Computational Software: Polymer Chain Generation for Coarse-Grained Models Using Radical-Like Polymerization

Morgane, Mahaud; Zhai, Zengqiang; Perez, Michel; Lame, Olivier; Fusco, Claudio; Chazeau, Laurent; Makke, Ali; Marque, G.; Morthomas, Julien

doi:10.4208/cicp.oa-2017-0146

Cited by 7 publications

(9 citation statements)

References 33 publications

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“…All the molecular dynamics simulations are performed using the classic LAMMPS code . The copolymer chains are built using a radical-like polymerization algorithm (RLP) previously developed by Perez and co-workers. , The simulation is performed in the NPT ensemble, using periodic boundary conditions, at P = 0.5 ε u /σ u 3 and T = 4 ε u / k B . It starts from a bath containing two types of loner beads (SS and HS types).…”

Section: Methodsmentioning

confidence: 99%

Coarse-Grained Molecular Dynamics Modeling of Segmented Block Copolymers: Impact of the Chain Architecture on Crystallization and Morphology

et al. 2020

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We extend our recent coarse-grained model describing semicrystalline homopolymers to simulate the morphol-ogy and phase transitions of thermoplastic elastomers made of segmented (hard/soft) block copolymers. The generic model is adapted to match the physical characteristics of the two chemical units involved in the copolymer chains by using classic scaling rules. We investigate the crystallization kinetics of the hard segments as well as their phase separation from the soft units in either triblock or pentablock copolymers. We identify the soft segment molecular weight as a key parameter resulting in the following observations when decreasing the temperature from a homogeneous state. On the one hand, the phase separation preceding the crystallization process in triblock copolymers results in a constant temperature of crystallization when varying the soft segment length. On the other hand, the limited phase separation achieved in pentablock copolymers constrains them to crystallize at progressively lower temperatures while increasing the soft segment length. Finally, increasing the soft segment molecular weight was found to lead to a higher relative crystallinity which can be interestingly related to a rise of the loop segment's content.

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Section: Methodsmentioning

confidence: 99%

Coarse-Grained Molecular Dynamics Modeling of Segmented Block Copolymers: Impact of the Chain Architecture on Crystallization and Morphology

et al. 2020

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“…At each growth step, each radical forms a bond with a new monomer and transfers the radical to the chosen monomer. At the end of the method, M chains of N units are formed (for details, see our previous work 40 ). The system is then equilibrated during 5 × 10 5 τ u at T = 3.3ϵ u /k B and P = 0.5ϵ u /σ u 3 in the NPT ensemble.…”

Section: Methodsmentioning

confidence: 99%

“…Polymer chains have been generated and equilibrated using the radical-like polymerization method. , This method starts with a LJ bath of N mon monomers, with M of them being radicals. At each growth step, each radical forms a bond with a new monomer and transfers the radical to the chosen monomer.…”

Section: Methodsmentioning

confidence: 99%

Crystallization and Molecular Topology of Linear Semicrystalline Polymers: Simulation of Uni- and Bimodal Molecular Weight Distribution Systems

et al. 2019

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The crystallization behavior and the molecular topology of bimodal molecular weight distribution (MWD) polymers are studied using a coarse-grained molecular dynamics model with varying weight fraction of short and long chains. Extensive simulations have been performed to prepare polymer melts and obtain semicrystalline polymers by homogeneous isothermal crystallization. The incubation time (the time elapsed before the establishment of steady-state nucleation) is calculated, and the interfacial free energy is obtained using a mean first-passage time analysis. The incubation time first decreases with the weight fraction of long chains, reaches its maximum at 30%, and then increases. This results from the conflicting effects of interfacial free energy and mobility of chain segments. The interfacial free energy decreases with the weight fraction of long chains, which is attributed to the transition from intermolecular to intramolecular nucleation, whereas the chain mobility decreases with increasing long-chain content. Nevertheless, the growth rate of crystals decreases continuously with the weight fraction of long chains, mainly resulting from reduced chain sliding diffusion. We have provided insights into how bimodal MWD polymers promote both nucleation and processability. Moreover, a numerical algorithm has been proposed, tracing each chain going back and forth among crystallites, to access quantitative data of molecular topology (i.e., loop, tie, and cilia segments). It turns out that the concentration of loop and tie segments increases with the increasing weight fraction of long chains. This could be important to understand the mechanical properties of semicrystalline polymers.

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“…To generate these systems with target number of chains and chain length, the radical-like polymerization method , has been employed (see more details in Zhai et al , ). The systems are then equilibrated during 5.0 × 10 5 τ at a temperature of T = 3.3ϵ/ k B and pressure P = 0.5ϵ/σ 3 in the NPT ensemble.…”

Section: Methodsmentioning

confidence: 99%

“…where = , = 5.0 is the cutoff radius, LJ is an adjusted parameter of the potential that favours crystallization and crystal stability for the FENE-LJ model chosen here. We take LJ = 1.888 as proposed in our previous work, 24 To generate these systems with target number of chains and chain length, the Radical-Like Polymerization (RLP) method 57,58 has been employed (see more details in Zhai et al 25,58 ). The until the crystallization of each system saturates.…”

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confidence: 99%

Disentangling and Lamellar Thickening of Linear Polymers during Crystallization: Simulation of Bimodal and Unimodal Molecular Weight Distribution Systems

et al. 2019

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We have perform coarse-grained molecular dynamics simulations to study the isothermal crystallization of bimodal and unimodal molecular weight distribution (MWD) polymers with equivalent average molecular weight (). By using primitive path analysis we can monitor the entanglement evolution during the process of crystallization. We have discovered a quantitative correlation between the degree of disentanglement and crystallinity, indicating that chain disentanglement permits the process of crystallization. In addition, the crystalline stem length also displays a linear relation with the degree of disentanglement at different temperatures. Based on the observation in our simulations, we can build a scenario of the whole process of chain disentangling and lamellar thickening on the basis of chain sliding diffusion. Furthermore, we have enough evidence to infer that the temperature dependence of crystalline stem length is basically a result of temperature dependence of chain sliding diffusion. Our observations are also in agreement with Hikosaka's sliding diffusion theory. Compared to the unimodal system, the disentanglement degree of the bimodal system is more delayed than its crystallinity due to the slower chain sliding of long-chain component; the bimodal system reaches a larger crystalline stem length at all temperatures due to the promotion of higher chain sliding mobility of short-chain component.

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Computational Software: Polymer Chain Generation for Coarse-Grained Models Using Radical-Like Polymerization

Cited by 7 publications

References 33 publications

Coarse-Grained Molecular Dynamics Modeling of Segmented Block Copolymers: Impact of the Chain Architecture on Crystallization and Morphology

Coarse-Grained Molecular Dynamics Modeling of Segmented Block Copolymers: Impact of the Chain Architecture on Crystallization and Morphology

Crystallization and Molecular Topology of Linear Semicrystalline Polymers: Simulation of Uni- and Bimodal Molecular Weight Distribution Systems

Disentangling and Lamellar Thickening of Linear Polymers during Crystallization: Simulation of Bimodal and Unimodal Molecular Weight Distribution Systems

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