Controlled Manipulation of Giant Hybrid Inorganic Nanowire Assemblies

Abstract

The ultimate goal of nanotechnology is the design and fabrication of nanosize building blocks with multiple functionalities and their assembly into large-scale functional structures that can be controllably manipulated. Here we show that hybrid inorganic multisegmented nanowires, with hydrophobic carbon nanotube tails and hydrophilic metal nanowire heads, allow the assembly and manipulation of massive ordered structures in solution, reminiscent of the organic molecular micellar assembly. Further, properly designed assemblies can be manipulated using external stimuli such as magnetic field and light. The hybrid nanowires can have multiple segments including magnetic components, allowing the assembly to be manipulated by external magnetic field. The assembled structures can also be manipulated by modifying the hydrophobicity of the respective components via chemical functionalization and optical irradiation. This approach brings the concept of environment sensitive self-assembling nanomaterials closer to reality.The design and building of mesoscale constructs of multifunctional attributes 1-3 could have a big impact on technologies such as drug delivery and microfludics. [4][5][6] Recently, Link et al. 2,7 has demonstrated the use of porous silicon as the building block for making smart materials. However, limited by the simple one-component system, it is difficult to incorporate additional functions into such designs. In order to provide broader capabilities, it is clear that materials of wider functionalities should be considered. One-dimensional nanoscale building blocks 8 such as nanotubes, 9-14 nanowires, [15][16][17][18][19] and their hybrids 20-23 could prove to be valuable materials in this endeavor. A previous report by Park et al. 22 showed that the amphiphilic properties of certain nanowires could be used to assemble structures based on the selfinteraction between nanowires. Yet, the true strength of such system lies in the ability to build complex structures that are responsive in real time to their environment. Such ability can be afforded by the interaction between the nanostructure and the environments (akin to surfactants). Here, we show for the first time that appropriately designed hybrid nanowires can be used to generate structures that can respond to their environment and can be manipulated using various external stimuli.Our approach is based on the use of one-dimensional hybrid nanowires consisting of multiple segments with hydrophobic carbon nanotubes on one end and hydrophilic metal nanowires on the other. 23 Through the hard template approach, the hybrid nanowire is fabricated by combination of electrodeposition and chemical vapor deposition for the

On the growth mechanism of nickel and cobalt nanowires and comparison of their magnetic properties

“…An understanding of the growth mechanism will help in the design of various heterogeneous structures and hybrid multifunctional nanostructures [24], and a mechanism for the formation of Co NTs using acetate precursors was proposed based on mobility assisted growth [25]. In the case of Co NTs a 5-h electrodeposition of cobalt acetate resulted in the formation of 50 μm long nanotubes.…”

Synthesis of High Coercivity Core–Shell Nanorods Based on Nickel and Cobalt and Their Magnetic Properties

“…Controlled synthesis of smart nanostructures based on magnetic materials assumes important due to their potential applications in various fields and the possibility for manipulating these structures using an external magnetic field [19,20]. Earlier, the authors reported the synthesis of Nickel nanowires (Ni NWs), Cobalt nanowires (Co NWs) [13] and Cobalt nanotubes (Co NTs) [2] employing different precursors by a single step potentiostatic electrodeposition technique.…”

Joining and Interconnect Formation of Nanowires and Carbon Nanotubes for Nanoelectronics and Nanosystems

“…After solder reflow or infrared heating, various soldered nanowire structures or prototype devices, as shown in Figure 6B, could be developed because the solder segment tends to coalesce (merge) in liquid form due to surface tension and thus form solidified joints or interconnects upon cooling. This synthetic method can easily be incorporated with other template deposition methods such as chemical vapor deposition (CVD), and it has been demonstrated that metallic nanowire segments can be integrated onto carbon nanotubes to produce hybrid structures 59. Thus, there is potential to combine solder segments with carbon‐nanotube structures and form solder joints/interconnects between carbon nanotubes and nanowires.…”