Scientists have developed self-assembling, transparent nanospheres that are stiffer than steel — and even Kevlar.
The Israeli scientists, led by Itay Rousso from Weizmann Institute of Science and Ehud Gazit from Tel Aviv University, developed the nanospheres from a simple protected dipeptide molecule.
The result is the stiffest organic material ever invented, the researchers claim. In fact, only diamond probes were able to make an indentation in the biological material, Rousso said.
The value of such a material lies in strengthening composites, for as diverse applications as medical implants and a space elevator.
Yes, a space elevator.
While the researchers are quick to admit in a Chemistry World report that there’s a big gap between their discovery and such uses, it’s certainly another step forward in materials science.
Specifically, the spheres were made from N-tert-butoxycarbonyl (Boc)-protected diphenylalanine, which in unprotected form is the key ingredient in the beta-amyloid protein that facilitates plaques in the brain that form as a result of Alzheimer’s disease.
The diameters of the highly-ordered spheres ranged from 30nm to 2um.
So how strong are these things? For comparison’s sake, a 1um-diameter particle had a 275GPa Young’s modulus — a measure of stiffness – compared to 200GPa for steel and 130GPa for Kevlar.
The difference is that the molecules’ structure — and thus stiffness — may rely on pH. That fact could limit the environments in which the material could be used, but could also give it a “trigger” that transforms it into a smart material.
