of chain ends from amorphous layers to crystalline layers causes the deformation and void generation in the amorphous region, indicating that the chain ends act as defect [1, 2]. In the large scale simulations, the buckling of crystalline layer and its fragmentations are observed, which can be compared directly with the experimental observation by electronic microscope. Our large-scale coarse-grained molecular dynamics simulations are useful to reveal the fracture process of polymers at molecular level. We develop the above molecular technology which can reveal the fracture processes of polymeric materials at the molecular level and successfully apply it to the fracture process of double network gels [3].
[1] Y. Higuchi et al., Macromolecules 50, 3690-3702 (2017).
[2] Y. Higuchi, Polym. J. in press (2018).
[3] Y. Higuchi et al., Macromolecules in press (2018).