Department of Chemical Engineering, National Cheng Kung University, Tainan, 701, Taiwan.
Macromol Rapid Commun. 2021 Oct;42(20):e2100359. doi: 10.1002/marc.202100359. Epub 2021 Sep 17.
The self-assembly structures of lamellae in optical ring bands have a critical effect on their optical and physical arrangements. Two different types of dendritic banded spherulites (namely ring-banded and zigzag ring-banded) are formed in poly(ε-caprolactone)/poly (phenyl methacrylate) blend at crystallization temperatures of 42 and 46 °C, respectively. The difference in optical birefringence of ring bands in two types of spherulites is resolved by means of direct morphological comparison. Banded spherulites are fractured carefully to facilitate lamellar orientation analyses of both the top surface and the interior surface. The results have revealed the existence of tree-like dendritic fractal growth lamellar assemblies in both banded spherulites. The optical ring patterns of the banded spherulites are differentiated mainly by the fractal orientation of the edge-on crystal branches in the ridge region. On the basis of detailed morphological analysis, 3D-lamellar assembly mechanisms are proposed to explain the growth of dendritic ring-banded spherulites at 42 °C and dendritic zigzag ring-banded spherulites at 46 °C.
光学环形带中片晶的自组装结构对其光学和物理排列有重要影响。在结晶温度分别为 42°C 和 46°C 时，聚己内酯/聚甲基丙烯酸苯酯共混物中形成了两种不同类型的枝状环带球晶（分别为环形带和锯齿形环形带）。通过直接的形态比较，可以解决两种球晶中环带的光学双折射差异。小心地将球晶断裂，以利于对其顶面和内表面的片层取向进行分析。结果表明，两种带片中都存在树状的枝状分形生长片层组装体。环形带球晶的光学环纹主要通过脊区中晶枝的边缘晶面的分形取向来区分。基于详细的形态分析，提出了 3D 片层组装机制来解释在 42°C 下形成的枝状环形带球晶和在 46°C 下形成的枝状锯齿形环形带球晶的生长过程。
