Creation of macroscopic chiral structures through twisting crystal growth and exploration of their functions

用有机基质研究了各种无机和有机晶体的扭曲生长。通过浸渍含有K_2Cr_2O_7和聚丙烯酸的水溶液，实现了微扭晶在玻璃基板上的定向组装。K_2Cr_2O_7的取向显微结构表现出一种独特的光学性质，源于周期性的扭曲晶体生长。在有机溶剂中形成的有机分子芘，其晶体形态随着聚合物聚乙烯吡咯烷酮浓度的增加而由多面体形状转变为具有特征的曲线形状，如s形和螺旋结构。推导出在扩散限制条件下，通过非对称单元的扭曲组合来构造曲线形式。利用聚合物基质控制无机和有机晶体的生长将提供一种具有宏观手性的新型功能材料。

Twisted growth of various inorganic and organic crystals was investigated by using organic matrix. Oriented assembly of micrometric twisted crystals on a glass substrate was achieved through dipping of an aqueous solution containing of K_2Cr_2O_7 and poly(acrylic acid). The oriented microstructures of K_2Cr_2O_7 exhibited a unique optical property originating from the periodic twisted crystal growth. The crystal morphology of an organic molecule, pyrene, formed in an organic solvent changed from polyhedral shapes into characteristic curving forms, such as sigmoidal and helical architectures, with increasing the concentration of a polymer, polyvinyl pyrrolidone. The curving forms are inferred to be constructed through a twisted assembly of asymmetric units under diffusion-limited conditions. The controlled growth of inorganic and organic crystals using the polymer matrix would provide a novel type of functional materials having macroscopic chirality.