2 - Special techniques and advanced structures

Abstract

Metal oxide materials with excellent properties are promising materials for various applications. Metal oxide with one-dimensional nanoarchitectures can provide a good material system to investigate the dependence of electrical, optical, thermal, and mechanical properties on dimensionality and size reduction. Metal oxide nanofibers can be fabricated by directly electrospinning from the precursor and by selectively removing the sacrificial polymer components from the suitable composite fibers. The structure and properties of electrospun metal oxide nanofibers can be modified by regulating the parameters during electrospinning and/or by postprocessing modifications of the as-spun nanofibers. Various secondary structures in terms of core-sheath, hollow, and side-by-side morphologies can be directly generated or constructed into the metal oxide nanofibers. The hierarchical pores of metal oxide nanofibers referring to porous structures in-fiber (i.e., within the individual nanofiber) and interfiber (i.e., among the stacked nanofibers) can be well regulated to suit for the application. Aligned arrays of metal oxide nanofibers play an important role in the relevant applications because of the remarkable anisotropy and enhanced mechanical properties relative to the case of randomly deposited nanofibers, which can be generated by controlling the deposition of the nanofibers during electrospinning. The intersection of metal oxide nanofibers can be welded to improve the mechanical strength and electrical properties. Three-dimensional aerogels composed of metal oxide nanofibers can also be produced. The mass production of electrospun nanofibers will promote the development of translating the electrospun metal oxide nanofibers into uses for industry.