Nanofibres are nanoscale materials

Nanofibres are an exciting class of nanoscale materials. Individually, nanofibres are so small they’re hard to imagine or to visualise, but when collected together, they form a tangible nanomaterial. These new nanomaterials are being used in many high-tech industries.

Nano

To discuss nanofibres, we need to start with the prefix ‘nano’. This prefix tells us that we are talking about something that is very, very small. Nano comes from the Greek term ‘nanos’ meaning dwarf and is the prefix for things that measure 10^-9 in at least one dimension. But what does this mean?

Nanoscale objects fall into the size range from approximately 1 nm (10^-9 nm) to 100 nm (10⁷ nm). They can be described by referring to their measurement, but this can be tricky to visualise. They can also be described by using comparisons, for example, they are smaller than a single cell but bigger than an atom or they are smaller than microscale objects but bigger than atomic scale objects. Comparisons are one way to make it easier to imagine a nanoscale object.

Another important feature of nanoscale objects is that we cannot see them with the naked eye – they are invisible to us. Working with nanoscale objects is possible partly because tools have been developed to ‘see’ particles of matter that are a nanometre across or smaller. We need to use electron microscope technologies (such as a scanning electron microscope or atomic probe microscope) to see them.

When the idea of nanotechnology was developed in the 1960s, it was just that – an idea. Scientists couldn’t do much to make nanotechnology happen, as they didn’t have the tools to see or work at the nanoscale. What has happened is that nanotechnology has advanced alongside developments in microscopy.

Nanofibres

Nanofibres are one example of a nanoscale material. They are very thin, long fibres. Their diameter is in the nanoscale while their length can range from nanometres to metres, depending on how the nanofibre is made and its end application. To help us understand just how thin a nanofibre is, you’ll often hear it being compared to the width of a human hair. A nanofibre is many hundreds of times thinner than a human hair.

An individual nanofibre is invisible to the naked eye. However, when masses of individual nanofibres have been collected together, they form a tangible nanofibre material called a non-woven mat. This material can be handled, touched and used like any other material. It’s made from a polymer or biopolymer and is very light and flexible – a bit like a very thin plastic. If you look at this material with a scanning electron microscope, you’ll be able to see the individual fibres that make up the material.

With a huge range of potential applications, the market for nanofibre materials is growing rapidly, New Zealand company Revolution Fibres is a high-tech start-up company that produces commercial quantities of electrospun nanofibre.

Novel properties

The excitement around nanoscale materials is that these materials behave in new or unexpected ways. Properties that we observe at the macroscale change as the material is reduced to the nanoscale. This is mostly due to changes in size, scale and the physics rules that govern the materials at the nanoscale. The novel properties of nanoscale materials are being used to create new or enhanced products for use in a wide variety of high-tech applications, for example, nanofibres are being used in fields as diverse as filtration, medicine, energy, composites and cosmetics.