Synthesis And Assembly Of One Dimentional Functional Nanomaterials

One dimensional nanomaterials have attracted more and more attentions duo to their unique properties within electronic, photonic, magnetic and catalytic areas. Many synthetic and fabrication routes have already been developed for modifing different functional materials to one dimensional nanostructure such as fibers, wires, rods, belts, tubes, spirals and rings. Among these methods, Electrospinning has become a widely acknowledged nanostructuring technique which not only easily producing nanofibers but also a highly versatile of controlling of their morphology and surface topology, as well as in terms of the properties of the final structures. Many functions can be incorporated into the nanofibers and providing extremely broad range of potential applications exist in which electrospun fibers can express major contributions, include not only textile, filter, and mechanical reinforcement applications but can be further extend to tissue engineering, drug delivery, wound healing, sensors design and production, optoelectronics, catalysis, and many more. As the demands increasing, preparation of hybrids nanofibers with multi-functional properties has been of current interest. However, how to fabricate and assembly of composite nanomaterials with controlled morphologies based on electrospun nanofibers and assemble them into controlled heterojunction structures are still big challenges.In this thesis, we have prepared aligned array electrospun nanofibers by adjusting electronic field, and also produced various composite organic/inorganic nanostructures by combining electrospinning and sol-gel technique or chemical vapour deposition technique. In which conclude:1) Preparation of nanoparticles/nanofibers composition structures. â‘ Synthesis of decorating single crystal Pd nanoparticles well dispersed on polyacrylonitrile electrospun fibers by post treatment of sol-gel technique. The PAN nanofibers were rinsed in PdCl2 solution for a little while and then in-situ reduced by glycol to generate Pd nanoparticles.â‘¡Polyacrylonitrile/F_e3O₄ nanocomposite fibers have been successfully obtained through electrospinning and sol-gel technology. Electrospun polyacrylonitrile /FeCl₃ nanofibers were prepared as templates and immerged into composite Fe salts/water solution for Fe₃O₄ nanoparticles growing on. The Magnetic Fe₃O₄ nanoparticles are homogeneously distributed on the surfaces of the PAN nanofibers, uniform and most of them are approximately spherical with the mean diameters of 8±3 nm. By simply adjusting the experimental parameters, the diameters of polyacrylonitrile nanofibers and nanoparticles can be easily controlled, respectively.â‘¢In-situ synthesis of homogeneous gold nanoparticles well dispersed on TiO2 electrospun nanofibers by adding HAuCl₄.3H₂O into the electrospinning precursor Ti (isopropoxide)4 solution and then electrospinning following by heat treatment.â‘£Synthesis of homogeneous Pt nanoparticles well dispersed on TiO2 electrospun nanofibers. Using as-prepared TiO₂ nanofibers as template, Pt nanoparticles were added by absorption inside a solution atmosphere.2) We have demonstrated that single-crystal Germanium or Silicon nanowires could directly grow on electrospun Titanium dioxide composite nanofibers by combining electrospinning and chemical vapor deposition. Not only these semiconductor nanowires on oxides nanofibers materials were synthesized, but also produced Germanium nanowires on Polyimide electrospun nanofibers structures. The size of the resulting nanowires could be controlled by the composition of the fibers and the parameters during CVD. This work provides a simple general route to the nanowire-on-nanofiber hierarchical structure also suggests that post spinning treatment of electrospun nanofibers of different materials offers an additional means to further modify the phase structure and morphology of nanofibers, enabling the fabrication of complex architectures and functional materials.3)We investigate the synthesis of CuO/Cu₂O nanorods on copper foil, investigate how the experiment parameters affect the nanorods formation, also the CuO nanorods are then used to construct a non-enzymatic glucose sensor which presents some attractive analytical features such as high sensitivity, good stability, reproducibility, and selectivity as well as fast response time.4) We investigate the mechanism of formation of Cu₂S nanorods on copper foil through a vapor-solid phase reaction by treating Cu foil under H₂S/O2 atmosphere at room temperature. At first, we studied the formation of Cu₂S nanorods on copper foil by introducing dislocations through physical machining, draw the conclusions that the rods are dislocation driven related because they were prone to form in dislocation accumulated areas. As reaction went on, an uneven dense film of Cu₂S was formed on copper foil in which the copper ions can diffuse with, following by forming single crystal nanorods at dislocation points because those domains have lower surface energy which can provide a more efficient way to grow than at the other areas.