Nanomaterials are chemicals substances that are manufactured and used at very small scales. They can be designed for increased strength, chemical reactivity, or conductivity, and are changing the field of engineering.
The key factor for a nanomaterial is its size: ranging from 1-100 nanometres. For reference, a nanometre is a billionth of a metre. They can be naturally occurring, like flakes of volcanic ash, or can occur as by-products of combustion. These can also be called ultra-fine particles.
Engineered nanomaterials are intentionally produced and specifically designed to achieve certain functions. This field of study has exploded in the last decade, with huge possibilities for engineering, manufacture, robotics, biomedicine, and energy storage.
Working in this field requires a great body of interdisciplinary study, requiring knowledge of physics, photonics, and mechanical, chemical, and electrical engineering.
Different Types of Nanomaterials:
There are different types of nanomaterials, classified by size and dimensions.
Nanoparticles have all three dimensions within the nanoscale. Multiple nanoparticles can form a nanocomposite. Nanoparticles often have unexpected visual properties because they are small enough to confine their electrons, producing quantum effects that change how they appear to the human eye.
A nanofiber has two dimensions in the nanoscale.
Nanotubes and Nanorods
Nanotubes are hollow nanofibers, nanorods are solid.
How Nanoparticles Are Made
There are two methods of producing nanoparticles. The ‘bottom up’ method involves placing atoms in nanostructured arrays, crystal planes which stack on top of each other, resulting in the synthesis of the nanostructures.
The ‘top down’ approach involves the removal of crystal planes from the substrate, similar to milling.
Why Nanomaterials Are Important For Engineering:
Nanoengineered materials can be designed to have greater structural strength, chemical sensitivity, conductivity, or optical properties. All of these have great potential in the field of engineering.
One of the most well-known and exciting developments that is emerging thanks to the study of nanomaterials is the application of carbon nanotubes. This nanomaterial has gained great fame due to having the highest strength-to-weight ratio of any known substance, having greater thermal conductivity than diamond, and better electrical conductivity than copper. Production of carbon nanotubes has increased tenfold over the last decade, meaning there is more opportunity for research and development with this material than ever before.
The huge surface area of carbon nanotubes allows them to be used as the electrodes in batteries and capacitors, providing better electrical and mechanical stability than other materials which have previously been used.
Carbon nanotubes are also extremely light, making them the perfect material for the construction of next-generation aircraft, cutting the weight of a commercial jet by around 20%.
Nanomaterials can be used as lubricant additives, having the ability to reduce friction in moving parts. Worn parts can even be repaired with self-assembling nanoparticles.
Developments like this give us more control over the materials we work with, unlocking new potential and new functions that can change the way we approach engineering problems.