Atomistic Molecular Insight into the Time Dependence of Polymer Glass Transition

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• 作者：Rongliang Wu ; Xinlong Qiu ; Tianyi Zhang ; Kangyu Fu ; Xiaozhen Yang
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：July 30, 2015
• 年：2015
• 卷：119
• 期：30
• 页码：9959-9969
• 全文大小：613K
• ISSN：1520-5207

文摘

The most atomistic molecular details of polymer glass transition were analyzed through the frozen torsions in our molecular dynamics simulations. Different observation times were used to determine the frozen fractions and frozen chain lengths. The glass transition temperature was found to coincide well with the temperature at which the frozen fractions were reduced to 1/e. The frozen chain segments grow as the temperature decreases in a similar way with that of linear polymerization, and the inverse number-average frozen chain length leads to the formulation of configuration entropy during glass transition. The ideal glass transition temperature extrapolated to zero configuration entropy corresponds well with those reported in the literature, and the relation between the relaxation time and the configuration entropy shows perfect agreement with the Adam鈥揋ibbs theory around the glass transition temperature. Volume spanning clusters are formed at the low temperature end, which might serve as a premature prototype for the formation of the 鈥渋deal glassy state鈥?with limited accessible configurations.