Moldable Supraspheres Made of Metal Nanoparticles

Metal nanoparticles crosslinked by dithiol linkers form “supraspherical” assemblies that behave like Play-doh and can glue to one another to form macroscopic materials. Researchers at the Northwestern University MRSEC have shown that such materials combine the properties of plastics and metals. Due to their “stickiness”, the supraspheres can be molded at room temperature into macroscopic structures of arbitrary shapes. Subsequent gentle heating hardens the objects and converts them to pure-metal monoliths. This general strategy has been successfully extended to various noble metals and their alloys.

The picture on the left shows supraspheres – that is, buildling blocks of “moldable metals”. The picture on the right shows a macroscopic (1 mm-wide) gear molded at room temperature and “hardened” by heating at 50 Celsius.