How Chain-Folding Crystal Growth Determines the Thermodynamic Stability of Polymer Crystals

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• 作者：Xiaoming Jiang ; Günter Reiter ; Wenbing Hu
• 刊名：Journal of Physical Chemistry B
• 出版年：2016
• 出版时间：January 28, 2016
• 年：2016
• 卷：120
• 期：3
• 页码：566-571
• 全文大小：358K
• ISSN：1520-5207

文摘

Chain-folding is a habit of polymer crystallization, which yields limited lamellar thickness of polymer crystals and thus determines their thermodynamic stability. We performed dynamic Monte Carlo simulations of a lattice polymer model with chain-folded lamellar crystal growth stopped by a critical spacing of two parallel-oriented bars. We confirmed the critical spacing as minimum lamellar thickness (l_min) proposed previously in the Lauritzen–Hoffman (LH) model; however, the temperature dependence of excess lamellar thickness beyond l_min appears opposite to the prediction of the LH model. Moreover, it reproduces Strobl et al.’s experimental observations, but our lattice-model approach rules out any mesophase hypothesis. We proposed a kinetic model combining intramolecular secondary nucleation and stem elongation to explain this temperature-dependence behavior, which reconciles the controversial arguments on the microscopic mechanism of lamellar crystal growth of polymers.