Numerous theoretical and experimental efforts have been made to explain the dependence of the static wrink^h~g morphology on the materials＇ physical properties, whereas the dy- namic wrinkling process remains elusive...Numerous theoretical and experimental efforts have been made to explain the dependence of the static wrink^h~g morphology on the materials＇ physical properties, whereas the dy- namic wrinkling process remains elusive. In the present work, we design a wrinkling model consisting of a soft substrate and a graphene-like rigid thin film to investigate this dynamic process. The simulation shows that the whole wrinkling process includes three stages. At the incubation and wrinkling stages, the stress along the horizon direction of the soft substrate transfers to the stiff film. However, at the equilibrium stage, the stress of the rigid film slowly transfers back to the substrate although the total energy still decreases. It is found that the stress of the substrate concentrates at the top surface, especially at the trough, whereas the stress distribution of the film depends on direction. In the perpendicular direc- tion, the stress at the wave＇s equilibrium position surpasses that at the crest and trough and, oppositely, the stress concentrates at the crest and trough in the horizon direction. Present model reproduces both wrinkling and delamination patterns and can be a powerful tool to deeply understand the structure deformation of material induced by stress release.展开更多
An implicit solvent coarse-grained （CG） lipid model using three beads to reflect the basically molecular structure of two-tailed lipid is developed. In this model, the nonbonded interaction employs a variant MIE pot...An implicit solvent coarse-grained （CG） lipid model using three beads to reflect the basically molecular structure of two-tailed lipid is developed. In this model, the nonbonded interaction employs a variant MIE potential and the bonded interaction utilizes a Harmonic potential form. The CG force field parameters are achieved by matching the structural and mechan-ical properties of dipalmitoylphosphatidylcholine （DPPC） bilayers. The model successfully reproduces the formation of lipid bilayer from a random initial state and the spontaneous vesiculation of lipid bilayer from a disk-like structure. After that, the model is used to sys-tematically study the vesiculation processes of spherical and cylindrical lipid droplets. The results show that the present CG model can effectively simulate the formation and evolution of mesoscale complex vesicles.展开更多
Nanoparticles with competitive interactions in solution can aggregate into complex structures. In this work, the synergistic self-assembles of binary particles with electrostatic and van der Waals interactions are stu...Nanoparticles with competitive interactions in solution can aggregate into complex structures. In this work, the synergistic self-assembles of binary particles with electrostatic and van der Waals interactions are studied with the particle Langevin dynamics simulation using a simple coarse-grained particle model. Various aggregations such as spherical, stacking-disk and tube structures are observed by varying the particles size and the interaction strength. The aggregation structures are explained with the packing theories of amphiphilic molecules in solution and dibolck copolymers in bulk. When the opposite ions are introduced into solution, the distribution of structures in the phase diagram appears an obvious offset. The simulation result is helpful to deeply understand the formation mechanism of complex nanostructures of multicomponent particles in solution.展开更多
基金the High Performance Computing Center of Tianjin University, China and the National Natural Science Foundation of China （No.91127046, No.21274107, and No.21474075）.
文摘Numerous theoretical and experimental efforts have been made to explain the dependence of the static wrink^h~g morphology on the materials＇ physical properties, whereas the dy- namic wrinkling process remains elusive. In the present work, we design a wrinkling model consisting of a soft substrate and a graphene-like rigid thin film to investigate this dynamic process. The simulation shows that the whole wrinkling process includes three stages. At the incubation and wrinkling stages, the stress along the horizon direction of the soft substrate transfers to the stiff film. However, at the equilibrium stage, the stress of the rigid film slowly transfers back to the substrate although the total energy still decreases. It is found that the stress of the substrate concentrates at the top surface, especially at the trough, whereas the stress distribution of the film depends on direction. In the perpendicular direc- tion, the stress at the wave＇s equilibrium position surpasses that at the crest and trough and, oppositely, the stress concentrates at the crest and trough in the horizon direction. Present model reproduces both wrinkling and delamination patterns and can be a powerful tool to deeply understand the structure deformation of material induced by stress release.
基金We thank Professor Dr. Markus Deserno （Department of Physics, Carnegie Mellon University）, Jemal Guven （Institute of Nuclear Science, Universidad Nacional Autonoma de Mexico）, and Zhan-chun Tu （Department of Physics, Beijing Normal University） for their valuable advice. This work is supported by the National Natural Science Foundation of China （No.20974078, No.21274107, and No.91127046）. The computation and simulation are partly carried out in High Performance Computing Center of Tianjin University.
文摘An implicit solvent coarse-grained （CG） lipid model using three beads to reflect the basically molecular structure of two-tailed lipid is developed. In this model, the nonbonded interaction employs a variant MIE potential and the bonded interaction utilizes a Harmonic potential form. The CG force field parameters are achieved by matching the structural and mechan-ical properties of dipalmitoylphosphatidylcholine （DPPC） bilayers. The model successfully reproduces the formation of lipid bilayer from a random initial state and the spontaneous vesiculation of lipid bilayer from a disk-like structure. After that, the model is used to sys-tematically study the vesiculation processes of spherical and cylindrical lipid droplets. The results show that the present CG model can effectively simulate the formation and evolution of mesoscale complex vesicles.
基金V. ACKNOWLEDGMENTS The computer simulation is performed on the High Performance Computing Center of Tianjin University,China. This work was supported by the National Natural Science Foundation of China （No.21274107 and No.91127046）. We thank Prof. Bin Zhang, Rui Xu, Bo Du, and Dr. Zi-lu Wang in Tianjin University for helpful discussions.
文摘Nanoparticles with competitive interactions in solution can aggregate into complex structures. In this work, the synergistic self-assembles of binary particles with electrostatic and van der Waals interactions are studied with the particle Langevin dynamics simulation using a simple coarse-grained particle model. Various aggregations such as spherical, stacking-disk and tube structures are observed by varying the particles size and the interaction strength. The aggregation structures are explained with the packing theories of amphiphilic molecules in solution and dibolck copolymers in bulk. When the opposite ions are introduced into solution, the distribution of structures in the phase diagram appears an obvious offset. The simulation result is helpful to deeply understand the formation mechanism of complex nanostructures of multicomponent particles in solution.
