Synthetic metal nanowires: Applications towards on -demand reactions and autonomous motions

Nanomaterial frameworks have been focused on structural designs, synthetic methods, characterizations, size-dependent properties and their applications. A number of applications in optics, electronics, sensing, photonic, magnetism, mechanics, self-assembly, catalysis and biomedicine have been extensively researched, yet challenges remain to combine each individual property into one multi-functional nanostructure and advance its use based upon that unique property. Nanowires are considered a one-dimensional nanomaterial regarding their anisotropic structure. Template-assisted nanowire synthesis offers a remarkable advantage in order to achieve the goal of a multi-functional structure. Metals, alloys, polymers, and semiconductors have been synthesized by sequential depositions into the nanopores of a membrane. In this dissertation, single and multi-segmented metallic nanowires have been synthesized via the template-guided technique. Designs of metallic segments and compositions were highly developed towards on-demand controlled reaction and autonomous motion. The use of a short nickel magnetic segment in conjunction with a gold segment facilitates the magnetic controlled manipulation and functionalizations of a biomolecule, respectively. Several adaptive sensing systems were developed and demonstrated their feasibility for tunable electrocatalytic and bioelectrocatalytic reactions in fuel cell, sensor and microfluidic separation. Compositions of catalytic segments of self-autonomous nanomotors were also realized in parts of this dissertation. A major improvement of catalytic designs was successfully achieved and provides a key step towards future applications in biomedicine.