Michieletto Davide, Turner Matthew S
School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom;
Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
Proc Natl Acad Sci U S A. 2016 May 10;113(19):5195-200. doi: 10.1073/pnas.1520665113. Epub 2016 Apr 26.
The static and dynamic properties of ring polymers in concentrated solutions remains one of the last deep unsolved questions in polymer physics. At the same time, the nature of the glass transition in polymeric systems is also not well understood. In this work, we study a novel glass transition in systems made of circular polymers by exploiting the topological constraints that are conjectured to populate concentrated solutions of rings. We show that such rings strongly interpenetrate through one another, generating an extensive network of topological interactions that dramatically affects their dynamics. We show that a kinetically arrested state can be induced by randomly pinning a small fraction of the rings. This occurs well above the classical glass transition temperature at which microscopic mobility is lost. Our work both demonstrates the existence of long-lived inter-ring penetrations and realizes a novel, topologically induced, glass transition.
环状聚合物在浓溶液中的静态和动态性质仍然是高分子物理领域最后几个尚未深入解决的问题之一。与此同时,聚合物体系中玻璃化转变的本质也尚未得到很好的理解。在这项工作中,我们通过利用推测存在于环状聚合物浓溶液中的拓扑约束,研究了由环状聚合物构成的体系中的一种新型玻璃化转变。我们表明,此类环相互强烈渗透,形成了广泛的拓扑相互作用网络,这极大地影响了它们的动力学。我们还表明,通过随机固定一小部分环,可以诱导出一种动力学受阻状态。这种情况发生在远高于微观流动性丧失的经典玻璃化转变温度之上。我们的工作既证明了环间长期渗透的存在,也实现了一种新型的、由拓扑诱导的玻璃化转变。