More and more frequently, natural protein materials are being used as inspiration for the design of synthetic materials that are based on nanowires and carbon nanotubes, which can be made to be much stronger than biological materials. The work of Buehler and Ackbarow, a graduate student at the Max Planck Institute of Colloids and Interfaces in Potsdam, Germany, demonstrates that by rearranging the same number of nanoscale elements into hierarchies, the performance of a material can be radically changed. This could eliminate the need to invent new materials for different applications.
In a follow-up study, Buehler and MIT graduate students Zhao Qin and Steve Cranford ran similar tests using more than 16,000 elements instead of eight. They found that 98 percent of the randomly arranged rope-like structures did not meet the optimal performance level of the self-assembled natural molecules, which made up the other 2 percent of the structures. The most successful of those again utilized the bundles of four alpha-helical proteins.
That analysis shows that random arrangements of elements typically lead to inferior performance, and may explain why many engineered materials are not yet capable of combining disparate properties such as robustness and strength.
"Only a few specific nanostructured arrangements provide the basis for optimal material performance, and this must be incorporated in the material design process," said Buehler.
|Contact: Denise Brehm|
Massachusetts Institute of Technology, Department of Civil and Environmental Engineering