Phillips, Francis Randall (2010-08). Fabrication and Characterization of Nanowires. Master's Thesis. Thesis uri icon

abstract

  • The use of nanostructures has become very common throughout high-tech industries. In order to enhance the applicability of Shape Memory Alloys (SMAs) in systems such as Nano-Electromechanical Systems, the phase transformation behavior of SMA nanostructures should be explored. The primary focus of this work is on the fabrication of metallic nanowires and the characterization of the phase transformation of SMA nanowires. Various metallic nanowires are fabricated through the use of the mechanical pressure injection method. The mechanical pressure injection method is a template assisted nanowire fabrication method in which an anodized aluminum oxide (AAO) template is impregnated with liquid metal. The fabrication procedure of the AAO templates is analyzed in order to determine the effect of the various fabrication steps. Furthermore, metallic nanowires are embedded into polymeric nano bers as a means to incorporate nanowires within other nanostructures. The knowledge obtained through the analysis of the AAO template fabrication guides the fabrication of SMA nanowires of various diameters. The fabrication of SMA nanowires with di fferent diameters is accomplished through the fabrication of AAO templates of varying diameters. The phase transformation behavior of the fabricated SMA nanowires is characterized through transmission electron microscopy. By analyzing the fabricated SMA nanowires, it is found that none of the fabricated SMA nanowires exhibit a size eff ect on the phase transformation. The lack of a size e ffect on the phase transition of SMA nanowires is contrary to the results for SMA nanograins, nanocrystals, and thin films, which all exhibit a size eff ect on the phase transformation. The lack of a size eff ect is further studied through molecular dynamic simulations. These simulations show that free-standing metallic nanowires will exhibit a phase transformation when their diameters are sufficiently small. Furthermore, the application of a constraint on metallic nanowires will inhibit the phase transformation shown for unconstrained metallic nanowires. Therefore, it is concluded that free-standing SMA nanowires will exhibit a phase transformation throughout the nanoscale, but constrained SMA nanowires will reach a critical size below which the phase transformation is inhibited.
  • The use of nanostructures has become very common throughout high-tech industries.

    In order to enhance the applicability of Shape Memory Alloys (SMAs) in

    systems such as Nano-Electromechanical Systems, the phase transformation behavior

    of SMA nanostructures should be explored. The primary focus of this work is on the

    fabrication of metallic nanowires and the characterization of the phase transformation

    of SMA nanowires. Various metallic nanowires are fabricated through the use of the

    mechanical pressure injection method. The mechanical pressure injection method is a

    template assisted nanowire fabrication method in which an anodized aluminum oxide

    (AAO) template is impregnated with liquid metal. The fabrication procedure of the

    AAO templates is analyzed in order to determine the effect of the various fabrication

    steps. Furthermore, metallic nanowires are embedded into polymeric nano bers as a

    means to incorporate nanowires within other nanostructures.

    The knowledge obtained through the analysis of the AAO template fabrication

    guides the fabrication of SMA nanowires of various diameters. The fabrication of

    SMA nanowires with di fferent diameters is accomplished through the fabrication of

    AAO templates of varying diameters. The phase transformation behavior of the fabricated

    SMA nanowires is characterized through transmission electron microscopy.

    By analyzing the fabricated SMA nanowires, it is found that none of the fabricated

    SMA nanowires exhibit a size eff ect on the phase transformation. The lack of a

    size e ffect on the phase transition of SMA nanowires is contrary to the results for

    SMA nanograins, nanocrystals, and thin films, which all exhibit a size eff ect on the phase transformation. The lack of a size eff ect is further studied through molecular

    dynamic simulations. These simulations show that free-standing metallic nanowires

    will exhibit a phase transformation when their diameters are sufficiently small. Furthermore,

    the application of a constraint on metallic nanowires will inhibit the phase

    transformation shown for unconstrained metallic nanowires. Therefore, it is concluded

    that free-standing SMA nanowires will exhibit a phase transformation throughout the

    nanoscale, but constrained SMA nanowires will reach a critical size below which the

    phase transformation is inhibited.

publication date

  • August 2010