Synthesised tooth enamel promises more resilient components
Fri 3 Mar 2017
A collaboration between the University of Michigan and the Defense Advanced Research Projects Agency (DARPA) has developed a new material, based on the structure of tooth enamel, that is set to help create circuitry, motherboards and other computer components which are more durable.
Resilience is a critical issue in components in use by the military and in aviation in general, where an above-average amount of vibration over the unit’s operational lifetime risks to cause cracks or other compromising damage that could have life-threatening consequences.
Professor of Chemical Engineering Nicholas Kotov was led to the utility of the honeycomb-style structure of teeth initially by examining the spine of a cuttlefish that he found on a beach. His team began to examine dental structures from sources as diverse as Tyrannosaurus Rex fossils, his own fillings, and sea urchins.
“Artificial enamel is better than solid commercial and experimental materials that are aimed at the same vibration damping,” Kotov observes. “It’s lighter, more effective and, perhaps, less expensive.”
Enamel’s properties have a superior resilience compared to bone, since it is designed to last a lifetime without the same possibility for self-repair as bone matter. It consists of columns of ceramic crystals suffused with a protein matrix set into a hard protective shell, with the layer often repeated for teeth which are likely to be under greater pressure.
The porous structure of tooth enamel is actually what enables it to survive under impact and long-term vibration and perturbation, since the gaps between the ceramic element and the proteins stop the forces communicating all the way through the structure, and enable absorption.
The enamel structure was recreated by post-doctoral researcher Bongjun Yeom at Kotov’s laboratory, using the development of oxide nanowires on a circuit chip. This was then covered in diffused polymers and baked.
The resulting structure was repeated over 40 layers, and then the whole process repeated twenty times in order to develop the artificial enamel, with the positioning of each adjacent layer critical to the efficacy of the material.
Computer modelling of the construct confirmed that it approached the performance limits of real tooth enamel in terms of its ability to absorb vibrations without structural compromise.
Kotov will publish his full research shortly, and hopes that the artificial enamel will find use in airplanes and other environments where the long-term effects of vibration are a risk factor for components.