Electrospinning is a process leading to the formation of ultra-fine fibres with controlled and uniform diameters in the micrometre to nanometre range (see Figure 1), starting from fluid polymers (molten or in solution).
The principle of the technique is the application of a strong electric field (in the kV range) to a drop of fluid polymer on the tip of a spinneret. As the intensity of the electric field increases, the hemispherical surface of the drop elongates to form a conical shape (the so-called Taylor cone). For a critical value of the applied electric field, the repulsive electrical forces overcome the surface tension of the drop and a charged jet of the solution is ejected from the tip of the Taylor cone. An unstable and rapid whipping of the jet occurs between the tip and the collector leading to the evaporation of the solvent and the formation of solidified continuous, ultra-thin fibres on the collector.
The conventional electrospinning set-up consists of a high voltage power supply, a spinneret and a grounded collector (static or rotating)
Electrospinning has the advantages of simplicity, efficiency, low cost, high yield and high degree of reproducibility of the obtained materials.
Furthermore, its versatility allows the production of organic, hybrid and inorganic nanofibres, as well as the elaboration of designed geometries (core-sheath, hollow fibres), assemblies and architectures (aligned or nonwoven fibres, cross-bars).
This great variety of electrospun nanofibres in term of materials, structures, architectures and functionalities explains the increased use of the electrospinning technique and its extensive applications range.