Electrospinning is a fiber-production method that uses electrostatic force, rather than mechanical drawing, to pull a polymer solution into extremely thin fibers. The result is a nonwoven mat of continuous fibers whose diameters typically range from tens of nanometers to a few micrometers — far finer than conventional textile fibers.

Because the equipment is relatively simple and works with a wide range of polymers, electrospinning has become one of the most widely used routes to nanofibers in university and industrial laboratories.

The basic setup

A laboratory electrospinning system has four essential parts:

  • A syringe pump that feeds polymer solution through a fine needle (the spinneret) at a constant, controlled flow rate.
  • A high-voltage power supply, usually providing several to a few tens of kilovolts, connected to the needle.
  • A grounded collector — a flat plate for random fiber mats, or a rotating drum for aligned fibers.
  • An enclosure that protects the operator from high voltage and helps stabilise the surrounding air.

What happens during spinning

When voltage is applied, charge accumulates on the surface of the droplet at the needle tip. As the electrostatic force grows, it competes with the solution’s surface tension and deforms the droplet into a cone — known as the Taylor cone. Beyond a critical voltage, a thin charged jet is ejected from the tip of the cone.

The jet first travels in a short straight segment, then becomes unstable and begins to whip and loop in rapidly expanding spirals. This “bending instability” stretches the jet enormously, which is why the final fibers are so thin. At the same time the solvent evaporates, so solid fibers arrive at the collector and build up layer by layer into a porous mat.

Key idea

Fiber formation depends on a balance: the solution must be viscous and entangled enough to stay continuous while being stretched, and the electric field must be strong enough to keep the jet stable.

Why nanofibers are useful

Electrospun mats combine several properties that are hard to obtain together with other methods:

  • a very high surface-area-to-volume ratio;
  • small, highly interconnected pores;
  • a fibrous architecture that resembles the extracellular matrix of tissue;
  • the freedom to blend polymers, add particles or build core–shell fibers.

These properties explain why electrospun nanofibers are studied for air and water filtration, tissue engineering scaffolds, drug delivery, wound dressings and battery separators.

Where to start

If you are new to the technique, begin with a well-documented polymer–solvent system — for example polyvinyl alcohol (PVA) in water or polyacrylonitrile (PAN) in DMF — and change one parameter at a time. Record the ambient temperature and humidity for every run; they influence results more than many beginners expect.

When you are ready to plan experiments, our guide to the parameters that control fiber diameter is a good next read.