Electrospun Metallic Nanofibers Fabricated by Electrospinning and Metallization

Abstract

The development of high value added one-dimensional (1D) electrospun nanofibers and structures (such as wires, belts and tubes) have tremendously increased over the last decade. Today, a wide variety of nano-objects (such as metal nanoparticles,[1–3] clays,[4] carbon nanotubes,[5, 6] ceramics,[7] etc.) can be immobilized onto nanofibers, which bring new materials’ properties and potential applications in a broad range of areas such as electronics, medicine, sensor, and controlled release technology. As a result, a tremendous amount of effort has been devoted to the synthesis, characterization and utilization of nanofibers composites with well-controlled dimensions and properties. Indeed, extensive research and development in the 21st century is directed towards the development of novel hybrid nanomaterials with tunable properties. The purpose of such formulations is to achieve unique and superior properties that can not be achieved using only a single component of the hybrids. In this way, one can combine the properties of an organic component (polymers, biomolecules) such as mechanical toughness and flexibility with the hardness and thermal stability of the inorganic component (carbon, metals, ceramics, and glass) into a single system.[8,9] The new nanofibrous products based on the immobilization of functional nanomaterials onto electrospun nanofibers have recently attracted significant attention from both the academic and industrial sectors.[10–12] The main strategies for developing new nanostructured nanofibers were mostly carried out by direct electrostatic spinning of various polymers with molecular building blocks or polymer solutions (or polymer melts) with well-dispersed nano-objects,[1–7] and by co-electrospinning core–shell polymer nanofiber using a single-nozzle technique,[13,14] and by mimicking natural self-assembled process to produce hierarchically ordered self-assembled nanofibers.[15] This chapter concentrates on metallized nanofibers which can be serving as the necessary functional components in building nanoelectronics. Nanofibers with uniform diameters represent an ideal model system to fabricate metal nanofibers. Long polymer fibers with sub-micrometer diameters down to a few nanometers can be prepared by electrospinning, which is a process where polymer solutions or polymer melts are processed in an electrical field.[16, 17] Electrospun nanofiber has a history of more than 70 years. In 1934, Formhals patented his first invention relating to the process and the apparatus for producing artificial filaments using electric charge.[18] This technique involves the use of a high voltage to charge the surface of a polymer solution (or melt) droplet and thus to induce the ejection of a liquid jet through a capillary spinneret. From then, this technique had gradually received