title: Coupling between intra- and inter-chain orderings in flow-induced crystallization of polyethylene: A non-equilibrium molecular dynamics simulation study.
abstract: Non-equilibrium molecular dynamics simulations have been performed to study the molecular mechanism of flow-induced crystallization (FIC) of polyethylene (PE). The end-to-end distance of chain Reteand the content of trans conformation Ctransare extracted out to represent intra-chain conformation ordering at whole chain and segment levels, respectively, while orientation correlation function P, density ρ, and bond orientational order parameter Q4are taken to depict inter-chain orders. Imposing the extension induces the intra-chain conformational ordering to occur first, which further couples with the inter-chain order and results in the formation of hexagonal packing. Further increasing strain leads to the appearance of orthorhombic order. The results demonstrate that the FIC of PE proceeds via a multi-stage ordering process, during which coupling occurs among stress, intra-chain conformation, and inter-chain orientation and density orderings. Analyzing the flow-induced energy evolution unveils that not only entropy but also energy plays an important role in the FIC.
authors.affiliation: National Synchrotron Radiation Lab and CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, China.
authors.forename: Junsheng
authors.initials: J
authors.lastname: Yang
authors.affiliation: National Synchrotron Radiation Lab and CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, China.
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Tang
authors.affiliation: National Synchrotron Radiation Lab and CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: National Synchrotron Radiation Lab and CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, China.
authors.forename: Tingyu
authors.initials: T
authors.lastname: Xu
authors.affiliation: National Synchrotron Radiation Lab and CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, China.
authors.forename: Fucheng
authors.initials: F
authors.lastname: Tian
authors.affiliation: National Synchrotron Radiation Lab and CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, China.
authors.forename: Youxin
authors.initials: Y
authors.lastname: Ji
authors.affiliation: National Synchrotron Radiation Lab and CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, China.
authors.forename: Liangbin
authors.initials: L
authors.lastname: Li