Smart materials sound better!

By Mariusz Bogacki, Researcher and Science Communicator, Edinburgh

With a new breakthrough in their production, they are predicted to be the defining material of the 21st century.

First things first. Material science is a branch of science that looks at how different objects and materials are constructed in terms of their atomic structure. Atoms determine the material’s properties such as hardness, flexibility or sharpness. Material scientists therefore study things like concrete, wool or steel in order to analyse the workings of atoms within them.

Smart materials react to external stimuli such as light or moisture. Examples include materials capable of changing colours, heating, cooling or even self-healing. Current applications range from photochromic sunglasses which darken when exposed sun light, to self-restoring car paints. But future possibilities extend to materials that react to weather conditions, self-repairing mobile phones screens and even drugs that are released into the bloodstream at the first sign of infection.

Unfortunately, until recently, one of the biggest problems with smart materials was their production. It could take hours or even days to produce and ‘activate’ a material, with both processes being largely environmentally unsustainable. However, scientists at the RMTI University in Melbourne believe they found a solution to fix those issues.

Utilising the power and precision of high-frequency sound waves, the researchers came up with a clean and green technique for production of smart materials. The technique relies on a microchip to produce high-frequency sound waves which cause molecules (a group of atoms bounded together) to order themselves and ‘activate’ the material in just minutes. Think of Lego blocks rapidly self-organising when played a specific song. Or, imagine plane’s wings shape-shifting before and after a take-off!

The ability to reliably control the interaction of sound waves with different materials has wide applications not only in the field of ultrasound-driven chemistry but also in manufacturing. The technique has already been successfully tested on copper and iron-based smart materials, so it is hoped that it can be applied to other materials and scaled out for efficient and environmentally friendly production. Should further trials prove satisfactory, smart materials have the potential of becoming as important to the 21st century as plastic was to the 20th.