One-dimensional. Limited Space Within The Preparation And Growth Mechanism Study

The quest for materials with molecular scale properties that can satisfy the demands of the 21st century has led to the development of one dimensional nanostructures, ODNS. Nearly, every class of traditional material has an ODNS counterpart. ODNS has a profound impact in nanoelectronics, nanodevices and systems, nanocomposite materials, alternative energy resources and national security. In the thesis, one dimensional nanomaterials arrays, such as polymer nanomaterials and metal nanomaterials, with integrated patterns have been successfully fabricated. Meanwhile, we developed new nanomaterials systems including metal coaxial nanocable and metal multilayer nanomaterials. However, only few systemic research works concerning the fabrication and growth mechanism in restricted spaces have been reported.Fabrication of nano- or micro- patterns with photolithographic technique has been marstered. Among those techniques, photolithography has been regarded as one of the most successful techniques in large-scale microfabrication, and the method is effective, low-cost and simple implementation. There are main 5 steps:coating, soft bake, exposure, hard bake and developing. The best experimental conditions have been found by systemic analysis and experiment. High-ordered large area patterns with different scales and patterns have been fabricated on the side of porous anodic aluminum oxide (AAO) templates.Patterned AAO template were used as a second template firstly to fabricate various patterned polymer (such ascommen molecular weight PS, PA6, PA66, PA11, ABS, PMMA) nanotube and nanowire arrays by polymer solution wetting and melt wetting templates. The diameters of the polymer nanotubes and nanowires are consistent with the pore diameters of the templates. The wall of the nanotubes increases with the solution concentration in solution wetting template. When the solution concentration reaches a certain value, nanowires are obtained. The concentration are different with the solvents, for example, trichloromethane was used as solvent in PS solution, and the concentration was 10.0 wt%, and PS nanowires were obtained. Whereas, if formic acid was used as solvent in PA6 solution, and the concentration was 8.0 wt%, then PA6 nanowires were obtained. With melt wetting templates, the wall of nanotubes is depended on the melt temperature. Generally, the more the melt temperature is, the thinner the wall of the nanotubes is, or, thicker. The crystallization phenomena of the low crystallinity PS and high crytallinity PA6 have been observed by high reolution transition electron microscope (HRTEM) firstly. The crystalline lattice fringes exist in some regions, while most regions show an amorphous nature. Compared with X-ray diffraction (XRD) patterns of the bulk polyer, the XRD patterns of polymer nanotubes are very different. It is proved that crystal phase have changed during the nanotubes growing in the restricted spaces. And, it was found that there is a crystal transformation from the a-form in bulk to theγ-form of PA6 in nanotubes.Fabrication and properties of metal nanomaterials were studied. Cu nanowires were prepared by the electrodeposition. The length of the Cu nanowires increases with the deposition time. HRTEM image and select area electron diffraction pattern show that the Cu nanowires have single crystal structure. The growth orientation is along [220] direction, and the broken orientation was obsvered firstly, it is along (202) and (022) directions, respectively. Regular cones were formed at the broken end of nanowires. Bent nanowires were also observed, this means that the copper nanowires have good mechanical properties when applied external force.In the meantime, ferromagnetic nanomaterials, such as Ni, Co and Fe, were studied on fabrication and magnetic property firstly. The process of the nanotube growth was observed by the HRTEM after a series of experiments. The deposition time is less than 15 min, nanotubes are obtained. While the deposition time is more than 40 min, nanowires are obtained. Come to the conclusion, the nanotubes are obtanined first, then nanowires. It was found that the nanotubes are magnetized along the long axis more, but have lower coercivity.Fabrication and magnetic property of Cu/Ni core/shell coaxial nanocables were investigated. There are two methods to obtain nanocables:the first method, Ni nanotubes were deposited first, and then deposited Cu naniwires in the obtained Ni nanotubes. The second method is codeposition. Compared with the magnetic property of Ni nanotubes, the remanent magnetization of the Cu/Ni nanocalbe is lager than that of Ni nanotubes.The new Cu-Ni block nanowire system was developed. TEM images show that the block nanowires have bamboo-like structure. SAED pattern at the interfaces between Ni and Cu layer shows where the matter possesses single crystal structure which is not consistent with polycrystal structure of Ni layer. The reasons for the formation may be caused by the atomic doping. Two growth mechanisms including bamboo-like and cylinder-shaped growth mechanism for the polymer nanotube forming in the restricted spaces were put forward firstly. According to the experimental results, the induction effect of the AAO templates for the polymer nanotubes formation was raised firstly. The induction effect can cause changes for crystal form and crystallinity, and affect molecular chains arrangement. For the magnetic metal nanotube formation, the Brick-Stacked Wirelike Growth (BSWG) mechanism was first proposed.