Direct observation of confined single chain dynamics by neutron scattering.
Direct observation of confined single chain dynamics by neutron scattering.
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DOI：
10.1103/physrevlett.104.197801
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发表时间：
2010-05
影响因子：
8.6
通讯作者：
J. Martin;M. Krutyeva;M. Monkenbusch;A. Arbe;J. Allgaier;A. Radulescu;P. Falus;J. Maiz;C. Mijangos;J. Colmenero;D. Richter
中科院分区：
文献类型：
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作者：
J. Martin;M. Krutyeva;M. Monkenbusch;A. Arbe;J. Allgaier;A. Radulescu;P. Falus;J. Maiz;C. Mijangos;J. Colmenero;D. Richter
中子自旋回波揭示了单链动态结构因子的纠缠聚合物链被限制在圆柱形纳米孔的链尺寸比侧孔尺寸大得多或小得多。在这两种情况下，仅在中间时间观察到相对于批量行为的动力学减慢。长时间的结果提供了约束条件下纠缠距离的直接微观测量。它们构成了强约束下聚合物熔体中总缠结密度稀释的第一个实验微观证据，这种现象迄今为止是根据各种宏观观察假设的。
Neutron spin echo has revealed the single chain dynamic structure factor of entangled polymer chains confined in cylindrical nanopores with chain dimensions either much larger or smaller than the lateral pore sizes. In both situations, a slowing down of the dynamics with respect to the bulk behavior is only observed at intermediate times. The results at long times provide a direct microscopic measurement of the entanglement distance under confinement. They constitute the first experimental microscopic evidence of the dilution of the total entanglement density in a polymer melt under strong confinement, a phenomenon that so far was hypothesized on the basis of various macroscopic observations.