Scientists in London have constructed a computer model that predicts the useful, physical properties of clay composites from their atomic makeup. Clay-polymer composites can be very strong, stiff and light, making them useful in components for cars and airplanes, but they are usually developed by a costly process of trial and error. The researchers say their “virtual lab” system could help take the guesswork out of making such new materials.
“Some of the most obvious things about the world around us are harder to extract than you’d think – even though we’ve had an atomic theory of matter for at least 120 years by now,” said Professor Peter Coveney, whose team at University College London (UCL) conducted the research. Coveney says that difficulty in extrapolating from small properties (forces between atoms and molecules) to large ones (like hardness, density and conductivity) has held up the development of applications for exciting new materials like superconductors and graphene.
Coveney and his team have set about tackling the problem using a process called “multiscale modelling.” This technique, whose pioneers were awarded last year’s Nobel Prize for chemistry, combines rules about tiny interactions – single atoms and electrons, at the quantum level – with an understanding of how larger chunks of matter interact. It allowed the UCL researchers to test different combinations of polymers and clay molecules, without having to actually make all the composites in the lab.
Producing different configurations can lead to important discoveries. For example, sheets of clay, about five atoms thick, can spread out within a composite. Toyota discovered the spread-out type of structure in the 1980s. Simply by trying out different mixtures of polymers and clay, the car company eventually produced and patented the first “nanocomposites.”
Coveney says his research can help reveal what ingredients and conditions produce these different configurations. “Now we’ve got a virtual laboratory – a simulation environment that can tell you a lot of detail about why there are so many variations in the products you could form, based on these different chemistries,” Coveney says.