Department of Chemical Engineering, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Taiwan, 30013 (ROC) http://www2.che.nthu.edu.tw/HO_LAB/
Angew Chem Int Ed Engl. 2014 Apr 22;53(17):4450-5. doi: 10.1002/anie.201310078. Epub 2014 Mar 18.
Banded spherulites are formed by crystallization of a chiral polymer that is end-capped with chromophore. Induced circular dichroism (ICD) of the chromophore can be found in the crystallized chiral polymers, giving exclusive optical response of the ICD. The ICD signals are presumed to be driven by the lamellar twisting in the crystalline spherulites, and the exclusive optical activity is attributed to the chirality transfer from molecular level to macroscopic level. To verify the suggested mechanism, the sense of the lamellar twisting in the crystalline spherulite is determined using PLM for the comparison with the ICD signals of the chromophore in the electron circular dichroism spectrum. The conformational chirality of the chiral polymer is determined by the vibrational circular dichroism spectrum. On the basis of the chiroptical results, evolution of homochirality from helical polymer chains (conformational chirality) to lamellar twisting in the banded spherulite (hierachical chirality) is suggested.
带状球晶是由末端带有发色团的手性聚合物结晶形成的。在结晶手性聚合物中可以发现发色团的诱导圆二色性（ICD），从而赋予 ICD 的独特光学响应。ICD 信号被认为是由结晶球晶中的层状扭曲驱动的，而独特的旋光活性归因于从分子水平到宏观水平的手性转移。为了验证所提出的机制，使用 PLM 确定结晶球晶中层状扭曲的方向，以便与电子圆二色光谱中发色团的 ICD 信号进行比较。手性聚合物的构象手性由振动圆二色光谱确定。基于旋光结果，从螺旋聚合物链（构象手性）到手性带状球晶中的层状扭曲（等级手性）的同手性的演变被提出。
