尺寸效应始终是纳米材料研究中的核心问题，当其尺寸减小到十纳米以下，甚至达到亚纳米级别的时候，纳米材料的性质往往会发生质的飞跃，而在纳米材料研究中，其尺寸减小所带来的性质上的质变是我们追求的核心。一维亚纳米材料的尺寸效应主要依赖于其径向尺寸的减小，径向尺寸减小到一定程度可能会使其结构，构象甚至性质发生巨大的转变。一维亚纳米材料尺寸接近线性大分子，能够表现出丰富的构象。能够像有机大分子体系一样，在溶剂中能够形成三维网络状结构，得到凝胶。另外，还可能出现类生物大分子组装现象，通过调节自身构象，组装得到三维块体。本论文主要是围绕一维纳米材料中的亚纳米线展开的。 利用羟基氧化钆亚纳米线通过湿纺法制备得到了透明的高柔性的纳米线纤维。通过表征纤维内部结构及拉伸断裂过程中结构的变化，证明了纤维的高柔性主要来源于其中有序排列的弹簧状的亚纳米线。这种亚纳米线在拉伸过程中能够发生一定程度的弹性形变和较大的塑形形变，这是之前报道的纳米线纤维材料无法实现的，为制备高柔性的类高分子亚纳米线材料奠定了基础。 接着又尝试制备亚纳米线薄膜，并对其光学性质进行了研究。我们通过湿纺法将羟基氧化钆亚纳米线加工成了透明柔性的薄膜。薄膜中亚纳米线沿其长轴方向规整排列，因而薄膜具有很强的各项异性，表现出明显的双折射，能够对光发生各向异性散射。另外，在薄膜中引入荧光量子点或量子棒后，薄膜能够发射偏振荧光。为亚纳米线材料在光学波片和量子点液晶显示中的应用提供了新的思路。进一步的，我们又发现羟基氧化钆亚纳米线能够百分之百自组装形成宏观螺旋组装体，并尝试向其中引入了非手性荧光有机染料。结合分子动态模拟，进一步阐明了宏观螺旋组装体的形成机理及手性的演化，有望应用于其他纳米线手性结构的构筑。 除了基于亚纳米线本征各向异性的各种性质及功能外，我们还尝试通过调控亚纳米线组分，丰富其功能。我们合成了钨青铜纳米线，探索了其光热性质及组装结构。进一步的利用多酸制备得到了磷钼酸团簇-羟基氧化铋复合亚纳米线，将其制成了光热薄膜，应用于海水淡化中。为制备组分多样化，功能丰富化的亚纳米线器件提供了思路。
Size effect has always been the core issue in the research of nanomaterials，and when the size of nanomaterials reduced to less than ten nanometers, or even sub-nanometer level, their properties can often undergo qualitative changes. In the research of nanomaterials, the core aim is the qualitative leaps of the properties brought by the size decrease. The size effect of one-dimensional nanomaterials mainly depends on the reduction of their radial size. Reducing the radial size to a certain extent may lead to great changes in their structure, conformation or even properties. One-dimentional sub-1 nm nanomaterials are similar to linear macromolecules, which can show abundant conformations. Like organic macromolecule system, they can form three-dimensional network structure in solvents and gels can be obtained. In addition, they can assemble like biomacromolecule assembly. By adjusting their conformation and three-dimensional bulk materials can be obtained. This dissertation focused on the sub-1 nm nanowires. Transparent and highly flexible nanowire fibers were prepared by wet spinning of GdOOH sub-1 nm nanowires. By characterizing the internal structure of the fibers and the structural changes during tensile fracture, it was proved that the high flexibility of the fibers mainly came from the ordered arrangement of spring-like sub-1 nm nanowires, which were like some small springs. The nanowire fibers could undergo elastic deformation to a certain extent and large plastic deformation in the stretching process, which hadn’t been reported before in the field of nanowire fibers, laying a foundation for the preparation of highly flexible nanowire materials like the polymer. Sub-1 nm nanowire films were prepared and their optical properties and functions were studied. GdOOH sub-1 nm nanowires were fabricated into transparent and flexible films by wet-spinning method. Because the sub-1 nm nanowires in the films were arranged regularly along their long axis, the films were strongly anisotropic, exhibiting obvious birefringence. Incident light would be scattered anisotropically through the nanowire films. By introducing fluorescent quantum dots or quantum rods into the films, they could show polarized fluorescence, providing a new idea for the application of nanowires in the wave plate and quantum dots-liquid crystal display. Furthermore, we found that GdOOH sub-1 nm nanowires can self-assemble with 100% efficiency and formed the macroscopic helical assemblies, and we also tried to introduce non-chiral fluorescent organic dyes into the assembly. Combining with the results of molecular dynamic simulation, the formation mechanism and chiral evolution of macroscopic helical assemblies were elucidated, which were expected to be applied to the construction of novel chiral structures. In addition to the various properties and functions based on the intrinsic anisotropy of sub-1 nm nanowires, we also tried to enrich their functions by adjusting the components of sub-1 nm nanowires. We synthesized tungsten bronze nanowires and investigate their assembled structures and photothermal performance. Phosphomolybdic acid cluster-bismuth hydroxide composite sub-1 nm nanowires were prepared. Photothermal films were prepared with the nanowires and applied in the seawater desalination. It provided ideas for the preparation of sub-1 nm nanowires devices with diverse components and rich functions.
