Giuntoli Andrea, Chremos Alexandros, Douglas Jack F
Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
J Chem Phys. 2020 Jan 31;152(4):044501. doi: 10.1063/1.5134983.
We investigate how varying molecular topology of polymers influences crystallization in thin polymer films. In particular, we simulate linear and star polymers of fixed mass having a progressively increasing number of arms (f ≤ 16) in a system where the linear polymer exhibits crystallization in a thin film geometry, but no apparent crystallization in the corresponding bulk material. The degree of crystallization of the polymer film at long times decreases progressively with increasing f, and no crystallization is observed beyond f = 8. Crystallization for smaller values of f develops as a sigmoidally shaped wavefront initiating from the supporting crystalline interface. We suggest that large shape fluctuations and the competition of length scales of star polymers with high f lead to inhibited crystallization.
我们研究了聚合物分子拓扑结构的变化如何影响聚合物薄膜中的结晶过程。具体而言，我们模拟了固定质量的线性和星形聚合物，其臂数逐渐增加（f ≤ 16），该系统中线性聚合物在薄膜几何结构中表现出结晶现象，但在相应的块状材料中没有明显的结晶现象。长时间后聚合物薄膜的结晶度随着f的增加而逐渐降低，并且在f > 8时未观察到结晶现象。对于较小f值的结晶过程，是从支撑结晶界面开始以S形波前的形式发展的。我们认为，具有高f值的星形聚合物的大形状波动和长度尺度竞争导致结晶受到抑制。
