Labyrinthine pattern of polymer crystals from supercooled ultrathin films
Labyrinthine pattern of polymer crystals from supercooled ultrathin films
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DOI：
10.1016/j.polymer.2009.11.061
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发表时间：
2010-01
期刊：
影响因子：
4.6
通讯作者：
Guoliang Zhang;Liuxin Jin;Ping Zheng;A. Shi;Wei Wang
中科院分区：
文献类型：
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作者：
Guoliang Zhang;Liuxin Jin;Ping Zheng;A. Shi;Wei Wang
本文报道了在分子量为25000 ~ 932000 g/mol的聚环氧乙烷组分超薄膜中，观察到晶体宽度方向上具有周期性结构的迷宫式晶体图案。聚合物薄膜在远低于体熔化温度的温度下结晶，因此该体系具有聚合物链扩散受限和晶体前沿快速生长的特点。这两种竞争因素的相互竞争导致了迷宫式格局的形成。长周期与分子量之间的标度关系（L¯∝M¯w−0.24±0.03）支持了这一机制，表明链扩散的重要性。此外，ln(L¯/M¯w−0.24)−ΔE/ rtc与Tm0/TcΔT呈线性关系，表明晶体生长以二次成核为主。
We report the observation of a labyrinthine crystal pattern with a periodic structure in the crystal width direction in ultrathin films of poly(ethylene oxide) fractions with molecular weight ranging from 25,000 to 932,000 g/mol. The polymer thin films are crystallized at temperatures well below the bulk melting temperature, thus the system is characterized by limited diffusion of the polymer chains and rapid growth of the crystal fronts. The competition of these two competing factors leads to the formation of the labyrinthine pattern. This mechanism is supported by a scaling relation between the long period and molecular weight, L¯∝M¯w−0.24±0.03, indicating the importance of chain diffusion. Furthermore, a linear relationship between ln(L¯/M¯w−0.24)−ΔE/RTcand Tm0/TcΔT is observed, implying that the crystal growth is dominated by a secondary nucleation.