Nano wires

Systems confined in two dimensions, or quasi-1D systems, include nanowires, nano rods, nanofilaments and nanotubes: again these could either be amorphous, single-crystalline or polycrystalline (with nanometre-sized grains). The term ‘nano-ropes’ is often employed to describe bundles of nanowires or nanotubes.

Types of Nanowires:

·         Metallic – Made from Nickel, Platinum or Gold

·         Semi-conducting – Comprises of Silicon, Indium phosphide or Gallium Nitride

·         Insulating – Silicon Dioxide or Titanium dioxide

·         Molecular – Involves repeating organic or inorganic molecular units

Synthesis methods:

1. Electro-spinning

·         Uses an electrical charge to draw very fine (typically on the micro or nanoscale) fibres from a liquid.

·         Sufficiently high voltage is applied to a liquid droplet and the body of the liquid becomes charged.

·         When the electrostatic repelling force overcomes the surface tension force of the polymer solution, the liquid spills out of the spinneret and forms an extremely fine continuous filament.

·         These filaments are collected onto a rotating or stationary collector with an electrode where they accumulate and bond together to form nanofiber fabric.

2. Template Base synthesis

·         Use in fabrication of nanorods, nanowires, and nanotubes of polymers, metals, semiconductors, and oxides.

·         Some porous membrane with Nano-size channels(pores) are used as templates to conduct the growing of nanowires.

·        Pore size ranging from 10 nm to 100 mm can be achieved.

Applications of Nanowires:

Nanowires are promising materials for many novel applications for their unique geometry and unique physical properties such as:

·         electrical

·         magnetic

·         optical

·         mechanical

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