Nabetani Yu, Uchikoshi Akino, Miyajima Souki, Hassan Syed Zahid, Ramakrishnan Vivek, Tachibana Hiroshi, Yamato Masafumi, Inoue Haruo
Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
Phys Chem Chem Phys. 2016 Apr 28;18(17):12108-14. doi: 10.1039/c6cp01547f.
The orientation of nanomaterials with an anisotropic nature such as nanoscrolls is very important for realizing their efficient and sophisticated functions in devices, including nanostructured electrodes in artificial photosynthetic cells. In this study, we successfully synthesized a nanoscroll by intercalation of a cationic polyfluorinated surfactant into the interlayer spaces of layered niobate and successfully controlled its orientation by applying an external magnetic field in water. The exfoliated niobate nanosheets were efficiently rolled-up to form nanoscrolls, which have a fine layered structure (d020 = 3.64 nm), by mixing with heptafluorobutanoylaminoethylhexadecyldimethylammonium bromide (C3F-S) in water, whereas the corresponding hydrocarbon analogue (C3H-S) did not form nanoscrolls. The synthetic yield for the purified and isolated nanoscrolls from the nanosheets was estimated to be 62% by weight. It was confirmed by atomic force microscopy (AFM) that most of the niobate nanosheets (98%) were converted to nanoscrolls. An external magnetic field was applied to the nanoscrolls to force them to align. After the magnetic treatment, the orientation of the nanoscrolls was investigated by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The non-uniform ring distribution of the SAXS patterns indicates that the nanoscrolls dispersed in water were aligned well on applying the magnetic field. The long axis of the nanoscroll was oriented in the direction of the applied field and long nanoscrolls were aligned more efficiently. When the intercalated C3F-S molecules were removed from the nanoscrolls by treating with an acid, the resultant nanoscrolls did not exhibit magnetic alignment, strongly suggesting that C3F-S plays an important role in the orientation control of the nanoscrolls by the magnetic field.
诸如纳米卷等具有各向异性的纳米材料的取向，对于在包括人工光合细胞中的纳米结构电极在内的器件中实现其高效且复杂的功能而言非常重要。在本研究中，我们通过将阳离子多氟表面活性剂插入层状铌酸盐的层间空间成功合成了纳米卷，并通过在水中施加外部磁场成功控制了其取向。通过在水中与七氟丁酰氨基乙基十六烷基二甲基溴化铵（C3F-S）混合，剥落的铌酸盐纳米片被有效地卷起来形成具有精细层状结构（d020 = 3.64 nm）的纳米卷，而相应的烃类似物（C3H-S）则未形成纳米卷。从纳米片中纯化和分离出的纳米卷的合成产率经估计按重量计为62%。通过原子力显微镜（AFM）证实，大多数铌酸盐纳米片（98%）已转化为纳米卷。对纳米卷施加外部磁场以使其排列。磁处理后，通过小角X射线散射（SAXS）和透射电子显微镜（TEM）研究纳米卷的取向。SAXS图案的非均匀环分布表明，施加磁场时分散在水中的纳米卷排列良好。纳米卷的长轴沿施加场的方向取向，并且长纳米卷排列得更有效。当通过用酸处理从纳米卷中除去插入的C3F-S分子时，所得纳米卷未表现出磁排列，这强烈表明C3F-S在通过磁场控制纳米卷的取向中起重要作用。
